An Improved ALD Coating Process for Plastic Scintillators

Authors:

  • Tomas Fritioff
  • Anders Mörtsell
  • Anders Ringbom
  • Ola Pettersson
  • Mårten Rooth

Publish date: 2014-12-15

Report number: FOI-R--3980--SE

Pages: 26

Written in: English

Keywords:

  • Noble Gas
  • Xenon
  • SAUNA
  • Beta Detector
  • Plastic Scintillator
  • ALD Coating
  • Memory Effect
  • CTBT

Abstract

This report summarises the experiences with Swedish Automatic Unit for Noble Gas Acquisition (SAUNA) beta detector cells with Atomic Layer Deposition (ALD) coating and the work performed to improve the ALD coating process in order to avoid an observed degradation of the electron energy resolution. ALD coating is applied to beta detector cells to reduce the memory effect, i.e. to reduce the diffusion of radioxenon into the plastic scintillator material of the detector cell resulting in degraded detector performance for subsequent measurements. Some problems have been observed with ALD coated detector cells: Cracking or flaking of the coating layer so that the memory effect reduction disappears (first generation of coated detector cells) and that the detector cell energy resolution performance is degraded in the coating process (second generation of coated detector cells). Studies were performed that resulted in a refined, reproducible coating process that increases the possibility to fulfil the energy resolution requirements for the SAUNA system.