Introduction The neutron capture cross sections are very important in the field of nuclear device design and basic physics research.Hydrogen-free liquid scintillator such as C_(6)D_(6)detectors are widely used in the ...Introduction The neutron capture cross sections are very important in the field of nuclear device design and basic physics research.Hydrogen-free liquid scintillator such as C_(6)D_(6)detectors are widely used in the neutron capture cross-sectional measurements for the low neutron sensitivity and fast time response.The Back-n white neutron source at China Spallation Neutron Source is the first spallation white neutron source in China,and it is suitable for neutron capture cross-sectional measurement.Materials and methods A C_(6)D_(6)detector system was built in the Back-n experimental station.The pulse height weighting technique was used to determine the system’s detection efficiency.The response to gamma rays of the C_(6)D_(6)detector was measured,and the energy resolution function was determined.Monte Carlo simulation with Geant4 code was carried out to get the weighting function of this C_(6)D_(6)detector system.Additionally,the systematic uncertainty of the weighting function was also determined.Conclusion According to the experimental and simulation results,this C_(6)D_(6)detector system can be used to measure neutron capture cross section.展开更多
The^6 Li(n,t)~4 He reaction was measured as the first experiment involving neutron-induced charged particle emission reactions at the CSNS(China Spallation Neutron Source)Back-n white neutron source.The differential c...The^6 Li(n,t)~4 He reaction was measured as the first experiment involving neutron-induced charged particle emission reactions at the CSNS(China Spallation Neutron Source)Back-n white neutron source.The differential cross-sections of the^6 Li(n,t)~4 He reaction at 15 detection angles ranging from 19.2°to 160.8°are obtained from 1.0 eV to 3.0 MeV at 80 neutron energy points;for 50 energy points below 0.1 MeV they are reported for the first time.The results indicate that the anisotropy of the emitted tritium is noticeable above E_n=100 eV.The angle-integrated cross-sections are also obtained.The present differential cross-sections agree in general with the previous evaluations,but there are some differences in the details.More importantly,the present results indicate that the cross-sections of the^6 Li(n,t)~4 He reaction might be overestimated by most evaluations in the 0.5-3.0 MeV region,although they are recommended as standards below 1.0 MeV.展开更多
For the paper industry, the disposal and management of the yielded sludge are a considerable challenge. In our work, the paper mill sludge-derived magnetically separable heterogeneous catalyst(PMS-Fe-380) was prepar...For the paper industry, the disposal and management of the yielded sludge are a considerable challenge. In our work, the paper mill sludge-derived magnetically separable heterogeneous catalyst(PMS-Fe-380) was prepared easily through a facile synthesis method. The morphology and structure of PMS-Fe-380 were fully characterized by means of X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and Brunauer–Emmet–Teller analysis. The catalytic activity of PMS-Fe-380 was evaluated by degradation of Methylene Blue(MB). The reusability and stability of PMS-Fe-380 were evaluated in five repeated runs, which suggested that PMS-Fe-380 manifested excellent stability of catalytic activity. Moreover,leaching tests indicated that the leached iron is negligible(〈0.5 mg/L). This study provides an alternative environmentally friendly reuse method for paper mill sludge and a novel catalyst PMS-Fe-380 that can be considered as a promising heterogeneous Fenton-like catalyst.展开更多
基金the National Natural Science Foundation of China(Grant Nos.11790321 and 11805282)the National Key R&D Program of China(Grant No.2016YFA0401601).
文摘Introduction The neutron capture cross sections are very important in the field of nuclear device design and basic physics research.Hydrogen-free liquid scintillator such as C_(6)D_(6)detectors are widely used in the neutron capture cross-sectional measurements for the low neutron sensitivity and fast time response.The Back-n white neutron source at China Spallation Neutron Source is the first spallation white neutron source in China,and it is suitable for neutron capture cross-sectional measurement.Materials and methods A C_(6)D_(6)detector system was built in the Back-n experimental station.The pulse height weighting technique was used to determine the system’s detection efficiency.The response to gamma rays of the C_(6)D_(6)detector was measured,and the energy resolution function was determined.Monte Carlo simulation with Geant4 code was carried out to get the weighting function of this C_(6)D_(6)detector system.Additionally,the systematic uncertainty of the weighting function was also determined.Conclusion According to the experimental and simulation results,this C_(6)D_(6)detector system can be used to measure neutron capture cross section.
基金Supported by National Key R&D Program of China(2016YFA0401604)National Natural Science Foundation of China(11775006)Science and Technology on Nuclear Data Laboratory and China Nuclear Data Center
文摘The^6 Li(n,t)~4 He reaction was measured as the first experiment involving neutron-induced charged particle emission reactions at the CSNS(China Spallation Neutron Source)Back-n white neutron source.The differential cross-sections of the^6 Li(n,t)~4 He reaction at 15 detection angles ranging from 19.2°to 160.8°are obtained from 1.0 eV to 3.0 MeV at 80 neutron energy points;for 50 energy points below 0.1 MeV they are reported for the first time.The results indicate that the anisotropy of the emitted tritium is noticeable above E_n=100 eV.The angle-integrated cross-sections are also obtained.The present differential cross-sections agree in general with the previous evaluations,but there are some differences in the details.More importantly,the present results indicate that the cross-sections of the^6 Li(n,t)~4 He reaction might be overestimated by most evaluations in the 0.5-3.0 MeV region,although they are recommended as standards below 1.0 MeV.
基金supported by the Major Science and Technology Projects Focus on Social Development Projects of Zhejiang Province (Nos. 2014C03002 and 2012C03004-1)
文摘For the paper industry, the disposal and management of the yielded sludge are a considerable challenge. In our work, the paper mill sludge-derived magnetically separable heterogeneous catalyst(PMS-Fe-380) was prepared easily through a facile synthesis method. The morphology and structure of PMS-Fe-380 were fully characterized by means of X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and Brunauer–Emmet–Teller analysis. The catalytic activity of PMS-Fe-380 was evaluated by degradation of Methylene Blue(MB). The reusability and stability of PMS-Fe-380 were evaluated in five repeated runs, which suggested that PMS-Fe-380 manifested excellent stability of catalytic activity. Moreover,leaching tests indicated that the leached iron is negligible(〈0.5 mg/L). This study provides an alternative environmentally friendly reuse method for paper mill sludge and a novel catalyst PMS-Fe-380 that can be considered as a promising heterogeneous Fenton-like catalyst.