The prototype neutron flux monitor consists of a high purity 235U fission chamberdetector and a 'blank' detector, which is a fissile material free detector with the same dimensionas the fission chamber detecto...The prototype neutron flux monitor consists of a high purity 235U fission chamberdetector and a 'blank' detector, which is a fissile material free detector with the same dimensionas the fission chamber detector to identify noise issues such as noise coming from gamma rays. Themain parameters of the fission chamber assembly that have been measured in the laboratory areconfirmed to approach the technological level of the International Thermonuclear ExperimentalReactor (ITER) in the near future. This prototype neutron flux monitor will be further developedto become a neutron flux monitor suitable for the operation phase of D-D fusion on the ITER.展开更多
Two fission chambers with different amounts of fissile material(enriched 90%uranium-235) have been manufactured for neutron flux detection in a thermonuclear fusion device.The characteristics of neutron signal and its...Two fission chambers with different amounts of fissile material(enriched 90%uranium-235) have been manufactured for neutron flux detection in a thermonuclear fusion device.The characteristics of neutron signal and its discrimination from other signals,and a plateau of high voltage between the anode and cathode have been validated in a thermal neutron source.The energy responses of the two fission chambers at seven energy levels have been calibrated in an accelerator fast neutron source and the results agree well with the simulations.展开更多
Neutron flux monitor (NFM) as an important diagnostic sub-system in ITER (in-ternational thermonuclear experimental reactor) provides a global neutron source intensity,fusionpower and neutron flux in real time.Three t...Neutron flux monitor (NFM) as an important diagnostic sub-system in ITER (in-ternational thermonuclear experimental reactor) provides a global neutron source intensity,fusionpower and neutron flux in real time.Three types of neutron flux monitor assemblies with differentsensitivities and shielding materials have been designed.Through MCNP (Mante-Carlo neutralparticle transport code) calculations,this extended system of NFM can detect the neutron flux ina range of 10~4 n/(cm^2.s) to 10^(14) n/(cm^2.s).It is capable of providing accurate neutron yield mea-surements for all operational modes encountered in the ITER experiments including the in-situcalibration.Combining both the counting mode and Campbelling (MSV;Mean Square Voltage)mode in the signal processing units,the requirement of the dynamic range (10~7) for these NFMsand time resolution (1 ms) can be met.Based on a uncertainty analysis,the estimated abso-lute measurement accuracies of the total fusion neutron yield can reach the required 10% level inboth the early stage of the DD-phase and the full power DT operation mode.In the advancedDD-phase,the absolute measurement accuracy would be better than 20%.展开更多
基金The project supported by the National Natural Science Foundation of China (No.10175021)the Retraining Foundation of the Southwestern Institute of Physics for Talented Personnel
文摘The prototype neutron flux monitor consists of a high purity 235U fission chamberdetector and a 'blank' detector, which is a fissile material free detector with the same dimensionas the fission chamber detector to identify noise issues such as noise coming from gamma rays. Themain parameters of the fission chamber assembly that have been measured in the laboratory areconfirmed to approach the technological level of the International Thermonuclear ExperimentalReactor (ITER) in the near future. This prototype neutron flux monitor will be further developedto become a neutron flux monitor suitable for the operation phase of D-D fusion on the ITER.
基金supported by the National Magnetic Confinement Fusion Science Program of China(Nos.2008GB109002 and 2012GB101003)
文摘Two fission chambers with different amounts of fissile material(enriched 90%uranium-235) have been manufactured for neutron flux detection in a thermonuclear fusion device.The characteristics of neutron signal and its discrimination from other signals,and a plateau of high voltage between the anode and cathode have been validated in a thermal neutron source.The energy responses of the two fission chambers at seven energy levels have been calibrated in an accelerator fast neutron source and the results agree well with the simulations.
基金National Natural Science Foundation of China(Nos.10175021,10675124)
文摘Neutron flux monitor (NFM) as an important diagnostic sub-system in ITER (in-ternational thermonuclear experimental reactor) provides a global neutron source intensity,fusionpower and neutron flux in real time.Three types of neutron flux monitor assemblies with differentsensitivities and shielding materials have been designed.Through MCNP (Mante-Carlo neutralparticle transport code) calculations,this extended system of NFM can detect the neutron flux ina range of 10~4 n/(cm^2.s) to 10^(14) n/(cm^2.s).It is capable of providing accurate neutron yield mea-surements for all operational modes encountered in the ITER experiments including the in-situcalibration.Combining both the counting mode and Campbelling (MSV;Mean Square Voltage)mode in the signal processing units,the requirement of the dynamic range (10~7) for these NFMsand time resolution (1 ms) can be met.Based on a uncertainty analysis,the estimated abso-lute measurement accuracies of the total fusion neutron yield can reach the required 10% level inboth the early stage of the DD-phase and the full power DT operation mode.In the advancedDD-phase,the absolute measurement accuracy would be better than 20%.
