Small Angle Neutron Scattering Spectrometer Detector of China Spallation Neutron Source

Abstract

The detector of SANS is one of the key instruments for Small Angle Neutron Scattering (SANS) Spectrometer. It needs large areas of detection, high efficiencies of detection and high spatial resolutions. It is also required to be able to work stably and move forward and backward in a vacuum tube. Two-dimensional detector array of an effective area of 1 000 mm (X)×1 020 mm (Y) is constructed using 120 position-sensitive 3He tubes of 8 mm in diameter. The SANS detector array is divided into 10 modules, each of which is completely independent and includes 12 3He tubes and corresponding readout electronics and data acquisition systems. The readout electronics located in the back of the detector is developed by CSNS independently. It takes 3 years in total since the detector of SANS was designed, selected, tested and installed. The experimental result of neutron beams shows that the detection efficiency of the detector is more than 50% (@2 A) and the spatial resolution of the detector is below 10 mm (FWHM). The performances fully meets the requirements of designs. The detector is working at the SANS of CSNS now.