Detector resolution in positron annihilation Doppler broadening experiments

Research output: Contribution to journalArticleScientificpeer-review

Researchers

Research units

Abstract

Positron annihilation Doppler broadening spectroscopy characterizes lattice point defects and is sensitive to very small vacancy densities. High-purity germanium detectors are generally used for recording the Doppler broadening spectrum because they provide good energy resolution and stability. However, the energy resolution of a germanium detector is somewhat dependent on the photon absorption geometry in the detector crystal. This change in the energy resolution changes also the Doppler broadening parameters. To observe the dependency of the resolution function and the Doppler broadening parameters, we performed experiments on Si samples in standard sandwich configuration with a Na-22 source. We changed the radiation geometry of the incident gamma photons via altering the distance of the sample-source package from the detector and by adding steel between the source and the detector. We observed the change of the absorption geometry in the germanium detector crystal by doing Monte Carlo simulations. The aim of this study is to help understand and decide what is the best way to compare the Doppler broadening parameters obtained with different measurement setups and even with the same setup when the geometry in the measurements has changed.

Details

Original languageEnglish
Pages (from-to)215-221
Number of pages7
JournalNUCLEAR INSTRUMENTS AND METHODS IN PHYSICS RESEARCH SECTION A: ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT
Volume867
Publication statusPublished - 21 Sep 2017
MoE publication typeA1 Journal article-refereed

    Research areas

  • Doppler broadening spectroscopy, Energy resolution, High-purity germanium detector, Positron annihilation spectroscopy

ID: 14300266