Development Of A Multi-layer Coated ¹⁰B High Resolution 2D Position Sensitive Thermal Neutron Detector Based On MWPC

Currently, neutron scattering technique is an ideal means of detection for the study of the internal structure and dynamics of materials, which has been widely applied to various scientific fields. The Chinese Spallation Neutron Source (CSNS) is under construction, and many high performance neutron detectors of neutron scattering spectrometers are built in the future to meet the demand for a large detector system of CSNS. At same time, facing the current international situation of the 3He gas shortage, we have launched the study of 10B conversion film multi-wire proportional Chamber (MWPC) using as a new neutron technique to replace the costly high pressure of 3He gas neutron detector.In this paper, we mainly research characteristics of multi-wire proportional Chamber, and use M.C. simulation and theoretical calculations for the neutron detection efficiency of this type detector to obtain the optimum design parameters, which guides the optimization structure design of the detector. To improve the maximum efficiency of the detector, we could use the multilayer structure of MWPC. For the 10 unit layers structure with 10B film, the maximum neutron detection efficiency can be reached 50%. The paper also illustrates the key technology research on the detector structure design, working-gas selection, wire tension control, testing for distance of between wires el at.A portable and fast wire tension measurement system has been developed in the key technology research of the MWPC’s construction. In this equipment, a short-time driving force was used to make the wire vibrate, and then measuring the signal of the vibration to analysis the wire inherent frequency. This system can measure the wire inherent frequency directly, and the measurement is quicker and more accurate. In whole measuring process, this system only takes 3-5 seconds to complete the wire tension measurement on a single wire and its measurement error is about 0.6%. At same time, a film-drawing machine with the active area of 250mmx250mm has developed to make smooth cathode windows for ensuring the uniformity of electric field. For the wire tension uniform measurements of the whole anode wire plane, its tension deviations is within 3.5%. The results show that the wire tension control can meet the stable and perfect performance of MWPC. Finally, a preliminary performance testing platform X-ray was built, and completed preliminary performance test. Also, we used the 241Am- alpha source to take a signal testing. The results indicated that the detector could work steady and normally.The whole work in this thesis solved some key technic problems for the coated 10B MWPC’s construction and has certain reference values in the research on the new detection technology.