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Ed O'Brien

Edward John O'Brien (born 15 April 1968) is an English guitarist, songwriter and member of the rock band Radiohead. He releases solo music under the name EOB.

O'Brien attended Abingdon School in Oxfordshire, England, where he formed Radiohead with schoolmates. O'Brien said his role was to "service the songs" and support the songwriter, Thom Yorke. He often creates ambient sounds and textures, using effects, sustain units and the EBow, and provides backing vocals.

O'Brien's first solo album, Earth, was released in 2020. O'Brien had been writing songs for years, but lacked confidence and felt they had a character that would be lost with Radiohead. He began a North American tour in February 2020; a larger tour was cancelled due to the COVID-19 pandemic.

Rolling Stone named O'Brien among the greatest guitarists of all time in 2010 and 2023. He was inducted into the Rock and Roll Hall of Fame as a member of Radiohead in 2019.

Early life
O'Brien was born on April 15, 1968. His family comes from Ballyporeen, Ireland. As a child, O'Brien enjoyed cricket and theatre. His parents split when he was 10; O'Brien said this was when music became his "refuge". He grew up listening to post-punk acts such as Siouxsie and the Banshees, Adam and the Ants, Depeche Mode, the Police and David Bowie. He said: "It was a very foetal [time] for music because people who went to art college or artists, or musicians, suddenly thought, 'Oh, I can be that.

The members of Radiohead met while attending Abingdon School, an independent school for boys in Abingdon, Oxfordshire. While O'Brien was playing Lysander in a school production of A Midsummer Night's Dream, he met Thom Yorke, who was scoring the production. Yorke asked him to join him for a jam. According to O'Brien, "Before that, [life] was a bit confusing, a bit crap. And then suddenly ... I felt something very strong, almost like some kind of epiphany, almost like: 'This is it.

Along with the drummer, Philip Selway, O'Brien was in the year above Yorke and the bassist, Colin Greenwood, and three years above Colin's brother, the guitarist Jonny Greenwood. In 1985, they formed On a Friday, the name referring to their usual rehearsal day in the school's music room. They continued to rehearse during holidays while the members attended university. O'Brien studied economics at the University of Manchester, where he took part in the Second Summer of Love.

Radiohead
In 1991, On a Friday signed a record contract with EMI and changed their name to Radiohead. They found early success with their debut single, "Creep", from their debut album, Pablo Honey (1993). For their second album, The Bends (1995), the guitarists' roles were more divided, with Yorke generally playing rhythm, Greenwood lead and Ed O'Brien providing effects. The Bends received positive reviews and elevated Radiohead's profile. Radiohead's third album, OK Computer (1997), brought them international fame and is often acclaimed as one of the best albums of all time. OK Computer saw O'Brien use less distortion and more delay and other effects, creating a sound that was "more about textures". O'Brien became depressed during the extensive OK Computer tour, but focused on supporting Yorke. After the tour, he returned to Oxford, used large amounts of drugs and fell further into depression. He said: "I was single, on my own … I was the lowest I've ever been. It was the irony as well – you're at the top, that old cliché."

Radiohead's next albums, Kid A (2000) and Amnesiac (2001), marked a dramatic change in sound, incorporating influences from electronic music, classical music, jazz and krautrock. O'Brien initially struggled with the change, saying: "It's scary – everyone feels insecure. I'm a guitarist and suddenly it's like, well, there are no guitars on this track, or no drums." He began using effects units more extensively to process his guitar, creating synthesiser-like sounds. O'Brien kept an online diary of Radiohead's progress during the recording.

During the sessions for In Rainbows (2007), O'Brien believed Radiohead might never record another album. He said later: "One of my mantras throughout the recording was, 'This is the last time I'm doing this. I'll never summon up the energy to do this again. So I'm going to put everything I can into it.'" He was motivated by a desire to cement Radiohead's status as a great band, and said in 2008: "In my view, we've made three really great records, The Bends, OK Computer and Kid A. What we needed was another great record just to seal it."

By 2011, Radiohead had sold more than 30 million albums worldwide. They were inducted into the Rock and Roll Hall of Fame in March 2019; O'Brien and Selway attended the induction ceremony and gave speeches. O'Brien thanked his bandmates for their musicianship and friendship, saying that "some of the nights we have in the rehearsal studio [are] like transcendental moments".

In 2020, O'Brien said his role in Radiohead was to "service the songs" and support Yorke. He said: "I've always been like his older brother ... I always say that he was like the dad of the band and I'm the mum. My job was to always put my arm around him, and his job was to be Thom." Radiohead's producer, Nigel Godrich, described O'Brien as "very much a diplomat".

Solo work
O'Brien releases solo music under the name EOB. After making demos with the producer Ian Davenport in 2014, he recorded with the producer Flood from late 2017 to early 2019. He had written songs for years, but lacked the confidence to bring them to Radiohead and felt they had a "distinct energy" that would be lost if they became a "hybrid product". O'Brien's debut solo work, the non-album track "Santa Teresa", was released on 4 October, 2019. Stereogum described it as a "haunting" ambient instrumental in the style of Brian Eno and Fennesz.

O'Brien's debut solo album, Earth, was released on 17 April 2020 on Capitol Records to positive reviews. It features the drummer Omar Hakim, the Invisible members Nathan East and Dave Okumu, the folk singer Laura Marling, the Portishead guitarist Adrian Utley, the Wilco drummer Glenn Kotche and the Radiohead bassist Colin Greenwood. The music was inspired by O'Brien's time living in Brazil and attending Carnival, which he described as a "musical eureka moment". The first track, "Brasil", was released on 5 December 2019, followed by "Shangri-La" on 6 February. O'Brien began a North American tour in February 2020; a larger Earth tour was cancelled due to the COVID-19 pandemic.

O'Brien contributed a remix of Paul McCartney's song "Slidin to the 2021 remix album McCartney III Imagined. In January 2024, O'Brien said he was "deep into" recording his second album.

Other work
In 1999, O'Brien contributed to the soundtrack for the BBC drama series Eureka Street. He contributed guitar to the 2003 Asian Dub Foundation album Enemy of the Enemy. O'Brien and Selway toured and recorded with Neil Finn as part of the 7 Worlds Collide project. O'Brien provided guitar and backing vocals on their 2001 live album and the 2009 studio album The Sun Came Out.

O'Brien is a founding director of the Featured Artists Coalition, a nonprofit organisation set up to protect the rights of featured musical artists, particularly in the digital age. He appeared in a 2011 episode of the BBC Radio 5 Live sports programme Fighting Talk in support of Record Shop Day. In 2013, O'Brien cofounded the Laundry, a workspace, restaurant and nightclub converted from a laundry in London Fields. In 2019, Hackney Council announced that the building would be demolished to make way for luxury flats.

In 2014, O'Brien and Selway signed an open letter protesting a ban on guitars in British prisons and stating that music was important for rehabilitation. O'Brien worked with Fender to design a signature model guitar, the EOB Stratocaster, which went on sale in November 2017. It features a tremolo bridge and a sustainer neck pickup. In 2018, he became an "informal patron" for the environmental pressure group Extinction Rebellion, which he described as "incredibly enlightened".

In 2019, O'Brien joined the RSPB Let Nature Sing project, which aimed to get birdsong into the UK charts to raise awareness of the decline in Britain's birdlife. In 2020, O'Brien contributed to Ear Opener, an online video course aimed at helping young people write music. That November, he gave evidence to a DCMS Committee inquiry into the impact of streaming on the music industry. He said he wanted to speak for less successful artists, who he felt were exploited.

Musicianship
O'Brien said of his playing: "I literally learned to play my instrument within the band, so I started off very limited — and I'm still very limited. But I've been lucky, because I've been in a band that has not required you to be a virtuoso." O'Brien also sings backing vocals, which Pitchfork described as Radiohead's "most consistent secret weapon".

While Jonny Greenwood plays most of Radiohead's lead guitar parts, O'Brien often creates ambient effects, making extensive use of effects units. He said of the technique: "It's a bit like you're creating a canvas. That would be in accompaniment with Thom playing chords on the piano — you're building up a cloud of effects behind."

O'Brien usually plays Fender Stratocasters, including an Eric Clapton Stratocaster. He also plays Gretsch and Rickenbacker guitars, including a twelve-string Rickenbacker. O'Brien said in 2017 that his most used effects are distortion, an Electro-Harmonix Memory Man delay and a DigiTech Whammy pitch shifter. He described the Boss DD-5 delay pedal as "key to the sound of The Bends and OK Computer ... It's the only delay that can make those OK Computer sounds." In the Kid A sessions, at the suggestion of Michael Brook, the creator of the Infinite Guitar, O'Brien began using sustain units, which allow guitar notes to be sustained indefinitely. He combined these with looping and delay effects to create synthesiser-like sounds.

To create the high-pitched chiming sound that introduces "Lucky", O'Brien strums above the guitar nut. He creates the reverberating pops on the introduction of "2 + 2 = 5". On "Karma Police", O'Brien distorts his guitar by driving a delay effect to self-oscillation, then lowering the delay rate, creating a "melting" effect. The ambient track "Treefingers" was created by processing O'Brien's guitar loops. On "Dollars and Cents", O'Brien uses a pitch shifter pedal to shift his guitar chords from minor to major. For "All I Need", he used a sustain unit and a guitar strung with four bottom E strings, creating a thicker sound. O'Brien uses the EBow, an electronic sustaining device, on his guitar to generate drones and ambient leads on songs such as "My Iron Lung", "Talk Show Host", "Jigsaw Falling Into Place", "Where I End and You Begin" and "Nude". On The King of Limbs and A Moon Shaped Pool, he used a Klon Centaur overdrive pedal.

In 2010, the Rolling Stone journalist David Fricke named O'Brien the 59th-greatest guitarist of all time. In 2023, Rolling Stone named O'Brien and Greenwood the joint 43rd-greatest guitarists, writing that O'Brien was "possibly the most underrated guitarist in rock ... adding subtle textures that enhance each song and keeping the band grounded with his cheerful, up-for-anything vibe. You might not be able to name his best solo, but it's impossible to imagine Radiohead without him."

Influences
O'Brien's earliest guitar influence was Andy Summers of the Police, particularly his use of delay and chorus effects on "Walking on the Moon". His other influences include Peter Buck of R.E.M, Paul Weller of the Jam, Johnny Marr of the Smiths, John McGeoch of Magazine and Siouxsie and the Banshees, and the Edge of U2. O'Brien admired how these guitarists created "space" rather than playing conventional solos. He said: "They were great guitarists, but they weren't lead guitarists ... My favourite guitarists know when not to play. Then you make more of it when you do play. Make it count."

O'Brien cited the American band Phish as an influence on his solo shows, saying: "[They're] like a jazz band; they are willing to take risks for a moment of musical transcendence. That's what I'm after — I want to tap into that." He cited the music of Brazil, such as the music of Carnival and Jorge Ben, as an influence on Earth. Other influences included Earth, Wind & Fire, Arcade Fire, Underworld, Bill Withers, Talking Heads and the "Celtic, folky" music of Led Zeppelin.

Personal life
O'Brien lives in north London. With his wife, Susan Kobrin, he has a son, born in January 2004, and a daughter, born in 2006.

Around 2000, O’Brien gave up alcohol, saying it was "fucking him up", and began using meditation. In 2011, O'Brien and his family moved to Brazil for a year, living on a farm near Ubatuba. In March 2020, O'Brien announced that he had contracted COVID-19 and was recovering in isolation.

title: Ed O'Brien


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Colin Greenwood

Colin Charles Greenwood (born 26 June 1969) is an English bassist and a member of the rock band Radiohead. Along with bass guitar, Greenwood plays upright bass and electronic instruments.

With his younger brother, the guitarist Jonny Greenwood, Colin attended Abingdon School in Abingdon, England, where they formed Radiohead. Radiohead have achieved acclaim and have sold more than 30 million albums. Greenwood was inducted into the Rock and Roll Hall of Fame as a member of Radiohead in 2019.

Greenwood has contributed to solo projects by the other members of Radiohead, and has collaborated with musicians including Tamino, Gaz Coombes, Nick Cave and Warren Ellis.

Early life
Colin Greenwood is the older brother of the Radiohead guitarist Jonny Greenwood. Their father served in the British Army as a bomb disposal expert. The Greenwood family has historical ties to the British Communist Party and the socialist Fabian Society.

Greenwood lived in Germany as a child and became fluent in German. He credited his older sister, Susan, with introducing him and Jonny to "miserable" bands such as the Fall, Magazine and Joy Division. He said: "We were ostracised at school because everyone else was into Iron Maiden."

The Greenwood brothers attended Abingdon School, a private school for boys in Oxfordshire. When he was 12, Colin met the future Radiohead singer Thom Yorke. Their future bandmates Ed O'Brien, whom Greenwood met during a school production of the opera Trial by Jury, and Philip Selway also attended the school.

Greenwood bought his first guitar when he was 15. He studied classical guitar under the Abingdon music teacher Terence Gilmore-James, who introduced him and his bandmates to jazz, film scores, postwar avant-garde music, and 20th-century classical music. Greenwood said: "When we started, it was very important that we got support from him, because we weren't getting any from the headmaster. You know, the man once sent us a bill, charging us for the use of school property, because we practiced in one of the music rooms on a Sunday."

Greenwood said he began playing bass out of necessity, teaching himself by playing along to New Order, Joy Division and Otis Redding. He said the band members picked their instruments "because we wanted to play music together, rather than just because we wanted to play that particular instrument. So it was more of a collective angle, and if you could contribute by having someone else play your instrument, then that was really cool."

Greenwood read English at Peterhouse, Cambridge, between 1987 and 1990, and read modern American literature including Raymond Carver, John Cheever and other postwar American writers. While at Peterhouse, he worked as an events and entertainments officer. After graduating, he took a job as a sales assistant at the record shop Our Price in Oxford.

Radiohead
In late 1991, the EMI sales representative Keith Wozencroft visited Our Price and struck up conversation with Greenwood. When Wozencroft mentioned that he was moving to a position as an A&R scout at the EMI subsidiary Parlophone, Greenwood gave him a copy of On a Friday's latest demo. On a Friday signed a six-album recording contract with EMI and changed their name to Radiohead. By 2011, Radiohead had sold more than 30 million albums worldwide. They were inducted into the Rock and Roll Hall of Fame in March 2019. On being in a band with his brother, Jonny, Colin said: "Beyond the normal brotherly thing, I respect him as a person and a musician."

Greenwood mostly plays fingerstyle, and said he was unskilled with plectrums. He mainly uses Fender basses and Ampeg and Ashdown amplifiers. He also plays double bass on tracks such as "Pyramid Song" and "You and Whose Army". While his main role is bass, Greenwood said "our ideas and suggestions in certain areas, as to where the music should go or develop, are listened to. We are very much a band." He said he did not think of himself as a bass player and was "just in a band with other people". Among his influences are Booker T and the MGs, Bill Withers, Curtis Mayfield and J Dilla. In 2008, Mojo wrote that Greenwood and Selway were "surely the most inventive rhythm section working close to the rock mainstream".

Other work
In 1997, Greenwood participated in a marketing campaign for his alma mater, Cambridge University, posing for a photo with students from both state and private schools for a poster titled "Put Yourself in the Picture". The poster was "designed to break down some of the stereotypes that deter able students from applying to Cambridge" and encourage more applicants from state schools.

Greenwood contributed bass to two soundtracks by his brother, Jonny, Bodysong (2003) and Inherent Vice, and on his score for the 2008 film Woodpecker. He played bass on the albums Amir (2018) and Sahar (2022) by the Belgian-Egyptian singer Tamino, the album World's Strongest Man (2018) by Gaz Coombes, and on "Brasil" from Earth (2020), the debut solo album by his Radiohead bandmate Ed O'Brien. He contributed beat programming to Yorke's song "Hearing Damage" from the soundtrack to The Twilight Saga: New Moon, and on "Guess Again!" from Yorke's album Tomorrow's Modern Boxes (2014).

In 2004, Greenwood participated on a panel in the annual sixth-form conference run by Radley College in collaboration with School of St Helen and St Katharine, speaking about digital rights management. In 2013, he soundtracked a Dries van Noten runway show, performing solo bass guitar. In 2018, he reviewed Michael Palin's book Erebus: The Story of a Ship for the Spectator.

In late 2022, Greenwood toured Australia as part of Nick Cave and Warren Ellis's band. He appears on the live album Australian Carnage. Greenwood joined Cave's North American tour in September 2023, and contributed bass to Cave's 2024 album Wild God. In October 2024, Greenwood is due to publish a book, How to Disappear: A Portrait of Radiohead, comprising his photographs of Radiohead taken between 2003 and 2016.

Personal life
In December 1998, Greenwood married Molly McGrann, an American literary critic and novelist. They have three sons, Jesse, born in December 2003; Asa, born in December 2005; and Henry, born in December 2009. They live in Oxford.

Greenwood enjoys writers such as Thomas Pynchon, V.S. Naipaul and Delmore Schwartz. Greenwood is an amateur photographer. In 2003, he discussed his favourite photographs in the Victoria and Albert Museum, choosing images by photographers including Frederick Sommer and Harold Edgerton.

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

title: Colin Greenwood


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Philip Selway

Philip James Selway (born 23 May 1967) is an English musician and the drummer of the rock band Radiohead. He combines rock drumming with electronic percussion. Selway was inducted into the Rock and Roll Hall of Fame as a member of Radiohead in 2019.

In 2010, Selway released his debut solo album, Familial, comprising folk music. It was followed by Weatherhouse in 2014 and Strange Dance in 2023. He also composed the soundtrack for the 2017 film Let Me Go. In 2023, Selway played drums with the band Lanterns on the Lake.

Early life
Selway was born on 23 May, 1967, in Abingdon, Berkshire. He started learning to play drums and guitar at the age of 15 for "the social cachet and love of music". His earliest influences were Joy Division, the Clash and the Velvet Underground.

The members of Radiohead met while attending Abingdon School, a private school for boys. Selway, along with the guitarist Ed O'Brien, was in the year above the singer, Thom Yorke, and the bassist, Colin Greenwood, and three years above Colin's brother, the multi-instrumentalist Jonny Greenwood. In 1985, they formed, the name referring to their usual rehearsal day in the school's music room.

After Abingdon, Selway studied English and history at Liverpool Polytechnic. He also worked as a TEFL teacher, a copyeditor, and as a drummer in pit bands for touring musicals.

Radiohead
In 1991, On a Friday signed a recording contract with EMI and changed their name to Radiohead. They found early success with their 1992 single "Creep". Their third album, OK Computer (1997), brought them international fame and is often acclaimed as one of the best albums of all time. With their fourth album, Kid A (2000), Radiohead began integrating drum machines and other electronic percussion into their music. Selway said this widened his options and pushed him to create new dynamics, enabling him to express himself more creatively. Describing the process of arranging electronic tracks such as "Idioteque" for live performance, he said: "Trying to give that sense of the electronic in the piece but doing it through your 'normal' instrument playing — that naturally develops your own musical voice ... Performing those songs live definitely affected how I sounded and how I would approach drum parts."

Since 2011, Radiohead have performed with a second drummer, Clive Deamer. Describing their collaboration during Radiohead's 2012 King of Limbs tour, Selway said: "One [of us] played in the traditional way, the other almost mimicked a drum machine. It was push-and-pull, like kids at play, really interesting." Selway contributed drums to "Impossible Knots" on Yorke's third solo album, Anima (2019). In 2019, Selway testified at an inquest into the 2012 stage collapse that killed Radiohead's drum technician, Scott Johnson.

By 2011, Radiohead had sold more than 30 million albums worldwide. They were inducted into the Rock and Roll Hall of Fame in March 2019. In a speech at the induction ceremony, Selway said: "We may not be the greatest musicians around and we're certainly not the most media-friendly of bands. But we have become very adept at being Radiohead. And when that connects with people, it feels amazing." In 2008, Mojo wrote that Selway and Colin Greenwood were "surely the most inventive rhythm section working close to the rock mainstream". In the same year, Gigwise named Selway the 26th-greatest drummer of all time, praising his "mathematical precision".

Solo work
Selway wrote songs as a teenager, but concentrated on drumming after forming Radiohead. He began writing again later in life, but decided the songs had a distinct character that did not fit Radiohead. Selway's debut solo album, Familial, was released on 30 August 2010. It features Selway on acoustic guitar and vocals, and performances from the Wilco members Glenn Kotche and Pat Sansone and the 7 Worlds Collide artists Lisa Germano and Sebastian Steinberg. Pitchfork described it as a collection of "hushed" folk songs in the tradition of Nick Drake. Selway began a solo tour in 2011. On 25 July, he released an EP, Running Blind, comprising songs left off Familial rerecorded with a full band.

Selway's second solo album, Weatherhouse, was released on 6 October 2014, featuring more ambitious instrumentation and electronic elements. In 2017, Selway composed the score for the feature film Let Me Go, directed by Polly Steele. His third solo album, Strange Dance, was released on 24 February 2023. He chose not to drum on the album, finding he was out of practice and "not in the right mindset", and enlisted the Italian drummer Valentina Magaletti. He began a European tour that year.

Selway contributed a cover of the Nick Drake song "Fly" to The Endless Coloured Ways – The Songs of Nick Drake, a tribute album featuring various artists released on 7 July, 2023. Selway described Drake as an influence on his songwriting, and said: "If I had to shrink my record collection to just one artist, then that would be Nick Drake ... Nick Drake is an artist that I feel speaks to me and for me." On 8 December, Selway released a live album, Live at Evolution Studios, recorded with the string quartet Elysian Collective and the percussionist Chris Vatalaro in Evolution Studios, Oxford.

Other work
Selway is a supporter of the emotional support charity Samaritans, with which he became involved while a university student. He volunteered as a telephone listener for years, including at the height of Radiohead's success, and said this "probably kept my sanity in that period". He is also an ambassador for Independent Venue Week, an initiative that promotes small music venues. In 2014, Selway and O'Brien signed an open letter protesting a ban on guitars in British prisons and stating that music was important for rehabilitation.

Selway performed with the band Dive Dive in March 2005. For the 2005 film Harry Potter and the Goblet of Fire, Selway appeared as part of the wizard rock band Weird Sisters with the Radiohead guitarist Jonny Greenwood, Jarvis Cocker and Steve Mackey of Pulp, Steven Claydon of Add N to (X), and Jason Buckle of All Seeing I.

Selway toured and recorded with the New Zealand songwriter Neil Finn as part of the 7 Worlds Collide project. He drummed on their 2001 live album and provided drums, guitar and vocals on their 2009 studio album The Sun Came Out, for which he also wrote two tracks. Selway joined as a drummer, but was encouraged by Finn to contribute his own material. It was the first record for which Selway wrote songs and sang.

Selway appears on "Rest on the Rock" and "Out of Light" on the album Before the Ruin by Roddy Woomble, Kris Drever, and John McCusker. He played drums and percussion on the fifth album by Lanterns on the Lake, Versions of Us (2023), after the departure of their previous drummer, Ol Ketteringham. According to the songwriter, Hazel Wilde, Selway helped them create a "whole other version" of the album and restored their confidence in the songs.

Personal life
Selway and his wife, Cait, have three sons and a daughter. Selway's mother Thea died in May 2006; Radiohead cancelled a concert in Amsterdam so that Selway could carry out his family duties. They returned to Amsterdam in August to play the missed show. Radiohead's 2007 album In Rainbows was dedicated to Thea Selway. As of February 2023, Selway had recently moved to London.

title: Philip Selway


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Talk:Lawrencium

6d1 7s2 vs 7s2 7p1
Which is the energy gap between states? If the d-configuration is only some 0.01 eV above the p-configuration, then practically the atom has no definite ground state. Incnis Mrsi (talk) 08:13, 16 August 2019 (UTC)
 * according to this paper (10.1140/epjd/e2007-00136-3), the lowest 6d7s2 level has calculated excitation energy 1331 cm−1, i.e. 0.1650 eV. Double sharp (talk) 10:25, 16 August 2019 (UTC)
 * Then comparisons against Lu and La are based on the Mendeleyev–Madelung dogma only, whereas IRL the atom looks to be something like thallium, albeit lacking d10 which is virtually non-functional in this context. Incnis Mrsi (talk) 12:05, 16 August 2019 (UTC)
 * Not really. Chemical bond energies can go to several eV (C≡O is 11.16 eV), and the difference between the d- and the p-configuration is well within that. What is known of Lr chemistry is very much like Lu and not at all like Tl: there is no Lr(I) that would parallel Tl(I). Lr(II) and Lr(III) compounds usually parallel Lu(II) and Lu(III) componds (only Lr(III) is known experimentally while Lr(II) is calculated); [LrII(C5H4SiMe3)3]− is even expected to have a valence configuration of 6d1 for Lr, as described in the article. It seems from calculations (and partly from experiment for Lr) that although Lr and E121 both have anomalous s2p configurations where we would expect something else, it doesn't seem to affect ther chemistry much, which is that of a good eka-Lu and eka-Ac respectively, not that of heavier congeners to Tl. Thorium has a 6d2 7s2 configuration in the ground state, with the first 5f electron appearing only at 0.966 eV, but no one doubts that Th is an f-block metal (it is even 5f1 in the +3 state). Double sharp (talk) 14:27, 16 August 2019 (UTC)
 * Wait… how far from the ground is 6p of lutetium? The same site claims it is within some 0.51 eV against 2.07 for thulium, 2.14 for ytterbium, 1.74 for hafnium, and 2.15 for tantalum. Seems that Lu can normally use the p-subshell for chemistry? If it can, then yes, we can agree that the two elements are congeners, and Lu with its little family is in some respect different from neighboring groups. Incnis Mrsi (talk) 16:43, 16 August 2019 (UTC)
 * … and 1.30 for yttrium. Lu and Lr are no members of group 3, dammit. It is rather lanthanum (having the nearest 6p at 1.64 eV) a congener of yttrium. Incnis Mrsi (talk) 16:58, 16 August 2019 (UTC)
 * The trend of the p-configurations lowering down the table seems to be shared with group 4: for Hf, 5d26s16p1 is at 1.74 eV, but for Rf 6d17s27p1 is expected to be at around 0.3 eV (10.1103/PhysRevLett.74.1079). (For Zr, 4d25s15p1 is at 1.83 eV, and for Ti, 3d24s14p1 is at 1.97 eV.) For a while it was actually also not certain if Rf had a 7p electron in the ground state or not. For the next groups we have Nb 2.07, Ta 2.15; Mo 3.18, W 2.40; Tc 2.04, Re 2.35; Ru 3.13, Os 2.80; Rh 3.36, Ir 3.26; Pd 4.22, Pt 3.74; Ag 3.66, Au 4.63; Cd 3.73, Hg 4.67. Due to relativistic stabilisation of 7p1/2 I would guess that at least some of these trends might drop precipitously for the 6d elements like we see for Rf. From what we know and have predicted it seems that the 6d elements are not actually that different from the 5d ones in spite of this: the homology only gets really bad at Nh. (It also does not seem to make much difference for Lu and Lr which act exactly like any other late lanthanide and actinide respectively.) So I wouldn't say that Lu and Lr in group 3 are ruled out by this (or else we'd have to say Rf is ruled out of being in group 4); group and block assignment is more about properties, and Lu and Lr act more like the other nine 5d and 6d metals than La and Ac do (because of f-contractions). Double sharp (talk) 03:53, 17 August 2019 (UTC)

"Laurentium" listed at Redirects for discussion
An editor has asked for a discussion to address the redirect Laurentium. Please participate in the redirect discussion if you wish to do so. Steel1943 (talk) 19:52, 20 September 2019 (UTC)
 * This seems to be a historical name suggestion. A Chemistry Stack Exchange answer quotes some past IUPAC deliberations from 1963 about it. I just haven't added it to the article because I can't find the original source. Double sharp (talk) 01:51, 6 November 2022 (UTC)

title: Talk:Lawrencium


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Superficial X-rays

Superficial X-rays are low-energy X-rays that do not penetrate very far before they are absorbed. They are produced by X-ray tubes operating at voltages in the 10–100 kV range, and therefore have peak energies in the 10–100 keV range. The Maximar-100 was a widely-adopted superficial radiation therapy unit.

Precise naming and definitions of energy ranges may vary, and X-rays at the lower end of this range may also be known as Grenz rays. They are useful in radiation therapy for the treatment of various benign or malignant skin problems, including skin cancer and severe eczema. They have a useful depth of up to 5 mm. In some locations, orthovoltage treatment is being replaced by electron therapy or brachytherapy.

As well as teletherapy, X-rays in this energy range (and the low orthovoltage range) are used for imaging patients, to analyse materials and objects in industrial radiography and for crystallography.

title: Superficial X-rays


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Orthovoltage X-rays

Orthovoltage X-rays are produced by X-ray tubes operating at voltages in the 100–500 kV range, and therefore the X-rays have a peak energy in the 100–500 keV range. Orthovoltage X-rays are sometimes termed "deep" X-rays (DXR). They cover the upper limit of energies used for diagnostic radiography, and are used in external beam radiotherapy to treat cancer and tumors. They penetrate tissue to a useful depth of about 4–6 cm. This makes them useful for treating skin, superficial tissues, and ribs, but not for deeper structures such as lungs or pelvic organs. The relatively low energy of orthovoltage X-rays causes them to interact with matter via different physical mechanisms compared to higher energy megavoltage X-rays or radionuclide γ-rays, increasing their relative biological effectiveness.

History
The energy and penetrating ability of the X-rays produced by an X-ray tube increases with the voltage on the tube. External beam radiotherapy began around the turn of the 20th century with ordinary diagnostic X-ray tubes, which used voltages below 150 kV. Physicians found that these were adequate for treating superficial tumors, but not tumors inside the body. Since these low energy X-rays were mostly absorbed in the first few centimeters of tissue, to deliver a large enough radiation dose to buried tumors would cause severe skin burns.

Therefore beginning in the 1920s "orthovoltage" 200–500 kV X-ray machines were built. These were found to be able to reach shallow tumors, but to treat tumors deep in the body more voltage was needed. By the 1930s and 1940s megavoltage X-rays produced by huge machines with 3–5 million volts on the tube, began to be employed. With the introduction of linear accelerators in the 1970s, which could produce 4–30 MV beams, orthovoltage X-rays are now considered quite shallow.

title: Orthovoltage X-rays


text:
Radiation oncologist

A radiation oncologist is a specialist physician who uses ionizing radiation (such as megavoltage X-rays or radionuclides) in the treatment of cancer. Radiation oncology is one of the three primary specialties, the other two being surgical and medical oncology, involved in the treatment of cancer. Radiation can be given as a curative modality, either alone or in combination with surgery and/or chemotherapy. It may also be used palliatively, to relieve symptoms in patients with incurable cancers. A radiation oncologist may also use radiation to treat some benign diseases, including benign tumors. In some countries (not the United States), radiotherapy and chemotherapy are controlled by a single oncologist who is a "clinical oncologist". Radiation oncologists work closely with other physicians such as surgical oncologists, interventional radiologists, internal medicine subspecialists, and medical oncologists, as well as medical physicists and technicians as part of the multi-disciplinary cancer team. Radiation oncologists undergo four years of oncology-specific training whereas oncologists who deliver chemotherapy have two years of additional training in cancer care during fellowship after internal medicine residency in the United States.

United States
In the United States, radiation oncologists undergo four years of residency (in addition to an internship), which is more dedicated to oncology training than any other medical specialty. During the four years of post-graduate training, residents learn about clinical oncology, the physics and biology of ionizing radiation, and the treatment of cancer patients with radiation. After completion of this training, a radiation oncologist may undergo certification by the American Board of Radiology (ABR). Board certification includes three written tests and an oral examination which is given only once per year. The written tests include separate exams in radiation physics, and radiobiology, clinical oncology, which is followed by an eight-part oral examination given in the late spring one year into practice. Successfully passing these tests leads to the granting of a time-limited board certification. Recertification is obtained via a series of continuing medical education and practice qualifications including a written exam, clinical practice parameter evaluation, continuing medical education credits, and meeting community practice standards.

India
Radiotherapy training in India encompasses the treatment of solid tumors in terms of Chemotherapy, radiation therapy, and palliative care in most states. Postgraduate MD degree is awarded after 3 years of post-MBBS in-service comprehensive training and a final university level exam. MD Radiation oncology practitioners are the most proficient oncologists in India delivering radiotherapy and chemotherapy. The first Radiotherapy department of Asia was set up in 1910 at Calcutta Medical College in the state of West Bengal and is still a leading oncology training center of India.

Canada
Radiation Oncology training in Canada is very similar to the United States. Radiation oncologists directly enter radiation oncology residencies of 5 years duration, with the first year as an internship year. During the next four years, residents complete intensive training in clinical oncology, in radiophysics and radiobiology, and in the treatment planning and delivery of radiotherapy. Most radiation oncologists also pursue a fellowship after their residency, examples of which include brachytherapy, intensity modulated radiation therapy (IMRT), gynecologic radiation oncology, and many others. Radiation oncologists in Canada commonly treat two or three different anatomic sites, such as head and neck, breast, genitourinary, hematologic, gynecologic, central nervous system, or lung cancer.

United Kingdom
In the United Kingdom, clinical oncologists, who practise radiotherapy are also fully qualified to administer chemotherapy. After completion of their basic medical degree, all oncologists must train fully in general internal medicine and pass the MRCP exam, normally 3–4 years after qualification. Following this, 5 years of Specialist Registrar (SpR) training is required in all non-surgical aspects of oncology in a recognised training program. During this time, the trainee must pass the FRCR examination in order to qualify for specialist registration as a clinical oncologist. A significant proportion of trainees will extend their time to undertake an academic fellowship, MD, or PhD. Almost all consultant clinical oncologists in the UK are Fellows of the Royal College of Radiologists, the governing body of the specialty. Whilst most oncologists will treat a selection of common general oncology cases, there is increasing specialisation, with the expectation that consultants will specialise in one or two subsites.

Australia and New Zealand
In Australia and New Zealand, The Royal Australian and New Zealand College of Radiologists (RANZCR Home | RANZCR) awards a Fellowship (FRANZCR) to trainees after a 5-year program and several sets of exams and modules. As in other countries, radiation oncologists tend to subspecialize although generalists will always exist in smaller centres. Although trained in the delivery of chemotherapy, radiation oncologists in Australia and New Zealand rarely prescribe it.

Iran
In Iran, radiation oncologists, who are trained in non-surgical aspects of oncology (including radiation therapy) directly enter a 5-year residency program after completion of 7 years of training in general medicine and acceptance in national comprehensive residency exam.

Nepal
In Nepal, only Bir Hospital runs residency program on Radiation Oncology, under NAMS. It's a 3 years residency program, and the main domains are Chemotherapy, Radiotherapy and Palliative Care.

Spain
In Spain Radiation Oncology Specialists undertake a 4 year specialization program and are recognized to apply both ionizing radiation therapies and chemotherapy. Most fellows follow the policies emerged from leading national society SEOR (Sociedad Española de Oncología Radioterápica).

Role of the Radiation oncologist
The Radiation oncologist is responsible for preparing the treatment plan where the radiation is required. Some of the treatment methods are radioactive implantations, external beam radiotherapy, hyperthermia, and combined modality therapy such as radiotherapy with surgery, chemotherapy, or immunotherapy.

Equipment
To provide the treatment correctly, a series of equipment is needed which will help to complement it. First, a simulator and treatment preparation must be carried out. This consists of locating the area where the tumor is located to know where exactly the patient will be exposed at the time of treatment. The equipment used to perform this work is a computed tomography (CT) scan, a Magnetic resonance imaging (MRI), and W x-ray. Subsequently, the site targeted for treatment is marked and an immobilizer is created which helps to limit exposure another body area to the radiation. To complement this immobilizer staff will employ tape, foam sponges, headrests, molds and plaster casts. When treatment is in the head and neck area a thermoplastic mask is employed. This mask is precisely molded to the patient's shape and secured it to fasteners on the treatment table. This improves patient stability. When the treatment plan is complete, the patient will be assigned (depending upon the type of cancer and its stage) appointments to perform the therapy and monitoring.

title: Radiation oncologist


text:
Talk:External beam radiotherapy

Tele-therapy?
This seems to be invalid title. It should be named External beam radiotherapy and possibly teletherapy should be a redirect. Kpjas

Protons/Light Ions?
Are you sure this isn't supposed to be "proton" instead of "photon" throughout the section? I hardly ever hear the word "photon" referenced to particle beams. I'd think they'd be more associated with laser applications. Fd-gunslinger (talk) 21:54, 1 December 2008 (UTC)

The article doesn't mention proton radiotherapy or light ion radiotherapy, both of which are variations of external beam RT. They are both becoming more common, and many believe light ions (combined with existing modalities) are the future of radiotherapy. I could slap something together, but I have no free time at the moment. AtomBum 03:52, 11 October 2005 (UTC)

 * "Photon" is correct. The article doesn't say much about how a medical linac works in the first place, and that generates some confusion. It also refers to X-rays as photons, which, while true, creates a little more confusion because it is a more abstract term. The way that a medical linac works (very briefly) is that it accelerates electrons first, taking advantage of their electrical and magnetic properties to push them to very high speeds in a straight line. This is done with both a voltage potential difference and a microwave beam. The electrons gain a large amount of kinetic energy through this process. Then, to produce x-rays, the electrons are directed into a target that stops them abruptly. Some of the electrons' kinetic energy is converted into x-rays, and these x-rays in turn are beamed into the patient. X-rays have no mass. They are pure electromagnetic radiation, just like visible light and radio waves. The term photon applies to a unit of electromagnetic radiation, whether it be visible light, x-rays, radiowaves, etc. --BAW (talk) 14:32, 26 February 2010 (UTC)

Cobalt
It would seem appropriate to mention cobalt machines together with Linacs. Cobalt EBRT has far more application on a world-wide basis than betatrons or exotic high LET particles.Jellytussle 23:10, 14 October 2005 (UTC)

 * The article does mention Co sources in the second paragraph. It could definitely be expanded upon, as it is very common.  The layout in that part is a little choppy; there's no reason to separate the radioisotope sources from the machines.  Proton therapy is hardly exotic, and there is already a wikipedia page on it, so a link should be provided at the very least.  Worldwide, proton therapy is becoming more and more common.  Also, there are carbon ion treatment centers in Europe and Japan, and quite a few are in the works (none in the US, our government doesn't chip in for that kind of thing...). The improvements these methods make (in the results I've read) over traditional EBRT warrant at least their mention.  AtomBum 20:30, 16 October 2005 (UTC)

Agreed, there is quite a lot of experience with proton therapy, though it is still limited in use in application, and in terms of number of centres worldwide (27) and total patients treated (~40000). I understand that 6 new proton facilities are being commissioned in the USA. Protons are not strictly speaking high LET particles. An up to date list of worldwide charged particle centres and patient totals is available from the "Particles" newsletter on www.ptog.com. I tried to paste it here but am unable to format. It is revealing. Pions have been abandoned worlwide. There are 2 C ion units in Japan, and 1 in Germany, and no clinical high LET anywhere else.Jellytussle 19:30, 5 January 2006 (UTC)

Error?
Neutrons

This is not a stub.
 * I've been bold and removed it. Could have been a request for someone to add more content, I suppose; if it was yours please add some content for it! Stonejag 10:14, 22 May 2007 (UTC)

Hadrons
I note sbHarris's recent amendment, and the link to the Triumf pion page, which is very old. In fact Triumf stopped using pions a number of years ago after their own research showed them to be of no real benefit e.g. Prostate cancer: Int J Radiat Oncol Biol Phys. 1999 Jan 1;43(1):47-55 Glioblastoma: Int J Radiat Oncol Biol Phys. 1997 Feb 1;37(3):491-7.

suggest delete mention of pions and the Triumf link. Jellytussle (talk) 16:17, 18 August 2011 (UTC)

See also comments in the Cobalt section above.Jellytussle (talk) 08:59, 19 August 2011 (UTC)

 * I think that it would be worthwhile to include a brief discussion of pions as a subject of historical interest, but I agree that we should make clear that they are no longer in clinical use. TenOfAllTrades(talk) 12:47, 19 August 2011 (UTC)

Someone with time could start a History of Radiotherapy page. IT is an interesting subject. Jellytussle (talk) 18:24, 21 August 2011 (UTC)

Need for synergy
The article on radiation therapy has a section on external beam radiotherapy which links to subtopics. That section should be a summary of this article, but there is not much congruence between these two right now.  Blue Rasberry   (talk)   14:10, 1 November 2013 (UTC)

"Teletherapy" listed at Redirects for discussion
An editor has asked for a discussion to address the redirect Teletherapy. Please participate in the redirect discussion if you wish to do so. Interstellarity (talk) 11:56, 25 April 2020 (UTC)

title: Talk:External beam radiotherapy


text:
Talk:Superficial X-rays

This article is not very meaningful by itself. What's the application (radiotherapy?), what's the wavelength, how are they generated?

title: Talk:Superficial X-rays


text:
Wellington College

Wellington College may refer to:

New Zealand

 * Wellington College, Wellington, New Zealand
 * Wellington College of Education, now the Faculty of Education of Victoria University of Wellington, New Zealand
 * Wellington Girls' College, Wellington, New Zealand

Other places

 * Wellington College, a fictional liberal arts college, setting of the 2005 novel On Beauty by Zadie Smith
 * Wellington College, Berkshire, an independent school in Crowthorne, Berkshire, England
 * Wellington College International Shanghai
 * Wellington College International Tianjin
 * Wellington College Belfast, a grammar school in Belfast, Northern Ireland
 * Wellington Secondary College, a state high school in Mulgrave, Melbourne, Victoria, Australia

title: Wellington College


text:
Talk:Wellington College

I have moved Wellington College (New Zealand) to the top of the list on this page as it has the largest school roll and it is therefore the most common usage of the term "Wellington College". Such an ordering is required by the Wikipedia policy on the the ordering of disambiguation pages (that they should be in order of the most commonly used). Although Wellington Girls' College has a greter school roll than Wellington College, Berkshire, I have left it on the bottom of the list as it is not actually called "Wellington College" and is therefore not a common usage of the term "Wellington College". I have not been able to find school roll information for the other two colleges on this list so I have not changed their position on the list. If someone else has this information they should fix the page accordingly. --Jol123 12:29, 31 March 2007 (UTC)

title: Talk:Wellington College


text:
User talk:Clattuc

Unspecified source for Image:Ockeghem.jpg
Thanks for uploading Image:Ockeghem.jpg. I noticed that the file's description page currently doesn't specify who created the content, so the copyright status is unclear. If you did not create this file yourself, then you will need to specify the owner of the copyright. If you obtained it from a website, then a link to the website from which it was taken, together with a restatement of that website's terms of use of its content, is usually sufficient information. However, if the copyright holder is different from the website's publisher, then their copyright should also be acknowledged.

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If you have uploaded other files, consider checking that you have specified their source and tagged them, too. You can find a list of files you have uploaded by following [ this link]. Unsourced and untagged images may be deleted one week after they have been tagged, as described on criteria for speedy deletion. If the image is copyrighted under a non-free license (per Fair use) then the image will be deleted 48 hours after 20:45, 27 June 2008 (UTC). If you have any questions please ask them at the Media copyright questions page. Thank you. Do you want to opt out of receiving this notice? OsamaK 20:45, 27 June 2008 (UTC)

title: User talk:Clattuc


text:
User talk:IceKarma

= Old =

= New =

title: User talk:IceKarma


text:
User talk:Hauser

Greetings! I hope you like the place and decide to stay. If you have questions or doubts of any sort, do not hesitate to post them on the Village Pump, somebody will respond ASAP. Other helpful pages include: Have fun! --Jiang 09:10 20 Jul 2003 (UTC)
 * Welcome, newcomers
 * How does one edit a page
 * Manual of style
 * Naming conventions

Welcome aboard. The Kiwi Wikipedians are obviously a very special bunchPing 09:35 20 Jul 2003 (UTC)

No prob. :) You can sign you name w/ three or four "~". It's a lot easier that way. --Jiang

Thanks for the comments, Culture in NZ was mostly Cameron Dewes, I did no more than tweak it slightly. If you don't agree with any thing feel free to change it. Ping 07:54 21 Jul 2003 (UTC)

Hi Hauser,

I hope I didn't step on your toes with my edit on 1948 Arab-Israeli War, but the Arab-Israeli conflict in general is one of the most contentious topics on wikipedia, and so we all have to take special care to treat each subject in the proper place, or else edit wars quickly spread across lots and lots of different pages. Feel free to reinsert it into another article (not sure exactly which one), though many people will edit it, for sure.

Peace,

DanKeshet

I think the main thing the 1948 war article needs is some more facts on the war. It's very sparse right now... But for the demographic outcome, it would be a good idea to link to the existing articles we have right now on Palestinian exodus and Palestinian refugee. In fact, that would help the article quite a bit. Peace, DanKeshet

esTotW
Since you put your name down as a spanish to english traslator i thought you might be interested in the new Spanish translation of the week collaboration project. This weeks collaboration is Género chico.(Disclosure: this is a bit of a "mass mailing", I'm working my way down the list of Spanish-to-English translators.)

paz y amor, The bellman 06:26, 24 Oct 2004 (UTC)

Spanish Translation of the Week
I would like to revive this project. I noticed that you've added yourself to the list of available Spanish-to-English translators. Are you interested in working on Spanish Translation of the Week? — J3ff 06:19, 21 Feb 2005 (UTC)

This week's Spanish translation is Hispania. Please help out with the article. Thanks — J3ff 07:06, 28 Feb 2005 (UTC)

Rfc regarding National Bolshevik Party
Please check out and comment on the Rfc filed against me for trying to have NBP libel about me removed. Requests_for_comment/69.253.195.228

Thanks you, Peter D. Ekman 69.253.195.228 14:05, 18 November 2005 (UTC)

Thanks for Contributing
Just wanted to thank you for your contribution to a brief discussion about 'Reds' and their contribution to Wikipedia on the Fascism Project talk page. Glad to know (of) you! --Dschor 10:23, 2 December 2005 (UTC)

Good Edit
I am happy with your recent edit. It achieves more balance. I was just aware that the New Zealand Herald is turning a lot of archived material in to premium content. Cheers, (Bofors40 11:24, 18 December 2005 (UTC))

AfD for Right- and Left- wing terrorism - have your say
Please take a look at Articles for deletion/Right-wing terrorism and also Articles for deletion/Left-wing terrorism and have your say, if possible. Thanks.

Welfare maniaC?
What are your recent edits on Economy of New Zealand supposed to be about? Should I think you're a left-wing pork-barrel nostalgic? Just asking. I'm new here and want to know what the boundaries of "POV" are. LibertariaNZgo 04:58, 14 May 2006 (UTC)

 * Left wing pork barrel nostalgic??? Get a user account, and learn that this isn't the place for insults, mate. I'm no such thing in Wikipedia. I would've added a free market/libertarian perspective on the New Zealand economy if it was dominated by left wing discourse (it was quite the opposite when I first found it). Neutral Point Of View is a major policy of the Wikipedia, and basically the idea is that you fairly balance articles to show the major points of difference over issues, not leaning toward one or another.

Mmm. I see. Sorry, mate.LibertariaNZgo 17:29, 14 May 2006 (UTC)

Speedy Deletion
Thanks for having the guts and conscience to pseak up about this Winstonwolfe 05:57, 6 June 2006 (UTC)

WikiProject Organized Labour
Hi Hauser. I saw your name at the project and just thought I would say hello, and welcome. Cheers.--Bookandcoffee 21:58, 6 June 2006 (UTC)

Ladino language
Hi!

I have a question for you as a Ladino speaker, in the articles about Ladino language, i found no information about the uses of 2nd person in Ladino. In Castillian, the 2nd person is quite important in dialectology (uses of vos-voseo-, uses of vosotros, vosotras, ustedes, etc), so if you know sth about that your contributions are more than welcome in the Spanish and English wikipedias.

Thanks

Gaudio 10:09, 8 June 2006 (UTC)
 * Well, it's up to you, i can speak both languages so if you're more confortable in Castillian, we can speak that tongue, you decide.

 * If you want to call me usted, you make me feel older, i'm only 25, but if you're more confortable, do it please :)

 * Hmm, about 2nd person in Spanish, hmm, there are some important differences among the dialects, that was the reason of my question. I input a litte sketch for you:

(In Spain, Maroc, Equatorial Guinea)
 * SINGULAR
 * tú: informal
 * usted:formal
 * PLURAL
 * vosotros, vosotras:informal
 * ustedes:formal

(in some parts of the South of Spain, Canary Islands and America)
 * SINGULAR
 * tú: informal
 * usted:formal
 * PLURAL
 * ustedes:only

(this system is also different in some parts of America, for instance Argentina) (voseo)
 * SINGULAR
 * vos: informal
 * usted:formal
 * PLURAL
 * ustedes:only

 * This can help you too:T-V distinction. So if you know a little, i guess you can put Ladino in one of those systems, right? Or maybe it's completely different, please do surprise me :)

Gaudio 13:24, 8 June 2006 (UTC)
 * Sure, it will be very useful. I guess when Castillian and Ladino split up that system was not created. It's much more complex than what i input the other day, you have to consider forms such as usuía, useñoría among others. I'm going to write something about what you told me :)

 * You know?, i'm learning Mandarin right now, i saw yo speak a little Mandarin. It's a very different language from those i'm used to, ay ay ay. Now i'm trying to find a program to change the pinyin to Chinese characters, they told me there is one somewhere.

 * CUÍDATE! zàijiàn Gaudio 19:05, 12 June 2006 (UTC)

Me vienes como caído del cielo
Thank you so much for all that information. If the system you asked me is Windows, i have to say Windows, right? I'm not very good with computation, today it's not the best day to install things, i'm afraid of viruses, that makes me supersticious i guess.

About what you told me about Ladino, don't be shy to write about that in the articles :)

Have a nice day

Gaudio 09:06, 13 June 2006 (UTC)

 * Yes, Hauser, i've got that, but they told me there was a method to change pinyin to ideograms. You typewrite in pinyin and it appears in Chinese characters, i've got everything the CD, etc...But i don't know if that's true and if i can :( Gaudio 13:18, 13 June 2006 (UTC)

Hey There
Thanks for that. If theres anything I need, I'll get in touch. Cheers Mattlore 03:49, 19 June 2006 (UTC)

Communitarian/Radical Centrist Forum
Interesting... I have in the past wanted to get something of a discussion place online that could serve as the source for a broader movement(s?). I'm not sure what you have in mind, but I would be interested in helping. Juan Ponderas

Hi there. Have you ever read this? ;) Justice III 18:42, 19 June 2006 (UTC)
 * Yes. It is an interesting conspiracy theory, reminds me of the New Chronology but with no academic backing. My more extensive arguments on it are on the talk page for Communitarianism, where I debated the creator of that site. Materialism is a discipline of complete mysticism. Juan Ponderas

 * To quote the first line of the second paragraph "Communitarians teach that all free American neighborhoods should be governed like Chinese-Soviet community collectives (Etzioni 1992)." That would probably fix the States up a little bit, Justice, get some solidarity going between Wall Street Bankers and immigrant workers at all those McDonald's around Wall Street ;). My real question is, though, what the writer defines as 'unfree' American neighbourhoods assuming that the adjective wasn't added there as a rhetorical device. Juan Ponderas, in terms of creating a discussion place, I was thinking of a sort of forum that we could post ideas and such like, and then everyone talks and debates them, with an obvious base around Communitarian (and also radical centrist of course) ideas. There really isn't anything like that for Communitarianism these days. I may be able to rig up a forum or such like at one of my websites (hosted in NZ though). Cheers, Hauser 22:54, 19 June 2006 (UTC)

Auckland Meetup 2 Scheduled - Feb 10 2007
You are invited to Auckland Meetup 2 on the afternoon of Saturday February 10th 2007 at Galbraith's Ale House in Mt Eden. Please see Meetup/Auckland 2 for details. You can also bookmark Meetup/Auckland to be informed of future NZ meetups. - SimonLyall 06:52, 7 January 2007 (UTC)

Rock music Wikiproject invitation
Hello WikiProject Metal member. WikiProject Metal music is important in expanding encyclopedic coverage of the metal. It brings attention to the lesser-known bands, and significantly improves the quality of the famous ones. Five Featured articles and two formers is proof of that. This is the stuff I wish to achieve with the somewhat recently resurrected WikiProject Rock music. I hope to also attract attention to rock music articles of all sorts, and hopefully change some to GA or FA status. I invite you to come join us, and embrace the links between metal and rock music in general. Rock on. -- Reaper  X  04:53, 18 February 2007 (UTC)

Meetup
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AfD nomination of Multiracialism
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Proposed deletion of Reference point
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AfD nomination of Reference point
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Synthetic fuel
Hi, Hauser. There is a plan to improve the Synthetic fuel article to the GA level. In this process, there are still several issues, which should be done before renominating this article for GAN. As you have contributed to the article and/or discussion, you may be interested to participate in the discussion about the article improvement. Thank you. Beagel (talk) 07:22, 27 June 2009 (UTC)

Unreferenced BLPs
Hello Hauser! Thank you for your contributions. I am a bot alerting you that 2 of the articles that you created  are tagged as Unreferenced Biographies of Living Persons. The biographies of living persons policy requires that all personal or potentially controversial information be sourced. In addition, to insure verifiability, all biographies should be based on reliable sources. if you were to bring these articles up to standards, it would greatly help us with the current Category:All_unreferenced_BLPs article backlog. Once the articles are adequately referenced, please remove the unreferencedBLP tag. Here is the list:

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Articles_for_deletion/Jed_Brandt_(activist)
I'll take your personal comments about me to task here, rather than on the AfD. If you're going to make assertions of prejudice and assume bad faith on the part of another editor, at least have the decency to get to know the real person upon whom you're casting aspersions. I made honest assessments of the article and what I could glean from my own searches. Call me out on that, but do not presume to know my motivations. As far as you know, my motivations are to support this project. - CobaltBlueTony™ talk 14:02, 3 March 2010 (UTC)

Auckland Meetup 5 on 9 May 2010
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Proposed deletion of New Zealand First candidates in the 2005 general election

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ArbCom elections are now open!
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Organized labour project
Hi - I noticed you are one of the original members of the organized labour project. I'm contacting active original members as the project has fallen inactive of late and have a couple of thoughts of getting things moving again: --Goldsztajn (talk) 12:01, 1 November 2019 (UTC)
 * redesign of the project page using the new project x tool - some examples here Wikipedia:WikiProject_X/Dashboard
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Nomination of Cultural institution for deletion
A discussion is taking place as to whether the article Cultural institution is suitable for inclusion in Wikipedia according to Wikipedia's policies and guidelines or whether it should be deleted.

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Left-wing terrorism
Hi, I've listed Left-Wing terrorism in Articles for Deletion. You were involved previously when it was discussed and you may be interested. AlanStalk 09:04, 29 July 2023 (UTC)

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User talk:Xouper

Greetings! I hope you like the place and decide to stay. If you have questions or doubts of any sort, do not hesitate to post them on the Village Pump, somebody will respond ASAP. Other helpful pages include: Have fun! --Jiang 09:11 20 Jul 2003 (UTC)
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Linear particle accelerator

A linear particle accelerator (often shortened to linac) is a type of particle accelerator that accelerates charged subatomic particles or ions to a high speed by subjecting them to a series of oscillating electric potentials along a linear beamline. The principles for such machines were proposed by Gustav Ising in 1924, while the first machine that worked was constructed by Rolf Widerøe in 1928 at the RWTH Aachen University. Linacs have many applications: they generate X-rays and high energy electrons for medicinal purposes in radiation therapy, serve as particle injectors for higher-energy accelerators, and are used directly to achieve the highest kinetic energy for light particles (electrons and positrons) for particle physics.

The design of a linac depends on the type of particle that is being accelerated: electrons, protons or ions. Linacs range in size from a cathode-ray tube (which is a type of linac) to the 3.2 km linac at the SLAC National Accelerator Laboratory in Menlo Park, California.

History
In 1924, Gustav Ising published the first description of a linear particle accelerator using a series of accelerating gaps. Particles would proceed down a series of tubes. At a regular frequency, an accelerating voltage would be applied across each gap. As the particles gained speed while the frequency remained constant, the gaps would be spaced farther and farther apart, in order to ensure the particle would see a voltage applied as it reached each gap. Ising never successfully implemented this design.

Rolf Wideroe discovered Ising's paper in 1927, and as part of his PhD thesis he built an 88-inch long, two gap version of the device. Where Ising had proposed a spark gap as the voltage source, Wideroe used a 25kV vacuum tube oscillator. He successfully demonstrated that he had accelerated sodium and potassium ions to an energy of 50,000 electron volts (50 keV), twice the energy they would have received if accelerated only once by the tube. By successfully accelerating a particle multiple times using the same voltage source, Wideroe demonstrated the utility of radio frequency (RF) acceleration.

This type of linac was limited by the voltage sources that were available at the time, and it was not until after World War II that Luis Alvarez was able to use newly developed high frequency oscillators to design the first resonant cavity drift tube linac. An Alvarez linac differs from the Wideroe type in that the RF power is applied to the entire resonant chamber through which the particle travels, and the central tubes are only used to shield the particles during the decelerating portion of the oscillator's phase. Using this approach to acceleration meant that Alvarez's first linac was able to achieve proton energies of 31.5 MeV in 1947, the highest that had ever been reached at the time.

The initial Alvarez type linacs had no strong mechanism for keeping the beam focused and were limited in length and energy as a result. The development of the strong focusing principle in the early 1950s led to the installation of focusing quadrupole magnets inside the drift tubes, allowing for longer and thus more powerful linacs. Two of the earliest examples of Alvarez linacs with strong focusing magnets were built at CERN and Brookhaven National Laboratory.

In 1947, at about the same time that Alvarez was developing his linac concept for protons, William Hansen constructed the first travelling-wave electron accelerator at Stanford University. Electrons are sufficiently lighter than protons that they achieve speeds close to the speed of light early in the acceleration process. As a result, "accelerating" electrons increase in energy but can be treated as having a constant velocity from an accelerator design standpoint. This allowed Hansen to use an accelerating structure consisting of a horizontal waveguide loaded by a series of discs. The 1947 accelerator had an energy of 6 MeV. Over time, electron acceleration at the SLAC National Accelerator Laboratory would extend to a size of 2 mi and an output energy of 50 GeV.

As linear accelerators were developed with higher beam currents, using magnetic fields to focus proton and heavy ion beams presented difficulties for the initial stages of the accelerator. Because the magnetic force is dependent on the particle velocity, it was desirable to create a type of accelerator which could simultaneously accelerate and focus low-to-mid energy hadrons. In 1970, Soviet physicists I. M. Kapchinsky and Vladimir Teplyakov proposed the radio-frequency quadrupole (RFQ) type of accelerating structure. RFQs use vanes or rods with precisely designed shapes in a resonant cavity to produce complex electric fields. These fields provide simultaneous acceleration and focusing to injected particle beams.

Beginning in the 1960s, scientists at Stanford and elsewhere began to explore the use of superconducting radio frequency cavities for particle acceleration. Superconducting cavities made of niobium alloys allow for much more efficient acceleration, as a substantially higher fraction of the input power could be applied to the beam rather than lost to heat. Some of the earliest superconducting linacs included the Superconducting Linear Accelerator (for electrons) at Stanford and the Argonne Tandem Linear Accelerator System (for protons and heavy ions) at Argonne National Laboratory.

Radiofrequency acceleration
When a charged particle is placed in an electromagnetic field it experiences a force given by the Lorentz force law:

 * $$\vec{F} = q \vec{E} + q \vec{v} \times \vec{B}$$

where $$q$$ is the charge on the particle, $$\vec{E}$$ is the electric field, $$\vec{v}$$ is the particle velocity, and $$\vec{B}$$ is the magnetic field. The cross product in the magnetic field term means that static magnetic fields cannot be used for particle acceleration, as the magnetic force acts perpendicularly to the direction of particle motion.

As electrostatic breakdown limits the maximum constant voltage which can be applied across a gap to produce an electric field, most accelerators use some form of RF acceleration. In RF acceleration, the particle traverses a series of accelerating regions, driven by a source of voltage in such a way that the particle sees an accelerating field as it crosses each region. In this type of acceleration, particles must necessarily travel in "bunches" corresponding to the portion of the oscillator's cycle where the electric field is pointing in the intended direction of acceleration.

If a single oscillating voltage source is used to drive a series of gaps, those gaps must be placed increasingly far apart as the speed of the particle increases. This is to ensure that the particle "sees" the same phase of the oscillator's cycle as it reaches each gap. As particles asymptotically approach the speed of light, the gap separation becomes constant: additional applied force increases the energy of the particles but does not significantly alter their speed.

Focusing
In order to ensure particles do not escape the accelerator, it is necessary to provide some form of focusing to redirect particles moving away from the central trajectory back towards the intended path. With the discovery of strong focusing, quadrupole magnets are used to actively redirect particles moving away from the reference path. As quadrupole magnets are focusing in one transverse direction and defocusing in the perpendicular direction, it is necessary to use groups of magnets to provide an overall focusing effect in both directions.

Phase stability
Focusing along the direction of travel, also known as phase stability, is an inherent property of RF acceleration. If the particles in a bunch all reach the accelerating region during the rising phase of the oscillating field, then particles which arrive early will see slightly less voltage than the "reference" particle at the center of the bunch. Those particles will therefore receive slightly less acceleration and eventually fall behind the reference particle. Correspondingly, particles which arrive after the reference particle will receive slightly more acceleration, and will catch up to the reference as a result. This automatic correction occurs at each accelerating gap, so the bunch is refocused along the direction of travel each time it is accelerated.

Construction and operation

A linear particle accelerator consists of the following parts:
 * A straight hollow pipe vacuum chamber which contains the other components. It is evacuated with a vacuum pump so that the accelerated particles will not collide with air molecules. The length will vary with the application. If the device is used for the production of X-rays for inspection or therapy, then the pipe may be only 0.5 to 1.5 meters long. If the device is to be an injector for a synchrotron, it may be about ten meters long. If the device is used as the primary accelerator for nuclear particle investigations, it may be several thousand meters long.
 * The particle source (S) at one end of the chamber which produces the charged particles which the machine accelerates. The design of the source depends on the particle that is being accelerated. Electrons are generated by a cold cathode, a hot cathode, a photocathode, or radio frequency ion sources. Protons are generated in an ion source, which can have many different designs. If heavier particles are to be accelerated, (e.g., uranium ions), a specialized ion source is needed. The source has its own high voltage supply to inject the particles into the beamline.
 * Extending along the pipe from the source is a series of open-ended cylindrical electrodes (C1, C2, C3, C4), whose length increases progressively with the distance from the source. The particles from the source pass through these electrodes. The length of each electrode is determined by the frequency and power of the driving power source and the particle to be accelerated, so that the particle passes through each electrode in exactly one-half cycle of the accelerating voltage. The mass of the particle has a large effect on the length of the cylindrical electrodes; for example an electron is considerably lighter than a proton and so will generally require a much smaller section of cylindrical electrodes as it accelerates very quickly.
 * A target with which the particles collide, located at the end of the accelerating electrodes. If electrons are accelerated to produce X-rays, then a water-cooled tungsten target is used. Various target materials are used when protons or other nuclei are accelerated, depending upon the specific investigation. Behind the target are various detectors to detect the particles resulting from the collision of the incoming particles with the atoms of the target. Many linacs serve as the initial accelerator stage for larger particle accelerators such as synchrotrons and storage rings, and in this case after leaving the electrodes the accelerated particles enter the next stage of the accelerator.
 * An electronic oscillator and amplifier (G) which generates a radio frequency AC voltage of high potential (usually thousands of volts) which is applied to the cylindrical electrodes. This is the accelerating voltage which produces the electric field which accelerates the particles. Opposite phase voltage is applied to successive electrodes. A high power accelerator will have a separate amplifier to power each electrode, all synchronized to the same frequency.

As shown in the animation, the oscillating voltage applied to alternate cylindrical electrodes has opposite polarity (180° out of phase), so adjacent electrodes have opposite voltages. This creates an oscillating electric field (E) in the gap between each pair of electrodes, which exerts force on the particles when they pass through, imparting energy to them by accelerating them. The particle source injects a group of particles into the first electrode once each cycle of the voltage, when the charge on the electrode is opposite to the charge on the particles. Each time the particle bunch passes through an electrode, the oscillating voltage changes polarity, so when the particles reach the gap between electrodes the electric field is in the correct direction to accelerate them. Therefore, the particles accelerate to a faster speed each time they pass between electrodes; there is little electric field inside the electrodes so the particles travel at a constant speed within each electrode.

The particles are injected at the right time so that the oscillating voltage differential between electrodes is maximum as the particles cross each gap. If the peak voltage applied between the electrodes is $$V_p$$ volts, and the charge on each particle is $$q$$ elementary charges, the particle gains an equal increment of energy of $$qV_p$$ electron volts when passing through each gap. Thus the output energy of the particles is
 * $$E = qNV_p$$

electron volts, where $$N$$ is the number of accelerating electrodes in the machine.

At speeds near the speed of light, the incremental velocity increase will be small, with the energy appearing as an increase in the mass of the particles. In portions of the accelerator where this occurs, the tubular electrode lengths will be almost constant. Additional magnetic or electrostatic lens elements may be included to ensure that the beam remains in the center of the pipe and its electrodes. Very long accelerators may maintain a precise alignment of their components through the use of servo systems guided by a laser beam.

Concepts in development
Various new concepts are in development as of 2021. The primary goal is to make linear accelerators cheaper, with better focused beams, higher energy or higher beam current.

Induction linear accelerator
Induction linear accelerators use the electric field induced by a time-varying magnetic field for acceleration—like the betatron. The particle beam passes through a series of ring-shaped ferrite cores standing one behind the other, which are magnetized by high-current pulses, and in turn each generate an electrical field strength pulse along the axis of the beam direction. Induction linear accelerators are considered for short high current pulses from electrons but also from heavy ions. The concept goes back to the work of Nicholas Christofilos. Its realization is highly dependent on progress in the development of more suitable ferrite materials. With electrons, pulse currents of up to 5 kiloamps at energies up to 5 MeV and pulse durations in the range of 20 to 300 nanoseconds were achieved.

Energy recovery linac
In previous electron linear accelerators, the accelerated particles are used only once and then fed into an absorber (beam dump), in which their residual energy is converted into heat. In an energy recovery linac (ERL), the accelerated in resonators and, for example, in undulators. The electrons used are fed back through the accelerator, out of phase by 180 degrees. They therefore pass through the resonators in the decelerating phase and thus return their remaining energy to the field. The concept is comparable to the hybrid drive of motor vehicles, where the kinetic energy released during braking is made available for the next acceleration by charging a battery.

The Brookhaven National Laboratory and the Helmholtz-Zentrum Berlin with the project "bERLinPro" reported on corresponding development work. The Berlin experimental accelerator uses superconducting niobium cavity resonators. In 2014, three free-electron lasers based on ERLs were in operation worldwide: in the Jefferson Lab (US), in the Budker Institute of Nuclear Physics (Russia) and at JAEA (Japan). At the University of Mainz, an ERL called MESA is expected to begin operation in 2024.

Compact Linear Collider
The concept of the Compact Linear Collider (CLIC) (original name CERN Linear Collider, with the same abbreviation) for electrons and positrons provides a traveling wave accelerator for energies of the order of 1 tera-electron volt (TeV). Instead of the otherwise necessary numerous klystron amplifiers to generate the acceleration power, a second parallel electron linear accelerator of lower energy is to be used, which works with superconducting cavities in which standing waves are formed. High-frequency power is extracted from it at regular intervals and transmitted to the main accelerator. In this way, the very high acceleration field strength of 80 MV / m should be achieved.

Kielfeld accelerator (plasma accelerator)
In cavity resonators, the dielectric strength limits the maximum acceleration that can be achieved within a certain distance. This limit can be circumvented using accelerated waves in plasma to generate the accelerating field in Kielfeld accelerators: A laser or particle beam excites an oscillation in a plasma, which is associated with very strong electric field strengths. This means that significantly (factors of 100s to 1000s ) more compact linear accelerators can possibly be built. Experiments involving high power lasers in metal vapour plasmas suggest that a beam line length reduction from some tens of metres to a few cm is quite possible.

Compact medical accelerators
The LIGHT program (Linac for Image-Guided Hadron Therapy) hopes to create a design capable of accelerating protons to 200MeV or so for medical use over a distance of a few tens of metres, by optimising and nesting existing accelerator techniques The current design (2020) uses the highest practical bunch frequency (currently ~ 3 GHz) for a Radio-frequency quadrupole (RFQ) stage from injection at 50kVdC  to ~5MeV bunches,  a  Side  Coupled  Drift  Tube  Linac  (SCDTL) to accelerate from 5Mev to ~ 40MeV and a Cell Coupled Linac (CCL) stage final, taking the output to 200-230MeV. Each stage is optimised to allow close coupling and synchronous operation during the beam energy build-up. The project aim is to make proton therapy a more accessible mainstream medicine as an alternative to existing radio therapy.

Modern concepts
The higher the frequency of the acceleration voltage selected, the more individual acceleration thrusts per path length a particle of a given speed experiences, and the shorter the accelerator can therefore be overall. That is why accelerator technology developed in the pursuit of higher particle energies, especially towards higher frequencies.

The linear accelerator concepts (often called accelerator structures in technical terms) that have been used since around 1950 work with frequencies in the range from around to a few gigahertz (GHz) and use the electric field component of electromagnetic waves.

Standing waves and traveling waves
When it comes to energies of more than a few MeV, accelerators for ions are different from those for electrons. The reason for this is the large mass difference between the particles. Electrons are already close to the speed of light, the absolute speed limit, at a few MeV; with further acceleration, as described by relativistic mechanics, almost only their energy and momentum increase. On the other hand, with ions of this energy range, the speed also increases significantly due to further acceleration.

The acceleration concepts used today for ions are always based on electromagnetic standing waves that are formed in suitable resonators. Depending on the type of particle, energy range and other parameters, very different types of resonators are used; the following sections only cover some of them. Electrons can also be accelerated with standing waves above a few MeV. An advantageous alternative here, however, is a progressive wave, a traveling wave. The phase velocity the traveling wave must be roughly equal to the particle speed. Therefore, this technique is only suitable when the particles are almost at the speed of light, so that their speed only increases very little.

The development of high-frequency oscillators and power amplifiers from the 1940s, especially the klystron, was essential for these two acceleration techniques. The first larger linear accelerator with standing waves - for protons - was built in 1945/46 in the Lawrence Berkeley National Laboratory under the direction of Luis W. Alvarez. The frequency used was. The first electron accelerator with traveling waves of around was developed a little later at Stanford University by W.W. Hansen and colleagues. In the two diagrams, the curve and arrows indicate the force acting on the particles. Only at the points with the correct direction of the electric field vector, i.e. the correct direction of force, can particles absorb energy from the wave. (An increase in speed cannot be seen in the scale of these images.)

Advantages

The linear accelerator could produce higher particle energies than the previous electrostatic particle accelerators (the Cockcroft-Walton accelerator and Van de Graaff generator) that were in use when it was invented. In these machines, the particles were only accelerated once by the applied voltage, so the particle energy in electron volts was equal to the accelerating voltage on the machine, which was limited to a few million volts by insulation breakdown. In the linac, the particles are accelerated multiple times by the applied voltage, so the particle energy is not limited by the accelerating voltage.

High power linacs are also being developed for production of electrons at relativistic speeds, required since fast electrons traveling in an arc will lose energy through synchrotron radiation; this limits the maximum power that can be imparted to electrons in a synchrotron of given size. Linacs are also capable of prodigious output, producing a nearly continuous stream of particles, whereas a synchrotron will only periodically raise the particles to sufficient energy to merit a "shot" at the target. (The burst can be held or stored in the ring at energy to give the experimental electronics time to work, but the average output current is still limited.) The high density of the output makes the linac particularly attractive for use in loading storage ring facilities with particles in preparation for particle to particle collisions. The high mass output also makes the device practical for the production of antimatter particles, which are generally difficult to obtain, being only a small fraction of a target's collision products. These may then be stored and further used to study matter-antimatter annihilation.

Medical linacs
Linac-based radiation therapy for cancer treatment began with the first patient treated in 1953 in London, UK, at the Hammersmith Hospital, with an 8 MV machine built by Metropolitan-Vickers and installed in 1952, as the first dedicated medical linac. A short while later in 1954, a 6 MV linac was installed in Stanford, USA, which began treatments in 1956.

Medical linear accelerators accelerate electrons using a tuned-cavity waveguide, in which the RF power creates a standing wave. Some linacs have short, vertically mounted waveguides, while higher energy machines tend to have a horizontal, longer waveguide and a bending magnet to turn the beam vertically towards the patient. Medical linacs use monoenergetic electron beams between 4 and 25 MeV, giving an X-ray output with a spectrum of energies up to and including the electron energy when the electrons are directed at a high-density (such as tungsten) target. The electrons or X-rays can be used to treat both benign and malignant disease. The LINAC produces a reliable, flexible and accurate radiation beam. The versatility of LINAC is a potential advantage over cobalt therapy as a treatment tool. In addition, the device can simply be powered off when not in use; there is no source requiring heavy shielding – although the treatment room itself requires considerable shielding of the walls, doors, ceiling etc. to prevent escape of scattered radiation. Prolonged use of high powered (>18 MeV) machines can induce a significant amount of radiation within the metal parts of the head of the machine after power to the machine has been removed (i.e. they become an active source and the necessary precautions must be observed). In 2019 a Little Linac model kit, containing 82 building blocks, was developed for children undergoing radiotherapy treatment for cancer. The hope is that building the model will alleviate some of the stress experienced by the child before undergoing treatment by helping them to understand what the treatment entails. The kit was developed by Professor David Brettle, Institute of Physics and Engineering in Medicine (IPEM) in collaboration with manufacturers Best-Lock Ltd. The model can be seen at the Science Museum, London.

Application for medical isotope development
The expected shortages of Mo-99, and the technetium-99m medical isotope obtained from it, have also shed light onto linear accelerator technology to produce Mo-99 from non-enriched Uranium through neutron bombardment. This would enable the medical isotope industry to manufacture this crucial isotope by a sub-critical process. The aging facilities, for example the Chalk River Laboratories in Ontario, Canada, which still now produce most Mo-99 from highly enriched uranium could be replaced by this new process. In this way, the sub-critical loading of soluble uranium salts in heavy water with subsequent photo neutron bombardment and extraction of the target product, Mo-99, will be achieved.

Disadvantages

 * The device length limits the locations where one may be placed.
 * A great number of driver devices and their associated power supplies are required, increasing the construction and maintenance expense of this portion.
 * If the walls of the accelerating cavities are made of normally conducting material and the accelerating fields are large, the wall resistivity converts electric energy into heat quickly. On the other hand, superconductors also need constant cooling to keep them below their critical temperature, and the accelerating fields are limited by quenches. Therefore, high energy accelerators such as SLAC, still the longest in the world (in its various generations), are run in short pulses, limiting the average current output and forcing the experimental detectors to handle data coming in short bursts.

title: Linear particle accelerator