An innovative monochromator shielding is designed and implemented for the cold neutron spectrometers XINGZHI and BOYA operated by Renmin University of China at China Advanced Research Reactor.Via Monte Carlo simulatio...An innovative monochromator shielding is designed and implemented for the cold neutron spectrometers XINGZHI and BOYA operated by Renmin University of China at China Advanced Research Reactor.Via Monte Carlo simulations and careful mechanical designs,a shielding configuration has been successfully developed to satisfy safety requirements of below 3μSv/h dose rate at its exterior,meanwhile fulfilling space,floor load and nonmagnetic requirements.Composite materials are utilized to form the sandwich-type shielding walls:the inner layer of boron carbide rubber,the middle layer of steel-encased lead and the outer layer of borated polyethylene.Special-shaped liftable shielding blocks are incorporated to facilitate a continuous adjustment of the neutron energy while preventing radiation leakage.Our work has demonstrated that by utilizing composite shielding materials,along with the sandwich structure and liftable shielding blocks,a compact and lightweight shielding solution can be achieved.This enables the realization of advanced neutron scattering instruments that provide expanded space of measurement,larger energy and momentum coverage,and higher flux on the sample.This shielding represents the first of its kind in neutron scattering instruments in China.Following its successful operation,it has been subsequently employed by other neutron instruments across the country.展开更多
Increased accuracy of proton beam delivery provides additional benefits to the patients undergo the treatment.A prompt gamma imaging detector can provide additional information during the treatment,as the prompt gamma...Increased accuracy of proton beam delivery provides additional benefits to the patients undergo the treatment.A prompt gamma imaging detector can provide additional information during the treatment,as the prompt gammas produced by the interactions between protons and human tissues are related to the range and profile of the beam in the patient.This paper makes a Monte Carlo feasibility study for a pixelated prompt gamma imaging detector which can not only measure the proton range but also merge the beam profile and 3D beam image inside the patient.FLUKA simulation result shows that this detector can reduce background noise and measure the range and beam profile by using of grated shielding material,vertical gammas selection and a 5MeV energy window.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12004426,U2030106,and 12304185)the National Key Scientific Instrument and Equipment Development Project of NSFC(Grant No.11227906)the National Key R&D Program of China(Grant No.2023YFA1406500)。
文摘An innovative monochromator shielding is designed and implemented for the cold neutron spectrometers XINGZHI and BOYA operated by Renmin University of China at China Advanced Research Reactor.Via Monte Carlo simulations and careful mechanical designs,a shielding configuration has been successfully developed to satisfy safety requirements of below 3μSv/h dose rate at its exterior,meanwhile fulfilling space,floor load and nonmagnetic requirements.Composite materials are utilized to form the sandwich-type shielding walls:the inner layer of boron carbide rubber,the middle layer of steel-encased lead and the outer layer of borated polyethylene.Special-shaped liftable shielding blocks are incorporated to facilitate a continuous adjustment of the neutron energy while preventing radiation leakage.Our work has demonstrated that by utilizing composite shielding materials,along with the sandwich structure and liftable shielding blocks,a compact and lightweight shielding solution can be achieved.This enables the realization of advanced neutron scattering instruments that provide expanded space of measurement,larger energy and momentum coverage,and higher flux on the sample.This shielding represents the first of its kind in neutron scattering instruments in China.Following its successful operation,it has been subsequently employed by other neutron instruments across the country.
文摘Increased accuracy of proton beam delivery provides additional benefits to the patients undergo the treatment.A prompt gamma imaging detector can provide additional information during the treatment,as the prompt gammas produced by the interactions between protons and human tissues are related to the range and profile of the beam in the patient.This paper makes a Monte Carlo feasibility study for a pixelated prompt gamma imaging detector which can not only measure the proton range but also merge the beam profile and 3D beam image inside the patient.FLUKA simulation result shows that this detector can reduce background noise and measure the range and beam profile by using of grated shielding material,vertical gammas selection and a 5MeV energy window.
