Design and construction of the multiplexing cold neutron spectrometer BOYA with double-column Rowland focusing analyzers

TL;DR

BOYA is a multiplexing cold neutron spectrometer with 34 channels, significantly increasing measurement efficiency and employing innovative double-column Rowland focusing analyzers to optimize performance.

Contribution

This work introduces BOYA, a novel multiplexing neutron spectrometer with a unique double-column Rowland focusing design, achieving high efficiency and resolution.

Findings

Enhanced measurement efficiency by two orders of magnitude

Successful commissioning with vanadium and MnWO4

Effective neutron beam coverage without double-scattering

Abstract

Developing neutron spectrometers with higher counting efficiency has been an essential pursuit in neutron instrumentation. In this work, we present BOYA, a multiplexing cold neutron spectrometers designed and implemented at the China Advanced Research Reactor. Equipped with 34 angular analyzing channels spanning 119{\deg}, each containing 5 inelastic channels and 1 diffraction channel, BOYA enhances the measurement efficiency by two orders of magnitude over a traditional triple-axis spectrometer. To optimize both intensity and energy resolution, innovative double-column Rowland focusing analyzers have been developed. By filling the crystal gaps in the traditional Rowland focusing geometry, our design enhances the neutron beam coverage without introducing appreciable double-scattering. Our commissioning results on vanadium and MnWO4 have confirmed the success of the design, establishing BOYA as a successful multiplexing instrument for neutron spectroscopy.