位置因子による直線型PSPCのX線回折強度曲線補正

抄録

PSPC (Position Sensitive Proportional Counter) makes it possible to obtain one-dimentional diffraction profiles without mechanical scanning. In a linear-type PSPC, the obtained profiles need correcting, because the position factor influences the intensity of the diffracted X-ray beam and the counting rate at each position on PSPC. The distances from the specimen are not the same at the center and at the edge of the detector, and the intensity decreases at the edge because of radiation and absorption. The counting rate varies with the incident angle of the diffracted beam at each position on PSPC.
The position factor f_i at channel i of the multichannel-analyser is given by
f_i=cos⁴α_i·exp{-μR(1/cosα_i-1)}
where R is the distance between the specimen and the center of PSPC, μ is the linear absorption coefficient and α_i is the incident angle of the diffracted beam at channel i. The background profiles of silicagel powder were measured with CrKα and CuKα. The parameters of the model function were fitted to the profiles by the non-linear least squares method. The agreement between these parameters and the calculated values shows that the position factor can correct the measured profiles properly.