Formation and evaluation of convex-curved crystals of lithium fluoride for use in analyzing x-ray spectra

Technical Report · Thu Jul 22 04:00:00 EDT 1976

DOI:https://doi.org/10.2172/7339537· OSTI ID:7339537

Sellick, B O

Lithium fluoride as received from the vendor in boule form is 38 x 38 x 13 mm thick. This block is cleaved to wafers of the desired thickness, x-ray-evaluated for ''d'' spacing and greatest intensity, bent to the required radius, and then acid-etched to remove foreign material. The diffraction and dispersion characteristics of a wafer are analyzed using well-collimated tungsten x rays that strike the crystal and are diffracted onto no-screen x-ray film. If the crystal is satisfactory, it is mounted in a spectrogoniometer and rotated through an x-ray beam while a detector is set at the optimized angle for the diffracted x rays. The average intensity across the length of the crystal is recorded by multichannel scaling. Any imperfections appear as peaks or dips compared to the average intensity. The crystal next goes to a 10-channel, filter-fluorescer x-ray unit that compares zero-order intensity to diffracted K..cap alpha.. and K..beta.. intensity. Counts for 100-s intervals are taken in groups of three and averaged. Correction factors for instrument geometry, air, pinhole diameter at zero order, K..cap alpha..-K..beta.., barometric pressure, temperature, etc., are added to the efficiency calculations to obtain the crystal efficiency (epsilon) vs keV data. The crystal is mounted in the spectrograph or spectrometer and calibrated to either the detector or film plane by using direct radiation with proper x-ray filters or absorbers. The crystal is then ready for use.

• Research Organization: California Univ., Livermore (USA). Lawrence Livermore Lab.
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 7339537
• Report Number(s): UCRL-52086
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360601* -- Other Materials-- Preparation & Manufacture
ALKALI METAL COMPOUNDS
CALIBRATION
CRYSTALS
EFFICIENCY
FABRICATION
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
LITHIUM COMPOUNDS
LITHIUM FLUORIDES
LITHIUM HALIDES
MEASURING INSTRUMENTS
MONOCHROMATORS
SPECTROMETERS
SURFACE TREATMENTS
X-RAY SPECTROMETERS