# Single-particle detection of products from atomic and molecular reactions in a cryogenic ion storage ring

## TL;DR

This paper demonstrates a highly efficient single-particle detector system used in a cryogenic ion storage ring, capable of counting low-energy atomic and molecular reaction products with high accuracy and stability at 6 K.

## Contribution

It introduces a movable secondary electron emission detector for cryogenic environments, enabling precise measurement of reaction products in a cryogenic ion storage ring.

## Key findings

- Detector efficiency close to unity at 6 K
- High dynamic range with low dark count rate
- Effective on-line pulse height monitoring

## Abstract

We have used a single-particle detector system, based on secondary electron emission, for counting low-energetic (~keV/u) massive products originating from atomic and molecular ion reactions in the electrostatic Cryogenic Storage Ring (CSR). The detector is movable within the cryogenic vacuum chamber of CSR, and was used to measure production rates of a variety of charged and neutral daughter particles. In operation at a temperature of ~6 K, the detector is characterised by a high dynamic range, combining a low dark event rate with good high-rate particle counting capability. On-line measurement of the pulse height distributions proved to be an important monitor of the detector response at low temperature. Statistical pulse-height analysis allows to infer the particle detection efficiency of the detector, which has been found to be close to unity also in cryogenic operation at 6 K.