Question

In total reflection X-ray fluorescence spectrometer, the specimen is excited by the primary X-ray beam at a grazing angle _______ the critical angle.

(a) Greater than

(b) Less than

(c) Equal to

(d) Which is a complement of

I had been asked this question in homework.

The query is from Total Reflection X-Ray Fluorescence Spectrometer in portion X-Ray Spectrometers of Analytical Instrumentation

Answer 1

The correct choice is (b) Less than

Easiest explanation: In total reflection X-ray fluorescence spectrometer, the specimen is excited by the primary X-ray beam at a grazing angle less than the critical angle. Total internal reflection occurs at the critical angle.