Validation of a model for Radon-induced background processes in electrostatic spectrometers

TL;DR

This paper validates a model for radon-induced background processes in electrostatic spectrometers, crucial for the KATRIN experiment's precision in measuring tritium beta-decay, by comparing simulations with experimental data.

Contribution

It presents a comprehensive comparison of simulations and measurements to characterize radon background in KATRIN's spectrometers, establishing a validated model for radon emanation and background signatures.

Findings

Simulations match measured radon background rates

Identified sources of radon emanation in spectrometer materials

Quantified radon emanation rates from vacuum components

Abstract

The Karlsruhe Tritium Neutrino (KATRIN) experiment investigating tritium beta-decay close to the endpoint with unprecedented precision has stringent requirements on the background level of less than 10^(-2) counts per second. Electron emission during the alpha-decay of Rn-219 and Rn-220 atoms in the electrostatic spectrometers of KATRIN is a serious source of background exceeding this limit. In this paper we compare extensive simulations of Rn-induced background to specific measurements with the KATRIN pre-spectrometer to fully characterize the observed Rn-background rates and signatures and determine generic Rn emanation rates from the pre-spectrometer bulk material and its vacuum components.