Test of LGAD as Potential Next-Generation {\mu}SR Spectrometer Detectors

TL;DR

This paper evaluates LGAD detectors for next-generation muon spin rotation spectrometers, aiming to handle higher muon intensities with faster, smaller detectors to improve performance at pulsed muon sources.

Contribution

It presents experimental validation of LGAD detectors as a promising upgrade for high-intensity muon spin rotation spectrometers.

Findings

LGAD detectors have a pulse width of 2 ns, suitable for high-rate applications.

Tests at ISIS demonstrated LGAD's capability to handle increased muon flux.

LGADs show potential to significantly improve muon spectrometer performance.

Abstract

Muon Spin Rotation/Relaxation/Resonance ($\mu$SR) is a versatile and powerful non-destructive technology for investigating the magnetic properties of materials at the microscopic level. The $\mu$SR technique typically utilizes fully spin polarized beams of positive muons generated at particle accelerator facilities and measures the evolution of the muon spin polarization inside a sample to extract information about the local magnetic environment in materials. With the development of accelerator technologies, intensities of muon beams are being continuously improved, which will cause a pile-up problem to the $\mu$SR spectrometer. The first muon source in China, named MELODY, is currently under construction and will be a pulsed source of muons operated at a repetition frequency of only 1 Hz due to limitations of the accelerator system at CSNS. Consequently, there is a strong motivation to operate MELODY at significantly higher muon intensities. This necessitates an upgrade of the detector system inside the spectrometer, which should be smaller and faster to accommodate the increased intensity per pulse of muons. The Low Gain Avalanche Diode (LGAD), characterized by a typical pulse width of 2 ns and a segmentation size in the centimeters range, has the potential to significantly improve the counting rates of $\mu$SR spectrometers that utilize a high intensity pulsed muon source. Thus, it is expected that the LGAD detector is a promising candidate to enhance the performance of $\mu$SR spectrometers at the new MELODY muon source.To validate this, tests on the LGAD were conducted at the ISIS pulsed muon source at the Rutherford Appleton Laboratory, UK. This paper will describe the setup of the candidate LGAD devices and the subsequent analysis of the experiment data.