Selection, Rejection and Optimization of Pyrolytic Graphite (PG) CrystalAnalyzers for Use on the New IRIS Graphite Analyzer Bank

摘要

This report discusses design problems incurred by equipping the IRIS high-resolution inelastic spectrometer at the ISIS pulsed neutron source, UK with a new 4212 piece pyrolytic graphite crystal analyzer array. Of the 4212 graphite pieces required, approximately 2500 wil be newly purchased PG crystals with the remainder comprising of the currently installed graphite analyzers. The quality of the new analyzer pieces, with respect to manufacturing specifications, is assessed, as is the optimum arrangement of new PG pieces amongst old to circumvent degradation of the spectrometer's current angular resolution. Techniques employed to achieve these criteria include accurate calliper measurements, FORTRAN programming and statistical analysis.