Calculation of Photoneutrons from Varian Clinac Accelerators and Their Transmissions in Materials

Conference · Mon Nov 13 04:00:00 EST 2006

OSTI ID:895272

Liu, J C; Kase, K R; Mao, X S; Nelson, W R; Kleck, J H; Johnson, S

Monte Carlo calculations of the giant-dipole-resonance photoneutrons (GRN) around the Varian Clinac 2100C/2300C medical accelerator heads (10-20 MV modes) were made using the coupled EGS4-MORSE code. The actual head materials and geometries were simulated in great detail using the Combinatorial Geometry facility of MORSE. The neutron production (i.e., sites and yields) was calculated with EGS4 and, then, the neutron transport in the accelerator head was done with MORSE. Both the evaporation and direct neutron components of the GRN were considered by incorporating the EVAP4 code and an empirical algorithm, respectively, into MORSE. With the calculated neutron spectra around the head as source terms, MCNP4a was used to estimate the corresponding dose equivalent transmission (considering both the neutron attenuation and the build-up of captured gamma rays) in several different types of concrete. The calculated results of the absolute neutron fluence and spectra around the heads, as well as the transmission curves, are presented and discussed.

• Research Organization: Stanford Linear Accelerator Center (SLAC)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-76SF00515
• OSTI ID: 895272
• Report Number(s): SLAC-PUB-7404
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
ACCELERATORS
ATTENUATION
Accelerators
ACCPHY
DOSE EQUIVALENTS
DOSIMETRY
EVAPORATION
GEOMETRY
NEUTRON FLUENCE
NEUTRON SPECTRA
NEUTRON TRANSPORT
NEUTRONS
PHOTONEUTRONS
PRODUCTION
SAFETY
SOURCE TERMS
SPECTRA