scholarly journals Monte Carlo simulation study on the 241Am-Be radionuclide source reference neutron radiation

2020 ◽  
Vol 35 (4) ◽  
pp. 283-293
Author(s):  
Yixin Liu ◽  
Song Zhang ◽  
Yikun Qian ◽  
Yuchen Huang ◽  
Benjiang Mao ◽  
...  
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Free Field ◽  
Neutron Radiation ◽  
Neutron Energy Spectrum ◽  
Measurement Instruments ◽  
Dose Equivalent ◽  
Monte Carlo Simulation Study ◽  
Neutron Measurement ◽  
Radionuclide Source

In order to study the feasibility of using lightweight 241Am-Be radionuclide reference neutron radiation field for the calibration of neutron measurement instruments, this paper reported the Monte Carlo simulation work on free field reference neutron radiation, standard reference neutron radiation regulated by ISO-8529 series standards and minitype reference neutron radiation we designed. The distributions of dose equivalent rates and neutron energy spectrum in different conditions, such as different room types, different room sizes and different shield materials were the main simulation contents for analyzing the characteristics of the three types of reference neutron radiation. According to the simulation results, theoretical supports were provided for the discussion on the minitype reference neutron radiation for calibration purpose.

EVALUATION OF NEUTRON AMBIENT DOSE EQUIVALENT IN CARBON-ION RADIOTHERAPY WITH ENERGY SCANNING

2020 ◽  
Vol 191 (3) ◽  
pp. 310-318
Author(s):  
Shinnosuke Matsumoto ◽  
Shunsuke Yonai
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Carbon Ion Radiotherapy ◽  
Neutron Energy Spectrum ◽  
Dose Equivalent ◽  
Realistic Case ◽  
Carbon Ion ◽  
Ambient Dose Equivalent ◽  
Secondary Neutrons ◽  
Ambient Dose

Abstract In carbon-ion radiotherapy (CIRT), secondary neutrons are produced by nuclear interactions in the beamline devices or patient. Herein, the characteristics of secondary neutrons in CIRT with energy scanning (ES) were evaluated. Neutron ambient dose equivalents (H*(10)) were measured using WENDI-II. The neutron energy spectrum was calculated using the Monte Carlo simulation. Measurement and calculation were performed under realistic case scenarios using maximum beam energies (Emax) of 290, 350 and 400 MeV u −1. Moreover, H*(10) in ES was compared with H*(10) in range-shifter scanning (RS) and hybrid scanning (HS). H*(10) in Emax = 290 MeV u−1 was 65% less than that in Emax = 400 MeV u−1. At Emax = 350 MeV u−1, H*(10) in ES at θ = 120 was 42% of that at θ = 60. The neutron dose in ES CIRT decreased to approximately 60 and 70% of that in RS and HS CIRT, respectively, at 50-cm distance from the beam axis.

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