散裂中子源高气压二维位置灵敏~3He探测器的实验研究

Experimental Study on Two-dimensional Position Sensitive Detector Filled with Helium-3 for the China Spallation Neutron Source

为满足中国散裂中子源多功能反射谱仪中子探测器的基本物理要求:有效面积达到200 mm×200 mm、探测效率大于50%(2?)、位置分辨好于2 mm等,中国科学院高能物理研究所研制了3He高气压二维多丝正比室位置灵敏中子探测器。该探测器采用二维多丝室结构,腔体内充3He/C3H8(6 atm/2.5 atm)的组合气体。本文首先利用Am/Be中子源完成对探测器全面积均匀性测试,均匀性指标达到了95.1%;探测器在中国散裂中子源的20号束流线站安装后,对其进行了在束测量,通过飞行时间选取波长2.8?的慢中子,测量了探测器二维位置分辨和二维成像性能。在X方向(垂直于阳极丝的方向)的位置分辨为0.99 mm,Y方向(平行于阳极丝的方向)的位置分辨为1.36 mm,探测器具有很好的二维位置分辨和二维成像能力。测量结果表明探测器满足反射谱仪的研制要求。

Aimed to the Multipurpose Reflectance spectrometer device(MR)physics requirements,which is that the active area with 200 mm×200 mm,the detection efficiency with more than 50%and the position resolution with better than 2 mm,for China Spallation Neutron Source(CSNS)in Dongguang,China.A3 He two-dimensional multi-wire proportional chamber position sensitive neutron detector has been developed by the Institute of High Energy Physics of the Chinese Academy of Sciences(IHEP,CAS).The high-pressure two-dimensional multiwire proportional chamber neutron detector filled with3 He/C3 H8(6 atm/2.5 atm)mixture gases and the multiwire technology.Firstly,the detection uniformity was tested using the Am/Be neutron source in IHEP and the uniformity could reach to 95.1%.After assembled at#20 beam station in CSNS,the performance of the detector were studied under the neutron beam.Under the selection neutron beam with 2.8?by the time of flight(TOF),the two-dimensional position resolution and two-dimensional imaging of the detector were measured.The position resolution is 0.99 mm in the X direction(perpendicular to the direction of the anode wire),1.36 mm in the Y direction(parallel to the direction of the anode wire)and the two-dimensional imaging is clear to identity.The results show that the detector has a good resolution and two-dimensional imaging capability,and it could meet the physics requirements of Multipurpose Reflectance spectrometer device in CSNS.