Why Cu Kalpha1 to Kalpha2 intensity ratio can be different than ca. 2:1?

I have a problem with refinement of a powder pattern in which Kalpha1 and Kalpha2 peaks are quite well separated at higher angles (low FWHM). What is weird, the ratio of Kalpha1 to Kalpha2 peaks...

08 July 2015 9,868 19 View