Hello, I came to this forum looking for an answer to a pretty simply question about the Scherrer equation for peak broadening in the XRD pattern. I understand that the full-width-half-maximum of the peak must be in radians, but when I measure the FWHM, it is in 2 theta. Do I need to half it to theta before plugging it into the equation? This is important because doing so doubles the answer you get for crystal size. Thanks for any help.