title: Angular distribution measurements of photo-neutron yields produced by 2.0 GeV electrons incident on thick targets.
abstract: A study of differential photo-neutron yields by irradiation with 2 GeV electrons has been carried out. In this extension of a previous study in which measurements were made at an angle of 90 degrees relative to incident electrons, the differential photo-neutron yield was obtained at two other angles, 48 degrees and 140 degrees, to study its angular characteristics. Photo-neutron spectra were measured using a pulsed beam time-of-flight method and a BC418 plastic scintillator. The reliable range of neutron energy measurement was 8-250 MeV. The neutron spectra were measured for 10 Xo-thick Cu, Sn, W and Pb targets. The angular distribution characteristics, together with the previous results for 90 degrees, are presented in the study. The experimental results are compared with Monte Carlo calculation results. The yields predicted by MCNPX 2.5 tend to underestimate the measured ones. The same trend holds for the comparison results using the EGS4 and PICA3 codes.
authors.affiliation: Pohang Accelerator Laboratory, POSTECH, Nam-gu, Pohang 790-784, South Korea. lee@postech.ac.kr
authors.forename: Hee-Seock
authors.initials: HS
authors.lastname: Lee
authors.forename: Syuichi
authors.initials: S
authors.lastname: Ban
authors.forename: Toshiya
authors.initials: T
authors.lastname: Sanami
authors.forename: Kazutoshi
authors.initials: K
authors.lastname: Takahashi
authors.forename: Tatsuhiko
authors.initials: T
authors.lastname: Sato
authors.forename: Kazuo
authors.initials: K
authors.lastname: Shin
authors.forename: Chinwha
authors.initials: C
authors.lastname: Chung
mesh_terms: D003198:Computer Simulation; D004583:Electrons; D015233:Models, Statistical; D009502:Neutrons; D010315:Particle Accelerators; D017785:Photons; D011829:Radiation Dosage; D011835:Radiation Protection / Q000379:methods*; D011874:Radiometry / Q000379:methods*; D012542:Scattering, Radiation