The development of a 6Li-based pixelated neutron detector for neutron reflectometry at the Spallation Neutron Source

We present a high-rate Li-6-based pixelated neutron detector developed for neutron reflectometry instruments at the Spallation Neutron Source (SNS). The neutron detector has a pixelated design: each Li-6 scintillator element has its own photosensor and independent channel readout. This paper focuses on the general overview of the detector design and construction, the characterization of the pixelated detector, and the results of the first neutron reflectivity experiments conducted using the pixelated neutron detector at the SNS Liquid Reflectometer (BL-4B). The pixelated neutron detector demonstrated a global time-average count rate of >= 1.8 x 10(6) cps, at least 3 orders of magnitude higher than that of the existing neutron detector (He-3-based Multi-Wire Proportional Counter), and a local instantaneous count rate of = 1.73x 10(6) cps/cm(2). The maximum counting rate of the detector has not yet been determined as the detector is capable of handling the maximum flux available at the beamline. The outcome of the neutron reflectivity experiments showed that the pixelated neutron detector is a promising candidate for next-generation neutron reflectometry instruments at the SNS.

Automated summary

A high-rate Li-6-based pixelated neutron detector has been developed for neutron reflectometry instruments at the Spallation Neutron Source (SNS). The pixelated design allows for independent readout and high count rates, making it a promising candidate for next-generation neutron reflectometry instruments.