Replacement of monochromator and proportional gas counter by mercuric iodide detector in X-ray powder diffraction

Low-resolution and therefore low-cost mercuric iodide detectors have successfully been applied to replace the combination of a graphite monochromator and a proportional gas radiation counter used in X-ray diffractometers. The mercuric iodide detector requires a lower DC bias of only 200 V rather than the 1500 V bias needed for the proportional gas counter. The much better stopping power of HgI₂ allows higher counting efficiency and therefore a better signal-to-noise ratio. Results are shown for X-ray powder diffractions of polycrystalline cubic silicon and tetragonal HgI₂.