Calculation of the neutron W value for neutron dosimetry below the MeV energy region.
The effective neutron W value for tissue-equivalent gas in the energy region from 5 keV to 5.7 MeV has been calculated using W values for recoil particles (protons, alpha particles, oxygen, carbon and nitrogen ions), which are produced by incident neutrons. The W value is assumed to be an energy-fluence-average over the W values of the recoil particles. The energy fluence spectra for the recoil particles are calculated by using a continuous slowing down approximation (CSDA). For the W values of recoil particles in the low-energy region, the recently evaluated data by Siebert et al and Taylor et al were used. Results are presented which show that the effective neutron W value depends strongly on energy in the low-energy region. This result indicates that neutron dose measurements using ionization chambers need a considerable correction of the W value in the low-energy region.
Endo
S
S
Applied Nuclear Physics, Faculty of Engineering, Hiroshima University, Higashi-Hiroshima, Japan. endos@ipc.hiroshima-u.ac.jp
Hoshi
M
M
Shizuma
K
K
Takada
J
J
Goodhead
D T
DT
D002244:Carbon / Q000737:chemistry; D015233:Models, Statistical; D009502:Neutrons; D009584:Nitrogen / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry; D011874:Radiometry
D002244:Carbon; D009584:Nitrogen; D010100:Oxygen