An accurate energy calibration of a 5＂× 2＂ BC501A liquid scintillator-based neutron detector by means of photon sources and the unfolding of pulse height spectra are described. The photon responses were measure...An accurate energy calibration of a 5＂× 2＂ BC501A liquid scintillator-based neutron detector by means of photon sources and the unfolding of pulse height spectra are described. The photon responses were measured with 22Na, 137Cs and 54Mn photon sources and simulated using the GRESP code, which was developed at the Physiknlisch Technische Bundesanstalt in Germany. Pulse height spectra produced by three different photon sources were employed to investigate the effects of the unfolding techniques. It was found that the four unfolding codes of the HEPRO and UMG3.3 packages, including GRAVEL, UNFANA, MIEKE and MAXED, performed well with the test spectra and produced generally consistent results. They could therefore be used to obtain neutron energy spectra in toknmak experiments.展开更多
Neutron energy spectrometry diagnosis plays an important role in magnetic con- finement fusion. A new neutron time-of-flight （TOF） spectrometer with double scintillators is designed and optimized for the EAST toknma...Neutron energy spectrometry diagnosis plays an important role in magnetic con- finement fusion. A new neutron time-of-flight （TOF） spectrometer with double scintillators is designed and optimized for the EAST toknmak. A set of optimM parameters is obtained by Monte Carlo simulation, based on the GEANT4 and ROOT codes. The electronic setup of the measurement system is designed. The count rate capability is increased by introducing a flash ADC. The designed spectrometer with high resolution and efficiency is capable of being applied to fusion neutron diagnostics. Applications in mixed-energy and continuous energy neutron fields can also be considered.展开更多
Plasma density and temperature can be diagnosed by x-ray line emission measurement with crystal,and bent crystals such as von Hamos and Hall structures are proposed to improve the diffraction brightness.In this study,...Plasma density and temperature can be diagnosed by x-ray line emission measurement with crystal,and bent crystals such as von Hamos and Hall structures are proposed to improve the diffraction brightness.In this study,a straightforward solution for the focusing schemes of flat and bent crystals is provided.Simulations with XOP code are performed to validate the analytical model,and good agreements are achieved.The von Hamos or multi-cone crystal can lead to several hundred times intensity enhancements for a 200μm plasma source.This model benefits the applications of the focusing bent crystals.展开更多
A compact neutron spectrometer based on the liquid scintillator is presented for neutron energy spectrum measurements at the HL-2A Tokamak. The spectrometer was well characterized and a fast digital pulse shape discri...A compact neutron spectrometer based on the liquid scintillator is presented for neutron energy spectrum measurements at the HL-2A Tokamak. The spectrometer was well characterized and a fast digital pulse shape discrimination software was developed using the charge comparison method. A digitizer data acquisition system with a maximum frequency of 1 MHz can work under an environment with a high count rate at HL-2A Tokamak. Specific radiation and magnetic shielding for the spectrometer were designed for the neutron spectrum measurement at the HL-2A Tokamak. For pulse height spectrum analysis, dedicated numerical simulation utilizing NUBEAM combined with GENESIS was performed to obtain the neutron energy spectrum. Subsequently, the transportation process from the plasma to the detector was evaluated with Monte Carlo calculations. The distorted neutron energy spectrum was folded with the response matrix of the liquid scintillation spectrometer, and good consistency was found between the simulated and measured pulse height spectra. This neutron spectrometer based on a digital acquisition system could be well adopted for the investigation of the auxiliary heating behavior and the fast-ion related phenomenon on different tokamak devices.展开更多
基金supported by the State Key Development Program for Basic Research of China (Nos. 2008CB717803, 2009GB107001,2007CB209903)the Research Fund for the Doctoral Program of Higher Education of China (No. 200610011023)National Natural Science Foundation of China (No. 10875002)
文摘An accurate energy calibration of a 5＂× 2＂ BC501A liquid scintillator-based neutron detector by means of photon sources and the unfolding of pulse height spectra are described. The photon responses were measured with 22Na, 137Cs and 54Mn photon sources and simulated using the GRESP code, which was developed at the Physiknlisch Technische Bundesanstalt in Germany. Pulse height spectra produced by three different photon sources were employed to investigate the effects of the unfolding techniques. It was found that the four unfolding codes of the HEPRO and UMG3.3 packages, including GRAVEL, UNFANA, MIEKE and MAXED, performed well with the test spectra and produced generally consistent results. They could therefore be used to obtain neutron energy spectra in toknmak experiments.
基金supported by the State Key Development Program for Basic Research of China(Nos.2008CB717803,2009GB107001,and2007CB209903)the Research Fund for the Doctoral Program of Higher Education of China(No.200610011023)the National Natural Science Foundation of China(No.10875002)
文摘Neutron energy spectrometry diagnosis plays an important role in magnetic con- finement fusion. A new neutron time-of-flight （TOF） spectrometer with double scintillators is designed and optimized for the EAST toknmak. A set of optimM parameters is obtained by Monte Carlo simulation, based on the GEANT4 and ROOT codes. The electronic setup of the measurement system is designed. The count rate capability is increased by introducing a flash ADC. The designed spectrometer with high resolution and efficiency is capable of being applied to fusion neutron diagnostics. Applications in mixed-energy and continuous energy neutron fields can also be considered.
基金Project supported by the National Natural Science Fundation of China(Grant Nos.11775203 and 12075219)the China Academy of Engineering Physics(CAEP)Foundation(Grant No.CX20210019).
文摘Plasma density and temperature can be diagnosed by x-ray line emission measurement with crystal,and bent crystals such as von Hamos and Hall structures are proposed to improve the diffraction brightness.In this study,a straightforward solution for the focusing schemes of flat and bent crystals is provided.Simulations with XOP code are performed to validate the analytical model,and good agreements are achieved.The von Hamos or multi-cone crystal can lead to several hundred times intensity enhancements for a 200μm plasma source.This model benefits the applications of the focusing bent crystals.
基金Supported by State Key Development Program for Basic Research of China(2013GB106004,2012GB101003,2008CB717803)National Natural Science Foundation of China(91226102)National Science and Technology Support Program(2011BAI02B01)
文摘A compact neutron spectrometer based on the liquid scintillator is presented for neutron energy spectrum measurements at the HL-2A Tokamak. The spectrometer was well characterized and a fast digital pulse shape discrimination software was developed using the charge comparison method. A digitizer data acquisition system with a maximum frequency of 1 MHz can work under an environment with a high count rate at HL-2A Tokamak. Specific radiation and magnetic shielding for the spectrometer were designed for the neutron spectrum measurement at the HL-2A Tokamak. For pulse height spectrum analysis, dedicated numerical simulation utilizing NUBEAM combined with GENESIS was performed to obtain the neutron energy spectrum. Subsequently, the transportation process from the plasma to the detector was evaluated with Monte Carlo calculations. The distorted neutron energy spectrum was folded with the response matrix of the liquid scintillation spectrometer, and good consistency was found between the simulated and measured pulse height spectra. This neutron spectrometer based on a digital acquisition system could be well adopted for the investigation of the auxiliary heating behavior and the fast-ion related phenomenon on different tokamak devices.
