Detritiation of the electrostatic spectrometer of Troitsk Nu-mass experiment

TL;DR

This paper details the methods and results of detritiation procedures applied to the Troitsk Nu-mass spectrometer, significantly reducing tritium contamination and enabling the resumption of its neutrino measurement research.

Contribution

It introduces effective detritiation techniques for large-volume spectrometers contaminated with tritium, facilitating recovery of experimental capabilities.

Findings

Background level decreased by over 10 times

Methods are effective for large-volume tritium cleanup

Results align with previous normal-condition data

Abstract

The paper describes methods and presents results of the Troitsk Nu-mass experiment spectrometer cleanup, which inner volume (40 m3) and surfaces (160 m2) was contaminated by 4.4 GBq of tritium. The Troitsk Nu-mass experiment of Institute for Nuclear Research of Russian Academy of Sciences, Moscow, is designed to measure the spectrum of electrons from tritium decays in order to search for hypothetical particles - sterile neutrinos. As a result of equipment failure, the spectrometer internal volume was contaminated with tritium. The contamination made measurements impossible and the research program stopped. The methods of vacuum extraction, hydrogen soaks, and water vapour soaks were used for cleanup. As a result of detritiation, the background level of the main detector of the Troitsk Nu-mass spectrometer decreased by more than 10 times, which made it possible to resume work. The results are consistent with the data obtained earlier for volumes in normal conditions in the air and can be used for planning work on detritiation of similar installations.