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Multi‐tube area detector developed for reactor small‐angle neutron scattering spectrometer SANS‐J‐II
Author(s) -
Noda Y.,
Koizumi S.,
Yamaguchi D.
Publication year - 2016
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s1600576715022797
Subject(s) - spectrometer , neutron , detector , optics , neutron scattering , neutron detection , nuclear physics , physics , scattering , neutron time of flight scattering , materials science , small angle neutron scattering
A newly developed multi‐tube area detector for a small‐angle neutron scattering (SANS) spectrometer (SANS‐J‐II) at the research reactor JRR‐3 in Tokai, Japan, has been implemented via the use of one‐dimensional position‐sensitive 3 He detectors (tubes). Ninety‐six active tubes of 8 mm in diameter and 650 and 580 mm in length were filled with 15 atm (1.52 MPa) of 3 He and aligned vertically parallel in order to cover a sufficiently large area for small‐angle scattering measurement. These tubes are enclosed in an air chamber together with neutron encode and GATENET modules (VME boards), which compose a standard data acquisition system for the spallation neutron source of the Japan Proton Accelerator Research Complex. This system facilitates the acquisition of time‐of‐flight neutron event data. The multi‐tube detector is mounted on a truck moving in a vacuum chamber of the SANS spectrometer. After discriminating noise originating from γ‐rays, and calibrating the positions and sensitivities of individual tubes, the resolution was determined ( i.e. channel widths along parallel and vertical directions along a tube). The counting rate of one tube was determined to be 1.4 × 10 3 counts per second with a counting loss of 1%. This implies that the new detector, composed of 96 tubes, can detect more than 10 5 neutrons per second with a counting loss of 1%. To demonstrate its use, small‐angle scattering originating from a diblock copolymer film with a highly oriented lamellar microdomain was observed. The data acquisition in event mode has a great advantage in time‐resolved measurements that are synchronized with external stimuli imposed on a sample.