A Bonner sphere spectrometer(BSS) was developed for neutron diagnostic on HL_2A Tokamak.It contains eight polyethylene spheres embedded with SP9~3 He proportional counter.Before setting up on the Tokamak experimental ...A Bonner sphere spectrometer(BSS) was developed for neutron diagnostic on HL_2A Tokamak.It contains eight polyethylene spheres embedded with SP9~3 He proportional counter.Before setting up on the Tokamak experimental hall,a verification experiment was arranged on a^(241)Am–Be neutron source to test its spectrometry capability.The neutron response functions were calculated by Monte Carlo code Geant4 to simulate the real measurement environments.By least square method,the neutron spectrum was finally unfolded on log domain from0.1 e V to 11 Me V.It has a remarkable consistency to the ISO 8529-1 standard^(241)Am–Be neutron spectrum.This shows that the BSS is effective and reliable for neutron spectrum determination.展开更多
Calibrations were performed for three types of neutron ambient dose equivalent rate meters, i.e., Aloka TPS-451C (Hitachi), KSAR1U.06 (Baltic Scientific Instruments), and Model 12-4 (Ludlum), using a standard field of...Calibrations were performed for three types of neutron ambient dose equivalent rate meters, i.e., Aloka TPS-451C (Hitachi), KSAR1U.06 (Baltic Scientific Instruments), and Model 12-4 (Ludlum), using a standard field of a 241Am–Be source. The measured total neutron ambient dose equivalent rates, H*(10)' tot, were analyzed to obtain the direct neutron ambient dose equivalent rates, H*(10)' dir, using the ISO 8529-2-recommended generalized- fit method, semiempirical fit method, and reducedfitting method (RFM) fit methods. The calibration factor (CF), defined as the ratio between the conventional true value of the neutron ambient dose equivalent rates in a free field, H*(10)' FF, and H*(10)' dir, was evaluated as one of the important characteristics of the neutron meters in the present work. The fitting results show that the H*(10)' dir values of the meters are in good agreement within the theoretical data within 4%. The averaged CFs of the three neutron meters were evaluated as 0:99 ± 0:01, 1:00 ± 0.03;and 0:99 ± 0:08, respectively. The largest standard uncertainty of these values was determined to be approximately 18.47%(k =1). The standard uncertainty of the CFs obtained using the RFM method was less than 4.23%(k=1), which is the smallest uncertainty among the three methods.展开更多
According to the requirements of improving production of Am source used for smoke-sensitice fire alarm making, a method and equipment of its fast relative calibration have been developed. Six measuring equipments have...According to the requirements of improving production of Am source used for smoke-sensitice fire alarm making, a method and equipment of its fast relative calibration have been developed. Six measuring equipments have being successfully applied at production lines of 241Am fire alarm source and factories of automatic smoke-sensitive fire alarm making.展开更多
基金supported by the National Natural Science Foundation of China(Nos.11375195 and 11375263)National Magnetic Confinement Fusion Science Program of China(No.2013GB104003)
文摘A Bonner sphere spectrometer(BSS) was developed for neutron diagnostic on HL_2A Tokamak.It contains eight polyethylene spheres embedded with SP9~3 He proportional counter.Before setting up on the Tokamak experimental hall,a verification experiment was arranged on a^(241)Am–Be neutron source to test its spectrometry capability.The neutron response functions were calculated by Monte Carlo code Geant4 to simulate the real measurement environments.By least square method,the neutron spectrum was finally unfolded on log domain from0.1 e V to 11 Me V.It has a remarkable consistency to the ISO 8529-1 standard^(241)Am–Be neutron spectrum.This shows that the BSS is effective and reliable for neutron spectrum determination.
基金supported by the Ministry of Science and Technology of Vietnam under Grant 07/HD/DTCB
文摘Calibrations were performed for three types of neutron ambient dose equivalent rate meters, i.e., Aloka TPS-451C (Hitachi), KSAR1U.06 (Baltic Scientific Instruments), and Model 12-4 (Ludlum), using a standard field of a 241Am–Be source. The measured total neutron ambient dose equivalent rates, H*(10)' tot, were analyzed to obtain the direct neutron ambient dose equivalent rates, H*(10)' dir, using the ISO 8529-2-recommended generalized- fit method, semiempirical fit method, and reducedfitting method (RFM) fit methods. The calibration factor (CF), defined as the ratio between the conventional true value of the neutron ambient dose equivalent rates in a free field, H*(10)' FF, and H*(10)' dir, was evaluated as one of the important characteristics of the neutron meters in the present work. The fitting results show that the H*(10)' dir values of the meters are in good agreement within the theoretical data within 4%. The averaged CFs of the three neutron meters were evaluated as 0:99 ± 0:01, 1:00 ± 0.03;and 0:99 ± 0:08, respectively. The largest standard uncertainty of these values was determined to be approximately 18.47%(k =1). The standard uncertainty of the CFs obtained using the RFM method was less than 4.23%(k=1), which is the smallest uncertainty among the three methods.
文摘According to the requirements of improving production of Am source used for smoke-sensitice fire alarm making, a method and equipment of its fast relative calibration have been developed. Six measuring equipments have being successfully applied at production lines of 241Am fire alarm source and factories of automatic smoke-sensitive fire alarm making.
