A novel thermal neutron collimator was successfully fabricated by coating the inner surface of the capillary plate （CP） with gadolinium oxide using atomic layer deposition （ALD） technology. This CP-based collimato...A novel thermal neutron collimator was successfully fabricated by coating the inner surface of the capillary plate （CP） with gadolinium oxide using atomic layer deposition （ALD） technology. This CP-based collimator is efficient and compact. A numerical model is presented in the paper to estimate the main performance characteristics of the collimator and to optimize the design for specific applications. According to the results of the calculation based on currently available CPs, the FWHM of the collimator’s rocking curve can be smaller than 0.15 while suppressing more than 99.9% of the incident thermal neutrons on the double wings of the curve. Such a coated CP is as thin as 1.25 mm or even thinner, providing high angular resolution with good transmission in a very limited space.展开更多
For the research of CCD neutron radiography, a neutron collimator was designed based on the exit of thermal neutron of the Boron Neutron Capture Therapy（BNCT） reactor. Based on the Geant4 simulations, the preliminar...For the research of CCD neutron radiography, a neutron collimator was designed based on the exit of thermal neutron of the Boron Neutron Capture Therapy（BNCT） reactor. Based on the Geant4 simulations, the preliminary choice of the size of the collimator was determined. The materials were selected according to the literature data. Then, a collimator was constructed and tested on site. The results of experiment and simulation show that the thermal neutron flux at the end of the neutron collimator is greater than 1.0×10^6n/cm^2/s, the maximum collimation ratio（L/D） is 58, the Cd-ratio（Mn） is 160 and the diameter of collimator end is 10 cm. This neutron collimator is considered to be applicable for neutron radiography.展开更多
基金Supported by the National Natural Science Foundation of China (10735020, 11075026)
文摘A novel thermal neutron collimator was successfully fabricated by coating the inner surface of the capillary plate （CP） with gadolinium oxide using atomic layer deposition （ALD） technology. This CP-based collimator is efficient and compact. A numerical model is presented in the paper to estimate the main performance characteristics of the collimator and to optimize the design for specific applications. According to the results of the calculation based on currently available CPs, the FWHM of the collimator’s rocking curve can be smaller than 0.15 while suppressing more than 99.9% of the incident thermal neutrons on the double wings of the curve. Such a coated CP is as thin as 1.25 mm or even thinner, providing high angular resolution with good transmission in a very limited space.
基金Supported by National Natural Science Foundation of China(11105160)
文摘For the research of CCD neutron radiography, a neutron collimator was designed based on the exit of thermal neutron of the Boron Neutron Capture Therapy（BNCT） reactor. Based on the Geant4 simulations, the preliminary choice of the size of the collimator was determined. The materials were selected according to the literature data. Then, a collimator was constructed and tested on site. The results of experiment and simulation show that the thermal neutron flux at the end of the neutron collimator is greater than 1.0×10^6n/cm^2/s, the maximum collimation ratio（L/D） is 58, the Cd-ratio（Mn） is 160 and the diameter of collimator end is 10 cm. This neutron collimator is considered to be applicable for neutron radiography.
