Determining the mass of plutonium metal is an important research objective in the field of nuclear material accounting and control.Based on the 3D neutron and photon transport code JMCT(Jointed Monte Carlo Transport),...Determining the mass of plutonium metal is an important research objective in the field of nuclear material accounting and control.Based on the 3D neutron and photon transport code JMCT(Jointed Monte Carlo Transport),the gamma ray multiplicity of ^(240)Pu was simulated in this study,and the average number of gamma rays leaking from ^(240)Pu solid spheres with different masses was also obtained.The simulation results show that there is a oneto-one correspondence between the average number of gamma rays and the mass of ^(240)Pu solid spheres in the range of 0.50–3.00 kg.This result provides a basis for using the average number of gamma rays to account for the mass of ^(240)Pu.展开更多
For photon detection, superconducting transition-edge sensor(TES) micro-calorimeters are excellent energy-resolving devices. In this study, we report our recent work in developing Ti-/Au-based TES. The Ti/Au TES devic...For photon detection, superconducting transition-edge sensor(TES) micro-calorimeters are excellent energy-resolving devices. In this study, we report our recent work in developing Ti-/Au-based TES. The Ti/Au TES devices were designed and implemented with a thickness ratio of 1:1 and different suspended structures using micromachining technology. The characteristics were evaluated and analyzed, including surface morphology, 3 D deformation of suspended Ti/Au TES device structure, I–V characteristics, and low-temperature superconductivity. The results showed that the surface of Ti/Au has good homogeneity and the surface roughness of Ti/Au is significantly increased compared with the substrate. The structure of Ti/Au bilayer film significantly affects the deformation of suspended devices, but the deformation does not affect the I–V characteristics of the devices. For devices with the Ti/Au bilayer(150 μm × 150 μm) and beams(100 μm × 25 μm), the transition temperature(T;) is 253 m K with a width of 6 m K, and the value of the temperature sensitivity α is 95.1.展开更多
Bilayer superconducting films with tunable transition temperature（Tc） are a critical ingredient to the fabrication of high-performance transition edge sensors. Commonly chosen materials include Mo/Au, Mo/Cu, Ti/Au, ...Bilayer superconducting films with tunable transition temperature（Tc） are a critical ingredient to the fabrication of high-performance transition edge sensors. Commonly chosen materials include Mo/Au, Mo/Cu, Ti/Au, and Ti/Al systems. Here in this work, titanium/indium（Ti/In） bilayer superconducting films are successfully fabricated on SiO2/Si（001）substrates by molecular beam epitaxy（MBE）. The success in the epitaxial growth of indium on titanium is achieved by lowering the substrate temperature to-150？C during indium evaporation. We measure the critical temperature under a bias current of 10 μA, and obtain different superconducting transition temperatures ranging from 645 m K to 2.7 K by adjusting the thickness ratio of Ti/In. Our results demonstrate that the transition temperature decreases as the thickness ratio of Ti/In increases.展开更多
基金supported by the National Natural Science Foundation of China(No.12005199)the fund project of the China Academy of Engineering Physics(Nos.TP03201601 and CX20210009)。
文摘Determining the mass of plutonium metal is an important research objective in the field of nuclear material accounting and control.Based on the 3D neutron and photon transport code JMCT(Jointed Monte Carlo Transport),the gamma ray multiplicity of ^(240)Pu was simulated in this study,and the average number of gamma rays leaking from ^(240)Pu solid spheres with different masses was also obtained.The simulation results show that there is a oneto-one correspondence between the average number of gamma rays and the mass of ^(240)Pu solid spheres in the range of 0.50–3.00 kg.This result provides a basis for using the average number of gamma rays to account for the mass of ^(240)Pu.
文摘For photon detection, superconducting transition-edge sensor(TES) micro-calorimeters are excellent energy-resolving devices. In this study, we report our recent work in developing Ti-/Au-based TES. The Ti/Au TES devices were designed and implemented with a thickness ratio of 1:1 and different suspended structures using micromachining technology. The characteristics were evaluated and analyzed, including surface morphology, 3 D deformation of suspended Ti/Au TES device structure, I–V characteristics, and low-temperature superconductivity. The results showed that the surface of Ti/Au has good homogeneity and the surface roughness of Ti/Au is significantly increased compared with the substrate. The structure of Ti/Au bilayer film significantly affects the deformation of suspended devices, but the deformation does not affect the I–V characteristics of the devices. For devices with the Ti/Au bilayer(150 μm × 150 μm) and beams(100 μm × 25 μm), the transition temperature(T;) is 253 m K with a width of 6 m K, and the value of the temperature sensitivity α is 95.1.
文摘Bilayer superconducting films with tunable transition temperature（Tc） are a critical ingredient to the fabrication of high-performance transition edge sensors. Commonly chosen materials include Mo/Au, Mo/Cu, Ti/Au, and Ti/Al systems. Here in this work, titanium/indium（Ti/In） bilayer superconducting films are successfully fabricated on SiO2/Si（001）substrates by molecular beam epitaxy（MBE）. The success in the epitaxial growth of indium on titanium is achieved by lowering the substrate temperature to-150？C during indium evaporation. We measure the critical temperature under a bias current of 10 μA, and obtain different superconducting transition temperatures ranging from 645 m K to 2.7 K by adjusting the thickness ratio of Ti/In. Our results demonstrate that the transition temperature decreases as the thickness ratio of Ti/In increases.
