No abstract

No abstract

No abstract

No abstract

In this study, the grid inefficiency $$\sigma $$ σ for a mesh-type Frisch-grid ionization chamber (FGIC) was investigated using the finite element method and Monte Carlo method. A grid inefficiency $$\sigma $$ σ evaluation model was developed, which can determine the relationship between the physical parameters of the detector and the grid inefficiency with reasonable accuracy. An artificial neural network (ANN) was applied in the investigation of the grid inefficiency factor $$\sigma $$ σ . The trained ANN was able to describe and predict the grid inefficiency factor $$\sigma $$ σ with different physical parameters for the mesh-type FGIC. Thus, it can serve as a reference for the development of mesh-type FGICs and correct grid inefficiency $$\sigma $$ σ measurements.

No abstract

Proton radiography is used for advanced hydrotesting as a new type radiography technology due to its powerful penetration capability and high detection efficiency. A new proton radiography terminal will be developed to radiograph static samples at Institute of Modern Physics of Chinese Academy of Science (IMP-CAS). The proton beam with the maximum energy of 2.6 GeV will be produced by Heavy Ion Research Facility in Lanzhou-Cooling Storage Ring (HIRFL-CSR). The proton radiography terminal consists of the matching magnetic lens and the Zumbro lens system. In this paper, the design scheme and all optic parameters of this beam terminal for 2.6GeV proton energy are presented by simulating the beam optics using WINAGILE code. My-BOC code is used to test the particle tracking of proton radiography beam line. Geant4 code and G4beamline code are used for simulating the proton radiography system. The results show that the transmission efficiency of proton without target is 100%, and the effect of secondary particles can be neglected. In order to test this proton radiography system, the proton images for an aluminum plate sample with two rectangular orifices and a step brass plate sample are respectively simulated using Geant4 code. The results show that the best spatial resolution is about 36μm, and the differences of the thickness are not greater than 10%.

The development of fourth-generation reactors and advanced nuclear energy systems require high-precision, multi-nuclide, and wide-energy-area neutron nuclear data. However, the current nuclear energy-related nuclear fission data in the China Nuclear Data Evaluation Library (CENDL library) are incomplete and cannot meet the current need. It is extremely important to establish the reliable calculation methods and tools for the neutron nuclear data. Based on the Monte-Carlo method, a model for calculating the pre-neutron fission fragment is established in this work. The mass and kinetic energy distribution of ²³²Th(n,f) reaction at the medium- and low- incident neutron energy are studied. The calculations of the mass distribution with the different values of incident energy are compared with the experimental results. The maximum deviation of this work from the experimental data is ~1%, which is advantageous compared with the GEF and TALYS code (maximum deviation from the experimental value is ~2%). The calculation of the pre-neutron fission fragment kinetic energy also shows good agreement with experimental result. The results indicate that this model can well describe and predict the characteristics of pre-neutron fission fragment for ²³²Th(n,f) reaction at the medium- and low- incident neutron energy. It also provides a new idea for calculating the neutron-induced actinide fission reactions.