A low background thermal neutron flux detection system has been designed to measure the ambient thermal neutron flux of the second phase of the China Jinping Underground Laboratory（CJPL-Ⅱ）,right after completion of...A low background thermal neutron flux detection system has been designed to measure the ambient thermal neutron flux of the second phase of the China Jinping Underground Laboratory（CJPL-Ⅱ）,right after completion of the rock bolting work.A ~3He proportional counter tube combined with an identical ~4He proportional counter tube was employed as the thermal neutron detector,which has been optimised in energy resolution,wall effect and radioactivity of construction materials for low background performance.The readout electronics were specially designed for long-term stable operation and easy maintenance in an underground laboratory under construction.The system was installed in Lab Hall No.3 of CJPL-Ⅱ and accumulated data for about 80 days.The ambient thermal neutron flux was determined under the assumption that the neutron field is fully thermalized,uniform and isotropic at the measurement position.展开更多
A kicker control system is used for beam extraction and injection between two cooling storage rings（CSRs） at the Heavy Ion Research Facility in Lanzhou（HIRFL）. To meet the requirements of special physics experimen...A kicker control system is used for beam extraction and injection between two cooling storage rings（CSRs） at the Heavy Ion Research Facility in Lanzhou（HIRFL）. To meet the requirements of special physics experiments, the kicker controller has been upgraded, with a new controller designed based on ARM＋DSP＋FPGA technology and monolithic circuit architecture, which can achieve a precision time delay of 2.5 ns. In September2014, the new kicker control system was installed in the kicker field, and the test experiment using the system was completed. In addition, a pre-trigger signal was provided by the controller, which was designed to synchronize the beam diagnostic system and physics experiments. Experimental results indicate that the phenomena of “missed kick”and “inefficient kick” were not observed, and the multichannel trigger signal delay could be adjusted individually for kick power supplies in digitization; thus, the beam transport efficiency was improved compared with that of the original system. The fast extraction and injection experiment was successfully completed based on the new kicker control systems for HIRFL.展开更多
基金Supported by National Natural Science Foundation of China(11475094)
文摘A low background thermal neutron flux detection system has been designed to measure the ambient thermal neutron flux of the second phase of the China Jinping Underground Laboratory（CJPL-Ⅱ）,right after completion of the rock bolting work.A ~3He proportional counter tube combined with an identical ~4He proportional counter tube was employed as the thermal neutron detector,which has been optimised in energy resolution,wall effect and radioactivity of construction materials for low background performance.The readout electronics were specially designed for long-term stable operation and easy maintenance in an underground laboratory under construction.The system was installed in Lab Hall No.3 of CJPL-Ⅱ and accumulated data for about 80 days.The ambient thermal neutron flux was determined under the assumption that the neutron field is fully thermalized,uniform and isotropic at the measurement position.
基金Supported by National Natural Science Foundation of China(U1232123)
文摘A kicker control system is used for beam extraction and injection between two cooling storage rings（CSRs） at the Heavy Ion Research Facility in Lanzhou（HIRFL）. To meet the requirements of special physics experiments, the kicker controller has been upgraded, with a new controller designed based on ARM＋DSP＋FPGA technology and monolithic circuit architecture, which can achieve a precision time delay of 2.5 ns. In September2014, the new kicker control system was installed in the kicker field, and the test experiment using the system was completed. In addition, a pre-trigger signal was provided by the controller, which was designed to synchronize the beam diagnostic system and physics experiments. Experimental results indicate that the phenomena of “missed kick”and “inefficient kick” were not observed, and the multichannel trigger signal delay could be adjusted individually for kick power supplies in digitization; thus, the beam transport efficiency was improved compared with that of the original system. The fast extraction and injection experiment was successfully completed based on the new kicker control systems for HIRFL.
