Reconstruction of 12 MV bremsstrahlung spectra from measured transmission data

Reconstruction of 12 MV bremsstrahlung spectra from measured transmission data 1 first-author 2 1 2 Institute of Southwest Nuclear Physics and Chemistry, Mianyang 621900; Institute of Southwest Nuclear Physics and Chemistry, Mianyang 621900; Key Laboratory for Radiation Physics and Technology of Education Ministry of China, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064 Key Laboratory for Radiation Physics and Technology of Education Ministry of China, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064 Transmission data for 12 MV bremsstrahlung beams produced by the process for continuous-pulsed 12 MV electrons coming from a linear accelerator hitting a 1.2mm thick plane tantalum target have been acquired with a combination of iron and Telfon attenuators. Two solid state dosimeters with LiF-TLD material surrounded Telfon were used as detectors. It has been checked that the experimental system achieves reasonably narrow-beam geometry by Monte Carlo simulations. From these transmission data, the original energy photon spectrum has been reconstructed using the iterative least-squares technique and compared with the spectrum calculated with Monte Carlo code system EGSnrc. The comparison shows that the numerical technique for analysis of transmission data can represent 12 MV bremsstrahlung spectrum acceptably well. The purpose of our work is to provide an effective way to reconstruct an unknown photon spectrum with high energy component and prove the correctness of this way. Electron bremsstrahlung spectra Attenuation analysis Least-squares method Monte Carlo simulation EGSnrc system References Huang P H , Kase K R , Bjärgard B E . Med Phys , 1981 , 8 ( 3 ): 368 - 374 Med Phys Gayton F M , Longworth J P . A passive gamma spectrometer for use in high fluxes in the energy range 0.01 to 10MV, RD/B/N2024 A passive gamma spectrometer for use in high fluxes in the energy range 0.01 to 10MV, RD/B/N2024 Huang P H , Kase K R , Bjarngard B E . Med Phys , 1982 , 9 ( 5 ): 695 - 702 Med Phys Huang P H , Kase K R , Bjargard B E . Med Phys , 1983 , 10 ( 8 ): 778 - 785 Med Phys Xiao K Y , Cui G X , Liu H C . Atom Energy Sci Technol (in Chinese) , 1998 , 32 ( 6 ): 499 - 502 Atom Energy Sci Technol (in Chinese) Nelson W R , Hirayama H , Rogers D W O . The EGS4 code system, SLAC-Report-265 , Stanford Linear Accelerator Center , 1985 The EGS4 code system, SLAC-Report-265 Bielajew A F , Rogers D W O . Nucl Instrum Methods Phys Res , 1987 , B18 : 165 - 81 Nucl Instrum Methods Phys Res Kawrakow I , Rogers D W O . The EGSnrc Code System: Monte Carlo simulation of electron and photon transport, NRCC Report PIRS-701 , 2000 The EGSnrc Code System: Monte Carlo simulation of electron and photon transport, NRCC Report PIRS-701 Attix F H . Introduction to radiological physics and radiation dosimetry , New York : Wiley , 1986 , 210 - 218 Introduction to radiological physics and radiation dosimetry Technical Reports Series No.127, Determination of absorbed dose in reactors , IAEA , VIENNA , 1971 , 170 - 171 Technical Reports Series No.127, Determination of absorbed dose in reactors Kreyszig E . Advanced engineering mathematics , 2 nd ed, New York : Wiley , 1962 Advanced engineering mathematics TL543,TL84 2002-05-15 2003-05-01 2021-01-19 2003 Nuclear Science and Techniques 02 14