Electron-photon cascade calculations and neutron yields from electrons in thick targets

Alsmiller, R.G.; Moran, H.S.

doi:10.1016/0029-554x(67)90469-7

Cited by 26 publications

(6 citation statements)

References 11 publications

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“…Provision was made for allowing the density t o v ary continuously in any given region. 16. A new subroutine PHOTO w as added in order to treat the photoelectric e ect in a manner comparable to the other interaction processes.…”

Section: Egs3mentioning

confidence: 99%

History, Overview and Recent Improvement of EGS4

Bielajew¹

2004

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A great deal of the content of the following historical sections of this report has been plagiarised unashamedly from the original EGS3 Electron Gamma Shower Code Version 3 document authored by Richard Ford and Ralph Nelson 1 . There are several reasons for this aside from laziness. This history predates one of the author's AFB involvement with EGS and he found it very di cult to improve upon the words penned by F ord and Nelson in that original document. Moreover, the EGS3 manual is now out-of-print and this history might h a v e e v entually been lost to the ever-burgeoning EGS-community n o w estimated to be at least 6000 strong. There had been one previous attempt to give a historical perspective of EGS 2 . However, this article was very brief and did not convey the large e ort that went i n to the development of EGS. In this report the historical section on EGS4 as well as the summary of EGS3 to EGS4 conversion and the overview of EGS4 was taken directly from the EGS4 manual 3 . This is done for completeness only. The EGS4 manual gives much more detail and ought to be referred to for technical details. Finally, recent improvements to EGS4 are listed herein and represent the rst time that this information is available in one place. The reader should consult the references cited in this report for more details regarding motivation and implementation.1.1 Before EGS The Monte Carlo method was originally suggested by Ulam and von Neumann 4 , and was rst used by Goldberger 5 in order to study nuclear disintegrations produced by high-energy particles. The rst application of the Monte Carlo technique to study shower production was done by Wilson 6 . Wilson's approach w as a simple graphical-mechanical that was described as follows:The procedure used was a simple graphical and mechanical one. The distance into the lead was broken into intervals of one-fth of a radiation length about 1 mm. The electrons or photons were followed through successive intervals and their fate in passing through a given interval was decided by spinning a wheel of chance; the fate being read from one of a family of curves drawn on a cylinder: : :A word a b out the wheel of chance; The cylinder, 4 in. outside diameter by 12 in. long is driven by a high speed motor geared down by a ratio 20 to 1. The motor armature i s h e avier than the cylinder and determines where the cylinder stops. The motor was observed to stop at random and, in so far as the cylinder is concerned, its randomness is multiplied by the gear ratio: : : " from R. R. Wilson, op. cit.Although apparently quite tedious, Wilson's method was still an improvement o v er the analytic methods of the time|particularly in studying the average behavior and uctuations about the average 7 . HISTORY & O VERVIEW OF EGS4 2The rst use of an electronic digital computer in simulating high-energy cascades by Monte Carlo methods was reported by Butcher and Messel 8, 9 , and independently by V arfolomeev and Svetlolobov 10 . These two groups collaborated in a much publicized work 11 that eventuall...

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Section: Egs3mentioning

confidence: 99%

History, Overview and Recent Improvement of EGS4

Bielajew¹

2004

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“…Eff-+e . Y (10) where P power level of the reactor, potential difference corresponding to an electron kinetic energy of E, efficiency for converting total reactor nuclear energy (via laser) to accelerated electrons, and photoneutron yield. Figure 7 illustrates the neutron source intensity versus the efficiency for converting nuclear energy to accelerated electrons for U and Pb targets.…”

Section: Conversion Of Reactor Power To Neutrons Per Secondmentioning

confidence: 99%

“…The analysis also indicated that the experimental system must be extremely stable over a period of a week or more. Stability requirements possibly could be met for periods of an hour if the available neutron flux (electron, proton, or deuteron pro-4 duced) could be increased by a factor of 10 The dineutron has been sought in various other experimental studies of to result from its existence. secondary reactions believed One such experiment (18) used 27 28 .…”

Section: Neutron Fundamental Properties Interactions and The Ludersmentioning

confidence: 99%

Laser Electron Accelerator as a Neutron Source.

Glasgow¹

1968

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An analysis was made of the feasibility of producing intense photoneutron sources by bombarding thick, heavy-metal targets with nuclear-pumped, laser-accelerated electrons. The maximum neutron yield per electron is obtained by bombarding thick lead or uranium targets with electrons of energy ~100 MeV. There is a tendency for the photoneutrons to be focused in the forward direction at high electron energies. The neutron energy distribution is maxwellian in shape with a pronounced highenergy tail. If the efficiency for converting energy from a 3000 MW reactor to accelerated electrons ~l%, then source

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“…The measurement of neutron yields induced by bremsstrahlung radiation and the research on accelerator-based neutron source have been under intense activity since the 1950s [5][6][7][8][9][10][11][12][13][14][15][16]. In most of these earlier investigations, the sources of bremsstrahlung radiation have been the linear electron accelerator, and Betatron and synchrotron radiation.…”

Section: Introductionmentioning

confidence: 99%