# Development of an alpha-particle imaging detector based on a low radioactivity micro-time-projection chamber

## TL;DR

This paper presents a low-radioactivity alpha-particle detector based on a micro-time-projection chamber, enabling precise imaging and measurement of surface contamination crucial for rare-event-search experiments.

## Contribution

It introduces a novel alpha-particle detector with position sensitivity using a low-alpha mu-PIC, improving contamination imaging and background measurement capabilities.

## Key findings

- Achieved effective alpha-particle detection with low background
- Demonstrated imaging of alpha contamination on samples
- Discussed the detector's sensitivity and performance

## Abstract

An important issue for rare-event-search experiments, such as the search for dark matter or neutrinoless double beta decay, is to reduce radioactivity of the detector materials and the experimental environment. The selection of materials with low radioactive impurities, such as isotopes of the uranium and thorium chains, requires a precise measurement of surface and bulk radioactivity. Focused on the first one, an alpha-particle detector has been developed based on a gaseous micro-time-projection chamber. A low-alpha mu-PIC with reduced alpha-emission background was installed in the detector. The detector offers the advantage of position sensitivity, which allows the alpha-particle contamination of the sample to be imaged and the background to be measured at the same time. The detector performance was measured by using an alpha-particle source. The measurement with a sample was also demonstrated and the sensitivity is discussed.