Experimentally determining the relative efficiency of spherically bent germanium and quartz crystals

We have used the EBIT-Ielectron beam ion trap at the Lawrence Livermore National Laboratory and a duplicate Orion High ResolutionX-ray Spectrometer (OHREX) to measure the relative efficiency of a spherically bentquartz (101̄1) crystal (2d = 6.687 Å) and a spherically bentgermanium (111) crystal (2d = 6.532 Å). L-shellX-ray photons from highly chargedmolybdenum ions generated in EBIT-I were simultaneously focussed and Bragg reflected by each crystal, both housed in a singlespectrometer, onto a single CCDX-ray detector. The flux from each crystal was then directly compared. Our results show that thegermanium crystal has a reflection efficiency significantly better than thequartz crystal, however, the energy resolution is significantly worse. Moreover, we find that the spatial focussing properties of thegermanium crystal are worse than those of thequartz crystal. Details of the experiment are presented, and we discuss the advantages of using either crystal on a streak-camera equipped OHREXspectrometer.
Source: Review of Scientific Instruments - Category: Physics Authors: Source Type: research