Filtered neutron technique was applied for producing quasi-monoenergetic neutron beams of 24 keV, 54 keV, 133 keV and 148 keV at the horizontal neutron channel No. 4 of the Dalat Nuclear Research Reactor. The study on...Filtered neutron technique was applied for producing quasi-monoenergetic neutron beams of 24 keV, 54 keV, 133 keV and 148 keV at the horizontal neutron channel No. 4 of the Dalat Nuclear Research Reactor. The study on physical characteristics of these beam lines has been carried out for efficient applications in neutron capture experiments. The filtered neutron spectrum of each beam has been simulated by Monte-Carlo method and experimentally measured by a gas-filled protonrecoil spectrometer. The neutron fluxes of these filtered beams were measured by the activation technique with standard foils of 197Au, using a high efficient HPGe digital gamma-ray spectrometer.展开更多
The thermal neutron capture gamma radiations for 51V(n, g)52V reaction have been studied at Dalat Nuclear Research Reactor (DNRR). The gamma two-step cascade transition was measured by event-event coincidence spectrom...The thermal neutron capture gamma radiations for 51V(n, g)52V reaction have been studied at Dalat Nuclear Research Reactor (DNRR). The gamma two-step cascade transition was measured by event-event coincidence spectrometer. The added-neutron binding energy in 52V was measured as 7.31 MeV. Energy and the intensity transition of cascades were consistent with prediction of single particle model. Furthermore, the spin and the parity of levels were confined.展开更多
The coincidence technique and the coincidence spectroscopy have been developed and applied for over 40 years. Most of popular coincidence measurement systems were based on analog electronics techniques such as time to...The coincidence technique and the coincidence spectroscopy have been developed and applied for over 40 years. Most of popular coincidence measurement systems were based on analog electronics techniques such as time to amplitude conversion (TAC) or logic selecting coincidence unit. The above-mentioned systems are relatively cumbersome and complicated to use. With the strong growth of digital electronics techniques and computational science, the coincidence measurement systems will be constructed simpler but more efficient with the sake of application. This article presents the design principle and signal processing of a simple two-channel coincidence system by a technique of digital signal processing (DSP) using Field Programmable Gate Arrays (FPGA) devices at Nuclear Research Institute (NRI), Dalat.展开更多
In the past, most of popular coincidence spectrometers were normally based on traditional electronics techniques such as time to amplitude conversion or logic selecting coincidence unit. They were complicated and it i...In the past, most of popular coincidence spectrometers were normally based on traditional electronics techniques such as time to amplitude conversion or logic selecting coincidence unit. They were complicated and it is not convenient for us to use them. This paper deals with a new design of a contemporary coincidence spectrometer which is based on Field Programmable Gate Arrays (FPGA) devices via Digital Signal Processing (DSP) techniques with Hardware Description Language (VHDL). The outstanding advantage of DSP techniques and FPGA technology is capable of enhancement of the quality of the experimental measurements for nuclear radiation. The designed configuration of the traditional system was tested on the PCI 7811R board of National Instruments while the digital systems were establishing with FPGA devices. The purpose of this work is referring to the principle for construction of an FPGA-based system capable of replacing a conventional system. Therefore, a novel approach for in-house development of digital techniques is presented. The method for designing the system is utilization of slow-fast coincidence configurations with two HPGe detectors obtaining a pair of coincidence events, processing data in DSP algorithms. The significant and noticeable results are the operating frequency of 80 MHz and system timestamp window of approximately 10 ns.展开更多
文摘Filtered neutron technique was applied for producing quasi-monoenergetic neutron beams of 24 keV, 54 keV, 133 keV and 148 keV at the horizontal neutron channel No. 4 of the Dalat Nuclear Research Reactor. The study on physical characteristics of these beam lines has been carried out for efficient applications in neutron capture experiments. The filtered neutron spectrum of each beam has been simulated by Monte-Carlo method and experimentally measured by a gas-filled protonrecoil spectrometer. The neutron fluxes of these filtered beams were measured by the activation technique with standard foils of 197Au, using a high efficient HPGe digital gamma-ray spectrometer.
文摘The thermal neutron capture gamma radiations for 51V(n, g)52V reaction have been studied at Dalat Nuclear Research Reactor (DNRR). The gamma two-step cascade transition was measured by event-event coincidence spectrometer. The added-neutron binding energy in 52V was measured as 7.31 MeV. Energy and the intensity transition of cascades were consistent with prediction of single particle model. Furthermore, the spin and the parity of levels were confined.
文摘The coincidence technique and the coincidence spectroscopy have been developed and applied for over 40 years. Most of popular coincidence measurement systems were based on analog electronics techniques such as time to amplitude conversion (TAC) or logic selecting coincidence unit. The above-mentioned systems are relatively cumbersome and complicated to use. With the strong growth of digital electronics techniques and computational science, the coincidence measurement systems will be constructed simpler but more efficient with the sake of application. This article presents the design principle and signal processing of a simple two-channel coincidence system by a technique of digital signal processing (DSP) using Field Programmable Gate Arrays (FPGA) devices at Nuclear Research Institute (NRI), Dalat.
文摘In the past, most of popular coincidence spectrometers were normally based on traditional electronics techniques such as time to amplitude conversion or logic selecting coincidence unit. They were complicated and it is not convenient for us to use them. This paper deals with a new design of a contemporary coincidence spectrometer which is based on Field Programmable Gate Arrays (FPGA) devices via Digital Signal Processing (DSP) techniques with Hardware Description Language (VHDL). The outstanding advantage of DSP techniques and FPGA technology is capable of enhancement of the quality of the experimental measurements for nuclear radiation. The designed configuration of the traditional system was tested on the PCI 7811R board of National Instruments while the digital systems were establishing with FPGA devices. The purpose of this work is referring to the principle for construction of an FPGA-based system capable of replacing a conventional system. Therefore, a novel approach for in-house development of digital techniques is presented. The method for designing the system is utilization of slow-fast coincidence configurations with two HPGe detectors obtaining a pair of coincidence events, processing data in DSP algorithms. The significant and noticeable results are the operating frequency of 80 MHz and system timestamp window of approximately 10 ns.
