# A pulsed, mono-energetic and angular-selective UV photo-electron source for the commissioning of the KATRIN experiment

## TL;DR

This paper presents a pulsed, mono-energetic, and angular-selective UV photo-electron source designed for calibrating the KATRIN experiment's main spectrometer, with experimental results validated against detailed simulations.

## Contribution

It introduces a novel electron source with specific energy and angular properties for KATRIN calibration, and demonstrates its performance through measurements and simulations.

## Key findings

- Successful development of the electron source.
- Agreement between measurements and simulations.
- Enhanced calibration capabilities for KATRIN.

## Abstract

The KATRIN experiment aims to determine the neutrino mass scale with a sensitivity of 200 meV/c^2 (90% C.L.) by a precision measurement of the shape of the tritium $\beta$-spectrum in the endpoint region. The energy analysis of the decay electrons is achieved by a MAC-E filter spectrometer. To determine the transmission properties of the KATRIN main spectrometer, a mono-energetic and angular-selective electron source has been developed. In preparation for the second commissioning phase of the main spectrometer, a measurement phase was carried out at the KATRIN monitor spectrometer where the device was operated in a MAC-E filter setup for testing. The results of these measurements are compared with simulations using the particle-tracking software "Kassiopeia", which was developed in the KATRIN collaboration over recent years.