The neutron response function and detection efficiency of a spherical proton recoil proportional counter (SP) play key roles in precise measurement of neutron spectra of the interior materials.In this paper,the respon...The neutron response function and detection efficiency of a spherical proton recoil proportional counter (SP) play key roles in precise measurement of neutron spectra of the interior materials.In this paper,the response functions and detection efficiency of three SPs developed at CAEP are simulated by Geant4.The simulated spectra are compared with pulse-height spectra measured at 0.165,0.575,1.4,and 14.1 MeV of incident neutrons.And the calculated detector efficiencies agree within 5%with the data obtained by neutron activation.展开更多
A spherical tissue equivalent proportional counter(TEPC) for neutron monitoring has been developed. It was properly designed to produce a uniform electric field intensity around the anode wire. An internal ^(241)Am al...A spherical tissue equivalent proportional counter(TEPC) for neutron monitoring has been developed. It was properly designed to produce a uniform electric field intensity around the anode wire. An internal ^(241)Am alpha source was adopted for lineal energy calibration. The TEPC was characterized in terms of dose equivalent response in a standard ^(252)Cf neutron field, and was tested with 2.45 MeV neutrons. Microdosimetric spectra, frequency mean lineal energy and dose-average mean lineal energy of 2.45 MeV neutrons were obtained and compared with FLUKA Monte Carlo simulation results. The measurement and simulation results agreed well. The mean quality factor and dose equivalent values evaluated from the 2.45 MeV neutron measurement were in good agreement with the recommended effective quality factor and ambient dose equivalent H*(10),respectively. Preliminary results have proved the availability of the developed TEPC for neutron monitoring.展开更多
The design principle for a multi-wire proportional chamber with a cathode strip and delay-line readout is described. A prototype chamber of a size of 10 cm×10 cm was made together with the readout electronics cir...The design principle for a multi-wire proportional chamber with a cathode strip and delay-line readout is described. A prototype chamber of a size of 10 cm×10 cm was made together with the readout electronics circuit. A very clean signal with very low background noise was obtained by applying a transformer between the delay-line and the pre-amplifier in order to match the resistance. Along the anode wire direction a position resolution of less than 0.5 mm was achieved with a ^55Fe-5.9 keV X ray source. The simple structure, large effective area and high position resolution allow the application of a gas chamber of this kind to many purposes.展开更多
To enhance the accuracy of 2πα and 2πβ particle surface emission rate measurements and address the identification issues of nuclides in conventional methods, this study introduces two artificial neural network(ANN...To enhance the accuracy of 2πα and 2πβ particle surface emission rate measurements and address the identification issues of nuclides in conventional methods, this study introduces two artificial neural network(ANN) algorithms: back-propagation(BP) and genetic algorithm-based back-propagation(GA-BP). These algorithms classify pulse signals from distinct α and β particles. Their discrimination efficacy is assessed by simulating standard pulse signals and those produced by contaminated sources, mixing α and β particles within the detector. This study initially showcases energy spectrum measurement outcomes, subsequently tests the ANNs on the measurement and validation datasets, and contrasts the pulse shape discrimination efficacy of both algorithms. Experimental findings reveal that the proportional counter's energy resolution is not ideal, thus rendering energy analysis insufficient for distinguishing between 2πα and 2πβ particles. The BP neural network realizes approximately 99% accuracy for 2πα particles and approximately 95% for 2πβ particles, thus surpassing the GA-BP's performance. Additionally, the results suggest enhancing β particle discrimination accuracy by increasing the digital acquisition card's threshold lower limit. This study offers an advanced solution for the 2πα and 2πβ surface emission rate measurement method, presenting superior adaptability and scalability over conventional techniques.展开更多
Neutron detection is used in a wide range of applications in nuclear physics,radiation protection,nuclear fuel cycle,reactor instrumentation,security and industrial measurement.Among the detectors used in this field,w...Neutron detection is used in a wide range of applications in nuclear physics,radiation protection,nuclear fuel cycle,reactor instrumentation,security and industrial measurement.Among the detectors used in this field,we notice the gas-filled 3He proportional counters which have been one of the main detecting tools for thermal and cold neutron detection for many years.This last characteristic has ensured that this detector is one of the best tools for thermal neutron flux measurements in a nuclear reactor control.In the instrumentation and detection laboratory of the Nuclear Research Center,of Birine,we are working toward the design and the development of this type of detectors,indeed,several prototypes of neutron detectors have been realized including the 3He proportional counters.Through this paper,we will present the experimental steps and the obtained results to carry out a 3He proportional counter prototype that was fully developed and tested in our laboratory.A comparison study was made between our detector and a commercial cylindrical 3He neutron detector which was considered in this work as a reference detector:LND252(3He)-PC.The results showed that the characteristics of the gas amplification and the counting plateau for the two counters reference LND 252(3He)-PC and our prototype was of the same order of scale.The experimental tests show that our developed prototype perfect fit with the standard International Electrotechnical Commission(IEC,www.iec.ch)in the operating principle,the technology adopted and obtained technical specifications.展开更多
文摘The neutron response function and detection efficiency of a spherical proton recoil proportional counter (SP) play key roles in precise measurement of neutron spectra of the interior materials.In this paper,the response functions and detection efficiency of three SPs developed at CAEP are simulated by Geant4.The simulated spectra are compared with pulse-height spectra measured at 0.165,0.575,1.4,and 14.1 MeV of incident neutrons.And the calculated detector efficiencies agree within 5%with the data obtained by neutron activation.
基金Supported by the Key Technology of Fusion Reactor Radiation Protection Foundation(No.2014GB112005)
文摘A spherical tissue equivalent proportional counter(TEPC) for neutron monitoring has been developed. It was properly designed to produce a uniform electric field intensity around the anode wire. An internal ^(241)Am alpha source was adopted for lineal energy calibration. The TEPC was characterized in terms of dose equivalent response in a standard ^(252)Cf neutron field, and was tested with 2.45 MeV neutrons. Microdosimetric spectra, frequency mean lineal energy and dose-average mean lineal energy of 2.45 MeV neutrons were obtained and compared with FLUKA Monte Carlo simulation results. The measurement and simulation results agreed well. The mean quality factor and dose equivalent values evaluated from the 2.45 MeV neutron measurement were in good agreement with the recommended effective quality factor and ambient dose equivalent H*(10),respectively. Preliminary results have proved the availability of the developed TEPC for neutron monitoring.
基金Major State Basic Research Development Program of China (2007CB815002)NSFC (10775003, 10827505)
文摘The design principle for a multi-wire proportional chamber with a cathode strip and delay-line readout is described. A prototype chamber of a size of 10 cm×10 cm was made together with the readout electronics circuit. A very clean signal with very low background noise was obtained by applying a transformer between the delay-line and the pre-amplifier in order to match the resistance. Along the anode wire direction a position resolution of less than 0.5 mm was achieved with a ^55Fe-5.9 keV X ray source. The simple structure, large effective area and high position resolution allow the application of a gas chamber of this kind to many purposes.
文摘To enhance the accuracy of 2πα and 2πβ particle surface emission rate measurements and address the identification issues of nuclides in conventional methods, this study introduces two artificial neural network(ANN) algorithms: back-propagation(BP) and genetic algorithm-based back-propagation(GA-BP). These algorithms classify pulse signals from distinct α and β particles. Their discrimination efficacy is assessed by simulating standard pulse signals and those produced by contaminated sources, mixing α and β particles within the detector. This study initially showcases energy spectrum measurement outcomes, subsequently tests the ANNs on the measurement and validation datasets, and contrasts the pulse shape discrimination efficacy of both algorithms. Experimental findings reveal that the proportional counter's energy resolution is not ideal, thus rendering energy analysis insufficient for distinguishing between 2πα and 2πβ particles. The BP neural network realizes approximately 99% accuracy for 2πα particles and approximately 95% for 2πβ particles, thus surpassing the GA-BP's performance. Additionally, the results suggest enhancing β particle discrimination accuracy by increasing the digital acquisition card's threshold lower limit. This study offers an advanced solution for the 2πα and 2πβ surface emission rate measurement method, presenting superior adaptability and scalability over conventional techniques.
文摘Neutron detection is used in a wide range of applications in nuclear physics,radiation protection,nuclear fuel cycle,reactor instrumentation,security and industrial measurement.Among the detectors used in this field,we notice the gas-filled 3He proportional counters which have been one of the main detecting tools for thermal and cold neutron detection for many years.This last characteristic has ensured that this detector is one of the best tools for thermal neutron flux measurements in a nuclear reactor control.In the instrumentation and detection laboratory of the Nuclear Research Center,of Birine,we are working toward the design and the development of this type of detectors,indeed,several prototypes of neutron detectors have been realized including the 3He proportional counters.Through this paper,we will present the experimental steps and the obtained results to carry out a 3He proportional counter prototype that was fully developed and tested in our laboratory.A comparison study was made between our detector and a commercial cylindrical 3He neutron detector which was considered in this work as a reference detector:LND252(3He)-PC.The results showed that the characteristics of the gas amplification and the counting plateau for the two counters reference LND 252(3He)-PC and our prototype was of the same order of scale.The experimental tests show that our developed prototype perfect fit with the standard International Electrotechnical Commission(IEC,www.iec.ch)in the operating principle,the technology adopted and obtained technical specifications.
