Multiwire Position-Sensitive Neutron Detector with Two Layers of Boron-10

Multiwire position-sensitive neutron detector with two layers of boron-10 was developed to detect both thermal and fast neutrons. Sensitive dimensions of two coordinate neutron detector are 50 × 50 mm. New detector characteristics are compared with ones of 100 × 100 mm detector built earlier which we used in neutron flux spatial distribution measurement. Plane-parallel design of new detector has symmetrical structure with respect to wire anode and also includes two intermediate grids and two cathodes made of parallel wires with 2 mm pitch and two silicon substrates coated boron-10 layers of 0.003 mm thickness. Detector geometry, working gas mixture and pressure are chosen so as to ensure full absorption of secondary alpha particle from reaction with thermal neutron within detector gas medium half thickness. Neutron coordinates are determined from measured ionization loss pulse heights produced by secondary nucleus. Detector expected efficiency to thermal neutrons is about 5%. The detector can be used in small-angle and diffraction scattering setups in condensed matter physics.