The Large-Area Detector for Small-Angle Neutron Scattering on iMATERIA at J-PARC

Yohei Noda,Satoshi Koizumi,Takumi Inada,Hideki Izunome,Tomoki Maeda,Satoru Ueda

doi:10.3390/qubs4040032

Abstract

An area detector with a central hole structure was built up for small-angle neutron scattering (SANS) on the iMATERIA instrument at Japan Proton Accelerator Research Complex (J-PARC). Linear position-sensitive detector tubes filled with 3He gas were arranged in three layers leaving a central hole. As a result of the calibration process, a SANS measurement with wide q-range from 0.007 Å−1 to 4.3 Å−1 was achieved in double-frame operation, supplying neutrons with wavelengths from 1 Å to 10 Å. As a merit of this central hole structure, neutron transmission can be measured simultaneously to reduce experimental time and effort. This is ideal for time-resolved studies, in which the sample transmission can be time-dependent, throughout the whole experiment. Additionally, the data storage system in ‘event mode’ format provides an excellent platform for such time-resolved experiments.

Highlights

Small-angle neutron scattering (SANS) has long been effectively used for studying mesoscopic and microscopic structures of polymeric, biological, and metallurgic materials
The totally combined profile agreed well with the absolute intensity profile measured by Dr Ilavsky, as shown by a red dotted line
We adjusted the prefactor for absolute intensity (K in Equation (10))

Summary

Introduction

Small-angle neutron scattering (SANS) has long been effectively used for studying mesoscopic and microscopic structures of polymeric, biological, and metallurgic materials. A variety of SANS spectrometers are in operation at neutron facilities. SANS instruments at pulsed spallation sources that typically employ the time-of-flight (TOF) approach to utilize neutrons over a wide wavelength range simultaneously. IMATERIA [24,25] at J-PARC’s Materials and Life Science Facility [25,26,27] is a versatile neutron scattering spectrometer with a large number of position-sensitive detectors (PSDs), classified into four detector banks; back scattering (BS, 2θ ≈ 180◦), sample environment (SE, 2θ ≈ 90◦), large angle. Quantum Beam Sci. 2020, 4, 32; doi:10.3390/qubs4040032 www.mdpi.com/journal/qubs.

Readout Module and Data Processing Software

Position Sensitive Detection by Charge Division Method

Event-Mode Data Histograming

Calibration of Position Detection

Conclusions