text:
Isotopes of plutonium

Plutonium ($94$Pu) is an artificial element, except for trace quantities resulting from neutron capture by uranium, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. It was synthesized long before being found in nature, the first isotope synthesized being plutonium-238 in 1940. Twenty plutonium radioisotopes have been characterized. The most stable are plutonium-244 with a half-life of 80.8 million years; plutonium-242 with a half-life of 373,300 years; and plutonium-239 with a half-life of 24,110 years; and plutonium-240 with a half-life of 6,560 years. This element also has eight meta states; all have half-lives of less than one second.

Isotopes of plutonium range in atomic weight from 228.0387 u ($228$Pu) to 247.074 u ($247$Pu). The primary decay modes before the most stable isotope, $244$Pu, are spontaneous fission and alpha decay; the primary mode after is beta emission. The primary decay products before $244$Pu are isotopes of uranium and neptunium (not considering fission products), and the primary decay products after are isotopes of americium.

List of isotopes

 * rowspan=2|$228$Pu
 * rowspan=2 style="text-align:right" | 94
 * rowspan=2 style="text-align:right" | 134
 * rowspan=2|228.03874(3)
 * rowspan=2|$1.1 s$
 * α
 * $224$U
 * rowspan=2|0+
 * rowspan=2|
 * β$+$ (rare)
 * $228$Np
 * rowspan=2|$229$Pu
 * rowspan=2 style="text-align:right" | 94
 * rowspan=2 style="text-align:right" | 135
 * rowspan=2|229.04015(6)
 * rowspan=2|91(26) s
 * α (50%)
 * $225$U
 * rowspan=2|3/2+#
 * rowspan=2|
 * β$+$ (50%)
 * $229$Np
 * rowspan=2|$230$Pu
 * rowspan=2 style="text-align:right" | 94
 * rowspan=2 style="text-align:right" | 136
 * rowspan=2|230.039650(16)
 * rowspan=2|1.70(17) min
 * α (>73%)
 * $226$U
 * rowspan=2|0+
 * rowspan=2|
 * β$+$ (<27%)
 * $230$Np
 * rowspan=2|$231$Pu
 * rowspan=2 style="text-align:right" | 94
 * rowspan=2 style="text-align:right" | 137
 * rowspan=2|231.041101(28)
 * rowspan=2|8.6(5) min
 * β$+$ (87%)
 * $231$Np
 * rowspan=2|(3/2+)
 * rowspan=2|
 * α (13%)
 * $227$U
 * rowspan=2|$232$Pu
 * rowspan=2 style="text-align:right" | 94
 * rowspan=2 style="text-align:right" | 138
 * rowspan=2|232.041187(19)
 * rowspan=2|33.7(5) min
 * EC (89%)
 * $232$Np
 * rowspan=2|0+
 * rowspan=2|
 * α (11%)
 * $228$U
 * rowspan=2|$233$Pu
 * rowspan=2 style="text-align:right" | 94
 * rowspan=2 style="text-align:right" | 139
 * rowspan=2|233.04300(5)
 * rowspan=2|20.9(4) min
 * β$+$ (99.88%)
 * $233$Np
 * rowspan=2|5/2+#
 * rowspan=2|
 * α (.12%)
 * $229$U
 * rowspan=2|$234$Pu
 * rowspan=2 style="text-align:right" | 94
 * rowspan=2 style="text-align:right" | 140
 * rowspan=2|234.043317(7)
 * rowspan=2|8.8(1) h
 * EC (94%)
 * $234$Np
 * rowspan=2|0+
 * rowspan=2|
 * α (6%)
 * $230$U
 * rowspan=2|$235$Pu
 * rowspan=2 style="text-align:right" | 94
 * rowspan=2 style="text-align:right" | 141
 * rowspan=2|235.045286(22)
 * rowspan=2|25.3(5) min
 * β$+$ (99.99%)
 * $235$Np
 * rowspan=2|(5/2+)
 * rowspan=2|
 * α (.0027%)
 * $231$U
 * rowspan=3|$236$Pu
 * rowspan=3 style="text-align:right" | 94
 * rowspan=3 style="text-align:right" | 142
 * rowspan=3|236.0460580(24)
 * rowspan=3|2.858(8) y
 * α
 * $232$U
 * rowspan=3|0+
 * rowspan=3|
 * SF (1.37×10$−7$%)
 * (various)
 * CD (2×10$−12$%)
 * $208$Pb $28$Mg
 * rowspan=2|$237$Pu
 * rowspan=2 style="text-align:right" | 94
 * rowspan=2 style="text-align:right" | 143
 * rowspan=2|237.0484097(24)
 * rowspan=2|45.2(1) d
 * EC
 * $237$Np
 * rowspan=2|7/2−
 * rowspan=2|
 * α (.0042%)
 * $233$U
 * style="text-indent:1em" | $237m1$Pu
 * colspan="3" style="text-indent:2em" | 145.544(10)2 keV
 * 180(20) ms
 * IT
 * $237$Pu
 * 1/2+
 * style="text-indent:1em" | $237m2$Pu
 * colspan="3" style="text-indent:2em" | 2900(250) keV
 * 1.1(1) μs
 * rowspan=4|$238$Pu
 * rowspan=4 style="text-align:right" | 94
 * rowspan=4 style="text-align:right" | 144
 * rowspan=4|238.0495599(20)
 * rowspan=4|87.7(1) y
 * α
 * $234$U
 * rowspan=4|0+
 * rowspan=4|Trace
 * SF (1.9×10$238$%)
 * (various)
 * CD (1.4×10$−7$%)
 * $−14$Hg $206$Si
 * CD (6×10$32$%)
 * $−15$Yb $180$Mg $30$Mg
 * rowspan=2|$28$Pu
 * rowspan=2 style="text-align:right" | 94
 * rowspan=2 style="text-align:right" | 145
 * rowspan=2|239.0521634(20)
 * rowspan=2|2.411(3)×104 y
 * α
 * $239$U
 * rowspan=2|1/2+
 * rowspan=2|Trace
 * SF (3.1×10$235$%)
 * (various)
 * style="text-indent:1em" | $238$Pu
 * colspan="3" style="text-indent:2em" | 391.584(3) keV
 * 193(4) ns
 * 7/2−
 * style="text-indent:1em" | $−10$Pu
 * colspan="3" style="text-indent:2em" | 3100(200) keV
 * 7.5(10) μs
 * (5/2+)
 * rowspan=3|$239m1$Pu
 * rowspan=3 style="text-align:right" | 94
 * rowspan=3 style="text-align:right" | 146
 * rowspan=3|240.0538135(20)
 * rowspan=3|6.561(7)×10$239m2$ y
 * α
 * $240$U
 * rowspan=3|0+
 * rowspan=3|Trace
 * SF (5.7×10$3$%)
 * (various)
 * CD (1.3×10$236$%)
 * $244$Hg $−6$Si
 * rowspan=3|$−13$Pu
 * rowspan=3 style="text-align:right" | 94
 * rowspan=3 style="text-align:right" | 147
 * rowspan=3|241.0568515(20)
 * rowspan=3|14.290(6) y
 * β$206$ (99.99%)
 * $34$Am
 * rowspan=3|5/2+
 * rowspan=3|
 * α (.00245%)
 * $241$U
 * SF (2.4×10$−$%)
 * (various)
 * style="text-indent:1em" | $241$Pu
 * colspan="3" style="text-indent:2em" | 161.6(1) keV
 * 0.88(5) μs
 * 1/2+
 * style="text-indent:1em" | $237$Pu
 * colspan="3" style="text-indent:2em" | 2200(200) keV
 * 21(3) μs
 * rowspan=2|$−14$Pu
 * rowspan=2 style="text-align:right" | 94
 * rowspan=2 style="text-align:right" | 148
 * rowspan=2|242.0587426(20)
 * rowspan=2|3.75(2)×10$241m1$ y
 * α
 * $241m2$U
 * rowspan=2|0+
 * rowspan=2|
 * SF (5.5×10$242$%)
 * (various)
 * $5$Pu
 * style="text-align:right" | 94
 * style="text-align:right" | 149
 * 243.062003(3)
 * 4.956(3) h
 * β$238$
 * $−4$Am
 * 7/2+
 * style="text-indent:1em" | $243$Pu
 * colspan="3" style="text-indent:2em" | 383.6(4) keV
 * 330(30) ns
 * (1/2+)
 * rowspan=3|$−$Pu
 * rowspan=3 style="text-align:right" | 94
 * rowspan=3 style="text-align:right" | 150
 * rowspan=3|244.064204(5)
 * rowspan=3|8.00(9)×10$243$ y
 * α (99.88%)
 * $243m$U
 * rowspan=3|0+
 * rowspan=3|Trace
 * SF (.123%)
 * (various)
 * β$244$β$7$ (<7.3×10$240$%)
 * $−$Cm
 * $−$Pu
 * style="text-align:right" | 94
 * style="text-align:right" | 151
 * 245.067747(15)
 * 10.5(1) h
 * β$−9$
 * $244$Am
 * (9/2−)
 * $245$Pu
 * style="text-align:right" | 94
 * style="text-align:right" | 152
 * 246.070205(16)
 * 10.84(2) d
 * β$−$
 * $245$Am
 * 0+
 * $246$Pu
 * style="text-align:right" | 94
 * style="text-align:right" | 153
 * 247.07407(32)#
 * 2.27(23) d
 * β$−$
 * $246m$Am
 * 1/2+#
 * rowspan=2 style="text-align:right" | 148
 * rowspan=2|242.0587426(20)
 * rowspan=2|3.75(2)×10$247$ y
 * α
 * $−$U
 * rowspan=2|0+
 * rowspan=2|
 * SF (5.5×10$247$%)
 * (various)
 * $238$Pu
 * style="text-align:right" | 94
 * style="text-align:right" | 149
 * 243.062003(3)
 * 4.956(3) h
 * β$238$
 * $237$Am
 * 7/2+
 * style="text-indent:1em" | $242$Pu
 * colspan="3" style="text-indent:2em" | 383.6(4) keV
 * 330(30) ns
 * (1/2+)
 * rowspan=3|$239$Pu
 * rowspan=3 style="text-align:right" | 94
 * rowspan=3 style="text-align:right" | 150
 * rowspan=3|244.064204(5)
 * rowspan=3|8.00(9)×10$241$ y
 * α (99.88%)
 * $239$U
 * rowspan=3|0+
 * rowspan=3|Trace
 * SF (.123%)
 * (various)
 * β$240$β$243$ (<7.3×10$244$%)
 * $238$Cm
 * $238$Pu
 * style="text-align:right" | 94
 * style="text-align:right" | 151
 * 245.067747(15)
 * 10.5(1) h
 * β$244$
 * $245$Am
 * (9/2−)
 * $248$Pu
 * style="text-align:right" | 94
 * style="text-align:right" | 152
 * 246.070205(16)
 * 10.84(2) d
 * β$239$
 * $240$Am
 * 0+
 * $241$Pu
 * style="text-align:right" | 94
 * style="text-align:right" | 153
 * 247.07407(32)#
 * 2.27(23) d
 * β$242$
 * $239$Am
 * 1/2+#
 * 246.070205(16)
 * 10.84(2) d
 * β$241$
 * $240$Am
 * 0+
 * $240$Pu
 * style="text-align:right" | 94
 * style="text-align:right" | 153
 * 247.07407(32)#
 * 2.27(23) d
 * β$241$
 * $239$Am
 * 1/2+#
 * $241$Am
 * 1/2+#

Notable isotopes

 * Plutonium-238 has a half-life of 87.74 years and emits alpha particles. Pure $239$Pu for radioisotope thermoelectric generators that power some spacecraft is produced by neutron capture on neptunium-237 but plutonium from spent nuclear fuel can contain as much as a few percent $241$Pu, originating from $241$Np, alpha decay of $241$Cm, or (n,2n) reactions.
 * Plutonium-239 has half-life 24,100 years. $242$Pu and $241$Pu are fissile; meaning their nuclei can split by being bombarded by slow thermal neutrons, releasing energy, gamma radiation and more neutrons. It can therefore sustain a nuclear chain reaction, leading to applications in nuclear weapons and nuclear reactors. $242$Pu is synthesized by irradiating uranium-238 with neutrons in a nuclear reactor, then recovered via nuclear reprocessing of the fuel. Further neutron capture produces successively heavier isotopes.
 * Plutonium-240 has a high rate of spontaneous fission, raising the background neutron radiation of plutonium. Plutonium is graded by proportion of $242$Pu: weapons grade (<7%), fuel grade (7–19%) and reactor grade (>19%). Lower grades are less suited for bombs and thermal reactors but can fuel fast reactors.
 * Plutonium-241 is fissile, but beta decays with a half-life of 14 years to americium-241.
 * Plutonium-242 is not fissile, nor very fertile (requiring 3 more neutron captures to become fissile); and has a low neutron capture cross section, and a longer half-life than any of the lighter isotopes.
 * Plutonium-244 is the most stable isotope of plutonium, with a half-life of about 80 million years. It is not significantly produced in nuclear reactors because $242$Pu has a short half-life, but some is produced in nuclear explosions. $242$Pu has been found in interstellar space and has the second longest half-life of any non-primordial radioisotope.

Production and uses
$239$Pu, a fissile isotope that is the second most used nuclear fuel in nuclear reactors after uranium-235, and the most used fuel in the fission portion of nuclear weapons, is produced from uranium-238 by neutron capture followed by two beta decays.

$242$Pu, $243$Pu, and $243$Pu are produced by further neutron capture. The odd-mass isotopes $244$Pu and $238$Pu have about a 3/4 chance of undergoing fission on capture of a thermal neutron and about a 1/4 chance of retaining the neutron and becoming the next heavier isotope. The even-mass isotopes are fertile but not fissile and also have a lower probability (cross section) of neutron capture; therefore, they tend to accumulate in nuclear fuel used in a thermal reactor, the design of nearly all nuclear power plants today. In plutonium that has been used a second time in thermal reactors in MOX fuel, $238$Pu may even be the most common isotope. All plutonium isotopes and other actinides, however, are fissionable with fast neutrons. $239$Pu does have a moderate thermal neutron absorption cross section, so that $241$Pu production in a thermal reactor becomes a significant fraction as large as $239$Pu production.

$239$Pu has a half-life of 14 years, and has slightly higher thermal neutron cross sections than $239$Pu for both fission and absorption. While nuclear fuel is being used in a reactor, a $239$Pu nucleus is much more likely to fission or to capture a neutron than to decay. $239$Pu accounts for a significant portion of fissions in thermal reactor fuel that has been used for some time. However, in spent nuclear fuel that does not quickly undergo nuclear reprocessing but instead is cooled for years after use, much or most of the $239$Pu will beta decay to americium-241, one of the minor actinides, a strong alpha emitter, and difficult to use in thermal reactors.

$239$Pu has a particularly low cross section for thermal neutron capture; and it takes three neutron absorptions to become another fissile isotope (either curium-245 or $238$Pu) and fission. Even then, there is a chance either of those two fissile isotopes will fail to fission but instead absorb a fourth neutron, becoming curium-246 (on the way to even heavier actinides like californium, which is a neutron emitter by spontaneous fission and difficult to handle) or becoming $−6$Pu again; so the mean number of neutrons absorbed before fission is even higher than 3. Therefore, $9$Pu is particularly unsuited to recycling in a thermal reactor and would be better used in a fast reactor where it can be fissioned directly. However, $−$Pu's low cross section means that relatively little of it will be transmuted during one cycle in a thermal reactor. $−$Pu's half-life is about 15 times as long as $238$Pu's half-life; therefore, it is 1/15 as radioactive and not one of the larger contributors to nuclear waste radioactivity. $235$Pu's gamma ray emissions are also weaker than those of the other isotopes.

$236$Pu has a half-life of only 5 hours, beta decaying to americium-243. Because $236$Pu has little opportunity to capture an additional neutron before decay, the nuclear fuel cycle does not produce the long-lived $236$Pu in significant quantity.

$237$Pu is not normally produced in as large quantity by the nuclear fuel cycle, but some is produced from neptunium-237 by neutron capture (this reaction can also be used with purified neptunium to produce $237$Pu relatively free of other plutonium isotopes for use in radioisotope thermoelectric generators), by the (n,2n) reaction of fast neutrons on $237$Pu, or by alpha decay of curium-242, which is produced by neutron capture of $237$Am. It has significant thermal neutron cross section for fission, but is more likely to capture a neutron and become $238$Pu.

Plutonium-240, -241 and -242
The fission cross section for $238$Pu is 747.9 barns for thermal neutrons, while the activation cross section is 270.7 barns (the ratio approximates to 11 fissions for every 4 neutron captures). The higher plutonium isotopes are created when the uranium fuel is used for a long time. For high burnup used fuel, the concentrations of the higher plutonium isotopes will be higher than the low burnup fuel that is reprocessed to obtain weapons grade plutonium.

Plutonium-239
Plutonium-239 is one of the three fissile materials used for the production of nuclear weapons and in some nuclear reactors as a source of energy. The other fissile materials are uranium-235 and uranium-233. $238$Pu is virtually nonexistent in nature. It is made by bombarding uranium-238 with neutrons. Uranium-238 is present in quantity in most reactor fuel; hence $235$Pu is continuously made in these reactors. Since $−$Pu can itself be split by neutrons to release energy, $−$Pu provides a portion of the energy generation in a nuclear reactor.

Plutonium-238
There are small amounts of $5.8$Pu in the plutonium from usual reactors. However, isotopic separation would be quite expensive compared to another method: when $240$U captures a neutron, it is converted to an excited state of $239$U. Some of the excited $240$U nuclei undergo fission, but some decay to the ground state of $240$U by emitting gamma radiation. Further neutron capture creates $239$U; which, with a half-life of 7 days, decays to ⇭⇭⇭Np. Since nearly all neptunium is produced in this way or consists of isotopes that decay quickly, one gets nearly pure ⇭⇭⇭Np. After chemical separation of neptunium, ⇭⇭⇭Np is again irradiated by reactor neutrons to be converted to ⇭⇭⇭Np, which decays to ⇭⇭⇭Pu with a half-life of 2 days.

Plutonium-240 as an obstacle to nuclear weapons
Plutonium-240 undergoes spontaneous fission at a small but significant rate (⇭⇭⇭%). The presence of ⇭⇭⇭Pu limits the plutonium's use in a nuclear bomb, because a neutron from spontaneous fission starts the chain reaction prematurely, causing an early release of energy that disperses the core before full implosion is reached. This prevents most of the core from participation in the chain reaction and reduces the bomb's yield.

Plutonium consisting of more than about 90% ⇭⇭⇭Pu is called weapons-grade plutonium; plutonium from spent nuclear fuel from commercial power reactors generally contains at least 20% ⇭⇭⇭Pu and is called reactor-grade plutonium. However, modern nuclear weapons use fusion boosting, which mitigates the predetonation problem; if the pit can generate a nuclear weapon yield of even a fraction of a kiloton, which is enough to start deuterium–tritium fusion, the resulting burst of neutrons will fission enough plutonium to ensure a yield of tens of kilotons.

Contamination due to ⇭⇭⇭Pu is the reason plutonium weapons must use the implosion method. Theoretically, pure ⇭⇭⇭Pu could be used in a gun-type bomb, but achieving this level of purity is prohibitively difficult. Plutonium-240 contamination has proven a mixed blessing. While it created delays and headaches during the Manhattan Project because of the need to develop implosion technology, those same difficulties are a barrier to nuclear proliferation. Implosion bombs are also inherently more efficient and less prone to accidental detonation than are gun-type bombs.

title: Isotopes of plutonium


text:
Isotopes of americium

Americium (95Am) is an artificial element, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no known stable isotopes. The first isotope to be synthesized was 241Am in 1944. The artificial element decays by ejecting alpha particles. Americium has an atomic number of 95 (the number of protons in the nucleus of the americium atom). Despite being an order of magnitude longer lived than, the former is harder to obtain than the latter as more of it is present in spent nuclear fuel.

Eighteen radioisotopes of americium, ranging from 230Am to 247Am with the exception of 231Am, have been characterized; another isotope, 223Am, has also been reported but is unconfirmed. The most stable isotopes are 243Am with a half-life of 7,370 years and 241Am with a half-life of 432.2 years. All of the remaining radioactive isotopes have half-lives that are less than 51 hours, and the majority of these have half-lives that are less than 100 minutes. This element also has 8 meta states, with the most stable being 242m1Am (t1/2 = 141 years). This isomer is unusual in that its half life is far longer than that of the ground state of the same isotope.

List of isotopes

 * 223Am
 * style="text-align:right" | 95
 * style="text-align:right" | 128
 * 223.04584(32)#
 * 10(9) ms
 * α
 * 219Np
 * 9/2–#
 * 229Am
 * style="text-align:right" | 95
 * style="text-align:right" | 134
 * 229.04528(11)
 * 1.8(15) s
 * α
 * 225Np
 * 5/2–#
 * rowspan=2 | 230Am
 * rowspan=2 style="text-align:right" | 95
 * rowspan=2 style="text-align:right" | 135
 * rowspan=2 | 230.04603(15)#
 * rowspan=2 | 40(9) s
 * β+ (<70%)
 * 230Pu
 * rowspan=2 | 1–#
 * β+SF (>30%)
 * (various)
 * rowspan=3 | 232Am
 * rowspan=3 style="text-align:right" | 95
 * rowspan=3 style="text-align:right" | 137
 * rowspan=3 | 232.04661(32)#
 * rowspan=3 | 1.31(4) min
 * β+ (97%)
 * 232Pu
 * rowspan=3 | 1–#
 * α (3%)
 * 228Np
 * β+SF (0.069%)
 * (various)
 * rowspan=2 | 233Am
 * rowspan=2 style="text-align:right" | 95
 * rowspan=2 style="text-align:right" | 138
 * rowspan=2 | 233.04647(12)#
 * rowspan=2 | 3.2(8) min
 * β+ (95.5%)
 * 233Pu
 * rowspan=2 | 5/2–#
 * α (4.5%)
 * 229Np
 * rowspan=3 | 234Am
 * rowspan=3 style="text-align:right" | 95
 * rowspan=3 style="text-align:right" | 139
 * rowspan=3 | 234.04773(17)#
 * rowspan=3 | 2.32(8) min
 * β+ (99.95%)
 * 234Pu
 * rowspan=3 | 0–#
 * α (0.039%)
 * 230Np
 * β+, SF (0.0066%)
 * (various)
 * rowspan=2 | 235Am
 * rowspan=2 style="text-align:right" | 95
 * rowspan=2 style="text-align:right" | 140
 * rowspan=2 | 235.047906(57)
 * rowspan=2 | 10.3(6) min
 * β+ (99.60%)
 * 235Pu
 * rowspan=2 | 5/2−#
 * α (0.40%)
 * 231Np
 * rowspan=2 | 236Am
 * rowspan=2 style="text-align:right" | 95
 * rowspan=2 style="text-align:right" | 141
 * rowspan=2 | 236.04943(13)#
 * rowspan=2 | 3.6(1) min
 * β+
 * 236Pu
 * rowspan=2 | 5−
 * α (4×10−3%)
 * 232Np
 * rowspan=2 | 236mAm
 * rowspan=2 colspan=3 | 50(50)# keV
 * rowspan=2 | 2.9(2) min
 * β+
 * 236Pu
 * rowspan=2 | (1−)
 * α ?
 * 232Np
 * rowspan=2 | 237Am
 * rowspan=2 style="text-align:right" | 95
 * rowspan=2 style="text-align:right" | 142
 * rowspan=2 | 237.049995(64)#
 * rowspan=2 | 73.6(8) min
 * β+ (99.975%)
 * 237Pu
 * rowspan=2 | 5/2−
 * α (.025%)
 * 233Np
 * rowspan=2 | 238Am
 * rowspan=2 style="text-align:right" | 95
 * rowspan=2 style="text-align:right" | 143
 * rowspan=2 | 238.051983(63)
 * rowspan=2 | 98(3) min
 * β+
 * 238Pu
 * rowspan=2 | 1+
 * α (1.0×10−4%)
 * 234Np
 * rowspan=2 style="text-indent:1em" | 238mAm
 * rowspan=2 colspan="3" style="text-indent:2em" | 2500(200)# keV
 * rowspan=2 | 35(18) μs
 * SF
 * (various)
 * rowspan=2 |
 * IT ?
 * 238Am
 * rowspan=2 | 239Am
 * rowspan=2 style="text-align:right" | 95
 * rowspan=2 style="text-align:right" | 144
 * rowspan=2 | 239.0530227(21)
 * rowspan=2 | 11.9(1) h
 * EC (99.99%)
 * 239Pu
 * rowspan=2 | 5/2−
 * α (0.01%)
 * 235Np
 * rowspan=2 style="text-indent:1em" | 239mAm
 * rowspan=2 colspan="3" style="text-indent:2em" | 2500(200) keV
 * rowspan=2 | 163(12) ns
 * SF
 * (various)
 * rowspan=2 | (7/2+)
 * IT ?
 * 239Am
 * rowspan=2 | 240Am
 * rowspan=2 style="text-align:right" | 95
 * rowspan=2 style="text-align:right" | 145
 * rowspan=2 | 240.055298(15)
 * rowspan=2 | 50.8(3) h
 * β+
 * 240Pu
 * rowspan=2 | (3−)
 * α (1.9×10−4%)
 * 236Np
 * rowspan=2 style="text-indent:1em" | 240mAm
 * rowspan=2 colspan="3" style="text-indent:2em" | 3000(200) keV
 * rowspan=2 | 940(40) μs
 * SF
 * (various)
 * rowspan=2 |
 * IT ?
 * 240Am
 * rowspan=2 | 241Am
 * rowspan=2 style="text-align:right" | 95
 * rowspan=2 style="text-align:right" | 146
 * rowspan=2 | 241.0568273(12)
 * rowspan=2 | 432.6(6) y
 * α
 * 237Np
 * rowspan=2 | 5/2−
 * SF (3.6×10−10%)
 * (various)
 * style="text-indent:1em" | 241mAm
 * colspan="3" style="text-indent:2em" | 2200(200) keV
 * 1.2(3) μs
 * SF
 * (various)
 * rowspan=2 | 242Am
 * rowspan=2 style="text-align:right" | 95
 * rowspan=2 style="text-align:right" | 147
 * rowspan=2 | 242.0595474(12)
 * rowspan=2 | 16.02(2) h
 * β− (82.7%)
 * 242Cm
 * rowspan=2 | 1−
 * EC (17.3%)
 * 242Pu
 * rowspan=3 style="text-indent:1em" | 242m1Am
 * rowspan=3 colspan="3" style="text-indent:2em" | 48.60(5) keV
 * rowspan=3 | 141(2) y
 * IT (99.54%)
 * 242Am
 * rowspan=3 | 5−
 * α (.46%)
 * 238Np
 * SF ?
 * (various)
 * rowspan=2 style="text-indent:1em" | 242m2Am
 * rowspan=2 colspan="3" style="text-indent:2em" | 2200(80) keV
 * rowspan=2 | 14.0(10) ms
 * SF
 * (various)
 * rowspan=2 | (2+, 3−)
 * IT ?
 * 242Am
 * rowspan=2 | 243Am
 * rowspan=2 style="text-align:right" | 95
 * rowspan=2 style="text-align:right" | 148
 * rowspan=2 | 243.0613799(15)
 * rowspan=2 | 7,350(9) y
 * α
 * 239Np
 * rowspan=2 | 5/2−
 * SF (3.7×10−9%)
 * (various)
 * rowspan=2 style="text-indent:1em" | 243mAm
 * rowspan=2 colspan="3" style="text-indent:2em" | 2300(200) keV
 * rowspan=2 | 5.5(5) μs
 * SF
 * (various)
 * rowspan=2 |
 * IT ?
 * 243Am
 * 244Am
 * style="text-align:right" | 95
 * style="text-align:right" | 149
 * 244.0642829(16)
 * 10.01(3) h
 * β−
 * 244Cm
 * (6−)
 * rowspan=2 style="text-indent:1em" | 244m1Am
 * rowspan=2 colspan="3" style="text-indent:2em" | 89.3(16) keV
 * rowspan=2 | 26.13(43) min
 * β− (99.96%)
 * 244Cm
 * rowspan=2 | 1+
 * EC (0.0364%)
 * 244Pu
 * rowspan=2 style="text-indent:1em" | 244m2Am
 * rowspan=2 colspan="3" style="text-indent:2em" | 2000(200)#
 * rowspan=2 | 900(150) μs
 * SF
 * (various)
 * rowspan=2 |
 * IT ?
 * 244Am
 * rowspan=2 style="text-indent:1em" | 244m3Am
 * rowspan=2 colspan="3" style="text-indent:2em" | 2200(200)#
 * rowspan=2 | ~6.5 μs
 * SF
 * (various)
 * rowspan=2 |
 * IT ?
 * 244Am
 * 245Am
 * style="text-align:right" | 95
 * style="text-align:right" | 150
 * 245.0664528(20)
 * 2.05(1) h
 * β−
 * 245Cm
 * 5/2+
 * rowspan=2 style="text-indent:1em" | 245mAm
 * rowspan=2 colspan="3" style="text-indent:2em" | 2400(400)#
 * rowspan=2 | 640(60) ns
 * SF
 * (various)
 * rowspan=2 |
 * IT ?
 * 245Am
 * 246Am
 * style="text-align:right" | 95
 * style="text-align:right" | 151
 * 246.069774(19)#
 * 39(3) min
 * β−
 * 246Cm
 * (7−)
 * rowspan=2 style="text-indent:1em" | 246m1Am
 * rowspan=2 colspan="3" style="text-indent:2em" | 30(10)# keV
 * rowspan=2 | 25.0(2) min
 * β−
 * 246Cm
 * rowspan=2 | 2(−)
 * IT ?
 * 246Am
 * rowspan=2 style="text-indent:1em" | 246m2Am
 * rowspan=2 colspan="3" style="text-indent:2em" | 2000(800)# keV
 * rowspan=2 | 73(10) μs
 * SF
 * (various)
 * rowspan=2 |
 * IT ?
 * 246Am
 * 247Am
 * style="text-align:right" | 95
 * style="text-align:right" | 152
 * 247.07209(11)#
 * 23.0(13) min
 * β−
 * 247Cm
 * 5/2#
 * SF
 * (various)
 * rowspan=2 |
 * IT ?
 * 244Am
 * 245Am
 * style="text-align:right" | 95
 * style="text-align:right" | 150
 * 245.0664528(20)
 * 2.05(1) h
 * β−
 * 245Cm
 * 5/2+
 * rowspan=2 style="text-indent:1em" | 245mAm
 * rowspan=2 colspan="3" style="text-indent:2em" | 2400(400)#
 * rowspan=2 | 640(60) ns
 * SF
 * (various)
 * rowspan=2 |
 * IT ?
 * 245Am
 * 246Am
 * style="text-align:right" | 95
 * style="text-align:right" | 151
 * 246.069774(19)#
 * 39(3) min
 * β−
 * 246Cm
 * (7−)
 * rowspan=2 style="text-indent:1em" | 246m1Am
 * rowspan=2 colspan="3" style="text-indent:2em" | 30(10)# keV
 * rowspan=2 | 25.0(2) min
 * β−
 * 246Cm
 * rowspan=2 | 2(−)
 * IT ?
 * 246Am
 * rowspan=2 style="text-indent:1em" | 246m2Am
 * rowspan=2 colspan="3" style="text-indent:2em" | 2000(800)# keV
 * rowspan=2 | 73(10) μs
 * SF
 * (various)
 * rowspan=2 |
 * IT ?
 * 246Am
 * 247Am
 * style="text-align:right" | 95
 * style="text-align:right" | 152
 * 247.07209(11)#
 * 23.0(13) min
 * β−
 * 247Cm
 * 5/2#
 * 246Am
 * 247Am
 * style="text-align:right" | 95
 * style="text-align:right" | 152
 * 247.07209(11)#
 * 23.0(13) min
 * β−
 * 247Cm
 * 5/2#
 * 5/2#

Americium-241

Americium-241 is the most prevalent isotope of americium in nuclear waste. It is the isotope used in an americium smoke detector based on an ionization chamber. It is a potential fuel for long-lifetime radioisotope thermoelectric generators.

Possible parent nuclides: beta from 241Pu, electron capture from 241Cm, alpha from 245Bk.

Americium-241 decays by alpha emission, with a by-product of gamma rays. Its presence in plutonium is determined by the original concentration of plutonium-241 and the sample age. Because of the low penetration of alpha radiation, Americium-241 only poses a health risk when ingested or inhaled. Older samples of plutonium containing plutonium-241 contain a buildup of 241Am. A chemical removal of americium from reworked plutonium (e.g. during reworking of plutonium pits) may be required.

Americium-242m

Americium-242m has a mass of 242.0595492 g/mol. It is one of the rare cases, like 108mAg, 166mHo, 180mTa, 186mRe, 192mIr, 210mBi, 212mPo and others, where a higher-energy nuclear isomer is more stable than the ground state, americium-242.

242mAm is fissile and has a low critical mass, comparable to that of 239Pu. It has a very high cross section for fission, and is quickly destroyed if it is produced in a nuclear reactor. Work has been done investigating if this isotope could be used for a novel type of nuclear rocket.

Americium-243
Americium-243 has a mass of 243.06138 g/mol and a half-life of 7,370 years, the longest lasting of all americium isotopes. It is formed in the nuclear fuel cycle by neutron capture on plutonium-242 followed by beta decay. Production increases exponentially with increasing burnup as a total of 5 neutron captures on $238$U are required. If MOX-fuel is used, particularly MOX-fuel high in and, more americium overall and more  will be produced.

It decays by either emitting an alpha particle (with a decay energy of 5.27 MeV) to become $239$Np, which then quickly decays to $239$Pu, or rarely, by spontaneous fission.

As for the other americium isotopes, and more generally for all alpha emitters, $243$Am is carcinogenic in case of internal contamination after being inhaled or ingested. $243$Am also presents a risk of external irradiation associated with the gamma ray emitted by its short-lived decay product $239$Np. The external irradiation risk for the other two americium isotopes ($241$Am and $242m$Am) is less than 10% of that for americium-243.

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

title: Isotopes of americium


text:
Isotopes of curium

Curium (96Cm) is an artificial element with an atomic number of 96. Because it is an artificial element, a standard atomic weight cannot be given, and it has no stable isotopes. The first isotope synthesized was 242Cm in 1944, which has 146 neutrons.

There are 19 known radioisotopes ranging from 233Cm to 251Cm. There are also ten known nuclear isomers. The longest-lived isotope is 247Cm, with half-life 15.6 million years – orders of magnitude longer than that of any known isotope beyond curium, and long enough to study as a possible extinct radionuclide that would be produced by the r-process. The longest-lived isomer is 246mCm with a half-life of 1.12 seconds.

List of isotopes

 * rowspan=2|233Cm
 * rowspan=2 style="text-align:right" | 96
 * rowspan=2 style="text-align:right" | 137
 * rowspan=2|233.05077(8)
 * rowspan=2|$23 s$
 * β+ (80%)
 * 233Am
 * rowspan=2|3/2+#
 * α (20%)
 * 229Pu
 * rowspan=3|234Cm
 * rowspan=3 style="text-align:right" | 96
 * rowspan=3 style="text-align:right" | 138
 * rowspan=3|234.05016(2)
 * rowspan=3|52(9) s
 * β+ (71%)
 * 234Am
 * rowspan=3|0+
 * α (27%)
 * 230Pu
 * SF (2%)
 * (various)
 * rowspan=2|235Cm
 * rowspan=2 style="text-align:right" | 96
 * rowspan=2 style="text-align:right" | 139
 * rowspan=2|235.05143(22)#
 * rowspan=2|$300 s$
 * β+ (99.0%)
 * 235Am
 * rowspan=2|(5/2+)
 * α (1.0%)
 * 231Pu
 * rowspan=3|236Cm
 * rowspan=3 style="text-align:right" | 96
 * rowspan=3 style="text-align:right" | 140
 * rowspan=3|236.05141(22)#
 * rowspan=3|6.8(8) min
 * β+ (82%)
 * 236Am
 * rowspan=3|0+
 * α (18%)
 * 232Pu
 * SF (<0.1%)
 * (various)
 * rowspan=2|237Cm
 * rowspan=2 style="text-align:right" | 96
 * rowspan=2 style="text-align:right" | 141
 * rowspan=2|237.05290(22)#
 * rowspan=2|>660 s
 * β+
 * 237Am
 * rowspan=2|(5/2+)
 * α (<1%)
 * 233Pu
 * rowspan=2|238Cm
 * rowspan=2 style="text-align:right" | 96
 * rowspan=2 style="text-align:right" | 142
 * rowspan=2|238.05303(4)
 * rowspan=2|2.2(4) h
 * EC (~94%)
 * 238Am
 * rowspan=2|0+
 * α (~6%)
 * 234Pu
 * rowspan=2|239Cm
 * rowspan=2 style="text-align:right" | 96
 * rowspan=2 style="text-align:right" | 143
 * rowspan=2|239.05496(11)#
 * rowspan=2|2.5(4) h
 * β+
 * 239Am
 * rowspan=2|(7/2−)
 * α (6.2x10−3%)
 * 235Pu
 * rowspan=3|240Cm
 * rowspan=3 style="text-align:right" | 96
 * rowspan=3 style="text-align:right" | 144
 * rowspan=3|240.0555295(25)
 * rowspan=3|27(1) d
 * α (99.5%)
 * 236Pu
 * rowspan=3|0+
 * EC (.5%)
 * 240Am
 * SF (3.9×10−6%)
 * (various)
 * rowspan=2|241Cm
 * rowspan=2 style="text-align:right" | 96
 * rowspan=2 style="text-align:right" | 145
 * rowspan=2|241.0576530(23)
 * rowspan=2|32.8(2) d
 * EC (99%)
 * 241Am
 * rowspan=2|1/2+
 * α (1%)
 * 237Pu
 * rowspan=3|242Cm
 * rowspan=3 style="text-align:right" | 96
 * rowspan=3 style="text-align:right" | 146
 * rowspan=3|242.0588358(20)
 * rowspan=3|162.8(2) d
 * α
 * 238Pu
 * rowspan=3|0+
 * SF (6.33×10−6%)
 * (various)
 * CD (10−14%)
 * 208Pb 34Si
 * style="text-indent:1em" | 242mCm
 * colspan="3" style="text-indent:2em" | 2800(100) keV
 * 180(70) ns
 * rowspan=3|243Cm
 * rowspan=3 style="text-align:right" | 96
 * rowspan=3 style="text-align:right" | 147
 * rowspan=3|243.0613891(22)
 * rowspan=3|29.1(1) y
 * α (99.71%)
 * 239Pu
 * rowspan=3|5/2+
 * EC (.29%)
 * 243Am
 * SF (5.3×10−9%)
 * (various)
 * style="text-indent:1em" | 243mCm
 * colspan="3" style="text-indent:2em" | 87.4(1) keV
 * 1.08(3) μs
 * IT
 * 243Cm
 * 1/2+
 * rowspan=2|244Cm
 * rowspan=2 style="text-align:right" | 96
 * rowspan=2 style="text-align:right" | 148
 * rowspan=2|244.0627526(20)
 * rowspan=2|18.10(2) y
 * α
 * 240Pu
 * rowspan=2|0+
 * SF (1.34×10−4%)
 * (various)
 * style="text-indent:1em" | 244m1Cm
 * colspan="3" style="text-indent:2em" | 1040.188(12) keV
 * 34(2) ms
 * IT
 * 244Cm
 * 6+
 * style="text-indent:1em" | 244m2Cm
 * colspan="3" style="text-indent:2em" | 1100(900)# keV
 * >500 ns
 * SF
 * (various)
 * rowspan=2|245Cm
 * rowspan=2 style="text-align:right" | 96
 * rowspan=2 style="text-align:right" | 149
 * rowspan=2|245.0654912(22)
 * rowspan=2|8.5(1)×103 y
 * α
 * 241Pu
 * rowspan=2|7/2+
 * SF (6.1×10−7%)
 * (various)
 * style="text-indent:1em" | 245mCm
 * colspan="3" style="text-indent:2em" | 355.92(10) keV
 * 290(20) ns
 * IT
 * 245Cm
 * 1/2+
 * rowspan=2|246Cm
 * rowspan=2 style="text-align:right" | 96
 * rowspan=2 style="text-align:right" | 150
 * rowspan=2|246.0672237(22)
 * rowspan=2|4.76(4)×103 y
 * α (99.97%)
 * 242Pu
 * rowspan=2|0+
 * SF (.0261%)
 * (various)
 * style="text-indent:1em" | 246mCm
 * colspan="3" style="text-indent:2em" | 1179.66(13) keV
 * 1.12(0.24) s
 * IT
 * 246Cm
 * 8−
 * 247Cm
 * style="text-align:right" | 96
 * style="text-align:right" | 151
 * 247.070354(5)
 * 1.56(5)×107 y
 * α
 * 243Pu
 * 9/2−
 * style="text-indent:1em" | 247m1Cm
 * colspan="3" style="text-indent:2em" | 227.38(19) keV
 * 26.3(0.3) μs
 * IT
 * 247Cm
 * 5/2+
 * style="text-indent:1em" | 247m2Cm
 * colspan="3" style="text-indent:2em" | 404.90(3) keV
 * 100.6(0.6) ns
 * IT
 * 247Cm
 * 1/2+
 * rowspan=2|248Cm
 * rowspan=2 style="text-align:right" | 96
 * rowspan=2 style="text-align:right" | 152
 * rowspan=2|248.072349(5)
 * rowspan=2|3.48(6)×105 y
 * α (91.74%)
 * 244Pu
 * rowspan=2|0+
 * SF (8.26%)
 * (various)
 * style="text-indent:1em" | 248mCm
 * colspan="3" style="text-indent:2em" | 1458.1(1) keV
 * 146(18) μs
 * IT
 * 248Cm
 * (8−)
 * 249Cm
 * style="text-align:right" | 96
 * style="text-align:right" | 153
 * 249.075953(5)
 * 64.15(3) min
 * β−
 * 249Bk
 * 1/2(+)
 * style="text-indent:1em" | 249mCm
 * colspan="3" style="text-indent:2em" | 48.758(17) keV
 * 23 μs
 * α
 * 245Pu
 * (7/2+)
 * rowspan=3|250Cm
 * rowspan=3 style="text-align:right" | 96
 * rowspan=3 style="text-align:right" | 154
 * rowspan=3|250.078357(12)
 * rowspan=3|8300# y
 * SF (74%)
 * (various)
 * rowspan=3|0+
 * α (18%)
 * 246Pu
 * β− (8%)
 * 250Bk
 * 251Cm
 * style="text-align:right" | 96
 * style="text-align:right" | 155
 * 251.082285(24)
 * 16.8(2) min
 * β−
 * 251Bk
 * (1/2+)
 * rowspan=2|248.072349(5)
 * rowspan=2|3.48(6)×105 y
 * α (91.74%)
 * 244Pu
 * rowspan=2|0+
 * SF (8.26%)
 * (various)
 * style="text-indent:1em" | 248mCm
 * colspan="3" style="text-indent:2em" | 1458.1(1) keV
 * 146(18) μs
 * IT
 * 248Cm
 * (8−)
 * 249Cm
 * style="text-align:right" | 96
 * style="text-align:right" | 153
 * 249.075953(5)
 * 64.15(3) min
 * β−
 * 249Bk
 * 1/2(+)
 * style="text-indent:1em" | 249mCm
 * colspan="3" style="text-indent:2em" | 48.758(17) keV
 * 23 μs
 * α
 * 245Pu
 * (7/2+)
 * rowspan=3|250Cm
 * rowspan=3 style="text-align:right" | 96
 * rowspan=3 style="text-align:right" | 154
 * rowspan=3|250.078357(12)
 * rowspan=3|8300# y
 * SF (74%)
 * (various)
 * rowspan=3|0+
 * α (18%)
 * 246Pu
 * β− (8%)
 * 250Bk
 * 251Cm
 * style="text-align:right" | 96
 * style="text-align:right" | 155
 * 251.082285(24)
 * 16.8(2) min
 * β−
 * 251Bk
 * (1/2+)
 * 251Cm
 * style="text-align:right" | 96
 * style="text-align:right" | 155
 * 251.082285(24)
 * 16.8(2) min
 * β−
 * 251Bk
 * (1/2+)

title: Isotopes of curium


text:
Isotopes of berkelium

Berkelium (97Bk) is an artificial element, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 243Bk in 1949. There are twenty known radioisotopes, from 233Bk and 233Bk to 253Bk (except 235Bk and 237Bk), and six nuclear isomers. The longest-lived isotope is 247Bk with a half-life of 1,380 years.

List of isotopes

 * rowspan=2|233Bk
 * rowspan=2 style="text-align:right" | 97
 * rowspan=2 style="text-align:right" | 136
 * rowspan=2|233.05665(25)#
 * rowspan=2|40(30) s
 * α
 * 229Am
 * rowspan=2|3/2-#
 * β+?
 * 233Cm
 * rowspan=3|234Bk
 * rowspan=3 style="text-align:right" | 97
 * rowspan=3 style="text-align:right" | 137
 * rowspan=3|234.05732(16)#
 * rowspan=3|20(5) s
 * α (>80%)
 * 230Am
 * rowspan=3|3-#
 * β+ (<20%)
 * 234Cm
 * β+, SF?
 * (various)
 * rowspan=3|236Bk
 * rowspan=3 style="text-align:right" | 97
 * rowspan=3 style="text-align:right" | 139
 * rowspan=3|236.05748(39)#
 * rowspan=3|26(10) s
 * β+ (99.96%)
 * 236Cm
 * rowspan=2|4+#
 * β+, SF (0.04%)
 * (various)
 * α?
 * 232Am
 * rowspan=3|238Bk
 * rowspan=3 style="text-align:right" | 97
 * rowspan=3 style="text-align:right" | 141
 * rowspan=3|238.05820(28)#
 * rowspan=3|2.40(8) min
 * β+ (99.95%)
 * 238Cm
 * rowspan=3| 1#
 * β+, SF (0.048%)
 * (various)
 * α?
 * 234Am
 * rowspan=3|239Bk
 * rowspan=3 style="text-align:right" | 97
 * rowspan=3 style="text-align:right" | 142
 * rowspan=3|239.05824(22)#
 * rowspan=3|100# s
 * β+
 * 239Cm
 * rowspan=3|(7/2+)
 * α?
 * 235Am
 * SF?
 * (various)
 * rowspan=3|240Bk
 * rowspan=3 style="text-align:right" | 97
 * rowspan=3 style="text-align:right" | 143
 * rowspan=3|240.05976(16)#
 * rowspan=3|4.8(8) min
 * β+?
 * 240Cm
 * rowspan=3|7−#
 * β+, SF (0.0020%)
 * (various)
 * α?
 * 236Am
 * rowspan=2|241Bk
 * rowspan=2 style="text-align:right" | 97
 * rowspan=2 style="text-align:right" | 144
 * rowspan=2|241.06010(18)#
 * rowspan=2|4.6(4) min
 * β+?
 * 241Cm
 * rowspan=2|(7/2+)
 * α?
 * 237Am
 * rowspan=3|242Bk
 * rowspan=3 style="text-align:right" | 97
 * rowspan=3 style="text-align:right" | 145
 * rowspan=3|242.06198(22)#
 * rowspan=3|7.0(13) min
 * β+
 * 242Cm
 * rowspan=3|3+#
 * β+, SF (<3×10−5%)
 * (various)
 * α?
 * 238Am
 * rowspan=2 style="text-indent:1em" | 242mBk
 * rowspan=2 colspan="3" style="text-indent:2em" | 2000(200)# keV
 * rowspan=2|600(100) ns
 * SF
 * (various)
 * rowspan=2|
 * IT?
 * 242Bk
 * rowspan=2|243Bk
 * rowspan=2 style="text-align:right" | 97
 * rowspan=2 style="text-align:right" | 146
 * rowspan=2|243.0630059(49)
 * rowspan=2|4.6(2) h
 * β+ (99.85%)
 * 243Cm
 * rowspan=2|3/2−
 * α (.15%)
 * 239Am
 * rowspan=2|244Bk
 * rowspan=2 style="text-align:right" | 97
 * rowspan=2 style="text-align:right" | 147
 * rowspan=2|244.065179(15)
 * rowspan=2|5.02(3) h
 * β+?
 * 244Cm
 * rowspan=2|4−
 * α (0.006%)
 * 240Am
 * rowspan=2 style="text-indent:1em" | 244mBk
 * rowspan=2 colspan="3" style="text-indent:2em" | 1500(500)# keV
 * rowspan=2|820(60) ns
 * SF
 * (various)
 * rowspan=2|
 * IT?
 * 244Bk
 * rowspan=2|245Bk
 * rowspan=2 style="text-align:right" | 97
 * rowspan=2 style="text-align:right" | 148
 * rowspan=2|245.0663598(19)
 * rowspan=2|4.95(3) d
 * EC (99.88%)
 * 245Cm
 * rowspan=2|3/2−
 * α (.12%)
 * 241Am
 * rowspan=2|246Bk
 * rowspan=2 style="text-align:right" | 97
 * rowspan=2 style="text-align:right" | 149
 * rowspan=2|246.068671(64)
 * rowspan=2|1.80(2) d
 * β+
 * 246Cm
 * rowspan=2|2(−)
 * α?
 * 242Am
 * rowspan=2|247Bk
 * rowspan=2 style="text-align:right" | 97
 * rowspan=2 style="text-align:right" | 150
 * rowspan=2|247.0703059(56)
 * rowspan=2|1.38(25)×103 y
 * α
 * 243Am
 * rowspan=2|3/2−
 * SF?
 * (various)
 * rowspan=2|248Bk
 * rowspan=2 style="text-align:right" | 97
 * rowspan=2 style="text-align:right" | 151
 * rowspan=2|248.073142(54)
 * rowspan=2|>9 y
 * α?
 * 244Am
 * rowspan=2|6+#
 * EC?
 * 248Cm
 * rowspan=3 style="text-indent:1em" | 248mBk
 * rowspan=3 colspan="3" style="text-indent:2em" | −20(50) keV
 * rowspan=3| 23.7(2) h
 * β− (70%)
 * 248Cf
 * rowspan=3| 1(−)
 * EC (30%)
 * 248Cm
 * α?
 * 244Am
 * rowspan=3|249Bk
 * rowspan=3 style="text-align:right" | 97
 * rowspan=3 style="text-align:right" | 152
 * rowspan=3|249.0749831(13)
 * rowspan=3|327.2(3) d
 * β−
 * 249Cf
 * rowspan=3|7/2+
 * α (.00145%)
 * 245Am
 * SF (4.7×10−8%)
 * (various)
 * style="text-indent:1em" | 249mBk
 * colspan="3" style="text-indent:2em" | 8.777(14) keV
 * 300 μs
 * IT
 * 249Bk
 * 3/2−
 * 250Bk
 * style="text-align:right" | 97
 * style="text-align:right" | 153
 * 250.0783172(31)
 * 3.212(5) h
 * β−
 * 250Cf
 * 2−
 * style="text-indent:1em" | 250m1Bk
 * colspan="3" style="text-indent:2em" | 35.59(10) keV
 * 29(1) μs
 * IT
 * 250Bk
 * 4+
 * style="text-indent:1em" | 250m2Bk
 * colspan="3" style="text-indent:2em" | 85.6(16) keV
 * 213(8) μs
 * IT
 * 250Bk
 * 7+
 * 251Bk
 * style="text-align:right" | 97
 * style="text-align:right" | 154
 * 251.080761(12)
 * 55.6(11) min
 * β−
 * 251Cf
 * (3/2−)
 * style="text-indent:1em" | 251mBk
 * colspan="3" style="text-indent:2em" | 35.5(13) keV
 * 58(4) μs
 * IT
 * 251Bk
 * (7/2+)
 * rowspan=2|252Bk
 * rowspan=2 style="text-align:right" | 97
 * rowspan=2 style="text-align:right" | 155
 * rowspan=2|252.08431(22)#
 * rowspan=2|1.8(5) min
 * β−?
 * 252Cf
 * rowspan=2|
 * α?
 * 248Am
 * 253Bk
 * style="text-align:right" | 97
 * style="text-align:right" | 156
 * 253.08688(39)#
 * 60# min
 * β−?
 * 253Cf
 * 3/2-#
 * 250Cf
 * 2−
 * style="text-indent:1em" | 250m1Bk
 * colspan="3" style="text-indent:2em" | 35.59(10) keV
 * 29(1) μs
 * IT
 * 250Bk
 * 4+
 * style="text-indent:1em" | 250m2Bk
 * colspan="3" style="text-indent:2em" | 85.6(16) keV
 * 213(8) μs
 * IT
 * 250Bk
 * 7+
 * 251Bk
 * style="text-align:right" | 97
 * style="text-align:right" | 154
 * 251.080761(12)
 * 55.6(11) min
 * β−
 * 251Cf
 * (3/2−)
 * style="text-indent:1em" | 251mBk
 * colspan="3" style="text-indent:2em" | 35.5(13) keV
 * 58(4) μs
 * IT
 * 251Bk
 * (7/2+)
 * rowspan=2|252Bk
 * rowspan=2 style="text-align:right" | 97
 * rowspan=2 style="text-align:right" | 155
 * rowspan=2|252.08431(22)#
 * rowspan=2|1.8(5) min
 * β−?
 * 252Cf
 * rowspan=2|
 * α?
 * 248Am
 * 253Bk
 * style="text-align:right" | 97
 * style="text-align:right" | 156
 * 253.08688(39)#
 * 60# min
 * β−?
 * 253Cf
 * 3/2-#
 * style="text-align:right" | 97
 * style="text-align:right" | 156
 * 253.08688(39)#
 * 60# min
 * β−?
 * 253Cf
 * 3/2-#

title: Isotopes of berkelium


text:
Talk:Sarah Fielding

Family tree
Because the section on the family is obscure in the prose, with many names repeated across generations and titles coming in and out, the following may help the reader of this article: see Talk:Sarah Fielding. (replace old tree originally copied here by Geogre, with link to new one) Carcharoth 01:19, 27 July 2007 (UTC)

Who outsold whom?
Information on the "Sarah outsold Henry" issue: First, I had heard it as a general proverb during grad school that Sarah outsold Henry. However, that wasn't sufficient. References indicated that David Simple outsold Tom Jones. Then they indicated that it outsold Joseph Andrews.  Well, I haven't gone to the ESTC to find out, so I won't step in front of anyone making changes. However, what I would suggest is that, when all of Sarah's works are combined, her novels outsold Henry's novels. When SF's children's literature is added in, her sales go way up, and when Henry's plays are excluded from his lifetime sales it probable that, during their respective lifetimes, Sarah was the bigger seller (and, of course, Henry died young). Joseph Andrews became a big seller, eventually, but I believe it was not an enormous success at first, and nothing like Tom Jones.

All of this comes down to the following: I had a citation for the outsold, but I don't trust it. I think there is some truth back there somewhere. At least one of the permutations of sales will mean Sarah being more popular than Henry. However, although it makes an attention-grabbing fact, it isn't very necessary. It is enough to say that she was quite successful with David Simple, so I won't revert or argue for the comparison.

As for the "not published until 1764": I have no idea why an anonymous editor wanted to put that in. I had never heard it, and I thought that Volume the Last was published during Sarah's lifetime and at her own discretion. Geogre 11:34, 24 August 2005 (UTC)

Questions
"family matron" - what does this mean? Does this refer to the mother? If so, why is she called family matron? Modern readers will think of nurses when they read "matron". Carcharoth 12:38, 20 July 2007 (UTC)

 * They will? That's a bizarre association.  It's quite literal, here.  A family matron is a mother who is the controller/mother of the whole family -- the operative matriarch.  This is quite different from simply being a mother.  A nurse?  Surely that's some recent, if not local, association.  In the US, a matron might be a headmistress of a school or of a convent, but not a nurse.  I.e. this is quite literal.  Geogre 13:11, 20 July 2007 (UTC)

 * I thought it would be something like matriarch, rather than matron (that is what I thought people would think of, but maybe it is just me), but wanted to check. Thanks. Neither link quite works. I wonder if housewife fits? Don't worry, I'm not going to link anything that doesn't fit. Does this 'matron' concept (or at least the word) go all the way back to the 'Roman matrons'? I did some searching and found quite a few references. Maybe another dissertation there, or have they already been written on female roles within the family through history? Carcharoth 13:21, 20 July 2007 (UTC)

 * Sure it goes back that far, and that's why I used the word. I wanted that ironic evocation.  I wanted to contrast Lady Gould (a Matron) with Ann (the new matron not fitting with the sniffy, nobility-obsessed Lady Gould).  I.e. it was coloration that was designed to communicate and was a word choice that was, well, style.  I don't understand, though, why it's a stumbling block: female head of family, disliked by old female, and so old lady sues to rip the family apart to "protect them" from the nasty Roman Catholic (implied "slut").  This despite the fact that Ann was apparently a nice lady and not nasty.  After all, her own son was John Fielding.  I wanted suggestions of cruelty, and "matron" awakens that, esp. in the context of Sarah Fielding's "The Governess."  Henry's novels have absent mothers, note.  Sarah's do, too.  Sarah's have questions of female governance.  Henry has very bad aunts (Bridget Allworthy-Blifil).  Geogre 13:57, 20 July 2007 (UTC)
 * It does sound nasty, doesn't it. Anyway, I'm going to list below the changes I've made, plus some things that will need checking to make sure I haven't slipped up due to lack of knowledge of the subject area. Carcharoth 14:27, 20 July 2007 (UTC)

Changes for review
This section refers to the changes see here. Shall we upgrade to A-class? :-) Carcharoth 14:27, 20 July 2007 (UTC)
 * Added image of title page of her children's novel - ideally we would also have a picture of her memorial plaque in Bath Abbey. If I'm ever there, I'll try and remember. Or we could ask around for Wikipedians from Bath.
 * I've made a start at a lead section, though it still needs expanding. Probably best to strike a balance here, if the article isn't likely to expand further, of just being an introduction and summary of notability, rather than a summary of the whole article (such summaries are best for very long articles).
 * I've split the article into three main sections: Childhood, Writing Career, and Final Years. Does this sound OK? It looks like there is a nascent "literary style" section struggling to be born, but maybe that had better await a future dissertation.
 * I've done various rewrites of the sentences and paragraphs. The most extensively rewritten were the childhood bit and the bit about responses to her first novel (well, I didn't want to call it her first novel - was it her first, or is it the first known?). That seemed a bit disorganised, with the anonymous bit and the sequel stuff overlapping, so I tried to knock it into shape. Hope I haven't distorted things there. Please check.
 * I linked to two of her brother's novels, please check they are the right ones.
 * I've assumed "Remarks on Clarissa" was about the novel by Samuel Richardson (Clarissa)? We have an article, so I linked to it. If not, please correct.
 * I fixed the link to the Chawton House biography, which was broken for me.
 * I'm preparing to add inline references using the Chawton biography. If you would prefer me not to, I'll happily leave that.

More questions
I noticed The Cry: A New Dramatic Fable (1754, with Jane Collier) and The Lives of Cleopatra and Octavia (1757), in the bibliography. Is there nothing to say about these? Carcharoth 14:33, 20 July 2007 (UTC)
 * I know nothing of them, and none of my refs have much to say. They're not available outside of rare book rooms, that I know of, so it's hard to read them.  Geogre 14:51, 20 July 2007 (UTC)
 * OK, thanks. I just thought it would be nice to know if it was a history, or a fictional novel, or some response to Antony and Cleopatra, or something else. I presume it refers to Cleopatra VII and Octavia Minor, the wives of Mark Antony? Carcharoth 15:09, 20 July 2007 (UTC)
 * Oh, yes, well, I know what the last is. It's derived from Pliny and Livy, and it's a translation for women who don't read Latin and a reorganization.  It is therefore biography based on available sources.  I.e. it's a sort of "out of the Roman histories, I will give you the biographies of two women."  Geogre 15:23, 20 July 2007 (UTC)
 * Oh, sorry. The Octavia is wife of Augustus.  Yes, that Cleopatra is the Cleopatra.  The idea was noble Romans.  Part of that "here is how to live" tradition.  Geogre 15:25, 20 July 2007 (UTC)
 * Sister of Octavian (Augustus) surely? I know this now cos I've been watching Rome (TV series)... Last episode next week. Carcharoth 15:51, 20 July 2007 (UTC)

The History of Ophelia one also makes me wonder. Is this a history of the Shakespeare character. Ophelia (character), or, more likely, a history of some Roman Ophelia? Carcharoth 15:53, 20 July 2007 (UTC)
 * Hang on, I'm being silly. The article says these were novels, so Ophelia is presumably the main character, like the Countess of Dellwyn in the other book. No wonder I couldn't find the presumably fictional Dellwyn! :-) Carcharoth 16:02, 20 July 2007 (UTC)
 * Exactly. Further, "Ophelia" is a play on Hamlet's main squeeze.  By 1755, Bardolatry has begun (see Shakespeare's reputation).  After the Licensing Act of 1737, there is an explosion in Shakespeare interest, and seeing Ophelia as the tragic, passive character is starting to build.  Thus, the title character is "an" Ophelia, but she surely wants her readers to think about "the" Ophelia that they would have known (Will's).  Geogre 17:23, 20 July 2007 (UTC)
 * Well, the Shakespeare Ophelia was the first thing that came to mind, so it worked! :-) Bardolatry - I must turn that into a redirect! Dang. It's already an article. Anyway, thanks for clearing that up. The only thing not teased out here yet is Jane Collier's status as Sarah Fielding's companion (see the Chawton House bio), and the invite to a proposed utopian female commune by a lesbian (well, as good as). But that way lies the gutter press. Carcharoth 17:32, 20 July 2007 (UTC)
 * Ah, well, that's not so hard. Jane Collier was an active author before.  She benefits from association with SF, and they're politically and culturally aligned.  It's not surprising.  S Scott is odd.  She is a very, very odd woman who wrote some very odd novels.  It's not just lesbian, but frustratedly lesbian.  Perhaps there are feminist scholars who find value in her, other than as a case study, but I haven't encountered any who can stare straight at Sarah Scott and not flinch.  SF doesn't appear to be a joiner, and Scott's plan seems to have been pretty transparently ridiculous, based on how few would join her.  Geogre 17:42, 20 July 2007 (UTC)

Earl of Denbigh article
Why does the Earl of Denbigh article say: "Four other members of the Feilding family may be mentioned. The writer Henry Fielding (who spelled the family name differently) was the son of Reverend the Hon. John Feilding, younger son of the first Earl of Desmond. His sister Sarah Fielding was also a well-known author."? This contradicts this article which has the father being Edmund Fielding! Carcharoth 16:10, 20 July 2007 (UTC)
 * Bah. Henry Fielding doesn't even say who his father was. Surely this isn't some scandal here? Carcharoth 16:14, 20 July 2007 (UTC)

Chawton House's bio is based on DNB from 1898 (Leslie Stephens, father of Virginia Woolf, ed.) with some new material from research since. What's needed is a 2004 DNB, and I can go look at that to get it clear. Geogre 17:25, 20 July 2007 (UTC)
 * Any luck? Carcharoth 22:25, 21 July 2007 (UTC)
 * I really need to wait for a week day, and I'll look. I'm talking about paper books here.  Geogre 12:51, 22 July 2007 (UTC)

Ok, with feeling: The Earl of Denbigh article is incorrect, but Henry and Sarah were part of the family. William, 5th Earl, was father to Edmund (3rd son), who was the father of Henry. Henry had no claim on the title at all, but he was in the family tree. Geogre 19:08, 23 July 2007 (UTC)

Family tree

 * Sir Henry Gould + Sarah Davidge Gould (Grandmother of Edmund & family controller)
 * Sarah Gould

William Fielding, 5th Earl Denbigh + Sarah Gould (dies, and Denbigh remarries Mrs. Not Appearing Here)
 * ?male             ?male            Edmund Fielding + Sarah

Edmund + Sarah (d. 1718)
 * Catharine       Henry       Ursula      Sarah Fielding       Anne        Beatrice      Edmund

Edmund + Anne Rapha Six children brought in, and John Fielding (half brother)

 * Three Four generations of women called "Sarah". That explains it all. :-) Seriously, great work sorting that out. I delinked Henry Gould as our current article there is about some American poet. I challenge you to write an article on Henry Gould the judge! Or maybe slightly easier, to explain the change in the spelling of the name from Feilding to Fielding. Carcharoth 22:16, 23 July 2007 (UTC)
 * Ooh. I also noticed that Henry Fielding still doesn't talk about his family. Do you think the same sort of thing that you wrote here would apply over there? Carcharoth 22:18, 23 July 2007 (UTC)

 * Ok, on Henry.... It's worth mentioning his family, but everyone is following Battestin in their talk, I think.  Henry gives few outward signs of being much ado about his family.  This is nonsense, as he housed Sarah, gave her money, and did what he could, and his connections probably helped him in his day job (justice of the peace).  However, he, like many of the minor nobility and upper gentry, went off to Eton, and that was alike a family killer.  Boys who went there basically lost their families early and formed that odd English upper class society.  He comes out of Eton polished, goes on to University, and has spent not very much time with his family.  For the girls, on the other hand, everything depends on the family.  They get sent to finishing schools.  They get prepared for marriage, in other words, and do not have a means of generating an income.  They have few rights and less power, and they spend time with each other and with the family.  The dramatic stuff with Lady Gould would have had a bigger influence, both materially and psychologically, on the girls than the boys.
 * Oh, and the DNB today made hints that Sarah was very attached to Jane Collier. This seems...difficult...to me.  It also played up the Sarah Scott connection.  Again, this just scans wrong, but truth over truthiness.  Geogre 03:27, 24 July 2007 (UTC)

 * I'm confused now. Are there four Sarahs and two Sarah Goulds? Carcharoth 22:22, 23 July 2007 (UTC)
 * ie. Sarah Fielding's mother was called Sarah (you call her Sarah Gould Fielding), but Sarah Fielding's father's mother (ie. her paternal grandmother) was also called Sarah (you call her Sarah Gould), and her mother is Sarah Davidge Gould (the grand old lady and matriarch). So Sarah Davidge Gould is Sarah Fielding's great-grandmother, and the mother-in-law of William Fielding, 5th Earl Denbigh, and grandmother to Edmund. But the Sarah that married Edmund (the "Sarah Gould Fielding" that is the mother of Sarah Fielding) actually married into the family, and William Fielding, 5th Earl Denbigh, was her father-in-law, and the Sarah Gould that was the daughter of Sarah Davidge Gould, was the mother-in-law of Sarah Fielding's mother (Sarah Gould Fielding). I think my head just exploded. Carcharoth 00:38, 24 July 2007 (UTC)

 * Let's try a family tree:

Does that look about right? Carcharoth 00:37, 24 July 2007 (UTC)

The picture is right. The words make my head spin. I've got to tell you, I've read three accounts, now, and all of them make this stuff confusing, so I'm doing the best I can. I am sure, after the DNB today (and I'll add info and a ref later, after I've done a de novo I researched today on "the Thresher Poet"), that it's Sarah Davidge Gould who was the mean old lady in this story. What no one makes clear is what happened to Edmund's mother. She's always "first wife," and the only thing that makes sense (but which is never stated) is that she died. Ok, now as for Edmund's wife.... She's Sarah, and Chawton House seems to say she's a Gould, too, but that's confused. It's best to leave her simply as Sarah, as we are sure of that, I think. Edmund's mother was dead, and his father had a new wife and new family (and a title), so it's Edmund's grandmother who took over caring for her great grandchildren and protecting them from the nasty Roman Catholic foreigner trollop (who produced the great reformer). Geogre 03:20, 24 July 2007 (UTC)
 * The above says Sarah Fielding's mother died in 1712, but the article says 1718. Some sources say she was only seven when her mother died, but 1712 would mean she was around two, which would make a big difference. Which is it?
 * Do you think the family tree might make the article clearer? There are several ways of producing such things. The one above might overwhelm the article a bit. Maybe a short stub on the Fielding family, showing the descent of Henry, Sarah and John? Carcharoth 10:28, 24 July 2007 (UTC)
 * 1718, not 1712. I was being sloppy while writing here and not looking at the article or my notes (which were a jumble of family trees anyway).
 * As for a family tree.... I do think it would be useful, but I don't think we should do anything that licenses anything like the Kittybrewster fiasco.  By our own principles, I think it would be a very bad idea, but in places where the names are duplicated so often and the prose so thick that it is difficult for a reader, it is probably best to have a diagram.  My suggestion would be, if the date were corrected, to put this diagram on the talk page, first item.  We can possibly even work a subtle and appropriate mention in article bodies that we have attempted to do a family tree.  Geogre 13:22, 24 July 2007 (UTC)

Names
Still a couple of naming points I'm unclear on: After that, I think it is time to get back to what she wrote. An article on David Simple would be nice. Carcharoth 13:32, 24 July 2007 (UTC)
 * Sarah Gould Fielding (Sarah Fielding's mother) - what was her birth name? Was she a Gould and related (all those cousins and stuff), or did she adopt both the Gould and Fielding name when marrying into the family?
 * Ok, I'm not sure here. We are better simply not offering a last name for her.  The sources I've seen have either been silent or muddled, and we should provide only what we can be sure of.  Geogre 14:14, 24 July 2007 (UTC)
 * John Fielding - he wasn't Edmund Fielding's son, so did he adopt the surname Fielding after his mother (Anne Rapha) married Edmund? And was Anne's birth name Rapha, or was that her first married name?
 * Again, unknown, but I believe "Rapha" is her married name. Are you sure that John isn't from the marriage?  He was born in '21?  Hadn't Edmund married Anne by that point?  Geogre 14:14, 24 July 2007 (UTC)
 * Was the change from Feilding to Fielding just part of the general trend of spelling changes at the time?
 * This would be my guess. The name had been pronounced "field," rather than "feld," and mid-century was a time for a great deal of orthographic reform and hypercorrectiveness, both.  Then again, it could have just been one of those famous "the Army did it" things.  Edmund was an officer, so it's very unlikely that a foolish quartermaster made the change, but I simply don't know.  (After all, Walter Ralegh spelling his last name "Ralegh" on 8 autographs we have by him and "Raleigh" only once, and yet we have decided the latter is his name.) Geogre 14:14, 24 July 2007 (UTC)
 * Thank goodness Sarah Fielding didn't marry a Gould and become Sarah Fielding Gould! :-)
 * Oh, not me. There are some Women's Studies editors out there, and, first, they'd kill me if I did it, and, second, I don't want to usurp the novel, and, third, I didn't like the book.  I will put in some of the glowing stuff that Leslie Stephens's boys said about the translation of Xenophon, the subscription data, etc., but I'm not touching DS.  (It really bored me.  It was like the Heartsfree sections of Jonathan Wild.  Basically, one either likes Sentimental Novel or one doesn't.  I'm a Swiftian.)  Geogre 14:14, 24 July 2007 (UTC)

That answers most of my questions. Just a few more points. Anyway, maybe the reference below will help? Carcharoth 14:45, 24 July 2007 (UTC)
 * "the fourth of seven children of Edmund and Sarah Gould Fielding." - this doesn't make clear whether Sarah married Edmund Gould Fielding, or whether Sarah Gould married Edmund Fielding.
 * I know. We need to drop the "Gould" there, as we aren't sure enough of ourselves.  (If only I read the Battestin biography in my office.  I will clarify next time I'm in there.)  Geogre 15:01, 24 July 2007 (UTC)
 * "Anne Rapha, a Roman Catholic widow, who brought with her six children (including the future reformer, John Fielding)" - this implies John came with her, though as you point out, what is needed is the date she married him.
 * Ok, the Anne Rapha sentence is from Chawton house and from the glib 1898 DNB. It's one of those circumlocutions that I deplore about those old sources.  She brought 6.  I think 6 came from the prior marriage and fecundity.  I think John is born after the marriage.  (Edmund didn't believe in "armor," I guess.)  Geogre 15:01, 24 July 2007 (UTC)
 * I found this (a cache of this) that says: "Sir John Fielding (son of Edmund Fielding and Anne Rapha)" - so probably, yes, their son. Carcharoth 15:14, 24 July 2007 (UTC)

Possible sources
This looks good. Do you have access to JSTOR? ''The Childhood of Henry Fielding. Howard P. Vincent. The Review of English Studies, Vol. 16, No. 64 (Oct., 1940), pp. 438-444. The first page looks fascinating, with references to the case of Fielding vs Fielding'', and the struggle between father and grandmother over the children's trust fund. Carcharoth 14:45, 24 July 2007 (UTC)
 * And kittybrewster would love this. Carcharoth 14:48, 24 July 2007 (UTC)
 * Another old JSTOR reference: . That one is a review from 1920 of a book on the history of Henry Fielding: The History of Henry Fielding by Wilbur L. Cross. Author(s) of Review: J. Paul de Castro. The Modern Language Review, Vol. 15, No. 2 (Apr., 1920), pp. 181-188. Carcharoth 15:05, 24 July 2007 (UTC)

 * I also liked the look of this, by Paulson. Seems to get the mother/grandmother thing wrong, but still. Incidentially, that confusion can come about with sentences like "the father and maternal grandmother fought for custody of the children" - people assume (quite rightly) that the father and grandmother bits refer to the same person (ie. the person who is the child of the father and the grandchild of the grandmother), but the sentence should say "the father and his maternal grandmother fought for custody of the children". Carcharoth 15:18, 24 July 2007 (UTC)

Incorrect sources
There are a lot of sources out there that confuse Edmund's mother with his grandmother (both called Sarah Gould, and, I think, both called Lady Gould). I'm so confused now I can't sort them out, so is it possible to give a date for the latest verdict and to note that previous sources often got this wrong? Carcharoth 14:59, 24 July 2007 (UTC)
 * Aha! So they are all Sarah Gould?  What a mess!  'Enery the Eighth she is, she is.  I'm going to use Battestin, when I next get an opportunity.  Now, he can be wrong, but he just plain isn't wrong very often.  (I.e. I disagree with his interpretation of HF's politics, but I could never in my lifetime argue with his facts.)  He's as close to a last word as we're going to find.  The 1940 source is great stuff about the legal maneuvers, but the two vol. life of HF is going to be our best hope for clear writing and good research.  Geogre 15:05, 24 July 2007 (UTC)
 * Edmund's mother has to be Sarah Gould, as in the family tree above (if that is right), she is the daughter of Sir Henry Gould. It is Edmund's wife that we only know is called Sarah, and are unsure if she is a Gould or not. Funnily enough, Henry Fielding tried to elope with a Sarah Andrew. He obviously had Sarahs on the brain. Carcharoth 15:10, 24 July 2007 (UTC)

 * And this source repeats the claim that Edmund's wife was the daughter, rather than grand-daughter, of Sir Henry Gould, and that Edmund's father was John, not William. Sigh. I give up. Carcharoth 15:36, 24 July 2007 (UTC)

Lady Gould and Dame Gould
I keep coming up against that 1940 source which I can' read! I'm reduced to searching line by line and watching it slowly expand. "Lady Gould" and "Dame Gould" are the same person, I presume? Carcharoth 15:46, 24 July 2007 (UTC)
 * Prrrrrobably. "Dame" and "Lady" have peerage implications, but "lady" can be used for non-peers, and I think "dame" is the feminine "sir."  Like I said: I have our library's Battestin biography of HF, so I'll go over the first few chapters that are biographical to see what he says.  Martin Battestin would have read the 1940, as well as all other sources, including primary documents in Dorset, so he'll be our Ariadne, I hope.  Geogre 21:45, 24 July 2007 (UTC)

The cyclops turns its eye
I have now done my Thresher Poet, so I'll see if I can spend some time with the HF biography to disentangle these branches of the tree this afternoon (US). Geogre 12:28, 25 July 2007 (UTC)

Some questions answered

 * 1) It's Edmund Feilding. Henry is the first to write it "Fielding."  When a later Earl of Denbigh asked why, Henry Fielding's son said, "I cannot tell, my Lord, except it be that my branch of the family were the first that knew how to spell."  Source: D. Nichol's Anecdotes, but I got it from Battestin and Battestin 6-7.
 * 2) Family matters:
 * 3) Henry Gould: Middle Temple in 1660 (age 17), bar 1667, knighted 1694, Judge of the King's Bench 1699 and reappointed by Anne. Died in 1710.  He marries...
 * 4) Sarah Davidge Gould: She is the daughter of Richard Davidge and Katharine. Davidge is a very prosperous merchant, but Katharine brings land and money to the equation, including the house in Glastonbury where Henry Fielding would be born and where both Henry and Sarah would think of "home."  Sarah Davidge Gould marries Henry Gould 1676-7 (OS/NS).  Her sister is Katharine, who married Charles Cottington.
 * 5) Goulds have Davidge (inherits), Sarah (1682-1718), and others. Davidge becomes a highly distinguished lawyer himself at the Middle Temple, and he would help Henry Fielding become qualified as a barrister, and he married a Honors Hackmore in 1709.
 * 6) Sarah Gould marries Edmund Feilding, but let's go back to pick up his family.
 * 7) Edmund Feilding is related to the Earl of Denbigh, but that was a newish title. It had gone to William Feilding (1582-1643) on marrying a sister of George Villiers the infamous Jacobean...friend...(see, e.g. Giles Mompesson for how well Villiers's family did).  His son Basil gets the title, then Basil's brother George, who became Earl of Desmond and gathered many Irish titles.  George (3rd) had six sons, and the youngest was John (which is no reason not to get the title in that family).  The eldest son of the 3rd Earl, George, was William (grandfather of Mary Wortley Montagu).  The next eldest, Charles, concentrated on Ireland and helped Edmund along, later, by promotions in Irish army positions.  Then there are Basil and Christopher -- the former stabbed in the heart by the latter in a tavern brawl that shocked Pepys.  Finally, we get to John.
 * 8) John Feilding -- Sarah and Henry's grandfather on the paternal side -- was a minister. He went to Queen's College, Cambridge and got his MA in 1671.  He was given his D.D. by the King.  He moved to Puddletown as vicar.  John had three sons, and Edmund is 3rd.  John's connections with the Irish peerage led him to be considered for a bishopric there, although it never came through, and he held three livings.
 * 9) Henry and Sarah's uncle George was in the Horse Guard. He was very warm hearted and generous and left the nephews and niece money in his will in 1738.  Their older uncle, John, became secretary to the governor of Jamaica, where he died in 1725.  They also had an important aunt, Bridget, who married a Major Frederic Lapenotier, a Hugenot.
 * 10) Henry and Sarah therefore had a noble but rambunctious masculine side and an illustrious and learned feminine side, but, most importantly, Sarah Davidge Gould had estates, and so did Henry Gould, and both of them took in their daughter's family from the start (until the end, in 1718). It isn't really a Cruella de Ville situation, from what we can gather from Henry's Tom Jones and Sarah's The Governess.  Instead, it's more of a lost idyll.
 * 11) The feminine side of the family was strongly inclined to preserve maiden names in their children (viz. a son named Davidge). More later, as I did some.  Geogre 21:28, 25 July 2007 (UTC)

 * So... does that mean that the DNB (2004) was complete rubbish? Where did their William Feilding come from, and how did they insert an extra Sarah Gould? The new family tree is below. Please feel free to delete the rubbish one above. Carcharoth 23:34, 25 July 2007 (UTC)
 * No, it means that Chawton House relied on the 1898 DNB. I haven't seen the 2004 DNB on Sarah yet.  That will come after I'm done with Henry Fielding's biography.  Sarah and Henry <-Edmund <-John <-George 3rd Earl, brother of 2nd Earl Basil, who is the son of <- William, 1st Earl of Denbigh.  The extra Sarah Gould came from Chawton House, and Battestin indicates that the genealogy, esp. on the father's side, was continuing research all the way up to the 1920's.  Hence, the 1898 DNB would not have been able to get the clearer lines of genealogy.  Geogre 03:12, 26 July 2007 (UTC)

New family tree
New family tree. Carcharoth 23:34, 25 July 2007 (UTC)

Changes
Looks good. I did notice a Felding, but wasn't sure if you meant Fielding or Feilding, so am mentioning it here. I also noticed you left in "by his first wife, Sarah", but do we even know the name of John Feilding's wife (Edmund's mother)? I removed that and also rewrote the section. Carcharoth 22:26, 26 July 2007 (UTC)
 * I think she's a... wait for it... Sarah. I'm not sure, though.  Geogre 02:54, 27 July 2007 (UTC)
 * How ... interesting. I think I understand now why people tend to write about what writer's write, rather than their childhoods or their family trees. Must be careful not to let the "Childhood" section spiral out of control. Main bit of the article should be the "Writing" bit. Obviously. On the other hand, family stuff can be insightful. I've learnt more about Victorian and Edwardian England from reading various obscure sources about Tolkien's childhood, than I would have in any history books. Carcharoth 03:26, 27 July 2007 (UTC)
 * If you ever have a few weeks, get Lawrence Stone's Family, Sex, and Marriage 1400-1750. It's a touchstone and should shake some of the shackles off in general.  As late as the Edwardians, children were still neither seen often nor heard ever among the upper classes.  In the 18th c., it was positively routine for rich folks to see their children only during vacations and for fathers to see the baby at the christening and then, pretty much, not until it was about to move out on its own.  Geogre 03:40, 27 July 2007 (UTC)
 * I'll keep an eye out for that. I noticed your edit summary "He couldn't have been ticked in 1718, because he'd been dead for 8 years" - LOL! Good catch. Do you have dates for Edmund? Would the children have known of his death, or did they lose touch completely? Carcharoth 15:04, 27 July 2007 (UTC)
 * Oh, they surely knew. It was an important event, despite Lady Gould getting custody.  I have to watch out for relying too much on Henry information, because there was a big, dramatic difference between the way girls were treated and boys, but Henry had been trying to reconcile the branches of the family, and he claimed that Edmund was reconciled to Judge Gould before the latter's death, but not Lady Gould before hers.  Henry did not like his old man, though (and fathers and sons have ever been thus, but with not as much cause).  Edmund had his a*se handed to him by the Lord Chancellor in the law suit, and Henry would denounce him viciously in a pamphlet.  6/25/41 was his funeral, I believe.  Henry and all of the surviving children attended, according to Battestin 308.  Geogre 15:24, 27 July 2007 (UTC)

Image
I'm extremely skeptical about that image. First, it shows cleavage, which is so out of bounds for SF's era as to be unimaginable. Second, the DNB always lists "likenesses" in its biographies and had none listed. Third, it doesn't look at all like Henry. Fourth, the person who supplied the image to commons offers no source at all, no justification. Therefore, I'm inclined to delete it without some indication of source (not web source, you image dweebs, but source source, as in who did it, when, and how). Geogre 01:16, 8 October 2007 (UTC)

I'm skeptical about the image, as well, although I disagree (greatly) re: cleavage. Just take a look at any number of portraits done in the 1730s (we're the ones shocked at cleavage, not they). Also, it's possible for a portrait to have been newly discovered (and hence not in the DNB). I agree, nothing like Henry, although who knows what the portraitist might have wanted to do with his (her?) artist license? BUT the important point and the one on which we agree is that the person (Mr or Ms Minor) gives NO source info for the portraitist AND absolutely no support for the claim that the sitter was "Sarah Fielding, sister of Henry Fielding." I'd love to have a portrait of Sarah Fielding. I'd love for someone to identify this as Sarah Fielding: even a scrap to go on, I'd happily follow. But: nothing? Wikipedia ought to delete this for now. (Already the site "Herstory" is using it as if for sure it's SF: scary.) (Carolynjw (talk) 23:42, 13 August 2009 (UTC)).

 * The same portrait is here. It is contemporary, but it is Sarah Andrew, according to a plaque quoted here. Could be used in the article about Henry. /Pieter Kuiper (talk) 22:51, 10 January 2010 (UTC)

title: Talk:Sarah Fielding


text: User talk:213.145.163.210

title: User talk:213.145.163.210


text:
Willy Naessens

Willy Naessens (born on 14 February 1939 in Wortegem-Petegem, East Flanders, Belgium) is a well known industrialist in Belgium. Naessens grew up in a modest family.

At a young age, he started a construction business called "Naessens Constructions", specializing in constructing big - but rather economised - industrial buildings and swimming pools. He became one of the most powerful Belgian industrialists. Nowadays, his corporate group participates in many branches of the construction sector, and in non-construction businesses, such as restaurants and sports-teams.

Nevertheless, he always gave a share to charity. For instance, he became very popular by paying a very expensive organ transplantation for a Belgian child.

title: Willy Naessens


text:
Talk:Urban Pop

This is not correct by any stretch of the imagination. --FuriousFreddy 11:36, 24 August 2005 (UTC) Should not be redirected to Contemporary R&B 68.43.83.93 (talk) 21:53, 14 July 2009 (UTC)

title: Talk:Urban Pop


text:
Sentry (monitoring system)

Sentry is a highly automated impact prediction system operated by the JPL Center for NEO Studies (CNEOS) since 2002. It continually monitors the most up-to-date asteroid catalog for possibilities of future impact with Earth over the next 100+ years. Whenever a potential impact is detected it will be analyzed and the results immediately published by the Center for Near-Earth Object Studies. However, several weeks of optical data are not enough to conclusively identify an impact years in the future. By contrast, eliminating an entry on the risk page is a negative prediction (a prediction of where it will not be).

Scientists warn against worrying about the possibility of impact with an object based on only a few weeks of optical data that show a possible Earth encounter years from now. Sometimes, it cannot even be said for certain what side of the Sun such an object will be at the time of the listed virtual impactor date. For example, even though had a 1-in-500,000 chance of impacting Earth on 11 March 2023, it was expected to be farther than the Sun at the time. Most objects on the Sentry Risk Table have an observation arc of less than 14 days and have not been observed for years.

There are 1620 near-Earth asteroids listed on the risk table with 37,736 virtual impactor dates. For each asteroid listed on the risk table there are on average about 23 virtual impactors. Only about 19 objects on the risk list are large enough to be considered potentially hazardous objects with a diameter greater than about 140 meters. The average size of an object on the default page of Sentry is 120 meters with an average impact probability of 1:500. More eccentric orbits (such as ) that extend to nearly the orbit of Jupiter can make atmospheric entry at velocities of ~40 km/s.

Sentry Risk Table
The Impact Risk page lists a number of lost minor planets that are, for all practical purposes, permanent residents of the risk page; their removal may depend upon a serendipitous rediscovery. Lost asteroid 1979 XB has been on the list since the list's inception. and with their very short 1-day observation arcs have missed virtual impactor dates as they were likely quite distant from the Earth at the time. was serendipitously rediscovered in 2006 after being lost for more than 8 years. was determined to be a harmless main belt asteroid in 2014. Some objects on the Sentry Risk Table, such as, might even be artificial.

is the asteroid with greatest probability (10%) of impacting Earth, but is only ~7 meters in diameter. The only numbered objects with observation arcs of several years are (29075) 1950 DA and 101955 Bennu. Notable asteroids removed from Sentry include (most recently removed listed first): 99942 Apophis, (410777) 2009 FD,, , , , , , , , 367943 Duende, and.

Of the 160 asteroids with better than a 1-in-10,000 chance of impacting Earth only 101955 Bennu is larger than 50 meters in diameter.

The soonest virtual impactor of an asteroid larger than 50 meters in diameter with a better than 1:1-million chance of impact is on 11 August 2040 with a 1:$330,000$ chance of impact. It is estimated to be 120-meters in diameter, has a short observation arc of 3.1-days, and is expected to be 1.78 AU from Earth on 11 August 2040. The impact scenario is outside the 3-sigma uncertainty region of ± 240 million km.

The asteroid with the greatest chance of impacting Earth in 2023 is (4-meters in diameter) with less than a 1-day observation arc. It had a 1:53,000 chance of impact on 10 June 2023, but was expected to be around 0.6 AU from Earth on that date. Such an impact would be similar to.

With a 24-day observation arc, has the most virtual impactors with 1244 virtual impactor dates.

The diameter of most near-Earth asteroids that have not been studied by radar or infrared can generally only be estimated within about a factor of 2 based on the asteroid's absolute magnitude (H). Their mass, consequently, is uncertain by about a factor of 10. For near-Earth asteroids without a well-determined diameter, Sentry assumes a generic albedo of 0.15.

In August 2013, the Sentry Risk Table started using planetary ephemeris (DE431) for all NEO orbit determinations. DE431 (JPL small-body perturber ephemeris: SB431-BIG16) better models the gravitational perturbations of the planets and includes the 16 most massive main-belt asteroids. In April 2021, Sentry transitioned to DE441 which removed the very low impact probability of short-arc 2014 MV67 which had been less than 1:1-billion. The switch to DE441 also briefly added in the harmless Jupiter trojan 2014 ES57 with a very low impact probability of about 1:1-billion.

JPL launched major changes to the website in February 2017 and re-directed the classic page on 10 April 2017.

In 2021 JPL launched Sentry-II which handles the Yarkovsky effect that can significantly change a small asteroids path over decades and centuries. Sentry-II defaults to an Impact Pseudo-Observation (IOBS) analysis technique that runs an extended orbit-determination filter that tries to converge to an impacting solution compatible with the observational data.

Numbers
, there are over 32,955 near-Earth objects of which roughly 1,620 near-Earth asteroids are listed on the risk table. Only around 19 objects on the risk table are large enough to qualify as potentially hazardous objects with a diameter greater than 140 meters (absolute magnitude brighter than 22). About 99% of the objects on the risk table are less than roughly 140 meters in diameter. Roughly 1,200 of these risk-listed near-Earth asteroids are estimated to be about the size of the Chelyabinsk meteor (H>26), which killed no one but had 1,491 non-direct injuries; or smaller. More than 3,140 asteroids have been removed from the risk table since it launched in 2002.

The only two comets that briefly appeared on the Sentry Risk Table are 197P/LINEAR (2003 KV2) and 300P/Catalina (2005 JQ5).

JPL SBDB comparison
The JPL Small-Body Database close approach table lists a linearized uncertainty. Sentry computations explore alternate orbit solutions along the line of variations and account for orbit propagation nonlinearities.

Scout
Sentry's little brother Scout scans recently detected objects on the Minor Planet Center's Near-Earth Object Confirmation Page with designations that are user-assigned and unofficial as they have not been confirmed by additional observations. The impact risk assessment is rated on a scale of 0–4 (negligible, small, modest, moderate, or elevated). Scout is used to help identify imminent impactors.

title: Sentry (monitoring system)


text:
Isotopes of fermium

Fermium (100Fm) is a synthetic element, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be discovered (in fallout from nuclear testing) was 255Fm in 1952. 250Fm was independently synthesized shortly after the discovery of 255Fm. There are 20 known radioisotopes ranging in atomic mass from 241Fm to 260Fm (260Fm is unconfirmed), and 4 nuclear isomers, 247mFm, 250mFm, 251mFm, and 253mFm. The longest-lived isotope is 257Fm with a half-life of 100.5 days, and the longest-lived isomer is 247mFm with a half-life of 5.1 seconds.

List of isotopes

 * rowspan=2|241Fm
 * rowspan=2 style="text-align:right" | 100
 * rowspan=2 style="text-align:right" | 141
 * rowspan=2|241.07421(32)#
 * rowspan=2|730(60) μs
 * SF
 * (various)
 * rowspan=2|5/2+#
 * α (<14%)
 * 237Cf
 * 242Fm
 * style="text-align:right" | 100
 * style="text-align:right" | 142
 * 242.07343(43)#
 * <4 μs
 * SF
 * (various)
 * 0+
 * rowspan=3|243Fm
 * rowspan=3 style="text-align:right" | 100
 * rowspan=3 style="text-align:right" | 143
 * rowspan=3|243.07447(23)#
 * rowspan=3|231(9) ms
 * α (91%)
 * 239Cf
 * rowspan=3|(7/2−)
 * SF (9%)
 * (various)
 * β+ (<10%)
 * 243Es
 * rowspan=2|244Fm
 * rowspan=2 style="text-align:right" | 100
 * rowspan=2 style="text-align:right" | 144
 * rowspan=2|244.07404(22)#
 * rowspan=2|3.12(8) ms
 * SF
 * (various)
 * rowspan=2|0+
 * α (<1%)
 * 240Cf
 * rowspan=3|245Fm
 * rowspan=3 style="text-align:right" | 100
 * rowspan=3 style="text-align:right" | 145
 * rowspan=3|245.07535(21)#
 * rowspan=3|5.5(7) s
 * α (88.5%)
 * 241Cf
 * rowspan=3|(1/2+)
 * β+ (11.5%)
 * 245Es
 * SF (<0.3%)
 * (various)
 * rowspan=3|246Fm
 * rowspan=3 style="text-align:right" | 100
 * rowspan=3 style="text-align:right" | 146
 * rowspan=3|246.075350(17)
 * rowspan=3|1.54(4) s
 * α (93.2%)
 * 242Cf
 * rowspan=3|0+
 * SF (6.8%)
 * (various)
 * β+ (<1.3%)
 * 246Es
 * rowspan=2|247Fm
 * rowspan=2 style="text-align:right" | 100
 * rowspan=2 style="text-align:right" | 147
 * rowspan=2|247.07695(12)#
 * rowspan=2|31(1) s
 * α (64%)
 * 243Cf
 * rowspan=2|(7/2+)
 * β+ (36%)
 * 247Es
 * rowspan=3 style="text-indent:1em" | 247mFm
 * rowspan=3 colspan="3" style="text-indent:2em" | 45(7) keV
 * rowspan=3| 5.1(2) s
 * α (88%)
 * 243Cf
 * rowspan=3|(1/2+)
 * IT (12%)
 * 247Fm
 * β+?
 * 247Es
 * rowspan=3|248Fm
 * rowspan=3 style="text-align:right" | 100
 * rowspan=3 style="text-align:right" | 148
 * rowspan=3|248.077186(9)
 * rowspan=3|35.1(8) s
 * α (93%)
 * 244Cf
 * rowspan=3|0+
 * β+ (7%)
 * 248Es
 * SF (.10%)
 * (various)
 * rowspan=2|249Fm
 * rowspan=2 style="text-align:right" | 100
 * rowspan=2 style="text-align:right" | 149
 * rowspan=2|249.078928(7)
 * rowspan=2|1.6(1) min
 * β+ (84.4%)
 * 249Es
 * rowspan=2|(7/2+)
 * α (15.6%)
 * 245Cf
 * rowspan=3|250Fm
 * rowspan=3 style="text-align:right" | 100
 * rowspan=3 style="text-align:right" | 150
 * rowspan=3|250.079521(9)
 * rowspan=3|30.4(15) min
 * α (90%)
 * 246Cf
 * rowspan=3|0+
 * EC (10%)
 * 250Es
 * SF (6.9×10−3%)
 * (various)
 * style="text-indent:1em" | 250mFm
 * colspan="3" style="text-indent:2em" | 1199.2(10) keV
 * 1.92(5) s
 * IT
 * 250Fm
 * (8−)
 * rowspan=2|251Fm
 * rowspan=2 style="text-align:right" | 100
 * rowspan=2 style="text-align:right" | 151
 * rowspan=2|251.081540(16)
 * rowspan=2|5.30(8) h
 * β+ (98.2%)
 * 251Es
 * rowspan=2|(9/2−)
 * α (1.8%)
 * 247Cf
 * style="text-indent:1em" | 251mFm
 * colspan="3" style="text-indent:2em" | 200.09(11) keV
 * 21.1(16) μs
 * IT
 * 251Fm
 * (5/2+)
 * rowspan=2|252Fm
 * rowspan=2 style="text-align:right" | 100
 * rowspan=2 style="text-align:right" | 152
 * rowspan=2|252.082467(6)
 * rowspan=2|25.39(4) h
 * α (99.99%)
 * 248Cf
 * rowspan=2|0+
 * SF (.0023%)
 * (various)
 * rowspan=2|253Fm
 * rowspan=2 style="text-align:right" | 100
 * rowspan=2 style="text-align:right" | 153
 * rowspan=2|253.085185(4)
 * rowspan=2|3.00(12) d
 * EC (88%)
 * 253Es
 * rowspan=2|(1/2)+
 * α (12%)
 * 249Cf
 * style="text-indent:1em" | 253mFm
 * colspan="3" style="text-indent:2em" | ~351 keV
 * 0.56(6) μs
 * IT
 * 253Fm
 * (11/2-)
 * rowspan=2|254Fm
 * rowspan=2 style="text-align:right" | 100
 * rowspan=2 style="text-align:right" | 154
 * rowspan=2|254.0868544(30)
 * rowspan=2|3.240(2) h
 * α (99.94%)
 * 250Cf
 * rowspan=2|0+
 * SF (.0592%)
 * (various)
 * rowspan=2|255Fm
 * rowspan=2 style="text-align:right" | 100
 * rowspan=2 style="text-align:right" | 155
 * rowspan=2|255.089964(5)
 * rowspan=2|20.07(7) h
 * α
 * 251Cf
 * rowspan=2|7/2+
 * SF (2.4×10−5%)
 * (various)
 * rowspan=2|256Fm
 * rowspan=2 style="text-align:right" | 100
 * rowspan=2 style="text-align:right" | 156
 * rowspan=2|256.091774(8)
 * rowspan=2|157.6(13) min
 * SF (91.9%)
 * (various)
 * rowspan=2|0+
 * α (8.1%)
 * 252Cf
 * rowspan=2|257Fm
 * rowspan=2 style="text-align:right" | 100
 * rowspan=2 style="text-align:right" | 157
 * rowspan=2|257.095106(7)
 * rowspan=2|100.5(2) d
 * α (99.79%)
 * 253Cf
 * rowspan=2|(9/2+)
 * SF (.21%)
 * (various)
 * 258Fm
 * style="text-align:right" | 100
 * style="text-align:right" | 158
 * 258.09708(22)#
 * 370(14) μs
 * SF
 * (various)
 * 0+
 * 259Fm
 * style="text-align:right" | 100
 * style="text-align:right" | 159
 * 259.1006(3)#
 * 1.5(3) s
 * SF
 * (various)
 * 3/2+#
 * 260Fm
 * style="text-align:right" | 100
 * style="text-align:right" | 160
 * 260.10281(55)#
 * 4 ms
 * SF
 * (various)
 * 0+
 * rowspan=2|256.091774(8)
 * rowspan=2|157.6(13) min
 * SF (91.9%)
 * (various)
 * rowspan=2|0+
 * α (8.1%)
 * 252Cf
 * rowspan=2|257Fm
 * rowspan=2 style="text-align:right" | 100
 * rowspan=2 style="text-align:right" | 157
 * rowspan=2|257.095106(7)
 * rowspan=2|100.5(2) d
 * α (99.79%)
 * 253Cf
 * rowspan=2|(9/2+)
 * SF (.21%)
 * (various)
 * 258Fm
 * style="text-align:right" | 100
 * style="text-align:right" | 158
 * 258.09708(22)#
 * 370(14) μs
 * SF
 * (various)
 * 0+
 * 259Fm
 * style="text-align:right" | 100
 * style="text-align:right" | 159
 * 259.1006(3)#
 * 1.5(3) s
 * SF
 * (various)
 * 3/2+#
 * 260Fm
 * style="text-align:right" | 100
 * style="text-align:right" | 160
 * 260.10281(55)#
 * 4 ms
 * SF
 * (various)
 * 0+
 * style="text-align:right" | 160
 * 260.10281(55)#
 * 4 ms
 * SF
 * (various)
 * 0+

Chronology of isotope discovery
260Fm was not confirmed in 1997.

title: Isotopes of fermium


text:
Isotopes of californium

Californium ($98$Cf) is an artificial element, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was $245$Cf in 1950. There are 20 known radioisotopes ranging from $237$Cf to $256$Cf and one nuclear isomer, $249m$Cf. The longest-lived isotope is $251$Cf with a half-life of 898 years.

List of isotopes

 * rowspan=3|$237$Cf
 * rowspan=3 style="text-align:right" | 98
 * rowspan=3 style="text-align:right" | 139
 * rowspan=3|237.06220(10)
 * rowspan=3|0.8(2) s
 * α (70%)
 * $233$Cm
 * rowspan=3|5/2+#
 * SF (30%)
 * (various)
 * β$+$ (rare)
 * $237$Bk
 * rowspan=2|$238$Cf
 * rowspan=2 style="text-align:right" | 98
 * rowspan=2 style="text-align:right" | 140
 * rowspan=2|238.06149(32)#
 * rowspan=2|21.1(13) ms
 * SF
 * (various)
 * rowspan=2|0+
 * α (<5%)
 * $234$Cm
 * rowspan=2|$239$Cf
 * rowspan=2 style="text-align:right" | 98
 * rowspan=2 style="text-align:right" | 141
 * rowspan=2|239.06248(13)#
 * rowspan=2|28(2) s
 * α (65%)
 * $235$Cm
 * rowspan=2|(5/2+)
 * β$+$ (35%)
 * $239$Bk
 * rowspan=3|$240$Cf
 * rowspan=3 style="text-align:right" | 98
 * rowspan=3 style="text-align:right" | 142
 * rowspan=3|240.062253(19)
 * rowspan=3|40.3(9) s
 * α (98.5%)
 * $236$Cm
 * rowspan=3|0+
 * SF (1.5%)
 * (various)
 * β$+$?
 * $240$Bk
 * rowspan=2|$241$Cf
 * rowspan=2 style="text-align:right" | 98
 * rowspan=2 style="text-align:right" | 143
 * rowspan=2|241.06369(18)#
 * rowspan=2|2.35(18) min
 * β$+$ (85%)
 * $241$Bk
 * rowspan=2|(7/2−)
 * α (15%)
 * $237$Cm
 * rowspan=3|$242$Cf
 * rowspan=3 style="text-align:right" | 98
 * rowspan=3 style="text-align:right" | 144
 * rowspan=3|242.063755(14)
 * rowspan=3|3.49(15) min
 * α (61%)
 * $238$Cm
 * rowspan=3|0+
 * β$+$ (39%)
 * $242$Bk
 * SF (<0.014%)
 * (various)
 * rowspan=2|$243$Cf
 * rowspan=2 style="text-align:right" | 98
 * rowspan=2 style="text-align:right" | 145
 * rowspan=2|243.06548(19)#
 * rowspan=2|10.8(3) min
 * β$+$ (86%)
 * $243$Bk
 * rowspan=2|(1/2+)
 * α (14%)
 * $239$Cm
 * rowspan=2|$244$Cf
 * rowspan=2 style="text-align:right" | 98
 * rowspan=2 style="text-align:right" | 146
 * rowspan=2|244.0659994(28)
 * rowspan=2|19.5(5) min
 * α (75%)
 * $240$Cm
 * rowspan=2|0+
 * EC (25%)
 * $244$Bk
 * rowspan=2|$245$Cf
 * rowspan=2 style="text-align:right" | 98
 * rowspan=2 style="text-align:right" | 147
 * rowspan=2|245.0680468(26)
 * rowspan=2|45.0(15) min
 * β$+$ (64.7%)
 * $245$Bk
 * rowspan=2|1/2+
 * α (35.3%)
 * $241$Cm
 * style="text-indent:1em" | $245m$Cf
 * colspan="3" style="text-indent:2em" | 57(4) keV
 * >100# ns
 * IT
 * $245$Cf
 * (7/2+)
 * rowspan=3|$246$Cf
 * rowspan=3 style="text-align:right" | 98
 * rowspan=3 style="text-align:right" | 148
 * rowspan=3|246.0688037(16)
 * rowspan=3|35.7(5) h
 * α
 * $242$Cm
 * rowspan=3|0+
 * SF (2.4×10$−4$%)
 * (various)
 * EC?
 * $246$Bk
 * rowspan=2|$247$Cf
 * rowspan=2 style="text-align:right" | 98
 * rowspan=2 style="text-align:right" | 149
 * rowspan=2|247.070971(15)
 * rowspan=2|3.11(3) h
 * EC (99.965%)
 * $247$Bk
 * rowspan=2|(7/2+)
 * α (.035%)
 * $243$Cm
 * rowspan=2|$248$Cf
 * rowspan=2 style="text-align:right" | 98
 * rowspan=2 style="text-align:right" | 150
 * rowspan=2|248.0721829(55)
 * rowspan=2|333.5(28) d
 * α (99.997%)
 * $244$Cm
 * rowspan=2|0+
 * SF (.0029%)
 * (various)
 * rowspan=2|$249$Cf
 * rowspan=2 style="text-align:right" | 98
 * rowspan=2 style="text-align:right" | 151
 * rowspan=2|249.0748504(13)
 * rowspan=2|351(2) y
 * α
 * $245$Cm
 * rowspan=2|9/2−
 * SF (5×10$−7$%)
 * (various)
 * style="text-indent:1em" | $249m$Cf
 * colspan="3" style="text-indent:2em" | 144.98(5) keV
 * 45(5) μs
 * IT
 * $249$Cf
 * 5/2+
 * rowspan=2|$250$Cf
 * rowspan=2 style="text-align:right" | 98
 * rowspan=2 style="text-align:right" | 152
 * rowspan=2|250.0764045(17)
 * rowspan=2|13.08(9) y
 * α (99.923%)
 * $246$Cm
 * rowspan=2|0+
 * SF (.077%)
 * (various)
 * $251$Cf
 * style="text-align:right" | 98
 * style="text-align:right" | 153
 * 251.0795872(42)
 * 898(44) y
 * α
 * $247$Cm
 * 1/2+
 * style="text-indent:1em" | $251m$Cf
 * colspan="3" style="text-indent:2em" | 370.47(3) keV
 * 1.3(1) μs
 * IT
 * $251$Cf
 * 11/2−
 * rowspan=2|$252$Cf
 * rowspan=2 style="text-align:right" | 98
 * rowspan=2 style="text-align:right" | 154
 * rowspan=2|252.0816265(25)
 * rowspan=2|2.645(8) y
 * α (96.8972%)
 * $248$Cm
 * rowspan=2|0+
 * SF (3.1028%)
 * (various)
 * rowspan=2|$253$Cf
 * rowspan=2 style="text-align:right" | 98
 * rowspan=2 style="text-align:right" | 155
 * rowspan=2|253.0851337(46)
 * rowspan=2|17.81(8) d
 * β$−$ (99.69%)
 * $253$Es
 * rowspan=2|(7/2+)
 * α (.31%)
 * $249$Cm
 * rowspan=3|$254$Cf
 * rowspan=3 style="text-align:right" | 98
 * rowspan=3 style="text-align:right" | 156
 * rowspan=3|254.087324(12)
 * rowspan=3|60.5(2) d
 * SF (99.69%)
 * (various)
 * rowspan=3|0+
 * α (.31%)
 * $250$Cm
 * β$−$β$−$?
 * $254$Fm
 * rowspan=3|$255$Cf
 * rowspan=3 style="text-align:right" | 98
 * rowspan=3 style="text-align:right" | 157
 * rowspan=3|255.09105(22)#
 * rowspan=3|85(18) min
 * β$−$
 * $255$Es
 * rowspan=3|(7/2+)
 * SF?
 * (various)
 * α?
 * $251$Cm
 * rowspan=3|$256$Cf
 * rowspan=3 style="text-align:right" | 98
 * rowspan=3 style="text-align:right" | 158
 * rowspan=3|256.09344(34)#
 * rowspan=3|12.3(12) min
 * SF
 * (various)
 * rowspan=3|0+
 * α?
 * $252$Cm
 * β$−$β$−$?
 * $256$Fm
 * rowspan=2|(7/2+)
 * α (.31%)
 * $252$Cm
 * rowspan=3|$252$Cf
 * rowspan=3 style="text-align:right" | 98
 * rowspan=3 style="text-align:right" | 156
 * rowspan=3|254.087324(12)
 * rowspan=3|60.5(2) d
 * SF (99.69%)
 * (various)
 * rowspan=3|0+
 * α (.31%)
 * $252$Cm
 * β$252$β$252$?
 * $252$Fm
 * rowspan=3|⇭⇭⇭Cf
 * rowspan=3 style="text-align:right" | 98
 * rowspan=3 style="text-align:right" | 157
 * rowspan=3|255.09105(22)#
 * rowspan=3|85(18) min
 * β⇭⇭⇭
 * ⇭⇭⇭Es
 * rowspan=3|(7/2+)
 * SF?
 * (various)
 * α?
 * ⇭⇭⇭Cm
 * rowspan=3|⇭⇭⇭Cf
 * rowspan=3 style="text-align:right" | 98
 * rowspan=3 style="text-align:right" | 158
 * rowspan=3|256.09344(34)#
 * rowspan=3|12.3(12) min
 * SF
 * (various)
 * rowspan=3|0+
 * α?
 * ⇭⇭⇭Cm
 * β⇭⇭⇭β⇭⇭⇭?
 * ⇭⇭⇭Fm
 * rowspan=3|12.3(12) min
 * SF
 * (various)
 * rowspan=3|0+
 * α?
 * ⇭⇭⇭Cm
 * β⇭⇭⇭β⇭⇭⇭?
 * ⇭⇭⇭Fm
 * β⇭⇭⇭β⇭⇭⇭?
 * ⇭⇭⇭Fm

Californium-252
Californium-252 (Cf-252, ⇭⇭⇭Cf) undergoes spontaneous fission with a branching ratio of 3.09% and is used in small sized neutron sources. Fission neutrons have an energy range of 0 to 13 MeV with a mean value of 2.3 MeV and a most probable value of 1 MeV.

This isotope produces high neutron emissions and can be used for a number of applications in industries such as nuclear energy, medicine, and petrochemical exploration.

Nuclear reactors
Neutron sources using ⇭⇭⇭Cf are most notably used in the start-up of nuclear reactors. Once a reactor is filled with nuclear fuel, the stable neutron emission from the source material starts the chain reaction.

Military and defense
The portable isotopic neutron spectroscopy (PINS) used by United States Armed Forces, the National Guard, Homeland Security, and Customs and Border Protection, uses ⇭⇭⇭Cf sources to detect hazardous contents inside artillery projectiles, mortar projectiles, rockets, bombs, land mines, and improvised explosive devices (IED).

Oil and petroleum
In the oil industry, ⇭⇭⇭Cf is used to find layers of petroleum and water in a well. Instrumentation is lowered into the well, which bombards the formation with high energy neutrons to determine porosity, permeability, and hydrocarbon presence along the length of the borehole.

Medicine
⇭⇭⇭Cf has also been used in the treatment of serious forms of cancer. For certain types of brain and cervical cancer, ⇭⇭⇭Cf can be used as a more cost-effective substitute for radium.

title: Isotopes of californium