text:
Isotopes of lanthanum

Naturally occurring lanthanum (57La) is composed of one stable (139La) and one radioactive (138La) isotope, with the stable isotope, 139La, being the most abundant (99.91% natural abundance). There are 39 radioisotopes that have been characterized, with the most stable being 138La, with a half-life of 1.02×1011 years; 137La, with a half-life of 60,000 years and 140La, with a half-life of 1.6781 days. The remaining radioactive isotopes have half-lives that are less than a day and the majority of these have half-lives that are less than 1 minute. This element also has 12 nuclear isomers, the longest-lived of which is 132mLa, with a half-life of 24.3 minutes. Lighter isotopes mostly decay to isotopes of barium and heavy ones mostly decay to isotopes of cerium. 138La can decay to both.

The isotopes of lanthanum range in atomic weight from 115.96 u (116La) to 154.96 u (155La).

List of isotopes

 * rowspan=2|116La
 * rowspan=2 style="text-align:right" | 57
 * rowspan=2 style="text-align:right" | 59
 * rowspan=2|
 * rowspan=2|50(22) ms
 * p (~60%)
 * 115Ba
 * rowspan=2|
 * rowspan=2|
 * rowspan=2|
 * β+ (~40%)
 * 116Ba
 * rowspan=2|117La
 * rowspan=2 style="text-align:right" | 57
 * rowspan=2 style="text-align:right" | 60
 * rowspan=2|116.95007(43)#
 * rowspan=2|23.5(26) ms
 * β+
 * 117Ba
 * rowspan=2|(3/2+, 3/2−)
 * rowspan=2|
 * rowspan=2|
 * p
 * 116Ba
 * style="text-indent:1em" | 117mLa
 * colspan="3" style="text-indent:2em" | 151(12) keV
 * 10(5) ms
 * (9/2+)
 * 118La
 * style="text-align:right" | 57
 * style="text-align:right" | 61
 * 117.94673(32)#
 * 200# ms
 * β+
 * 118Ba
 * 119La
 * style="text-align:right" | 57
 * style="text-align:right" | 62
 * 118.94099(43)#
 * 1# s
 * β+
 * 119Ba
 * 11/2−#
 * rowspan=2|120La
 * rowspan=2 style="text-align:right" | 57
 * rowspan=2 style="text-align:right" | 63
 * rowspan=2|119.93807(54)#
 * rowspan=2|2.8(2) s
 * β+
 * 120Ba
 * rowspan=2|
 * rowspan=2|
 * rowspan=2|
 * β+, p
 * 119Cs
 * rowspan=2|121La
 * rowspan=2 style="text-align:right" | 57
 * rowspan=2 style="text-align:right" | 64
 * rowspan=2|120.93301(54)#
 * rowspan=2|5.3(2) s
 * β+
 * 121Ba
 * rowspan=2|11/2−#
 * rowspan=2|
 * rowspan=2|
 * β+, p
 * 120Cs
 * rowspan=2|122La
 * rowspan=2 style="text-align:right" | 57
 * rowspan=2 style="text-align:right" | 65
 * rowspan=2|121.93071(32)#
 * rowspan=2|8.6(5) s
 * β+
 * 122Ba
 * rowspan=2|
 * rowspan=2|
 * rowspan=2|
 * β+, p
 * 121Cs
 * 123La
 * style="text-align:right" | 57
 * style="text-align:right" | 66
 * 122.92624(21)#
 * 17(3) s
 * β+
 * 123Ba
 * 11/2−#
 * 124La
 * style="text-align:right" | 57
 * style="text-align:right" | 67
 * 123.92457(6)
 * 29.21(17) s
 * β+
 * 124Ba
 * (7−, 8−)
 * style="text-indent:1em" | 124mLa
 * colspan="3" style="text-indent:2em" | 100(100)# keV
 * 21(4) s
 * low(+#)
 * 125La
 * style="text-align:right" | 57
 * style="text-align:right" | 68
 * 124.920816(28)
 * 64.8(12) s
 * β+
 * 125Ba
 * (11/2−)
 * style="text-indent:1em" | 125mLa
 * colspan="3" style="text-indent:2em" | 107.0(10) keV
 * 390(40) ms
 * (3/2+)
 * 126La
 * style="text-align:right" | 57
 * style="text-align:right" | 69
 * 125.91951(10)
 * 54(2) s
 * β+
 * 126Ba
 * (5)(+#)
 * style="text-indent:1em" | 126mLa
 * colspan="3" style="text-indent:2em" | 210(410) keV
 * 20(20) s
 * (0−, 1−, 2−)
 * 127La
 * style="text-align:right" | 57
 * style="text-align:right" | 70
 * 126.916375(28)
 * 5.1(1) min
 * β+
 * 127Ba
 * (11/2−)
 * rowspan=2 style="text-indent:1em" | 127mLa
 * rowspan=2 colspan="3" style="text-indent:2em" | 14.8(12) keV
 * rowspan=2|3.7(4) min
 * β+
 * 127Ba
 * rowspan=2|(3/2+)
 * rowspan=2|
 * rowspan=2|
 * IT
 * 127La
 * 128La
 * style="text-align:right" | 57
 * style="text-align:right" | 71
 * 127.91559(6)
 * 5.18(14) min
 * β+
 * 128Ba
 * (5+)
 * style="text-indent:1em" | 128mLa
 * colspan="3" style="text-indent:2em" | 100(100)# keV
 * <1.4 min
 * IT
 * 128La
 * (1+, 2−)
 * 129La
 * style="text-align:right" | 57
 * style="text-align:right" | 72
 * 128.912693(22)
 * 11.6(2) min
 * β+
 * 129Ba
 * 3/2+
 * style="text-indent:1em" | 129mLa
 * colspan="3" style="text-indent:2em" | 172.1(4) keV
 * 560(50) ms
 * IT
 * 129La
 * 11/2−
 * 130La
 * style="text-align:right" | 57
 * style="text-align:right" | 73
 * 129.912369(28)
 * 8.7(1) min
 * β+
 * 130Ba
 * 3(+)
 * 131La
 * style="text-align:right" | 57
 * style="text-align:right" | 74
 * 130.91007(3)
 * 59(2) min
 * β+
 * 131Ba
 * 3/2+
 * style="text-indent:1em" | 131mLa
 * colspan="3" style="text-indent:2em" | 304.52(24) keV
 * 170(10) μs
 * 11/2−
 * 132La
 * style="text-align:right" | 57
 * style="text-align:right" | 75
 * 131.91010(4)
 * 4.8(2) h
 * β+
 * 132Ba
 * 2−
 * rowspan=2 style="text-indent:1em" | 132mLa
 * rowspan=2 colspan="3" style="text-indent:2em" | 188.18(11) keV
 * rowspan=2|24.3(5) min
 * IT (76%)
 * 132La
 * rowspan=2|6−
 * rowspan=2|
 * rowspan=2|
 * β+ (24%)
 * 132Ba
 * 133La
 * style="text-align:right" | 57
 * style="text-align:right" | 76
 * 132.90822(3)
 * 3.912(8) h
 * β+
 * 133Ba
 * 5/2+
 * 134La
 * style="text-align:right" | 57
 * style="text-align:right" | 77
 * 133.908514(21)
 * 6.45(16) min
 * β+
 * 134Ba
 * 1+
 * 135La
 * style="text-align:right" | 57
 * style="text-align:right" | 78
 * 134.906977(11)
 * 19.5(2) h
 * β+
 * 135Ba
 * 5/2+
 * 136La
 * style="text-align:right" | 57
 * style="text-align:right" | 79
 * 135.90764(6)
 * 9.87(3) min
 * β+
 * 136Ba
 * 1+
 * style="text-indent:1em" | 136mLa
 * colspan="3" style="text-indent:2em" | 255(9) keV
 * 114(3) ms
 * IT
 * 136La
 * (8)(−#)
 * 137La
 * style="text-align:right" | 57
 * style="text-align:right" | 80
 * 136.906494(14)
 * 6(2)×104 y
 * EC
 * 137Ba
 * 7/2+
 * extinct
 * rowspan=2|138La
 * rowspan=2 style="text-align:right" | 57
 * rowspan=2 style="text-align:right" | 81
 * rowspan=2|137.907112(4)
 * rowspan=2|1.02(1)×1011 y
 * β+ (66.4%)
 * 138Ba
 * rowspan=2|5+
 * rowspan=2|9.0(1)×10−4
 * rowspan=2|
 * β− (33.6%)
 * 138Ce
 * style="text-indent:1em" | 138mLa
 * colspan="3" style="text-indent:2em" | 72.57(3) keV
 * 116(5) ns
 * (3)+
 * 139La
 * style="text-align:right" | 57
 * style="text-align:right" | 82
 * 138.9063533(26)
 * colspan=3 align=center|Stable
 * 7/2+
 * 0.99910(1)
 * 140La
 * style="text-align:right" | 57
 * style="text-align:right" | 83
 * 139.9094776(26)
 * 1.6781(3) d
 * β−
 * 140Ce
 * 3−
 * 141La
 * style="text-align:right" | 57
 * style="text-align:right" | 84
 * 140.910962(5)
 * 3.92(3) h
 * β−
 * 141Ce
 * (7/2+)
 * 142La
 * style="text-align:right" | 57
 * style="text-align:right" | 85
 * 141.914079(6)
 * 91.1(5) min
 * β−
 * 142Ce
 * 2−
 * 143La
 * style="text-align:right" | 57
 * style="text-align:right" | 86
 * 142.916063(17)
 * 14.2(1) min
 * β−
 * 143Ce
 * (7/2)+
 * 144La
 * style="text-align:right" | 57
 * style="text-align:right" | 87
 * 143.91960(5)
 * 40.8(4) s
 * β−
 * 144Ce
 * (3−)
 * 145La
 * style="text-align:right" | 57
 * style="text-align:right" | 88
 * 144.92165(10)
 * 24.8(20) s
 * β−
 * 145Ce
 * (5/2+)
 * rowspan=2|146La
 * rowspan=2 style="text-align:right" | 57
 * rowspan=2 style="text-align:right" | 89
 * rowspan=2|145.92579(8)
 * rowspan=2|6.27(10) s
 * β− (99.99%)
 * 146Ce
 * rowspan=2|2−
 * rowspan=2|
 * rowspan=2|
 * β−, n (.007%)
 * 145Ce
 * style="text-indent:1em" | 146mLa
 * colspan="3" style="text-indent:2em" | 130(130) keV
 * 10.0(1) s
 * β−
 * 146Ce
 * (6−)
 * rowspan=2|147La
 * rowspan=2 style="text-align:right" | 57
 * rowspan=2 style="text-align:right" | 90
 * rowspan=2|146.92824(5)
 * rowspan=2|4.015(8) s
 * β− (99.96%)
 * 147Ce
 * rowspan=2|(5/2+)
 * rowspan=2|
 * rowspan=2|
 * β−, n (.04%)
 * 146Ce
 * rowspan=2|148La
 * rowspan=2 style="text-align:right" | 57
 * rowspan=2 style="text-align:right" | 91
 * rowspan=2|147.93223(6)
 * rowspan=2|1.26(8) s
 * β− (99.85%)
 * 148Ce
 * rowspan=2|(2−)
 * rowspan=2|
 * rowspan=2|
 * β−, n (.15%)
 * 147Ce
 * rowspan=2|149La
 * rowspan=2 style="text-align:right" | 57
 * rowspan=2 style="text-align:right" | 92
 * rowspan=2|148.93473(34)#
 * rowspan=2|1.05(3) s
 * β− (98.6%)
 * 149Ce
 * rowspan=2|5/2+#
 * rowspan=2|
 * rowspan=2|
 * β−, n (1.4%)
 * 148Ce
 * rowspan=2|150La
 * rowspan=2 style="text-align:right" | 57
 * rowspan=2 style="text-align:right" | 93
 * rowspan=2|149.93877(43)#
 * rowspan=2|510(30) ms
 * β− (97.3%)
 * 150Ce
 * rowspan=2|(3+)
 * rowspan=2|
 * rowspan=2|
 * β−, n (2.7%)
 * 149Ce
 * 151La
 * style="text-align:right" | 57
 * style="text-align:right" | 94
 * 150.94172(43)#
 * 300# ms [>300 ns]
 * β−
 * 151Ce
 * 5/2+#
 * 152La
 * style="text-align:right" | 57
 * style="text-align:right" | 95
 * 151.94625(43)#
 * 200# ms [>300 ns]
 * β−
 * 152Ce
 * 153La
 * style="text-align:right" | 57
 * style="text-align:right" | 96
 * 152.94962(64)#
 * 150# ms [>300 ns]
 * β−
 * 153Ce
 * 5/2+#
 * 154La
 * style="text-align:right" | 57
 * style="text-align:right" | 97
 * 153.95450(64)#
 * 100# ms
 * β−
 * 154Ce
 * 155La
 * style="text-align:right" | 57
 * style="text-align:right" | 98
 * 154.95835(86)#
 * 60# ms
 * β−
 * 155Ce
 * 5/2+#
 * 144La
 * style="text-align:right" | 57
 * style="text-align:right" | 87
 * 143.91960(5)
 * 40.8(4) s
 * β−
 * 144Ce
 * (3−)
 * 145La
 * style="text-align:right" | 57
 * style="text-align:right" | 88
 * 144.92165(10)
 * 24.8(20) s
 * β−
 * 145Ce
 * (5/2+)
 * rowspan=2|146La
 * rowspan=2 style="text-align:right" | 57
 * rowspan=2 style="text-align:right" | 89
 * rowspan=2|145.92579(8)
 * rowspan=2|6.27(10) s
 * β− (99.99%)
 * 146Ce
 * rowspan=2|2−
 * rowspan=2|
 * rowspan=2|
 * β−, n (.007%)
 * 145Ce
 * style="text-indent:1em" | 146mLa
 * colspan="3" style="text-indent:2em" | 130(130) keV
 * 10.0(1) s
 * β−
 * 146Ce
 * (6−)
 * rowspan=2|147La
 * rowspan=2 style="text-align:right" | 57
 * rowspan=2 style="text-align:right" | 90
 * rowspan=2|146.92824(5)
 * rowspan=2|4.015(8) s
 * β− (99.96%)
 * 147Ce
 * rowspan=2|(5/2+)
 * rowspan=2|
 * rowspan=2|
 * β−, n (.04%)
 * 146Ce
 * rowspan=2|148La
 * rowspan=2 style="text-align:right" | 57
 * rowspan=2 style="text-align:right" | 91
 * rowspan=2|147.93223(6)
 * rowspan=2|1.26(8) s
 * β− (99.85%)
 * 148Ce
 * rowspan=2|(2−)
 * rowspan=2|
 * rowspan=2|
 * β−, n (.15%)
 * 147Ce
 * rowspan=2|149La
 * rowspan=2 style="text-align:right" | 57
 * rowspan=2 style="text-align:right" | 92
 * rowspan=2|148.93473(34)#
 * rowspan=2|1.05(3) s
 * β− (98.6%)
 * 149Ce
 * rowspan=2|5/2+#
 * rowspan=2|
 * rowspan=2|
 * β−, n (1.4%)
 * 148Ce
 * rowspan=2|150La
 * rowspan=2 style="text-align:right" | 57
 * rowspan=2 style="text-align:right" | 93
 * rowspan=2|149.93877(43)#
 * rowspan=2|510(30) ms
 * β− (97.3%)
 * 150Ce
 * rowspan=2|(3+)
 * rowspan=2|
 * rowspan=2|
 * β−, n (2.7%)
 * 149Ce
 * 151La
 * style="text-align:right" | 57
 * style="text-align:right" | 94
 * 150.94172(43)#
 * 300# ms [>300 ns]
 * β−
 * 151Ce
 * 5/2+#
 * 152La
 * style="text-align:right" | 57
 * style="text-align:right" | 95
 * 151.94625(43)#
 * 200# ms [>300 ns]
 * β−
 * 152Ce
 * 153La
 * style="text-align:right" | 57
 * style="text-align:right" | 96
 * 152.94962(64)#
 * 150# ms [>300 ns]
 * β−
 * 153Ce
 * 5/2+#
 * 154La
 * style="text-align:right" | 57
 * style="text-align:right" | 97
 * 153.95450(64)#
 * 100# ms
 * β−
 * 154Ce
 * 155La
 * style="text-align:right" | 57
 * style="text-align:right" | 98
 * 154.95835(86)#
 * 60# ms
 * β−
 * 155Ce
 * 5/2+#
 * 152Ce
 * 153La
 * style="text-align:right" | 57
 * style="text-align:right" | 96
 * 152.94962(64)#
 * 150# ms [>300 ns]
 * β−
 * 153Ce
 * 5/2+#
 * 154La
 * style="text-align:right" | 57
 * style="text-align:right" | 97
 * 153.95450(64)#
 * 100# ms
 * β−
 * 154Ce
 * 155La
 * style="text-align:right" | 57
 * style="text-align:right" | 98
 * 154.95835(86)#
 * 60# ms
 * β−
 * 155Ce
 * 5/2+#
 * 155La
 * style="text-align:right" | 57
 * style="text-align:right" | 98
 * 154.95835(86)#
 * 60# ms
 * β−
 * 155Ce
 * 5/2+#
 * β−
 * 155Ce
 * 5/2+#

title: Isotopes of lanthanum


text:
User:Dmafackler/Installing MediaWiki on Solaris 9

The toolsets built into MediaWiki and Bugzilla provide a freely available boost toward the management of product development. This reference document derives from my first experience instantiating MediaWiki [and Bugzilla] software stacks on Solaris 9. It is intended as a guide for others who walk this path. It is intended to be refined and automated.

Software Stack Selection
MediaWiki is architected using the PHP language, HTTP document services, and a relational back-end database. These are the components of the software stack chosen to operate MediaWiki:

 * MySQL 4.1.13
 * Apache 1.3.x
 * PHP 5.0.4
 * MediaWiki 1.4.7

The following packages obtained from http://sunfreeware.org/sol9 are required to support retrieval, installation, and/or configuration of the above components. Indented items indicate supporting pre-requisites for the parent package.

 * gunzip or bunzip2
 * tar (GNU or Solaris Ok)
 * pkgadd
 * wget
 * lynx
 * ncurses
 * iconv
 * GCC 3.4.2
 * make
 * autoconf
 * m4
 * ImageMagick 6.4.2
 * your favorite text editor

Selection criteria
Additional notes regarding the decision trees leading to the matrix above.

The driving project goal was to get operational as quickly as possible. Total configurability and control is the desirable characteristic of open source tooling for the experienced integrator with very clear use cases. The same characteristic is a pitfall of decision tree paralysis for the novice integrator. Build on the shoulders of giants: select pre-built binaries where possible. Configuration refinements can and will be made "later"--when operational needs are better quantified and personal experience is greater.

Blastwave.org and Sunfreeware.org are the premiere sites for pre-packaged Solaris software. Blastwave builds all of its packages using Sun's FORTE compiler tool stack. Sunfreeware builds all of its packages using the GNU compiler collection (GCC) [with Sun's linker and loader at the back-end of the tool chain for object level compatibility]. The decision tilted to Sunfreeware.org:

 * out of the need to compile PHP, because the pre-packaged copies at both Sunfreeware and Blastwave were not compatible with the pre-built and configured Apache 1.3.x;

 * out of convenience of access and installation of the GCC suite on the target platform for compiling PHP. Footnote: Our organization licenses the Sun FORTE suite, but the necessary products were not installed and configured on the target test platform.

 * we already use a variety of Sunfreeware packages and are familiar with the file-system organization and layout encouraged by that group of package maintainers.

Blastwave.org is worth a revisit for automating this installation. Its package install and dependency checking support is thorough.

Policy Considerations
MediaWiki is perceived here as a collaborative documentation tool with effective version control and increasingly capable document management features.

 * Everyone in the organization should be able to read and comment on the documentation.
 * Only traceable and authenticated users may create and revise the published content.

We will likely deploy a read-only version for remote reference, synchronized from a master read-write version.

Data Storage Considerations
Our documents reference a considerable amount of imagery for laboratory equipment integration, development and deployment: image and media upload must be enabled. Accordingly, due consideration must be given to storage requirements (location and mass) for these common resources.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
The Demon in the Freezer

The Demon in the Freezer is a 2002 nonfiction book on the biological weapon agents smallpox and anthrax and how the American government  develops defensive measures against them. It was written by journalist Richard Preston, also author of the best-selling book The Hot Zone (1994), about ebolavirus outbreaks in Africa and Reston, Virginia and the U.S. government's response to them.

The book is primarily an account of the Smallpox Eradication Program (1967–1980), the ongoing belief of the U.S. government that smallpox is still a potential bioterrorism agent, and the controversy over whether or not the remaining samples of smallpox virus in Atlanta and Moscow (the "demon" in the freezer) should be finally destroyed. However, the writer was overtaken by events—the 9/11 attacks and the anthrax letter incidents (called "Amerithrax"), both in 2001—and so much of the book interweaves the anthrax investigation with the smallpox material in a manner some critics have said is "awkward" and somewhat "disjointed".

Synopsis

 * Section 1, "Something in the Air", begins with a day-by-day account of the anthrax letter attacks in Florida and Washington, D.C., for the period 2 to 15 October 2001. Robert Stevens, a photo retoucher for the tabloid The Sun, was a victim and US Senator Tom Daschle was an intended victim. The facts of the FBI, the CDC and the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID) are detailed.
 * Section 2, "The Dreaming Demon", looks back to an outbreak of smallpox at St Walburga Hospital in Meschede, Germany. The successful efforts organized by local public health authorities and the WHO—including a textbook example of ring vaccination containment—are described.
 * Section 3, "To Bhola Island", describes the varieties and evolution of poxviruses and the history of smallpox in particular. The story of the SEP (Smallpox Eradication Program, referred to throughout as "the Eradication"), led by DA Henderson and others is recounted. The more personal story of physician, counterculture figure, and future virtual community pioneer Lawrence Brilliant is told as his Indian guru, Neem Karoli Baba, exhorts him in 1970 to join the SEP and "go eradicate smallpox". (Brilliant ended up fighting the outbreak at the Tatanagar Railway Station in Bihar.) Finally, the Maximum Containment Facility (MCF) of the CDC in Atlanta is described.
 * Section 4, "The Other Side of the Moon", begins with an account of the 1989 defection to the United Kingdom of Vladimir Pasechnik, the first Soviet bioweaponeer to flee to the West. Pasechnik described Biopreparat, the Soviet biological weapons program, to MI6, including their genetically modified, antibiotic resistant plague and their smallpox program at the site known as Vector. The fact that the Russians had ICBMs armed with both plague and smallpox is revealed. Various biological weapon facilities in Russia and Iraq are described. Finally, the history and work of the Ad Hoc Committee on Orthopox Infections is related. This group of the WHO has been hotly debated since 1980 over the fate of the remaining samples of smallpox in the last two official repositories. DA Henderson has been in favor of destruction, while US Army scientist Peter Jahrling has been against it on the basis that further research is needed since smallpox almost certainly exists (he believes) outside of the repositories.
 * Section 5, "A Woman with a Peaceful Life", tells the story of USAMRIID microbiologist and epidemiologist Dr. Lisa E. Hensley, who was originally recruited to do Ebola work. A January 2000 accident in the AA4 "Hot Suite" that Hensley experienced, along with the protocols that followed it, is described. The efforts of USAMRIID scientists to get approval to do smallpox research on animals is described including the FDA's "animal efficacy rule" and the WHO General Assembly's provisional permission to do research for three years (1999–2002). A "Monkey Cabinet" is designed at USAMRIID and CDC for use in the possible investigation of the question of whether animals can be infected with smallpox. The development of a lethal, genetically engineered mousepox virus (the Jackson-Ramshaw virus) and its implications for bioterrorism are described. Finally, the "awakening" of the smallpox at the CDC's MCF West in 2001 by US Army investigators to induce smallpox disease in monkeys for the first time is dramatically recounted.
 * Section 6, "The Demon's Eyes", continues the story of the induction of smallpox disease in monkeys at the CDC in 2001. It was determined that the Harper strain of smallpox kills monkeys slowly while the India strain kills them quickly. This was the first time that smallpox had ever been shown capable of infecting non-humans. Of eight monkeys infected, seven died—six of hemorrhagic smallpox and one of the classic pustular type. There follows a discussion of the need and justification for animal-use smallpox experiments. The emergency evacuation of the Army workers in the MCF West on 9/11 is described.
 * Section 7, "The Anthrax Skulls", relates the atmosphere at the Department of Health and Human Services and their actions at the time of the 9/11 attacks. The story of the Amerithrax investigations is picked up again in day-by-day detail for the period 16 to 25 October 2001. The response by the FBI, HHS, DOJ, CIA and the White House are detailed. Actions at USAMRIID and USAMRMC are also described. (USAMRIID became the FBI's reference lab for forensic evidence related to the bioterror incident.) The events leading to Dr. Steven Hatfill becoming a DOJ "person of interest" are related. Finally, the indignation of Alfred Sommer, dean of the Johns Hopkins School of Public Health, at the news of the Army animal smallpox experiments is described as well as a reiteration of DA Henderson's opposition to the same.
 * Section 8, "Superpox", begins with a description of an attempt at replication of the Jackson-Ramshaw virus at a lab at the Saint Louis University School of Medicine by Mark Buller working for USAMRIID. The potential for a similarly engineered "super-smallpox" virus for use by a terrorist is examined. The procedure for the transfection of an interleukin-4 gene into a mousepox virus is described. Finally, an unusual artifact—the preserved arm of a three- or four-year-old child with classic smallpox lesions, discovered in 1999 and now housed at USAMRIID—is described. This leads the author to muse that "the dream of the total eradication had failed", because although we could eradicate smallpox from nature, "we could not uproot the virus from the human heart".

title: The Demon in the Freezer


text:
Talk:Hever

Untitled
I cannot understand why this article was originally redirected to Heber, with which it has no connection whatsoever Peter Shearan 10:35, 24 August 2005 (UTC)
 * I have now included the details of Hever as a civil parish, and other information. It is part of an exercise I am carrying out with all the civil parishes in Kent. As can be seen from this very good example, Hever is not just a "small village" as it was first described Peter Shearan 12:08, 27 February 2006 (UTC)

title: Talk:Hever


text:
Isotopes of barium

Naturally occurring barium (56Ba) is a mix of six stable isotopes and one very long-lived radioactive primordial isotope, barium-130, identified as being unstable by geochemical means (from analysis of the presence of its daughter xenon-130 in rocks) in 2001. This nuclide decays by double electron capture (absorbing two electrons and emitting two neutrinos), with a half-life of (0.5–2.7)×1021 years (about 1011 times the age of the universe).

There are a total of thirty-three known radioisotopes in addition to 130Ba. The longest-lived of these is 133Ba, which has a half-life of 10.51 years. All other radioisotopes have half-lives shorter than two weeks. The longest-lived isomer is 133mBa, which has a half-life of 38.9 hours. The shorter-lived 137mBa (half-life 2.55 minutes) arises as the decay product of the common fission product caesium-137.

Barium-114 is predicted to undergo cluster decay, emitting a nucleus of stable 12C to produce 102Sn. However this decay is not yet observed; the upper limit on the branching ratio of such decay is 0.0034%.

List of isotopes

 * rowspan=4|114Ba
 * rowspan=4 style="text-align:right" | 56
 * rowspan=4 style="text-align:right" | 58
 * rowspan=4|113.95072(11)
 * rowspan=4|460(125) ms
 * β+ (79%)
 * 114Cs
 * rowspan=4|0+
 * rowspan=4|
 * rowspan=4|
 * α (0.9%)
 * 110Xe
 * β+, p (20%)
 * 113Xe
 * CD (<.0034%)
 * 102Sn, 12C
 * rowspan=2|115Ba
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2 style="text-align:right" | 59
 * rowspan=2|114.94748(22)#
 * rowspan=2|0.45(5) s
 * β+
 * 115Cs
 * rowspan=2|5/2+#
 * rowspan=2|
 * rowspan=2|
 * β+, p (>15%)
 * 114Xe
 * rowspan=2|116Ba
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2 style="text-align:right" | 60
 * rowspan=2|115.94162(22)#
 * rowspan=2|1.3(2) s
 * β+ (97%)
 * 116Cs
 * rowspan=2|0+
 * rowspan=2|
 * rowspan=2|
 * β+, p (3%)
 * 115Xe
 * rowspan=3|117Ba
 * rowspan=3 style="text-align:right" | 56
 * rowspan=3 style="text-align:right" | 61
 * rowspan=3|116.93832(27)
 * rowspan=3|1.75(7) s
 * β+ (87%)
 * 117Cs
 * rowspan=3|(3/2+)
 * rowspan=3|
 * rowspan=3|
 * β+, p (13%)
 * 116Xe
 * β+, α (0.024%)
 * 113I
 * 118Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 62
 * 117.93323(22)#
 * 5.2(2) s
 * β+
 * 118Cs
 * 0+
 * rowspan=2|119Ba
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2 style="text-align:right" | 63
 * rowspan=2|118.93066(21)
 * rowspan=2|5.4(3) s
 * β+ (75%)
 * 119Cs
 * rowspan=2|(5/2+)
 * rowspan=2|
 * rowspan=2|
 * β+, p (25%)
 * 118Xe
 * 120Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 64
 * 119.92604(32)
 * 24(2) s
 * β+
 * 120Cs
 * 0+
 * rowspan=2|121Ba
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2 style="text-align:right" | 65
 * rowspan=2|120.92405(15)
 * rowspan=2|29.7(15) s
 * β+ (99.98%)
 * 121Cs
 * rowspan=2|5/2+
 * rowspan=2|
 * rowspan=2|
 * β+, p (0.02%)
 * 120Xe
 * 122Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 66
 * 121.91990(3)
 * 1.95(15) min
 * β+
 * 122Cs
 * 0+
 * 123Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 67
 * 122.918781(13)
 * 2.7(4) min
 * β+
 * 123Cs
 * 5/2+
 * style="text-indent:1em" | 123mBa
 * colspan="3" style="text-indent:2em" | 120.95(8) keV
 * 830(60) ns
 * IT
 * 123Ba
 * 1/2+#
 * 124Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 68
 * 123.915094(13)
 * 11.0(5) min
 * β+
 * 124Cs
 * 0+
 * 125Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 69
 * 124.914472(12)
 * 3.3(3) min
 * β+
 * 125Cs
 * 1/2+
 * style="text-indent:1em" | 125mBa
 * colspan="3" style="text-indent:2em" | 120(20)# keV
 * 2.76(14) μs
 * IT
 * 125Ba
 * (7/2−)
 * 126Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 70
 * 125.911250(13)
 * 100(2) min
 * β+
 * 126Cs
 * 0+
 * 127Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 71
 * 126.911091(12)
 * 12.7(4) min
 * β+
 * 127Cs
 * 1/2+
 * style="text-indent:1em" | 127mBa
 * colspan="3" style="text-indent:2em" | 80.32(11) keV
 * 1.93(7) s
 * IT
 * 127Ba
 * 7/2−
 * 128Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 72
 * 127.9083524(17)
 * 2.43(5) d
 * EC
 * 128Cs
 * 0+
 * 129Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 73
 * 128.908683(11)
 * 2.23(11) h
 * β+
 * 129Cs
 * 1/2+
 * rowspan=2 style="text-indent:1em" | 129mBa
 * rowspan=2 colspan="3" style="text-indent:2em" | 8.42(6) keV
 * rowspan=2|2.135(10) h
 * β+
 * 129Cs
 * rowspan=2|7/2+
 * rowspan=2|
 * rowspan=2|
 * IT
 * 129Ba
 * 130Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 74
 * 129.9063260(3)
 * ≈ 1×1021 y
 * 2EC?
 * 130Xe
 * 0+
 * 0.0011(1)
 * style="text-indent:1em" | 130mBa
 * colspan="3" style="text-indent:2em" | 2475.12(18) keV
 * 9.54(14) ms
 * IT
 * 130Ba
 * 8−
 * 131Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 75
 * 130.9069463(4)
 * 11.52(1) d
 * β+
 * 131Cs
 * 1/2+
 * style="text-indent:1em" | 131mBa
 * colspan="3" style="text-indent:2em" | 187.995(9) keV
 * 14.26(9) min
 * IT
 * 131Ba
 * 9/2−
 * 132Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 76
 * 131.9050612(11)
 * colspan=3 align=center|Observationally Stable
 * 0+
 * 0.0010(1)
 * 133Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 77
 * 132.9060074(11)
 * 10.5379(16) y
 * EC
 * 133Cs
 * 1/2+
 * rowspan=2 style="text-indent:1em" | 133mBa
 * rowspan=2 colspan="3" style="text-indent:2em" | 288.252(9) keV
 * rowspan=2|38.90(6) h
 * IT (99.99%)
 * 133Ba
 * rowspan=2|11/2−
 * rowspan=2|
 * rowspan=2|
 * EC (0.0104%)
 * 133Cs
 * 134Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 78
 * 133.90450825(27)
 * colspan=3 align=center|Stable
 * 0+
 * 0.0242(15)
 * style="text-indent:1em" | 134mBa
 * colspan="3" style="text-indent:2em" | 2957.2(5) keV
 * 2.61(13) μs
 * IT
 * 134Ba
 * 10+
 * 135Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 79
 * 134.90568845(26)
 * colspan=3 align=center|Stable
 * 3/2+
 * 0.0659(10)
 * style="text-indent:1em" | 135m1Ba
 * colspan="3" style="text-indent:2em" | 268.218(20) keV
 * 28.11(2) h
 * IT
 * 135Ba
 * 11/2−
 * style="text-indent:1em" | 135m2Ba
 * colspan="3" style="text-indent:2em" | 2388.0(5) keV
 * 1.06(4) ms
 * IT
 * 135Ba
 * (23/2+)
 * 136Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 80
 * 135.90457580(26)
 * colspan=3 align=center|Stable
 * 0+
 * 0.0785(24)
 * style="text-indent:1em" | 136m1Ba
 * colspan="3" style="text-indent:2em" | 2030.535(18) keV
 * 308.4(19) ms
 * IT
 * 136Ba
 * 7−
 * style="text-indent:1em" | 136m2Ba
 * colspan="3" style="text-indent:2em" | 3357.19(25) keV
 * 91(2) ns
 * IT
 * 136Ba
 * 10+
 * 137Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 81
 * 136.90582721(27)
 * colspan=3 align=center|Stable
 * 3/2+
 * 0.1123(23)
 * style="text-indent:1em" | 137m1Ba
 * colspan="3" style="text-indent:2em" | 661.659(3) keV
 * 2.552(1) min
 * IT
 * 137Ba
 * 11/2−
 * style="text-indent:1em" | 137m2Ba
 * colspan="3" style="text-indent:2em" | 2349.1(5) keV
 * 589(20) ns
 * IT
 * 137Ba
 * (19/2−)
 * 138Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 82
 * 137.90524706(27)
 * colspan=3 align=center|Stable
 * 0+
 * 0.7170(29)
 * style="text-indent:1em" | 138mBa
 * colspan="3" style="text-indent:2em" | 2090.536(21) keV
 * 850(100) ns
 * IT
 * 138Ba
 * 6+
 * 139Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 83
 * 138.90884116(27)
 * 82.93(9) min
 * β−
 * 139La
 * 7/2−
 * 140Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 84
 * 139.910608(8)
 * 12.7534(21) d
 * β−
 * 140La
 * 0+
 * 141Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 85
 * 140.914404(6)
 * 18.27(7) min
 * β−
 * 141La
 * 3/2−
 * 142Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 86
 * 141.916433(6)
 * 10.6(2) min
 * β−
 * 142La
 * 0+
 * 143Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 87
 * 142.920625(7)
 * 14.5(3) s
 * β−
 * 143La
 * 5/2−
 * 144Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 88
 * 143.922955(8)
 * 11.73(8) s
 * β−
 * 144La
 * 0+
 * 145Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 89
 * 144.927518(9)
 * 4.31(16) s
 * β−
 * 145La
 * 5/2−
 * 146Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 90
 * 145.9303632(19)
 * 2.15(4) s
 * β−
 * 146La
 * 0+
 * rowspan=2|147Ba
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2 style="text-align:right" | 91
 * rowspan=2|146.935304(21)
 * rowspan=2|893(1) ms
 * β− (99.93%)
 * 147La
 * rowspan=2|5/2−
 * rowspan=2|
 * rowspan=2|
 * β−, n (0.07%)
 * 146La
 * rowspan=2|148Ba
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2 style="text-align:right" | 92
 * rowspan=2| 147.9382230(16)
 * rowspan=2|620(5) ms
 * β− (99.6%)
 * 148La
 * rowspan=2|0+
 * rowspan=2|
 * rowspan=2|
 * β−, n (0.4%)
 * 147La
 * rowspan=2|149Ba
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2 style="text-align:right" | 93
 * rowspan=2|148.9432840(27)
 * rowspan=2|349(4) ms
 * β− (96.1%)
 * 149La
 * rowspan=2|3/2−#
 * rowspan=2|
 * rowspan=2|
 * β−, n (3.9%)
 * 148La
 * rowspan=2|150Ba
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2 style="text-align:right" | 94
 * rowspan=2| 149.946441(6)
 * rowspan=2|258(5) ms
 * β− (99.0%)
 * 150La
 * rowspan=2|0+
 * rowspan=2|
 * rowspan=2|
 * β−, n (1.0%)
 * 149La
 * rowspan=2|151Ba
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2 style="text-align:right" | 95
 * rowspan=2|150.95176(43)#
 * rowspan=2|167(5) ms
 * β−
 * 151La
 * rowspan=2|3/2−#
 * rowspan=2|
 * rowspan=2|
 * β−, n?
 * 150La
 * rowspan=2|152Ba
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2 style="text-align:right" | 96
 * rowspan=2|151.95533(43)#
 * rowspan=2|139(8) ms
 * β−
 * 152La
 * rowspan=2|0+
 * rowspan=2|
 * rowspan=2|
 * β−, n?
 * 151La
 * rowspan=3|153Ba
 * rowspan=3 style="text-align:right" | 56
 * rowspan=3 style="text-align:right" | 97
 * rowspan=3|152.96085(43)#
 * rowspan=3|113(39) ms
 * β−
 * 153La
 * rowspan=3|5/2−#
 * rowspan=3|
 * rowspan=3|
 * β−, n?
 * 152La
 * β−, 2n?
 * 151La
 * 154Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 98
 * 153.96466(54)#
 * 53(48) ms
 * β−
 * 154La
 * 0+
 * β−
 * 143La
 * 5/2−
 * 144Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 88
 * 143.922955(8)
 * 11.73(8) s
 * β−
 * 144La
 * 0+
 * 145Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 89
 * 144.927518(9)
 * 4.31(16) s
 * β−
 * 145La
 * 5/2−
 * 146Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 90
 * 145.9303632(19)
 * 2.15(4) s
 * β−
 * 146La
 * 0+
 * rowspan=2|147Ba
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2 style="text-align:right" | 91
 * rowspan=2|146.935304(21)
 * rowspan=2|893(1) ms
 * β− (99.93%)
 * 147La
 * rowspan=2|5/2−
 * rowspan=2|
 * rowspan=2|
 * β−, n (0.07%)
 * 146La
 * rowspan=2|148Ba
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2 style="text-align:right" | 92
 * rowspan=2| 147.9382230(16)
 * rowspan=2|620(5) ms
 * β− (99.6%)
 * 148La
 * rowspan=2|0+
 * rowspan=2|
 * rowspan=2|
 * β−, n (0.4%)
 * 147La
 * rowspan=2|149Ba
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2 style="text-align:right" | 93
 * rowspan=2|148.9432840(27)
 * rowspan=2|349(4) ms
 * β− (96.1%)
 * 149La
 * rowspan=2|3/2−#
 * rowspan=2|
 * rowspan=2|
 * β−, n (3.9%)
 * 148La
 * rowspan=2|150Ba
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2 style="text-align:right" | 94
 * rowspan=2| 149.946441(6)
 * rowspan=2|258(5) ms
 * β− (99.0%)
 * 150La
 * rowspan=2|0+
 * rowspan=2|
 * rowspan=2|
 * β−, n (1.0%)
 * 149La
 * rowspan=2|151Ba
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2 style="text-align:right" | 95
 * rowspan=2|150.95176(43)#
 * rowspan=2|167(5) ms
 * β−
 * 151La
 * rowspan=2|3/2−#
 * rowspan=2|
 * rowspan=2|
 * β−, n?
 * 150La
 * rowspan=2|152Ba
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2 style="text-align:right" | 96
 * rowspan=2|151.95533(43)#
 * rowspan=2|139(8) ms
 * β−
 * 152La
 * rowspan=2|0+
 * rowspan=2|
 * rowspan=2|
 * β−, n?
 * 151La
 * rowspan=3|153Ba
 * rowspan=3 style="text-align:right" | 56
 * rowspan=3 style="text-align:right" | 97
 * rowspan=3|152.96085(43)#
 * rowspan=3|113(39) ms
 * β−
 * 153La
 * rowspan=3|5/2−#
 * rowspan=3|
 * rowspan=3|
 * β−, n?
 * 152La
 * β−, 2n?
 * 151La
 * 154Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 98
 * 153.96466(54)#
 * 53(48) ms
 * β−
 * 154La
 * 0+
 * 151La
 * rowspan=3|153Ba
 * rowspan=3 style="text-align:right" | 56
 * rowspan=3 style="text-align:right" | 97
 * rowspan=3|152.96085(43)#
 * rowspan=3|113(39) ms
 * β−
 * 153La
 * rowspan=3|5/2−#
 * rowspan=3|
 * rowspan=3|
 * β−, n?
 * 152La
 * β−, 2n?
 * 151La
 * 154Ba
 * style="text-align:right" | 56
 * style="text-align:right" | 98
 * 153.96466(54)#
 * 53(48) ms
 * β−
 * 154La
 * 0+
 * 53(48) ms
 * β−
 * 154La
 * 0+

title: Isotopes of barium


text:
Isotopes of xenon

Naturally occurring xenon (54Xe) consists of seven stable isotopes and two very long-lived isotopes. Double electron capture has been observed in 124Xe (half-life 1.8 ± 0.5(stat) ± 0.1(sys) years) and double beta decay in 136Xe (half-life 2.165 ± 0.016(stat) ± 0.059(sys) years), which are among the longest measured half-lives of all nuclides. The isotopes 126Xe and 134Xe are also predicted to undergo double beta decay, but this process has never been observed in these isotopes, so they are considered to be stable. Beyond these stable forms, 32 artificial unstable isotopes and various isomers have been studied, the longest-lived of which is 127Xe with a half-life of 36.345 days. All other isotopes have half-lives less than 12 days, most less than 20 hours. The shortest-lived isotope, 108Xe, has a half-life of 58 μs, and is the heaviest known nuclide with equal numbers of protons and neutrons. Of known isomers, the longest-lived is 131mXe with a half-life of 11.934 days. 129Xe is produced by beta decay of 129I (half-life: 16 million years); 131mXe, 133Xe, 133mXe, and 135Xe are some of the fission products of both 235U and 239Pu, so are used as indicators of nuclear explosions.

The artificial isotope 135Xe is of considerable significance in the operation of nuclear fission reactors. 135Xe has a huge cross section for thermal neutrons, 2.65×106 barns, so it acts as a neutron absorber or "poison" that can slow or stop the chain reaction after a period of operation. This was discovered in the earliest nuclear reactors built by the American Manhattan Project for plutonium production. Because of this effect, designers must make provisions to increase the reactor's reactivity (the number of neutrons per fission that go on to fission other atoms of nuclear fuel) over the initial value needed to start the chain reaction. For the same reason, the fission products produced in a nuclear explosion and a power plant differ significantly as a large share of will absorb neutrons in a steady state reactor, while basically none of the  will have had time to decay to xenon before the explosion of the bomb removes it from the neutron radiation.

Relatively high concentrations of radioactive xenon isotopes are also found emanating from nuclear reactors due to the release of this fission gas from cracked fuel rods or fissioning of uranium in cooling water. The concentrations of these isotopes are still usually low compared to the naturally occurring radioactive noble gas 222Rn.

Because xenon is a tracer for two parent isotopes, Xe isotope ratios in meteorites are a powerful tool for studying the formation of the Solar System. The I-Xe method of dating gives the time elapsed between nucleosynthesis and the condensation of a solid object from the solar nebula (xenon being a gas, only that part of it that formed after condensation will be present inside the object). Xenon isotopes are also a powerful tool for understanding terrestrial differentiation. Excess 129Xe found in carbon dioxide well gases from New Mexico was believed to be from the decay of mantle-derived gases soon after Earth's formation. It has been suggested that the isotopic composition of atmospheric xenon fluctuated prior to the GOE before stabilizing, perhaps as a result of the rise in atmospheric O2.

List of isotopes

 * 108Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 54
 * α
 * 104Te
 * 0+
 * 109Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 55
 * 13(2) ms
 * α
 * 105Te
 * rowspan=2|110Xe
 * rowspan=2 style="text-align:right" | 54
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2|109.94428(14)
 * rowspan=2|310(190) ms [$58 us$]
 * β+
 * 110I
 * rowspan=2|0+
 * rowspan=2|
 * rowspan=2|
 * α
 * 106Te
 * rowspan=2|111Xe
 * rowspan=2 style="text-align:right" | 54
 * rowspan=2 style="text-align:right" | 57
 * rowspan=2|110.94160(33)#
 * rowspan=2|740(200) ms
 * β+ (90%)
 * 111I
 * rowspan=2|5/2+#
 * rowspan=2|
 * rowspan=2|
 * α (10%)
 * 107Te
 * rowspan=2|112Xe
 * rowspan=2 style="text-align:right" | 54
 * rowspan=2 style="text-align:right" | 58
 * rowspan=2|111.93562(11)
 * rowspan=2|2.7(8) s
 * β+ (99.1%)
 * 112I
 * rowspan=2|0+
 * rowspan=2|
 * rowspan=2|
 * α (.9%)
 * 108Te
 * rowspan=4|113Xe
 * rowspan=4 style="text-align:right" | 54
 * rowspan=4 style="text-align:right" | 59
 * rowspan=4|112.93334(9)
 * rowspan=4|2.74(8) s
 * β+ (92.98%)
 * 113I
 * rowspan=4|(5/2+)#
 * rowspan=4|
 * rowspan=4|
 * β+, p (7%)
 * 112Te
 * α (.011%)
 * 109Te
 * β+, α (.007%)
 * 109Sb
 * 114Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 60
 * 113.927980(12)
 * 10.0(4) s
 * β+
 * 114I
 * 0+
 * rowspan=3|115Xe
 * rowspan=3 style="text-align:right" | 54
 * rowspan=3 style="text-align:right" | 61
 * rowspan=3|114.926294(13)
 * rowspan=3|18(4) s
 * β+ (99.65%)
 * 115I
 * rowspan=3|(5/2+)
 * rowspan=3|
 * rowspan=3|
 * β+, p (.34%)
 * 114Te
 * β+, α (3×10−4%)
 * 111Sb
 * 116Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 62
 * 115.921581(14)
 * 59(2) s
 * β+
 * 116I
 * 0+
 * rowspan=2|117Xe
 * rowspan=2 style="text-align:right" | 54
 * rowspan=2 style="text-align:right" | 63
 * rowspan=2|116.920359(11)
 * rowspan=2|61(2) s
 * β+ (99.99%)
 * 117I
 * rowspan=2|5/2(+)
 * rowspan=2|
 * rowspan=2|
 * β+, p (.0029%)
 * 116Te
 * 118Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 64
 * 117.916179(11)
 * 3.8(9) min
 * β+
 * 118I
 * 0+
 * 119Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 65
 * 118.915411(11)
 * 5.8(3) min
 * β+
 * 119I
 * 5/2(+)
 * 120Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 66
 * 119.911784(13)
 * 40(1) min
 * β+
 * 120I
 * 0+
 * 121Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 67
 * 120.911462(12)
 * 40.1(20) min
 * β+
 * 121I
 * (5/2+)
 * 122Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 68
 * 121.908368(12)
 * 20.1(1) h
 * EC
 * 122I
 * 0+
 * 123Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 69
 * 122.908482(10)
 * 2.08(2) h
 * β+
 * 123I
 * 1/2+
 * style="text-indent:1em" | 123mXe
 * colspan="3" style="text-indent:2em" | 185.18(22) keV
 * 5.49(26) μs
 * 7/2(−)
 * 124Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 70
 * 123.905893(2)
 * 1.8(5 (stat), 1 (sys)) y
 * Double EC
 * 124Te
 * 0+
 * 9.52(3)×10−4
 * 125Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 71
 * 124.9063955(20)
 * 16.9(2) h
 * β+
 * 125I
 * 1/2(+)
 * style="text-indent:1em" | 125m1Xe
 * colspan="3" style="text-indent:2em" | 252.60(14) keV
 * 56.9(9) s
 * IT
 * 125Xe
 * 9/2(−)
 * style="text-indent:1em" | 125m2Xe
 * colspan="3" style="text-indent:2em" | 295.86(15) keV
 * 0.14(3) μs
 * 7/2(+)
 * 126Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 72
 * 125.904274(7)
 * colspan=3 align=center|Observationally Stable
 * 0+
 * 8.90(2)×10−4
 * 127Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 73
 * 126.905184(4)
 * 36.345(3) d
 * EC
 * 127I
 * 1/2+
 * style="text-indent:1em" | 127mXe
 * colspan="3" style="text-indent:2em" | 297.10(8) keV
 * 69.2(9) s
 * IT
 * 127Xe
 * 9/2−
 * 128Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 74
 * 127.9035313(15)
 * colspan=3 align=center|Stable
 * 0+
 * 0.019102(8)
 * 129Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 75
 * 128.9047794(8)
 * colspan=3 align=center|Stable
 * 1/2+
 * 0.264006(82)
 * style="text-indent:1em" | 129mXe
 * colspan="3" style="text-indent:2em" | 236.14(3) keV
 * 8.88(2) d
 * IT
 * 129Xe
 * 11/2−
 * 130Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 76
 * 129.9035080(8)
 * colspan=3 align=center|Stable
 * 0+
 * 0.040710(13)
 * 131Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 77
 * 130.9050824(10)
 * colspan=3 align=center|Stable
 * 3/2+
 * 0.212324(30)
 * style="text-indent:1em" | 131mXe
 * colspan="3" style="text-indent:2em" | 163.930(8) keV
 * 11.934(21) d
 * IT
 * 131Xe
 * 11/2−
 * 132Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 78
 * 131.9041535(10)
 * colspan=3 align=center|Stable
 * 0+
 * 0.269086(33)
 * style="text-indent:1em" | 132mXe
 * colspan="3" style="text-indent:2em" | 2752.27(17) keV
 * 8.39(11) ms
 * IT
 * 132Xe
 * (10+)
 * 133Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 79
 * 132.9059107(26)
 * 5.2475(5) d
 * β−
 * 133Cs
 * 3/2+
 * style="text-indent:1em" | 133mXe
 * colspan="3" style="text-indent:2em" | 233.221(18) keV
 * 2.19(1) d
 * IT
 * 133Xe
 * 11/2−
 * 134Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 80
 * 133.9053945(9)
 * colspan=3 align=center|Observationally Stable
 * 0+
 * 0.104357(21)
 * style="text-indent:1em" | 134m1Xe
 * colspan="3" style="text-indent:2em" | 1965.5(5) keV
 * 290(17) ms
 * IT
 * 134Xe
 * 7−
 * style="text-indent:1em" | 134m2Xe
 * colspan="3" style="text-indent:2em" | 3025.2(15) keV
 * 5(1) μs
 * (10+)
 * 135Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 81
 * 134.907227(5)
 * 9.14(2) h
 * β−
 * 135Cs
 * 3/2+
 * rowspan=2 style="text-indent:1em" | 135mXe
 * rowspan=2 colspan="3" style="text-indent:2em" | 526.551(13) keV
 * rowspan=2|15.29(5) min
 * IT (99.99%)
 * 135Xe
 * rowspan=2|11/2−
 * rowspan=2|
 * rowspan=2|
 * β− (.004%)
 * 135Cs
 * 136Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 82
 * 135.907219(8)
 * 2.165(16 (stat), 59 (sys)) y
 * β−β−
 * 136Ba
 * 0+
 * 0.088573(44)
 * style="text-indent:1em" | 136mXe
 * colspan="3" style="text-indent:2em" | 1891.703(14) keV
 * 2.95(9) μs
 * 6+
 * 137Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 83
 * 136.911562(8)
 * 3.818(13) min
 * β−
 * 137Cs
 * 7/2−
 * 138Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 84
 * 137.91395(5)
 * 14.08(8) min
 * β−
 * 138Cs
 * 0+
 * 139Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 85
 * 138.918793(22)
 * 39.68(14) s
 * β−
 * 139Cs
 * 3/2−
 * 140Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 86
 * 139.92164(7)
 * 13.60(10) s
 * β−
 * 140Cs
 * 0+
 * rowspan=2|141Xe
 * rowspan=2 style="text-align:right" | 54
 * rowspan=2 style="text-align:right" | 87
 * rowspan=2|140.92665(10)
 * rowspan=2|1.73(1) s
 * β− (99.45%)
 * 141Cs
 * rowspan=2|5/2(−#)
 * rowspan=2|
 * rowspan=2|
 * β−, n (.043%)
 * 140Cs
 * rowspan=2|142Xe
 * rowspan=2 style="text-align:right" | 54
 * rowspan=2 style="text-align:right" | 88
 * rowspan=2|141.92971(11)
 * rowspan=2|1.22(2) s
 * β− (99.59%)
 * 142Cs
 * rowspan=2|0+
 * rowspan=2|
 * rowspan=2|
 * β−, n (.41%)
 * 141Cs
 * 143Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 89
 * 142.93511(21)#
 * 0.511(6) s
 * β−
 * 143Cs
 * 5/2−
 * rowspan=2|144Xe
 * rowspan=2 style="text-align:right" | 54
 * rowspan=2 style="text-align:right" | 90
 * rowspan=2|143.93851(32)#
 * rowspan=2|0.388(7) s
 * β−
 * 144Cs
 * rowspan=2|0+
 * rowspan=2|
 * rowspan=2|
 * β−, n
 * 143Cs
 * 145Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 91
 * 144.94407(32)#
 * 188(4) ms
 * β−
 * 145Cs
 * (3/2−)#
 * 146Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 92
 * 145.94775(43)#
 * 146(6) ms
 * β−
 * 146Cs
 * 0+
 * rowspan=2|147Xe
 * rowspan=2 style="text-align:right" | 54
 * rowspan=2 style="text-align:right" | 93
 * rowspan=2|146.95356(43)#
 * rowspan=2|130(80) ms [0.10(+10−5) s]
 * β−
 * 147Cs
 * rowspan=2|3/2−#
 * rowspan=2|
 * rowspan=2|
 * β−, n
 * 146Cs
 * 148Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 94
 * 85(15) ms
 * β−
 * 148Cs
 * 0+
 * 149Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 95
 * 50 ms#
 * 3/2−#
 * 150Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 96
 * 40 ms#
 * 0+
 * 137Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 83
 * 136.911562(8)
 * 3.818(13) min
 * β−
 * 137Cs
 * 7/2−
 * 138Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 84
 * 137.91395(5)
 * 14.08(8) min
 * β−
 * 138Cs
 * 0+
 * 139Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 85
 * 138.918793(22)
 * 39.68(14) s
 * β−
 * 139Cs
 * 3/2−
 * 140Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 86
 * 139.92164(7)
 * 13.60(10) s
 * β−
 * 140Cs
 * 0+
 * rowspan=2|141Xe
 * rowspan=2 style="text-align:right" | 54
 * rowspan=2 style="text-align:right" | 87
 * rowspan=2|140.92665(10)
 * rowspan=2|1.73(1) s
 * β− (99.45%)
 * 141Cs
 * rowspan=2|5/2(−#)
 * rowspan=2|
 * rowspan=2|
 * β−, n (.043%)
 * 140Cs
 * rowspan=2|142Xe
 * rowspan=2 style="text-align:right" | 54
 * rowspan=2 style="text-align:right" | 88
 * rowspan=2|141.92971(11)
 * rowspan=2|1.22(2) s
 * β− (99.59%)
 * 142Cs
 * rowspan=2|0+
 * rowspan=2|
 * rowspan=2|
 * β−, n (.41%)
 * 141Cs
 * 143Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 89
 * 142.93511(21)#
 * 0.511(6) s
 * β−
 * 143Cs
 * 5/2−
 * rowspan=2|144Xe
 * rowspan=2 style="text-align:right" | 54
 * rowspan=2 style="text-align:right" | 90
 * rowspan=2|143.93851(32)#
 * rowspan=2|0.388(7) s
 * β−
 * 144Cs
 * rowspan=2|0+
 * rowspan=2|
 * rowspan=2|
 * β−, n
 * 143Cs
 * 145Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 91
 * 144.94407(32)#
 * 188(4) ms
 * β−
 * 145Cs
 * (3/2−)#
 * 146Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 92
 * 145.94775(43)#
 * 146(6) ms
 * β−
 * 146Cs
 * 0+
 * rowspan=2|147Xe
 * rowspan=2 style="text-align:right" | 54
 * rowspan=2 style="text-align:right" | 93
 * rowspan=2|146.95356(43)#
 * rowspan=2|130(80) ms [0.10(+10−5) s]
 * β−
 * 147Cs
 * rowspan=2|3/2−#
 * rowspan=2|
 * rowspan=2|
 * β−, n
 * 146Cs
 * 148Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 94
 * 85(15) ms
 * β−
 * 148Cs
 * 0+
 * 149Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 95
 * 50 ms#
 * 3/2−#
 * 150Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 96
 * 40 ms#
 * 0+
 * rowspan=2|147Xe
 * rowspan=2 style="text-align:right" | 54
 * rowspan=2 style="text-align:right" | 93
 * rowspan=2|146.95356(43)#
 * rowspan=2|130(80) ms [0.10(+10−5) s]
 * β−
 * 147Cs
 * rowspan=2|3/2−#
 * rowspan=2|
 * rowspan=2|
 * β−, n
 * 146Cs
 * 148Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 94
 * 85(15) ms
 * β−
 * 148Cs
 * 0+
 * 149Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 95
 * 50 ms#
 * 3/2−#
 * 150Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 96
 * 40 ms#
 * 0+
 * 50 ms#
 * 3/2−#
 * 150Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 96
 * 40 ms#
 * 0+
 * 150Xe
 * style="text-align:right" | 54
 * style="text-align:right" | 96
 * 40 ms#
 * 0+
 * 0+
 * 0+
 * 0+

 * The isotopic composition refers to that in air.

Xenon-124
Xenon-124 is an isotope of xenon that undergoes double electron capture to tellurium-124 with a very long half-life of $105 ms$ years, more than 12 orders of magnitude longer than the age of the universe ($2.8$). Such decays have been observed in the XENON1T detector in 2019, and are the rarest processes ever directly observed. (Even slower decays of other nuclei have been measured, but by detecting decay products that have accumulated over billions of years rather than observing them directly. )

Xenon-133
Xenon-133 (sold as a drug under the brand name Xeneisol, ATC code ) is an isotope of xenon. It is a radionuclide that is inhaled to assess pulmonary function, and to image the lungs. It is also used to image blood flow, particularly in the brain. 133Xe is also an important fission product. It is discharged to the atmosphere in small quantities by some nuclear power plants.

Xenon-135
Xenon-135 is a radioactive isotope of xenon, produced as a fission product of uranium. It has a half-life of about 9.2 hours and is the most powerful known neutron-absorbing nuclear poison (having a neutron absorption cross-section of 2 million barns ). The overall yield of xenon-135 from fission is 6.3%, though most of this results from the radioactive decay of fission-produced tellurium-135 and iodine-135. Xe-135 exerts a significant effect on nuclear reactor operation (xenon pit). It is discharged to the atmosphere in small quantities by some nuclear power plants.

Xenon-136
Xenon-136 is an isotope of xenon that undergoes double beta decay to barium-136 with a very long half-life of $1.8$ years, more than 10 orders of magnitude longer than the age of the universe ($13.799 years$). It is being used in the Enriched Xenon Observatory experiment to search for neutrinoless double beta decay.

title: Isotopes of xenon


text:
Isotopes of iodine

There are 37 known isotopes of iodine (53I) from 108I to 144I; all undergo radioactive decay except 127I, which is stable. Iodine is thus a monoisotopic element.

Its longest-lived radioactive isotope, 129I, has a half-life of 15.7 million years, which is far too short for it to exist as a primordial nuclide. Cosmogenic sources of 129I produce very tiny quantities of it that are too small to affect atomic weight measurements; iodine is thus also a mononuclidic element—one that is found in nature only as a single nuclide. Most 129I derived radioactivity on Earth is man-made, an unwanted long-lived byproduct of early nuclear tests and nuclear fission accidents.

All other iodine radioisotopes have half-lives less than 60 days, and four of these are used as tracers and therapeutic agents in medicine. These are 123I, 124I, 125I, and 131I. All industrial production of radioactive iodine isotopes involves these four useful radionuclides.

The isotope 135I has a half-life less than seven hours, which is too short to be used in biology. Unavoidable in situ production of this isotope is important in nuclear reactor control, as it decays to 135Xe, the most powerful known neutron absorber, and the nuclide responsible for the so-called iodine pit phenomenon.

In addition to commercial production, 131I (half-life 8 days) is one of the common radioactive fission products of nuclear fission, and is thus produced inadvertently in very large amounts inside nuclear reactors. Due to its volatility, short half-life, and high abundance in fission products, 131I (along with the short-lived iodine isotope 132I, which is produced from the decay of 132Te with a half-life of 3 days) is responsible for the largest part of radioactive contamination during the first week after accidental environmental contamination from the radioactive waste from a nuclear power plant. Thus highly dosed iodine supplements (usually potassium iodide) are given to the populace after nuclear accidents or explosions (and in some cases prior to any such incident as a civil defense mechanism) to reduce the uptake of radioactive iodine compounds by the thyroid before the highly radioactive isotopes have had time to decay.

List of isotopes

 * rowspan=3|108I
 * rowspan=3 style="text-align:right" | 53
 * rowspan=3 style="text-align:right" | 55
 * rowspan=3|107.94348(39)#
 * rowspan=3|36(6) ms
 * α (90%)
 * 104Sb
 * rowspan=3|(1)#
 * rowspan=3|
 * β+ (9%)
 * 108Te
 * p (1%)
 * 107Te
 * rowspan=2|109I
 * rowspan=2 style="text-align:right" | 53
 * rowspan=2 style="text-align:right" | 56
 * rowspan=2|108.93815(11)
 * rowspan=2|103(5) μs
 * p (99.5%)
 * 108Te
 * rowspan=2|(5/2+)
 * rowspan=2|
 * α (.5%)
 * 105Sb
 * rowspan=4|110I
 * rowspan=4 style="text-align:right" | 53
 * rowspan=4 style="text-align:right" | 57
 * rowspan=4|109.93524(33)#
 * rowspan=4|650(20) ms
 * β+ (70.9%)
 * 110Te
 * rowspan=4|1+#
 * rowspan=4|
 * α (17%)
 * 106Sb
 * β+, p (11%)
 * 109Sb
 * β+, α (1.09%)
 * 106Sn
 * rowspan=2|111I
 * rowspan=2 style="text-align:right" | 53
 * rowspan=2 style="text-align:right" | 58
 * rowspan=2|110.93028(32)#
 * rowspan=2|2.5(2) s
 * β+ (99.92%)
 * 111Te
 * rowspan=2|(5/2+)#
 * rowspan=2|
 * α (.088%)
 * 107Sb
 * rowspan=4|112I
 * rowspan=4 style="text-align:right" | 53
 * rowspan=4 style="text-align:right" | 59
 * rowspan=4|111.92797(23)#
 * rowspan=4|3.42(11) s
 * β+ (99.01%)
 * 112Te
 * rowspan=4|
 * rowspan=4|
 * β+, p (.88%)
 * 111Sb
 * β+, α (.104%)
 * 108Sn
 * α (.0012%)
 * 108Sb
 * rowspan=3|113I
 * rowspan=3 style="text-align:right" | 53
 * rowspan=3 style="text-align:right" | 60
 * rowspan=3|112.92364(6)
 * rowspan=3|6.6(2) s
 * β+ (100%)
 * 113Te
 * rowspan=3|5/2+#
 * rowspan=3|
 * α (3.3×10−7%)
 * 109Sb
 * β+, α
 * 109Sn
 * rowspan=2|114I
 * rowspan=2 style="text-align:right" | 53
 * rowspan=2 style="text-align:right" | 61
 * rowspan=2|113.92185(32)#
 * rowspan=2|2.1(2) s
 * β+
 * 114Te
 * rowspan=2|1+
 * rowspan=2|
 * β+, p (rare)
 * 113Sb
 * rowspan=2 style="text-indent:1em" | 114mI
 * rowspan=2 colspan="3" style="text-indent:2em" | 265.9(5) keV
 * rowspan=2|6.2(5) s
 * β+ (91%)
 * 114Te
 * rowspan=2|(7)
 * rowspan=2|
 * IT (9%)
 * 114I
 * 115I
 * style="text-align:right" | 53
 * style="text-align:right" | 62
 * 114.91805(3)
 * 1.3(2) min
 * β+
 * 115Te
 * (5/2+)#
 * 116I
 * style="text-align:right" | 53
 * style="text-align:right" | 63
 * 115.91681(10)
 * 2.91(15) s
 * β+
 * 116Te
 * 1+
 * style="text-indent:1em" | 116mI
 * colspan="3" style="text-indent:2em" | 400(50)# keV
 * 3.27(16) μs
 * (7−)
 * 117I
 * style="text-align:right" | 53
 * style="text-align:right" | 64
 * 116.91365(3)
 * 2.22(4) min
 * β+
 * 117Te
 * (5/2)+
 * 118I
 * style="text-align:right" | 53
 * style="text-align:right" | 65
 * 117.913074(21)
 * 13.7(5) min
 * β+
 * 118Te
 * 2−
 * rowspan=2 style="text-indent:1em" | 118mI
 * rowspan=2 colspan="3" style="text-indent:2em" | 190.1(10) keV
 * rowspan=2|8.5(5) min
 * β+
 * 118Te
 * rowspan=2|(7−)
 * rowspan=2|
 * IT (rare)
 * 118I
 * 119I
 * style="text-align:right" | 53
 * style="text-align:right" | 66
 * 118.91007(3)
 * 19.1(4) min
 * β+
 * 119Te
 * 5/2+
 * 120I
 * style="text-align:right" | 53
 * style="text-align:right" | 67
 * 119.910048(19)
 * 81.6(2) min
 * β+
 * 120Te
 * 2−
 * style="text-indent:1em" | 120m1I
 * colspan="3" style="text-indent:2em" | 72.61(9) keV
 * 228(15) ns
 * (1+, 2+, 3+)
 * style="text-indent:1em" | 120m2I
 * colspan="3" style="text-indent:2em" | 320(15) keV
 * 53(4) min
 * β+
 * 120Te
 * (7−)
 * 121I
 * style="text-align:right" | 53
 * style="text-align:right" | 68
 * 120.907367(11)
 * 2.12(1) h
 * β+
 * 121Te
 * 5/2+
 * style="text-indent:1em" | 121mI
 * colspan="3" style="text-indent:2em" | 2376.9(4) keV
 * 9.0(15) μs
 * 122I
 * style="text-align:right" | 53
 * style="text-align:right" | 69
 * 121.907589(6)
 * 3.63(6) min
 * β+
 * 122Te
 * 1+
 * 123I
 * style="text-align:right" | 53
 * style="text-align:right" | 70
 * 122.905589(4)
 * 13.2235(19) h
 * EC
 * 123Te
 * 5/2+
 * 124I
 * style="text-align:right" | 53
 * style="text-align:right" | 71
 * 123.9062099(25)
 * 4.1760(3) d
 * β+
 * 124Te
 * 2−
 * 125I
 * style="text-align:right" | 53
 * style="text-align:right" | 72
 * 124.9046302(16)
 * 59.400(10) d
 * EC
 * 125Te
 * 5/2+
 * rowspan=2|126I
 * rowspan=2 style="text-align:right" | 53
 * rowspan=2 style="text-align:right" | 73
 * rowspan=2|125.905624(4)
 * rowspan=2|12.93(5) d
 * β+ (56.3%)
 * 126Te
 * rowspan=2|2−
 * rowspan=2|
 * β− (43.7%)
 * 126Xe
 * 127I
 * style="text-align:right" | 53
 * style="text-align:right" | 74
 * 126.904473(4)
 * colspan=3 align=center|Stable
 * 5/2+
 * 1.0000
 * rowspan=2|128I
 * rowspan=2 style="text-align:right" | 53
 * rowspan=2 style="text-align:right" | 75
 * rowspan=2|127.905809(4)
 * rowspan=2|24.99(2) min
 * β− (93.1%)
 * 128Xe
 * rowspan=2|1+
 * rowspan=2|
 * β+ (6.9%)
 * 128Te
 * style="text-indent:1em" | 128m1I
 * colspan="3" style="text-indent:2em" | 137.850(4) keV
 * 845(20) ns
 * 4−
 * style="text-indent:1em" | 128m2I
 * colspan="3" style="text-indent:2em" | 167.367(5) keV
 * 175(15) ns
 * (6)−
 * 129I
 * style="text-align:right" | 53
 * style="text-align:right" | 76
 * 128.904988(3)
 * 1.57(4)×107 y
 * β−
 * 129Xe
 * 7/2+
 * Trace
 * 130I
 * style="text-align:right" | 53
 * style="text-align:right" | 77
 * 129.906674(3)
 * 12.36(1) h
 * β−
 * 130Xe
 * 5+
 * rowspan=2 style="text-indent:1em" | 130m1I
 * rowspan=2 colspan="3" style="text-indent:2em" | 39.9525(13) keV
 * rowspan=2|8.84(6) min
 * IT (84%)
 * 130I
 * rowspan=2|2+
 * rowspan=2|
 * β− (16%)
 * 130Xe
 * style="text-indent:1em" | 130m2I
 * colspan="3" style="text-indent:2em" | 69.5865(7) keV
 * 133(7) ns
 * (6)−
 * style="text-indent:1em" | 130m3I
 * colspan="3" style="text-indent:2em" | 82.3960(19) keV
 * 315(15) ns
 * style="text-indent:1em" | 130m4I
 * colspan="3" style="text-indent:2em" | 85.1099(10) keV
 * 254(4) ns
 * (6)−
 * 131I
 * style="text-align:right" | 53
 * style="text-align:right" | 78
 * 130.9061246(12)
 * 8.02070(11) d
 * β−
 * 131Xe
 * 7/2+
 * 132I
 * style="text-align:right" | 53
 * style="text-align:right" | 79
 * 131.907997(6)
 * 2.295(13) h
 * β−
 * 132Xe
 * 4+
 * rowspan=2 style="text-indent:1em" | 132mI
 * rowspan=2 colspan="3" style="text-indent:2em" | 104(12) keV
 * rowspan=2|1.387(15) h
 * IT (86%)
 * 132I
 * rowspan=2|(8−)
 * rowspan=2|
 * β− (14%)
 * 132Xe
 * 133I
 * style="text-align:right" | 53
 * style="text-align:right" | 80
 * 132.907797(5)
 * 20.8(1) h
 * β−
 * 133Xe
 * 7/2+
 * style="text-indent:1em" | 133m1I
 * colspan="3" style="text-indent:2em" | 1634.174(17) keV
 * 9(2) s
 * IT
 * 133I
 * (19/2−)
 * style="text-indent:1em" | 133m2I
 * colspan="3" style="text-indent:2em" | 1729.160(17) keV
 * ~170 ns
 * (15/2−)
 * 134I
 * style="text-align:right" | 53
 * style="text-align:right" | 81
 * 133.909744(9)
 * 52.5(2) min
 * β−
 * 134Xe
 * (4)+
 * rowspan=2 style="text-indent:1em" | 134mI
 * rowspan=2 colspan="3" style="text-indent:2em" | 316.49(22) keV
 * rowspan=2|3.52(4) min
 * IT (97.7%)
 * 134I
 * rowspan=2|(8)−
 * rowspan=2|
 * β− (2.3%)
 * 134Xe
 * 135I
 * style="text-align:right" | 53
 * style="text-align:right" | 82
 * 134.910048(8)
 * 6.57(2) h
 * β−
 * 135Xe
 * 7/2+
 * 136I
 * style="text-align:right" | 53
 * style="text-align:right" | 83
 * 135.91465(5)
 * 83.4(10) s
 * β−
 * 136Xe
 * (1−)
 * style="text-indent:1em" | 136mI
 * colspan="3" style="text-indent:2em" | 650(120) keV
 * 46.9(10) s
 * β−
 * 136Xe
 * (6−)
 * rowspan=2|137I
 * rowspan=2 style="text-align:right" | 53
 * rowspan=2 style="text-align:right" | 84
 * rowspan=2|136.917871(30)
 * rowspan=2|24.13(12) s
 * β− (92.86%)
 * 137Xe
 * rowspan=2|(7/2+)
 * rowspan=2|
 * β−, n (7.14%)
 * 136Xe
 * rowspan=2|138I
 * rowspan=2 style="text-align:right" | 53
 * rowspan=2 style="text-align:right" | 85
 * rowspan=2|137.92235(9)
 * rowspan=2|6.23(3) s
 * β− (94.54%)
 * 138Xe
 * rowspan=2|(2−)
 * rowspan=2|
 * β−, n (5.46%)
 * 137Xe
 * rowspan=2|139I
 * rowspan=2 style="text-align:right" | 53
 * rowspan=2 style="text-align:right" | 86
 * rowspan=2|138.92610(3)
 * rowspan=2|2.282(10) s
 * β− (90%)
 * 139Xe
 * rowspan=2|7/2+#
 * rowspan=2|
 * β−, n (10%)
 * 138Xe
 * rowspan=2|140I
 * rowspan=2 style="text-align:right" | 53
 * rowspan=2 style="text-align:right" | 87
 * rowspan=2|139.93100(21)#
 * rowspan=2|860(40) ms
 * β− (90.7%)
 * 140Xe
 * rowspan=2|(3)(−#)
 * rowspan=2|
 * β−, n (9.3%)
 * 139Xe
 * rowspan=2|141I
 * rowspan=2 style="text-align:right" | 53
 * rowspan=2 style="text-align:right" | 88
 * rowspan=2|140.93503(21)#
 * rowspan=2|430(20) ms
 * β− (78%)
 * 141Xe
 * rowspan=2|7/2+#
 * rowspan=2|
 * β−, n (22%)
 * 140Xe
 * rowspan=2|142I
 * rowspan=2 style="text-align:right" | 53
 * rowspan=2 style="text-align:right" | 89
 * rowspan=2|141.94018(43)#
 * rowspan=2|~200 ms
 * β− (75%)
 * 142Xe
 * rowspan=2|2−#
 * rowspan=2|
 * β−, n (25%)
 * 141Xe
 * 143I
 * style="text-align:right" | 53
 * style="text-align:right" | 90
 * 142.94456(43)#
 * 100# ms [> 300 ns]
 * β−
 * 143Xe
 * 7/2+#
 * 144I
 * style="text-align:right" | 53
 * style="text-align:right" | 91
 * 143.94999(54)#
 * 50# ms [> 300 ns]
 * β−
 * 144Xe
 * 1−#
 * 134I
 * rowspan=2|(8)−
 * rowspan=2|
 * β− (2.3%)
 * 134Xe
 * 135I
 * style="text-align:right" | 53
 * style="text-align:right" | 82
 * 134.910048(8)
 * 6.57(2) h
 * β−
 * 135Xe
 * 7/2+
 * 136I
 * style="text-align:right" | 53
 * style="text-align:right" | 83
 * 135.91465(5)
 * 83.4(10) s
 * β−
 * 136Xe
 * (1−)
 * style="text-indent:1em" | 136mI
 * colspan="3" style="text-indent:2em" | 650(120) keV
 * 46.9(10) s
 * β−
 * 136Xe
 * (6−)
 * rowspan=2|137I
 * rowspan=2 style="text-align:right" | 53
 * rowspan=2 style="text-align:right" | 84
 * rowspan=2|136.917871(30)
 * rowspan=2|24.13(12) s
 * β− (92.86%)
 * 137Xe
 * rowspan=2|(7/2+)
 * rowspan=2|
 * β−, n (7.14%)
 * 136Xe
 * rowspan=2|138I
 * rowspan=2 style="text-align:right" | 53
 * rowspan=2 style="text-align:right" | 85
 * rowspan=2|137.92235(9)
 * rowspan=2|6.23(3) s
 * β− (94.54%)
 * 138Xe
 * rowspan=2|(2−)
 * rowspan=2|
 * β−, n (5.46%)
 * 137Xe
 * rowspan=2|139I
 * rowspan=2 style="text-align:right" | 53
 * rowspan=2 style="text-align:right" | 86
 * rowspan=2|138.92610(3)
 * rowspan=2|2.282(10) s
 * β− (90%)
 * 139Xe
 * rowspan=2|7/2+#
 * rowspan=2|
 * β−, n (10%)
 * 138Xe
 * rowspan=2|140I
 * rowspan=2 style="text-align:right" | 53
 * rowspan=2 style="text-align:right" | 87
 * rowspan=2|139.93100(21)#
 * rowspan=2|860(40) ms
 * β− (90.7%)
 * 140Xe
 * rowspan=2|(3)(−#)
 * rowspan=2|
 * β−, n (9.3%)
 * 139Xe
 * rowspan=2|141I
 * rowspan=2 style="text-align:right" | 53
 * rowspan=2 style="text-align:right" | 88
 * rowspan=2|140.93503(21)#
 * rowspan=2|430(20) ms
 * β− (78%)
 * 141Xe
 * rowspan=2|7/2+#
 * rowspan=2|
 * β−, n (22%)
 * 140Xe
 * rowspan=2|142I
 * rowspan=2 style="text-align:right" | 53
 * rowspan=2 style="text-align:right" | 89
 * rowspan=2|141.94018(43)#
 * rowspan=2|~200 ms
 * β− (75%)
 * 142Xe
 * rowspan=2|2−#
 * rowspan=2|
 * β−, n (25%)
 * 141Xe
 * 143I
 * style="text-align:right" | 53
 * style="text-align:right" | 90
 * 142.94456(43)#
 * 100# ms [> 300 ns]
 * β−
 * 143Xe
 * 7/2+#
 * 144I
 * style="text-align:right" | 53
 * style="text-align:right" | 91
 * 143.94999(54)#
 * 50# ms [> 300 ns]
 * β−
 * 144Xe
 * 1−#
 * β−, n (25%)
 * 141Xe
 * 143I
 * style="text-align:right" | 53
 * style="text-align:right" | 90
 * 142.94456(43)#
 * 100# ms [> 300 ns]
 * β−
 * 143Xe
 * 7/2+#
 * 144I
 * style="text-align:right" | 53
 * style="text-align:right" | 91
 * 143.94999(54)#
 * 50# ms [> 300 ns]
 * β−
 * 144Xe
 * 1−#
 * 50# ms [> 300 ns]
 * β−
 * 144Xe
 * 1−#

Notable radioisotopes
Radioisotopes of iodine are called radioactive iodine or radioiodine. Dozens exist, but about a half dozen are the most notable in applied sciences such as the life sciences and nuclear power, as detailed below. Mentions of radioiodine in health care contexts refer more often to iodine-131 than to other isotopes.

Of the many isotopes of iodine, only two are typically used in a medical setting: iodine-123 and iodine-131. Since 131I has both a beta and gamma decay mode, it can be used for radiotherapy or for imaging. 123I, which has no beta activity, is more suited for routine nuclear medicine imaging of the thyroid and other medical processes and less damaging internally to the patient. There are some situations in which iodine-124 and iodine-125 are also used in medicine.

Due to preferential uptake of iodine by the thyroid, radioiodine is extensively used in imaging of and, in the case of 131I, destroying dysfunctional thyroid tissues. Other types of tissue selectively take up certain iodine-131-containing tissue-targeting and killing radiopharmaceutical agents (such as MIBG). Iodine-125 is the only other iodine radioisotope used in radiation therapy, but only as an implanted capsule in brachytherapy, where the isotope never has a chance to be released for chemical interaction with the body's tissues.

Iodine-123 and iodine-125
The gamma-emitting isotopes iodine-123 (half-life 13 hours), and (less commonly) the longer-lived and less energetic iodine-125 (half-life 59 days) are used as nuclear imaging tracers to evaluate the anatomic and physiologic function of the thyroid. Abnormal results may be caused by disorders such as Graves' disease or Hashimoto's thyroiditis. Both isotopes decay by electron capture (EC) to the corresponding tellurium nuclides, but in neither case are these the metastable nuclides 123mTe and 125mTe (which are of higher energy, and are not produced from radioiodine). Instead, the excited tellurium nuclides decay immediately (half-life too short to detect). Following EC, the excited 123Te from 123I emits a high-speed 127 keV internal conversion electron (not a beta ray) about 13% of the time, but this does little cellular damage due to the nuclide's short half-life and the relatively small fraction of such events. In the remainder of cases, a 159 keV gamma ray is emitted, which is well-suited for gamma imaging.

Excited 125Te resulting from electron capture of 125I also emits a much lower-energy internal conversion electron (35.5 keV), which does relatively little damage due to its low energy, even though its emission is more common. The relatively low-energy gamma from 125I/125Te decay is poorly suited for imaging, but can still be seen, and this longer-lived isotope is necessary in tests that require several days of imaging, for example, fibrinogen scan imaging to detect blood clots.

Both 123I and 125I emit copious low energy Auger electrons after their decay, but these do not cause serious damage (double-stranded DNA breaks) in cells, unless the nuclide is incorporated into a medication that accumulates in the nucleus, or into DNA (this is never the case is clinical medicine, but it has been seen in experimental animal models).

Iodine-125 is also commonly used by radiation oncologists in low dose rate brachytherapy in the treatment of cancer at sites other than the thyroid, especially in prostate cancer. When 125I is used therapeutically, it is encapsulated in titanium seeds and implanted in the area of the tumor, where it remains. The low energy of the gamma spectrum in this case limits radiation damage to tissues far from the implanted capsule. Iodine-125, due to its suitable longer half-life and less penetrating gamma spectrum, is also often preferred for laboratory tests that rely on iodine as a tracer that is counted by a gamma counter, such as in radioimmunoassaying.

$125$I is used as the radiolabel in investigating which ligands go to which plant pattern recognition receptors (PRRs).

Iodine-124
Iodine-124 is a proton-rich isotope of iodine with a half-life of 4.18 days. Its modes of decay are: 74.4% electron capture, 25.6% positron emission. 124I decays to 124Te. Iodine-124 can be made by numerous nuclear reactions via a cyclotron. The most common starting material used is 124Te.

Iodine-124 as the iodide salt can be used to directly image the thyroid using positron emission tomography (PET). Iodine-124 can also be used as a PET radiotracer with a usefully longer half-life compared with fluorine-18. In this use, the nuclide is chemically bonded to a pharmaceutical to form a positron-emitting radiopharmaceutical, and injected into the body, where again it is imaged by PET scan.

Iodine-129
Iodine-129 (129I; half-life 15.7 million years) is a product of cosmic ray spallation on various isotopes of xenon in the atmosphere, in cosmic ray muon interaction with tellurium-130, and also uranium and plutonium fission, both in subsurface rocks and nuclear reactors. Artificial nuclear processes, in particular nuclear fuel reprocessing and atmospheric nuclear weapons tests, have now swamped the natural signal for this isotope. Nevertheless, it now serves as a groundwater tracer as indicator of nuclear waste dispersion into the natural environment. In a similar fashion, 129I was used in rainwater studies to track fission products following the Chernobyl disaster.

In some ways, 129I is similar to 36Cl. It is a soluble halogen, exists mainly as a non-sorbing anion, and is produced by cosmogenic, thermonuclear, and in-situ reactions. In hydrologic studies, 129I concentrations are usually reported as the ratio of 129I to total I (which is virtually all 127I). As is the case with 36Cl/Cl, 129I/I ratios in nature are quite small, 10−14 to 10−10 (peak thermonuclear 129I/I during the 1960s and 1970s reached about 10−7). 129I differs from 36Cl in that its half-life is longer (15.7 vs. 0.301 million years), it is highly biophilic, and occurs in multiple ionic forms (commonly, I− and IO3−), which have different chemical behaviors. This makes it fairly easy for 129I to enter the biosphere as it becomes incorporated into vegetation, soil, milk, animal tissue, etc. Excesses of stable 129Xe in meteorites have been shown to result from decay of "primordial" iodine-129 produced newly by the supernovas that created the dust and gas from which the solar system formed. This isotope has long decayed and is thus referred to as "extinct". Historically, 129I was the first extinct radionuclide to be identified as present in the early Solar System. Its decay is the basis of the I-Xe iodine-xenon radiometric dating scheme, which covers the first 85 million years of Solar System evolution.

Iodine-131

Iodine-131 (I|131I) is a beta-emitting isotope with a half-life of eight days, and comparatively energetic (190 keV average and 606 keV maximum energy) beta radiation, which penetrates 0.6 to 2.0 mm from the site of uptake. This beta radiation can be used for the destruction of thyroid nodules or hyperfunctioning thyroid tissue and for elimination of remaining thyroid tissue after surgery for the treatment of Graves' disease. The purpose of this therapy, which was first explored by Dr. Saul Hertz in 1941, is to destroy thyroid tissue that could not be removed surgically. In this procedure, 131I is administered either intravenously or orally following a diagnostic scan. This procedure may also be used, with higher doses of radio-iodine, to treat patients with thyroid cancer.

The 131I is taken up into thyroid tissue and concentrated there. The beta particles emitted by the radioisotope destroys the associated thyroid tissue with little damage to surrounding tissues (more than 2.0 mm from the tissues absorbing the iodine). Due to similar destruction, 131I is the iodine radioisotope used in other water-soluble iodine-labeled radiopharmaceuticals (such as MIBG) used therapeutically to destroy tissues.

The high energy beta radiation (up to 606 keV) from 131I causes it to be the most carcinogenic of the iodine isotopes. It is thought to cause the majority of excess thyroid cancers seen after nuclear fission contamination (such as bomb fallout or severe nuclear reactor accidents like the Chernobyl disaster) However, these epidemiological effects are seen primarily in children, and treatment of adults and children with therapeutic 131I, and epidemiology of adults exposed to low-dose 131I has not demonstrated carcinogenicity.

Iodine-135
Iodine-135 is an isotope of iodine with a half-life of 6.6 hours. It is an important isotope from the viewpoint of nuclear reactor physics. It is produced in relatively large amounts as a fission product, and decays to xenon-135, which is a nuclear poison with a very large thermal neutron cross section, which is a cause of multiple complications in the control of nuclear reactors. The process of buildup of xenon-135 from accumulated iodine-135 can temporarily preclude a shut-down reactor from restarting. This is known as xenon poisoning or "falling into an iodine pit".

Iodine-128 and other isotopes
Iodine fission-produced isotopes not discussed above (iodine-128, iodine-130, iodine-132, and iodine-133) have half-lives of several hours or minutes, rendering them almost useless in other applicable areas. Those mentioned are neutron-rich and undergo beta decay to isotopes of xenon. Iodine-128 (half-life 25 minutes) can decay to either tellurium-128 by electron capture or to xenon-128 by beta decay. It has a specific radioactivity of $2.177 TBq/g$.

Nonradioactive iodide (127I) as protection from unwanted radioiodine uptake by the thyroid
Colloquially, radioactive materials can be described as "hot," and non-radioactive materials can be described as "cold." There are instances in which cold iodide is administered to people in order to prevent the uptake of hot iodide by the thyroid gland. For example, blockade of thyroid iodine uptake with potassium iodide is used in nuclear medicine scintigraphy and therapy with some radioiodinated compounds that are not targeted to the thyroid, such as iobenguane (MIBG), which is used to image or treat neural tissue tumors, or iodinated fibrinogen, which is used in fibrinogen scans to investigate clotting. These compounds contain iodine, but not in the iodide form. However, since they may be ultimately metabolized or break down to radioactive iodide, it is common to administer non-radioactive potassium iodide to insure that metabolites of these radiopharmaceuticals is not sequestered by thyroid gland and inadvertently administer a radiological dose to that tissue.

Potassium iodide has been distributed to populations exposed to nuclear fission accidents such as the Chernobyl disaster. The iodide solution SSKI, a saturated solution of potassium (K) iodide in water, has been used to block absorption of the radioiodine (it has no effect on other radioisotopes from fission). Tablets containing potassium iodide are now also manufactured and stocked in central disaster sites by some governments for this purpose. In theory, many harmful late-cancer effects of nuclear fallout might be prevented in this way, since an excess of thyroid cancers, presumably due to radioiodine uptake, is the only proven radioisotope contamination effect after a fission accident, or from contamination by fallout from an atomic bomb (prompt radiation from the bomb also causes other cancers, such as leukemias, directly). Taking large amounts of iodide saturates thyroid receptors and prevents uptake of most radioactive iodine-131 that may be present from fission product exposure (although it does not protect from other radioisotopes, nor from any other form of direct radiation). The protective effect of KI lasts approximately 24 hours, so must be dosed daily until a risk of significant exposure to radioiodines from fission products no longer exists. Iodine-131 (the most common radioiodine contaminant in fallout) also decays relatively rapidly with a half-life of eight days, so that 99.95% of the original radioiodine has vanished after three months.

title: Isotopes of iodine


text:
Isotopes of caesium

Caesium (55Cs) has 41 known isotopes, the atomic masses of these isotopes range from 112 to 152. Only one isotope, 133Cs, is stable. The longest-lived radioisotopes are 135Cs with a half-life of 1.33 million years, 137Caesium with a half-life of 30.1671 years and 134Cs with a half-life of 2.0652 years. All other isotopes have half-lives less than 2 weeks, most under an hour.

Beginning in 1945 with the commencement of nuclear testing, caesium radioisotopes were released into the atmosphere where caesium is absorbed readily into solution and is returned to the surface of the Earth as a component of radioactive fallout. Once caesium enters the ground water, it is deposited on soil surfaces and removed from the landscape primarily by particle transport. As a result, the input function of these isotopes can be estimated as a function of time.

List of isotopes

 * rowspan=2|112Cs
 * rowspan=2 style="text-align:right" | 55
 * rowspan=2 style="text-align:right" | 57
 * rowspan=2|111.95030(33)#
 * rowspan=2|500(100) μs
 * p
 * 111Xe
 * rowspan=2|1+#
 * rowspan=2|
 * α
 * 108I
 * rowspan=2|113Cs
 * rowspan=2 style="text-align:right" | 55
 * rowspan=2 style="text-align:right" | 58
 * rowspan=2|112.94449(11)
 * rowspan=2|16.7(7) μs
 * p (99.97%)
 * 112Xe
 * rowspan=2|5/2+#
 * rowspan=2|
 * β+ (.03%)
 * 113Xe
 * rowspan=4|114Cs
 * rowspan=4 style="text-align:right" | 55
 * rowspan=4 style="text-align:right" | 59
 * rowspan=4|113.94145(33)#
 * rowspan=4|0.57(2) s
 * β+ (91.09%)
 * 114Xe
 * rowspan=4|(1+)
 * rowspan=4|
 * β+, p (8.69%)
 * 113I
 * β+, α (.19%)
 * 110Te
 * α (.018%)
 * 110I
 * rowspan=2|115Cs
 * rowspan=2 style="text-align:right" | 55
 * rowspan=2 style="text-align:right" | 60
 * rowspan=2|114.93591(32)#
 * rowspan=2|1.4(8) s
 * β+ (99.93%)
 * 115Xe
 * rowspan=2|9/2+#
 * rowspan=2|
 * β+, p (.07%)
 * 114I
 * rowspan=3|116Cs
 * rowspan=3 style="text-align:right" | 55
 * rowspan=3 style="text-align:right" | 61
 * rowspan=3|115.93337(11)#
 * rowspan=3|0.70(4) s
 * β+ (99.67%)
 * 116Xe
 * rowspan=3|(1+)
 * rowspan=3|
 * β+, p (.279%)
 * 115I
 * β+, α (.049%)
 * 112Te
 * rowspan=3 style="text-indent:1em" | 116mCs
 * rowspan=3 colspan="3" style="text-indent:2em" | 100(60)# keV
 * rowspan=3|3.85(13) s
 * β+ (99.48%)
 * 116Xe
 * rowspan=3|4+, 5, 6
 * rowspan=3|
 * β+, p (.51%)
 * 115I
 * β+, α (.008%)
 * 112Te
 * 117Cs
 * style="text-align:right" | 55
 * style="text-align:right" | 62
 * 116.92867(7)
 * 8.4(6) s
 * β+
 * 117Xe
 * (9/2+)#
 * style="text-indent:1em" | 117mCs
 * colspan="3" style="text-indent:2em" | 150(80)# keV
 * 6.5(4) s
 * β+
 * 117Xe
 * 3/2+#
 * rowspan=3|118Cs
 * rowspan=3 style="text-align:right" | 55
 * rowspan=3 style="text-align:right" | 63
 * rowspan=3|117.926559(14)
 * rowspan=3|14(2) s
 * β+ (99.95%)
 * 118Xe
 * rowspan=3|2
 * rowspan=3|
 * β+, p (.042%)
 * 117I
 * β+, α (.0024%)
 * 114Te
 * rowspan=3 style="text-indent:1em" | 118mCs
 * rowspan=3 colspan="3" style="text-indent:2em" | 100(60)# keV
 * rowspan=3|17(3) s
 * β+ (99.95%)
 * 118Xe
 * rowspan=3|(7−)
 * rowspan=3|
 * β+, p (.042%)
 * 117I
 * β+, α (.0024%)
 * 114Te
 * rowspan=2|119Cs
 * rowspan=2 style="text-align:right" | 55
 * rowspan=2 style="text-align:right" | 64
 * rowspan=2|118.922377(15)
 * rowspan=2|43.0(2) s
 * β+
 * 119Xe
 * rowspan=2|9/2+
 * rowspan=2|
 * β+, α (2×10−6%)
 * 115Te
 * style="text-indent:1em" | 119mCs
 * colspan="3" style="text-indent:2em" | 50(30)# keV
 * 30.4(1) s
 * β+
 * 119Xe
 * 3/2(+)
 * rowspan=3|120Cs
 * rowspan=3 style="text-align:right" | 55
 * rowspan=3 style="text-align:right" | 65
 * rowspan=3|119.920677(11)
 * rowspan=3|61.2(18) s
 * β+
 * 120Xe
 * rowspan=3|2(−#)
 * rowspan=3|
 * β+, α (2×10−5%)
 * 116Te
 * β+, p (7×10−6%)
 * 119I
 * rowspan=3 style="text-indent:1em" | 120mCs
 * rowspan=3 colspan="3" style="text-indent:2em" | 100(60)# keV
 * rowspan=3|57(6) s
 * β+
 * 120Xe
 * rowspan=3|(7−)
 * rowspan=3|
 * β+, α (2×10−5%)
 * 116Te
 * β+, p (7×10−6%)
 * 119I
 * 121Cs
 * style="text-align:right" | 55
 * style="text-align:right" | 66
 * 120.917229(15)
 * 155(4) s
 * β+
 * 121Xe
 * 3/2(+)
 * rowspan=2 style="text-indent:1em" | 121mCs
 * rowspan=2 colspan="3" style="text-indent:2em" | 68.5(3) keV
 * rowspan=2|122(3) s
 * β+ (83%)
 * 121Xe
 * rowspan=2|9/2(+)
 * rowspan=2|
 * IT (17%)
 * 121Cs
 * rowspan=2|122Cs
 * rowspan=2 style="text-align:right" | 55
 * rowspan=2 style="text-align:right" | 67
 * rowspan=2|121.91611(3)
 * rowspan=2|21.18(19) s
 * β+
 * 122Xe
 * rowspan=2|1+
 * rowspan=2|
 * β+, α (2×10−7%)
 * 118Te
 * style="text-indent:1em" | 122m1Cs
 * colspan="3" style="text-indent:2em" | 45.8 keV
 * >1 μs
 * (3)+
 * style="text-indent:1em" | 122m2Cs
 * colspan="3" style="text-indent:2em" | 140(30) keV
 * 3.70(11) min
 * β+
 * 122Xe
 * 8−
 * style="text-indent:1em" | 122m3Cs
 * colspan="3" style="text-indent:2em" | 127.0(5) keV
 * 360(20) ms
 * (5)−
 * 123Cs
 * style="text-align:right" | 55
 * style="text-align:right" | 68
 * 122.912996(13)
 * 5.88(3) min
 * β+
 * 123Xe
 * 1/2+
 * style="text-indent:1em" | 123m1Cs
 * colspan="3" style="text-indent:2em" | 156.27(5) keV
 * 1.64(12) s
 * IT
 * 123Cs
 * (11/2)−
 * style="text-indent:1em" | 123m2Cs
 * colspan="3" style="text-indent:2em" | 231.63+X keV
 * 114(5) ns
 * (9/2+)
 * 124Cs
 * style="text-align:right" | 55
 * style="text-align:right" | 69
 * 123.912258(9)
 * 30.9(4) s
 * β+
 * 124Xe
 * 1+
 * style="text-indent:1em" | 124mCs
 * colspan="3" style="text-indent:2em" | 462.55(17) keV
 * 6.3(2) s
 * IT
 * 124Cs
 * (7)+
 * 125Cs
 * style="text-align:right" | 55
 * style="text-align:right" | 70
 * 124.909728(8)
 * 46.7(1) min
 * β+
 * 125Xe
 * 1/2(+)
 * style="text-indent:1em" | 125mCs
 * colspan="3" style="text-indent:2em" | 266.6(11) keV
 * 900(30) ms
 * (11/2−)
 * 126Cs
 * style="text-align:right" | 55
 * style="text-align:right" | 71
 * 125.909452(13)
 * 1.64(2) min
 * β+
 * 126Xe
 * 1+
 * style="text-indent:1em" | 126m1Cs
 * colspan="3" style="text-indent:2em" | 273.0(7) keV
 * >1 μs
 * style="text-indent:1em" | 126m2Cs
 * colspan="3" style="text-indent:2em" | 596.1(11) keV
 * 171(14) μs
 * 127Cs
 * style="text-align:right" | 55
 * style="text-align:right" | 72
 * 126.907418(6)
 * 6.25(10) h
 * β+
 * 127Xe
 * 1/2+
 * style="text-indent:1em" | 127mCs
 * colspan="3" style="text-indent:2em" | 452.23(21) keV
 * 55(3) μs
 * (11/2)−
 * 128Cs
 * style="text-align:right" | 55
 * style="text-align:right" | 73
 * 127.907749(6)
 * 3.640(14) min
 * β+
 * 128Xe
 * 1+
 * 129Cs
 * style="text-align:right" | 55
 * style="text-align:right" | 74
 * 128.906064(5)
 * 32.06(6) h
 * β+
 * 129Xe
 * 1/2+
 * rowspan=2|130Cs
 * rowspan=2 style="text-align:right" | 55
 * rowspan=2 style="text-align:right" | 75
 * rowspan=2|129.906709(9)
 * rowspan=2|29.21(4) min
 * β+ (98.4%)
 * 130Xe
 * rowspan=2|1+
 * rowspan=2|
 * β− (1.6%)
 * 130Ba
 * rowspan=2 style="text-indent:1em" | 130mCs
 * rowspan=2 colspan="3" style="text-indent:2em" | 163.25(11) keV
 * rowspan=2|3.46(6) min
 * IT (99.83%)
 * 130Cs
 * rowspan=2|5−
 * rowspan=2|
 * β+ (.16%)
 * 130Xe
 * 131Cs
 * style="text-align:right" | 55
 * style="text-align:right" | 76
 * 130.905464(5)
 * 9.689(16) d
 * EC
 * 131Xe
 * 5/2+
 * rowspan=2|132Cs
 * rowspan=2 style="text-align:right" | 55
 * rowspan=2 style="text-align:right" | 77
 * rowspan=2|131.9064343(20)
 * rowspan=2|6.480(6) d
 * β+ (98.13%)
 * 132Xe
 * rowspan=2|2+
 * rowspan=2|
 * β− (1.87%)
 * 132Ba
 * 133Cs
 * style="text-align:right" | 55
 * style="text-align:right" | 78
 * 132.905451933(24)
 * colspan=3 align=center|Stable
 * 7/2+
 * 1.0000
 * rowspan=2|134Cs
 * rowspan=2 style="text-align:right" | 55
 * rowspan=2 style="text-align:right" | 79
 * rowspan=2|133.906718475(28)
 * rowspan=2|2.0652(4) y
 * β−
 * 134Ba
 * rowspan=2|4+
 * rowspan=2|
 * EC (3×10−4%)
 * 134Xe
 * style="text-indent:1em" | 134mCs
 * colspan="3" style="text-indent:2em" | 138.7441(26) keV
 * 2.912(2) h
 * IT
 * 134Cs
 * 8−
 * 135Cs
 * style="text-align:right" | 55
 * style="text-align:right" | 80
 * 134.9059770(11)
 * 2.3 x106 y
 * β−
 * 135Ba
 * 7/2+
 * style="text-indent:1em" | 135mCs
 * colspan="3" style="text-indent:2em" | 1632.9(15) keV
 * 53(2) min
 * IT
 * 135Cs
 * 19/2−
 * 136Cs
 * style="text-align:right" | 55
 * style="text-align:right" | 81
 * 135.9073116(20)
 * 13.16(3) d
 * β−
 * 136Ba
 * 5+
 * rowspan=2 style="text-indent:1em" | 136mCs
 * rowspan=2 colspan="3" style="text-indent:2em" | 518(5) keV
 * rowspan=2|19(2) s
 * β−
 * 136Ba
 * rowspan=2|8−
 * rowspan=2|
 * IT
 * 136Cs
 * rowspan=2|137Cs
 * rowspan=2 style="text-align:right" | 55
 * rowspan=2 style="text-align:right" | 82
 * rowspan=2|136.9070895(5)
 * rowspan=2|30.1671(13) y
 * β− (95%)
 * 137mBa
 * rowspan=2|7/2+
 * rowspan=2|
 * β− (5%)
 * 137Ba
 * 138Cs
 * style="text-align:right" | 55
 * style="text-align:right" | 83
 * 137.911017(10)
 * 33.41(18) min
 * β−
 * 138Ba
 * 3−
 * rowspan=2 style="text-indent:1em" | 138mCs
 * rowspan=2 colspan="3" style="text-indent:2em" | 79.9(3) keV
 * rowspan=2|2.91(8) min
 * IT (81%)
 * 138Cs
 * rowspan=2|6−
 * rowspan=2|
 * β− (19%)
 * 138Ba
 * 139Cs
 * style="text-align:right" | 55
 * style="text-align:right" | 84
 * 138.913364(3)
 * 9.27(5) min
 * β−
 * 139Ba
 * 7/2+
 * 140Cs
 * style="text-align:right" | 55
 * style="text-align:right" | 85
 * 139.917282(9)
 * 63.7(3) s
 * β−
 * 140Ba
 * 1−
 * rowspan=2|141Cs
 * rowspan=2 style="text-align:right" | 55
 * rowspan=2 style="text-align:right" | 86
 * rowspan=2|140.920046(11)
 * rowspan=2|24.84(16) s
 * β− (99.96%)
 * 141Ba
 * rowspan=2|7/2+
 * rowspan=2|
 * β−, n (.0349%)
 * 140Ba
 * rowspan=2|142Cs
 * rowspan=2 style="text-align:right" | 55
 * rowspan=2 style="text-align:right" | 87
 * rowspan=2|141.924299(11)
 * rowspan=2|1.689(11) s
 * β− (99.9%)
 * 142Ba
 * rowspan=2|0−
 * rowspan=2|
 * β−, n (.091%)
 * 141Ba
 * rowspan=2|143Cs
 * rowspan=2 style="text-align:right" | 55
 * rowspan=2 style="text-align:right" | 88
 * rowspan=2|142.927352(25)
 * rowspan=2|1.791(7) s
 * β− (98.38%)
 * 143Ba
 * rowspan=2|3/2+
 * rowspan=2|
 * β−, n (1.62%)
 * 142Ba
 * rowspan=2|144Cs
 * rowspan=2 style="text-align:right" | 55
 * rowspan=2 style="text-align:right" | 89
 * rowspan=2|143.932077(28)
 * rowspan=2|994(4) ms
 * β− (96.8%)
 * 144Ba
 * rowspan=2|1(−#)
 * rowspan=2|
 * β−, n (3.2%)
 * 143Ba
 * rowspan=2 style="text-indent:1em" | 144mCs
 * rowspan=2 colspan="3" style="text-indent:2em" | 300(200)# keV
 * rowspan=2|<1 s
 * β−
 * 144Ba
 * rowspan=2|(>3)
 * rowspan=2|
 * IT
 * 144Cs
 * rowspan=2|145Cs
 * rowspan=2 style="text-align:right" | 55
 * rowspan=2 style="text-align:right" | 90
 * rowspan=2|144.935526(12)
 * rowspan=2|582(6) ms
 * β− (85.7%)
 * 145Ba
 * rowspan=2|3/2+
 * rowspan=2|
 * β−, n (14.3%)
 * 144Ba
 * rowspan=2|146Cs
 * rowspan=2 style="text-align:right" | 55
 * rowspan=2 style="text-align:right" | 91
 * rowspan=2|145.94029(8)
 * rowspan=2|0.321(2) s
 * β− (85.8%)
 * 146Ba
 * rowspan=2|1−
 * rowspan=2|
 * β−, n (14.2%)
 * 145Ba
 * rowspan=2|147Cs
 * rowspan=2 style="text-align:right" | 55
 * rowspan=2 style="text-align:right" | 92
 * rowspan=2|146.94416(6)
 * rowspan=2|0.235(3) s
 * β− (71.5%)
 * 147Ba
 * rowspan=2|(3/2+)
 * rowspan=2|
 * β−, n (28.49%)
 * 146Ba
 * rowspan=2|148Cs
 * rowspan=2 style="text-align:right" | 55
 * rowspan=2 style="text-align:right" | 93
 * rowspan=2|147.94922(62)
 * rowspan=2|146(6) ms
 * β− (74.9%)
 * 148Ba
 * rowspan=2|
 * rowspan=2|
 * β−, n (25.1%)
 * 147Ba
 * rowspan=2|149Cs
 * rowspan=2 style="text-align:right" | 55
 * rowspan=2 style="text-align:right" | 94
 * rowspan=2|148.95293(21)#
 * rowspan=2|150# ms [>50 ms]
 * β−
 * 149Ba
 * rowspan=2|3/2+#
 * rowspan=2|
 * β−, n
 * 148Ba
 * rowspan=2|150Cs
 * rowspan=2 style="text-align:right" | 55
 * rowspan=2 style="text-align:right" | 95
 * rowspan=2|149.95817(32)#
 * rowspan=2|100# ms [>50 ms]
 * β−
 * 150Ba
 * rowspan=2|
 * rowspan=2|
 * β−, n
 * 149Ba
 * rowspan=2|151Cs
 * rowspan=2 style="text-align:right" | 55
 * rowspan=2 style="text-align:right" | 96
 * rowspan=2|150.96219(54)#
 * rowspan=2|60# ms [>50 ms]
 * β−
 * 151Ba
 * rowspan=2|3/2+#
 * rowspan=2|
 * β−, n
 * 150Ba
 * 141Ba
 * rowspan=2|7/2+
 * rowspan=2|
 * β−, n (.0349%)
 * 140Ba
 * rowspan=2|142Cs
 * rowspan=2 style="text-align:right" | 55
 * rowspan=2 style="text-align:right" | 87
 * rowspan=2|141.924299(11)
 * rowspan=2|1.689(11) s
 * β− (99.9%)
 * 142Ba
 * rowspan=2|0−
 * rowspan=2|
 * β−, n (.091%)
 * 141Ba
 * rowspan=2|143Cs
 * rowspan=2 style="text-align:right" | 55
 * rowspan=2 style="text-align:right" | 88
 * rowspan=2|142.927352(25)
 * rowspan=2|1.791(7) s
 * β− (98.38%)
 * 143Ba
 * rowspan=2|3/2+
 * rowspan=2|
 * β−, n (1.62%)
 * 142Ba
 * rowspan=2|144Cs
 * rowspan=2 style="text-align:right" | 55
 * rowspan=2 style="text-align:right" | 89
 * rowspan=2|143.932077(28)
 * rowspan=2|994(4) ms
 * β− (96.8%)
 * 144Ba
 * rowspan=2|1(−#)
 * rowspan=2|
 * β−, n (3.2%)
 * 143Ba
 * rowspan=2 style="text-indent:1em" | 144mCs
 * rowspan=2 colspan="3" style="text-indent:2em" | 300(200)# keV
 * rowspan=2|<1 s
 * β−
 * 144Ba
 * rowspan=2|(>3)
 * rowspan=2|
 * IT
 * 144Cs
 * rowspan=2|145Cs
 * rowspan=2 style="text-align:right" | 55
 * rowspan=2 style="text-align:right" | 90
 * rowspan=2|144.935526(12)
 * rowspan=2|582(6) ms
 * β− (85.7%)
 * 145Ba
 * rowspan=2|3/2+
 * rowspan=2|
 * β−, n (14.3%)
 * 144Ba
 * rowspan=2|146Cs
 * rowspan=2 style="text-align:right" | 55
 * rowspan=2 style="text-align:right" | 91
 * rowspan=2|145.94029(8)
 * rowspan=2|0.321(2) s
 * β− (85.8%)
 * 146Ba
 * rowspan=2|1−
 * rowspan=2|
 * β−, n (14.2%)
 * 145Ba
 * rowspan=2|147Cs
 * rowspan=2 style="text-align:right" | 55
 * rowspan=2 style="text-align:right" | 92
 * rowspan=2|146.94416(6)
 * rowspan=2|0.235(3) s
 * β− (71.5%)
 * 147Ba
 * rowspan=2|(3/2+)
 * rowspan=2|
 * β−, n (28.49%)
 * 146Ba
 * rowspan=2|148Cs
 * rowspan=2 style="text-align:right" | 55
 * rowspan=2 style="text-align:right" | 93
 * rowspan=2|147.94922(62)
 * rowspan=2|146(6) ms
 * β− (74.9%)
 * 148Ba
 * rowspan=2|
 * rowspan=2|
 * β−, n (25.1%)
 * 147Ba
 * rowspan=2|149Cs
 * rowspan=2 style="text-align:right" | 55
 * rowspan=2 style="text-align:right" | 94
 * rowspan=2|148.95293(21)#
 * rowspan=2|150# ms [>50 ms]
 * β−
 * 149Ba
 * rowspan=2|3/2+#
 * rowspan=2|
 * β−, n
 * 148Ba
 * rowspan=2|150Cs
 * rowspan=2 style="text-align:right" | 55
 * rowspan=2 style="text-align:right" | 95
 * rowspan=2|149.95817(32)#
 * rowspan=2|100# ms [>50 ms]
 * β−
 * 150Ba
 * rowspan=2|
 * rowspan=2|
 * β−, n
 * 149Ba
 * rowspan=2|151Cs
 * rowspan=2 style="text-align:right" | 55
 * rowspan=2 style="text-align:right" | 96
 * rowspan=2|150.96219(54)#
 * rowspan=2|60# ms [>50 ms]
 * β−
 * 151Ba
 * rowspan=2|3/2+#
 * rowspan=2|
 * β−, n
 * 150Ba
 * rowspan=2 style="text-align:right" | 95
 * rowspan=2|149.95817(32)#
 * rowspan=2|100# ms [>50 ms]
 * β−
 * 150Ba
 * rowspan=2|
 * rowspan=2|
 * β−, n
 * 149Ba
 * rowspan=2|151Cs
 * rowspan=2 style="text-align:right" | 55
 * rowspan=2 style="text-align:right" | 96
 * rowspan=2|150.96219(54)#
 * rowspan=2|60# ms [>50 ms]
 * β−
 * 151Ba
 * rowspan=2|3/2+#
 * rowspan=2|
 * β−, n
 * 150Ba
 * β−, n
 * 150Ba
 * 150Ba

Caesium-131
Caesium-131, introduced in 2004 for brachytherapy by Isoray, has a half-life of 9.7 days and 30.4 keV energy.

Caesium-133
Caesium-133 is the only stable isotope of caesium. The SI base unit of time, the second, is defined by a specific caesium-133 transition. Since 1967, the official definition of a second is:

"The second, symbol s, is defined by taking the fixed numerical value of the caesium frequency, $Δν_{Cs}$, the unperturbed ground-state hyperfine transition frequency of the caesium-133 atom, to be $9,192,631,770$ when expressed in the unit Hz, which is equal to s−1."

Caesium-134
Caesium-134 has a half-life of 2.0652 years. It is produced both directly (at a very small yield because 134Xe is stable) as a fission product and via neutron capture from nonradioactive 133Cs (neutron capture cross section 29 barns), which is a common fission product. Caesium-134 is not produced via beta decay of other fission product nuclides of mass 134 since beta decay stops at stable 134Xe. It is also not produced by nuclear weapons because 133Cs is created by beta decay of original fission products only long after the nuclear explosion is over.

The combined yield of 133Cs and 134Cs is given as 6.7896%. The proportion between the two will change with continued neutron irradiation. 134Cs also captures neutrons with a cross section of 140 barns, becoming long-lived radioactive 135Cs.

Caesium-134 undergoes beta decay (β−), producing 134Ba directly and emitting on average 2.23 gamma ray photons (mean energy 0.698 MeV).

Caesium-135
Caesium-135 is a mildly radioactive isotope of caesium with a half-life of 2.3 million years. It decays via emission of a low-energy beta particle into the stable isotope barium-135. Caesium-135 is one of the seven long-lived fission products and the only alkaline one. In most types of nuclear reprocessing, it stays with the medium-lived fission products (including which can only be separated from Cs-135 via isotope separation) rather than with other long-lived fission products. Except in the Molten salt reactor, where Cs-135 is created as a completely separate stream outside the fuel (after the decay of bubble-separated Xe-135). The low decay energy, lack of gamma radiation, and long half-life of 135Cs make this isotope much less hazardous than 137Cs or 134Cs.

Its precursor 135Xe has a high fission product yield (e.g. 6.3333% for 235U and thermal neutrons) but also has the highest known thermal neutron capture cross section of any nuclide. Because of this, much of the 135Xe produced in current thermal reactors (as much as >90% at steady-state full power) will be converted to extremely long-lived (half-life on the order of 1021 years)  before it can decay to  despite the relatively short half life of. Little or no will be destroyed by neutron capture after a reactor shutdown, or in a molten salt reactor that continuously removes xenon from its fuel, a fast neutron reactor, or a nuclear weapon. The xenon pit is a phenomenon of excess neutron absorption through buildup in the reactor after a reduction in power or a shutdown and is often managed by letting the  decay away to a level at which neutron flux can be safely controlled via control rods again.

A nuclear reactor will also produce much smaller amounts of 135Cs from the nonradioactive fission product 133Cs by successive neutron capture to 134Cs and then 135Cs.

The thermal neutron capture cross section and resonance integral of 135Cs are 8.3 ± 0.3 and 38.1 ± 2.6 barns respectively. Disposal of 135Cs by nuclear transmutation is difficult, because of the low cross section as well as because neutron irradiation of mixed-isotope fission caesium produces more 135Cs from stable 133Cs. In addition, the intense medium-term radioactivity of 137Cs makes handling of nuclear waste difficult.
 * ANL factsheet

Caesium-136
Caesium-136 has a half-life of 13.16 days. It is produced both directly (at a very small yield because 136Xe is beta-stable) as a fission product and via neutron capture from long-lived 135Cs (neutron capture cross section 8.702 barns), which is a common fission product. Caesium-136 is not produced via beta decay of other fission product nuclides of mass 136 since beta decay stops at almost-stable 136Xe. It is also not produced by nuclear weapons because 135Cs is created by beta decay of original fission products only long after the nuclear explosion is over. 136Cs also captures neutrons with a cross section of 13.00 barns, becoming medium-lived radioactive 137Cs. Caesium-136 undergoes beta decay (β−), producing 136Ba directly.

Caesium-137
Caesium-137, with a half-life of 30.17 years, is one of the two principal medium-lived fission products, along with 90Sr, which are responsible for most of the radioactivity of spent nuclear fuel after several years of cooling, up to several hundred years after use. It constitutes most of the radioactivity still left from the Chernobyl accident and is a major health concern for decontaminating land near the Fukushima nuclear power plant. 137Cs beta decays to barium-137m (a short-lived nuclear isomer) then to nonradioactive barium-137. Caesium-137 does not emit gamma radiation directly, all observed radiation is due to the daughter isotope barium-137m.

137Cs has a very low rate of neutron capture and cannot yet be feasibly disposed of in this way unless advances in neutron beam collimation (not otherwise achievable by magnetic fields), uniquely available only from within muon catalyzed fusion experiments (not in the other forms of Accelerator Transmutation of Nuclear Waste) enables production of neutrons at high enough intensity to offset and overcome these low capture rates; until then, therefore, 137Cs must simply be allowed to decay.

137Cs has been used as a tracer in hydrologic studies, analogous to the use of 3H.

Other isotopes of caesium
The other isotopes have half-lives from a few days to fractions of a second. Almost all caesium produced from nuclear fission comes from beta decay of originally more neutron-rich fission products, passing through isotopes of iodine then isotopes of xenon. Because these elements are volatile and can diffuse through nuclear fuel or air, caesium is often created far from the original site of fission.

title: Isotopes of caesium