A wavelength calibration of the small angle neutron spectrometer at HANARO

A NVS was installed and its installation condition of the NVS was established for obtaining optimized neutron beam. The operation characteristics of the NVS was evaluated. The wavelength and the resolution of the neutron beam monochromatized by the NVS were calibrated using both time of flight method and diffraction measurement on standard material, silver behenate. Condition of tilting the NVS relative to the neutron beam direction by an angle of -3 .deg. was obtained as an optimum installation condition of the NVS. The wavelengths of neutron beam monochromatized by NVS were measured of 4.31, 5.14, 6.38 and 8.29A at 25500, 21300, 17100 and 13100 rpm of NVS, respectively. The relationship between the selector speed U[rpm] and the neutron wavelength λ [A] was obtained as λ [A]=A+B/U[rpm], with A=0.11077 and B=107171. In accordance with the manufacturer's specification, the wavelength resolution(FWHM) was measured and confirmed as Δ λ/λ10%. The wavelength measured by Silver Behenate diffraction standard was in accord with the wavelength measured by a TOF method, and its difference between both measurements is within 0.05%. The wavelength and the resolution data measured and analysed in this study will be used as the basic data for continuing SANS experiments