A compact ultra-clean system for deploying radioactive sources inside the KamLAND detector

TL;DR

This paper presents a compact, ultra-clean deployment system for radioactive sources in the KamLAND neutrino detector, ensuring contamination prevention and precise source placement for calibration.

Contribution

The paper introduces a novel, ultra-clean deployment device with real-time monitoring and control, tailored for sensitive neutrino detector calibration.

Findings

Successful deployment of radioactive sources without contaminating the scintillator

Real-time visual monitoring of source movement achieved

System maintained ultra-clean conditions during operation

Abstract

We describe a compact, ultra-clean device used to deploy radioactive sources along the vertical axis of the KamLAND liquid-scintillator neutrino detector for purposes of calibration. The device worked by paying out and reeling in precise lengths of a hanging, small-gauge wire rope (cable); an assortment of interchangeable radioactive sources could be attached to a weight at the end of the cable. All components exposed to the radiopure liquid scintillator were made of chemically compatible UHV-cleaned materials, primarily stainless steel, in order to avoid contaminating or degrading the scintillator. To prevent radon intrusion, the apparatus was enclosed in a hermetically sealed housing inside a glove box, and both volumes were regularly flushed with purified nitrogen gas. An infrared camera attached to the side of the housing permitted real-time visual monitoring of the cable's motion, and the system was controlled via a graphical user interface.