The neutron yield from thick target of Pb irradiated with 250 MeV protons has been studied experimentally.The Pb target was surrounded by a water bath, where this size effectively contained most of the neutrons emitte...The neutron yield from thick target of Pb irradiated with 250 MeV protons has been studied experimentally.The Pb target was surrounded by a water bath, where this size effectively contained most of the neutrons emittedfrom the target. The moderated neutrons were measured by the activity induced in an array of Au activation foils(with or without Cd cover). The axial coordinates of the foils without Cd cover were Z = -15, -10, -5, 0, 5, 10, 15,20 cm along the target axial, and the radial coordinates of the foils were R = 7.5, 12.5, 17.5, 22.5 and 27.5 cm abovethe target axial. The Au-foil activities were determined by measuring the peak intensities of the 412 keV line from198Au[1], and the results are shown in Fig. 1.展开更多
Accelerator-Driven Systems(ADS)are one of the proposed options for the transmutation of long lived nuclides and minor actinid es based on spallation reaction.The creation and the accumulation of stable and radioactive...Accelerator-Driven Systems(ADS)are one of the proposed options for the transmutation of long lived nuclides and minor actinid es based on spallation reaction.The creation and the accumulation of stable and radioactive nuclides in the target material during the irradiation is a very important issue for safety concerns target handling and disposal after irradiation.展开更多
The segregation of Mg to phase interfaces in a nickel base superalloy IN 100 has been investi- gated using EPT(Electron Microprobe Technique).AES(Auger Electron Spectroscopy) and EDS analyses on thin TEM film.The resu...The segregation of Mg to phase interfaces in a nickel base superalloy IN 100 has been investi- gated using EPT(Electron Microprobe Technique).AES(Auger Electron Spectroscopy) and EDS analyses on thin TEM film.The results show that Mg segregates to the phase inter- faces of MC/γ and γ′/γ.The segregation concentration and layer thickness of Mg on MC/γ phase interface are larger than that on γ′/γ phase interface.Mg is not only a grain boundary segregation element,but also a phase interface segregation one.展开更多
Spallation reactions which are induced by high-energy and high-current proton accelerators play an important role in many fields, such as environmental sciences, medicine, nuclear waste transmutation and energy amplif...Spallation reactions which are induced by high-energy and high-current proton accelerators play an important role in many fields, such as environmental sciences, medicine, nuclear waste transmutation and energy amplification,etc[1;2]. The residual products are the most difficult ones to predict by the models. Moreover, there are very large discrepancies among the calculations based on different models.展开更多
The spallation reaction was studied with 250 MeV proton beam and 400 MeV/u carbon beam at the HIRFL-CSRin Lanzhou. The neutron and residual radionuclide production were measured by using the off-line -spectroscopymeth...The spallation reaction was studied with 250 MeV proton beam and 400 MeV/u carbon beam at the HIRFL-CSRin Lanzhou. The neutron and residual radionuclide production were measured by using the off-line -spectroscopymethod. The radiation dose induced in spallation reaction was studied by using the thermoluminescent detectors.Moreover, an on-line neutron measurement method was developed by using a digital pulse shape discriminationsystem. All of the experimental method will be used to study the neurotics of the ADS system.展开更多
Irradiation experiment was performed at the HIRFL-CSR in Lanzhou. A Pb foil with 100 mm diameter and0.15 mm thickness was used to measure the mass-yield distributions of induced radionuclides. A natural Pb cylinderwit...Irradiation experiment was performed at the HIRFL-CSR in Lanzhou. A Pb foil with 100 mm diameter and0.15 mm thickness was used to measure the mass-yield distributions of induced radionuclides. A natural Pb cylinderwith 100 mm diameter and 250 mm length was used as the beam dump behind the Pb foil. An ionization chamberwas placed in front of the Pb foil to monitor the beam current. The carbon beam with an energy of 400 MeV/uwas stopped in the Pb cylinder after through the Pb foil. The irradiation was lasted about 20 h to make the beamfluence enough. After irradiation, the gamma spectra of Pb foil were measured by a off-line -spectrometry method.The measurements were performed by using a high-purity germanium (HPGe) detector.展开更多
The Accelerator Driven Sub-critical System(ADS)has an extensive application prospect in energy production and transmutation.In the operation of an ADS facility,the subcritical reactivity monitoring is of great signifi...The Accelerator Driven Sub-critical System(ADS)has an extensive application prospect in energy production and transmutation.In the operation of an ADS facility,the subcritical reactivity monitoring is of great significance for safety reasons.Hence,a lead-based zero power reactor VENUS-II has been built in Bejjing.展开更多
基金National Natural Science Foundation of China (11305229, 11105186, 91226107, 91026009, 11205208) StrategicPriority Research Program of Chinese Academy of Sciences (XDA03030300)
文摘The neutron yield from thick target of Pb irradiated with 250 MeV protons has been studied experimentally.The Pb target was surrounded by a water bath, where this size effectively contained most of the neutrons emittedfrom the target. The moderated neutrons were measured by the activity induced in an array of Au activation foils(with or without Cd cover). The axial coordinates of the foils without Cd cover were Z = -15, -10, -5, 0, 5, 10, 15,20 cm along the target axial, and the radial coordinates of the foils were R = 7.5, 12.5, 17.5, 22.5 and 27.5 cm abovethe target axial. The Au-foil activities were determined by measuring the peak intensities of the 412 keV line from198Au[1], and the results are shown in Fig. 1.
文摘Accelerator-Driven Systems(ADS)are one of the proposed options for the transmutation of long lived nuclides and minor actinid es based on spallation reaction.The creation and the accumulation of stable and radioactive nuclides in the target material during the irradiation is a very important issue for safety concerns target handling and disposal after irradiation.
文摘The segregation of Mg to phase interfaces in a nickel base superalloy IN 100 has been investi- gated using EPT(Electron Microprobe Technique).AES(Auger Electron Spectroscopy) and EDS analyses on thin TEM film.The results show that Mg segregates to the phase inter- faces of MC/γ and γ′/γ.The segregation concentration and layer thickness of Mg on MC/γ phase interface are larger than that on γ′/γ phase interface.Mg is not only a grain boundary segregation element,but also a phase interface segregation one.
文摘Spallation reactions which are induced by high-energy and high-current proton accelerators play an important role in many fields, such as environmental sciences, medicine, nuclear waste transmutation and energy amplification,etc[1;2]. The residual products are the most difficult ones to predict by the models. Moreover, there are very large discrepancies among the calculations based on different models.
基金National Natural Science Foundation of China (11305229, 11105186, 91226107, 91026009, 11205208) StrategicPriority Research Program of Chinese Academy of Sciences (XDA03030300)
文摘The spallation reaction was studied with 250 MeV proton beam and 400 MeV/u carbon beam at the HIRFL-CSRin Lanzhou. The neutron and residual radionuclide production were measured by using the off-line -spectroscopymethod. The radiation dose induced in spallation reaction was studied by using the thermoluminescent detectors.Moreover, an on-line neutron measurement method was developed by using a digital pulse shape discriminationsystem. All of the experimental method will be used to study the neurotics of the ADS system.
基金National Natural Science Foundation of China (11305229, 11105186, 91226107, 91026009) Strategic PriorityResearch Program of the Chinese Academy of Sciences (XDA03030300)
文摘Irradiation experiment was performed at the HIRFL-CSR in Lanzhou. A Pb foil with 100 mm diameter and0.15 mm thickness was used to measure the mass-yield distributions of induced radionuclides. A natural Pb cylinderwith 100 mm diameter and 250 mm length was used as the beam dump behind the Pb foil. An ionization chamberwas placed in front of the Pb foil to monitor the beam current. The carbon beam with an energy of 400 MeV/uwas stopped in the Pb cylinder after through the Pb foil. The irradiation was lasted about 20 h to make the beamfluence enough. After irradiation, the gamma spectra of Pb foil were measured by a off-line -spectrometry method.The measurements were performed by using a high-purity germanium (HPGe) detector.
文摘The Accelerator Driven Sub-critical System(ADS)has an extensive application prospect in energy production and transmutation.In the operation of an ADS facility,the subcritical reactivity monitoring is of great significance for safety reasons.Hence,a lead-based zero power reactor VENUS-II has been built in Bejjing.
