Design and development of position sensitive detectors for neutron scattering instruments at National Facility for Neutron Beam Research in India

International Workshop on Neutron Optics and Detectors

Desai, Shraddha S.^1

Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai, 400085, India^1

关键词: Curvilinear geometry;    Data acquisition electronics;    Design and Development;    Detector fabrication;    Linear positions;    Neutron scattering instruments;    Position-Sensitive Detectors;    Time-of-flight instruments;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/528/1/012037/pdf
DOI  :  10.1088/1742-6596/528/1/012037

来源: IOP

【 摘 要 】

Various neutron scattering instruments at Dhruva reactor, BARC, are equipped with indigenously developed neutron detectors. Range of detectors includes proportional counters, beam monitors and linear position sensitive detectors (PSD). One of the instruments is recently upgraded with multi-PSD system of high efficiency and high resolution PSDs arranged in stacking geometry. These efforts have resulted in improving the throughput of the instrument and reducing experiment time. Global scarcity of3He has made essential to explore other options like BF3gas and10B coatings. PSDs with coaxial geometry using BF3gas and10B coating (90% enriched) are fabricated and characterized successfully. These PSDs are used as the alternative to3He PSD in equivalent geometry. Though efficiency of PSDs in similar dimensions is lower than that with3He, these large numbers of PSDs can be arranged in multi-PSD system. The PSD design is optimized for reasonable efficiency. An array of 60 BF3filled PSDs (1 m long) is under development for the Time of Flight Instrument at Dhruva. Further improvement in efficiency can be obtained with novel designs with complex anode-cathode geometry. Various challenges arise for long term operation of PSDs with BF3gas, in addition to complexity of data acquisition electronics. Study of gas aging with detector fabrication materials has been carried out. PSDs with10B coating show advantage of non toxic nature but have low efficiency. Multiple10B layers intercepting neutron beam are used to increase the efficiency. PSD designed with small anode- cathode spacing and array of multiwire grids placed between double sided10B coated plates are being fabricated. Assembly is arranged in curvilinear geometry with zero parallax. Overview of these developments is presented.