A high temporal resolution solid state thermal neutron detector

Abstract

Neutron diffraction is a major method for investigation of material structure at a molecular level and has applications in investigation of metals, ceramics, polymers and organic molecules. There are two major methods, 1. diffraction using a monochromatic beam and 2. diffraction based on the Laue time-of-flight method.(1,2,3,4,5) The Laue time-of-flight technique has considerable advantage, due to the total utilisation of the neutrons. The integrated intensity of the Laue-spot from a single crystal in simple form (see formula in attachment). To extract structural information care has to be taken in evaluating λ since Rλ ∝ λ4 The design goal was to build a thermal-neutron detector capable of a time resolution at least two orders of magnitude better than that currently available .The thermal-neutron detector consists of a thin foil of Gadolinium on which a beam of thermal-neutrons is incident, and whose isotropically scattered internal conversion electrons (6) are detected by a Passivated Implanted Planar Silicon ( PIPS ) detector This detector will be incorporated in a time-of-flight diffractometer with much greater wavelength resolution, which will enable greater precision in determination of molecular structure of materials. The detector will also be applied (8, 9) to a new instrument currently being designed at HIFAR (8,9) based on the "Time Correlated Diffraction Method"(7).