Design and Construction of a Channel Electron Multiplier Based Mossbauer Spectroscopy System
Abstract
A channel electron multiplier (cem) detector system was designed and built to provide a signal to a Mossbauer spectroscopy system in an effort to obtain a better signal-to-noise ratio than achievable with a proportional counter system. Three cems are contained in a vacuum chamber built using standard components. Gamma, rays of 14.4-keV energy from a Co-57 source enter from outside the chamber through a window and are absorbed by an Fe-57 target near the cems. The target emits internal conversion electrons which are collected by the cems and a Mossbauer spectrometer collects the signal. The system produces a usable signal, but the signal-to-noise ratio is unacceptably high. The strongest peak has a maximum count only 2.1% of the total background count. The corresponding peak in a spectrum collected using the proportional detector system is 3.4% of the total background count. One possible cause is that some gamma rays are striking two of the cems, producing ionizations in the detectors. The cems need to be repositioned. A screen should be added in front of the cems and grounded to reduce counting of low energy electrons. These improvements should reduce the background count rate. Mossbauer Spectrometry, Channel electron multipliers, Detectors spectrometry, Vacuum systems, Conversion electronspectrometry.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1992
- Accession Number
- ADA248154
Entities
People
- Daniel J. Robbins
Organizations
- Air Force Institute of Technology