Applied strain effect to the luminosity and divergence of neutron monochromator with fully asymmetric diffraction

Abstract

The effect of applied strain on the luminosity and divergence of neutron monochromator with fully asymmetric diffraction geometry will be reported. The monochromator used silicon single crystal with 200 x 30 x 4 mm3, which has the parallel face of the crystal to the planes (220). The plain used for this monochromator was (311), which has a 31.5 degree to the (220) face. Fully asymmetric diffraction geometry had been fulfilled with the take-of-angle of the monochromator at 63 degrees. Four lines are bending system used for applying the strain to the crystal, which remote-controlled by computer. The 0, 25, 50, 75, 100, 125, 150, 175, 200 microStrain (uStrain) applied the monochromator crystal respectively. Diffracted neutron from the monochromator was monitored by using a neutron camera for evaluating the luminosity and divergence of the beam. The wavelength of the monochromatized beam was calibrated by using a Nickel rod.