Use of scattered radiation for absolute x-ray energy calibration

A small, simple, and effective x-ray energy monitor has been built for use in energy-sensitive experiments where normal transmission monitoring is not an option. The instrument uses x rays scattered elastically from air, thin polymer films, or other featureless scatterers as a secondary source for measuring the transmission versus energy through a calibrated x-ray spectroscopy standard. In general, this type of energy monitor can be made from many combinations of detectors and scatterers, including ultrahigh vacuum compatible components. We show experimental results from a miniature, p-i-n diode-based monitor, which fits unobtrusively anywhere along the optical path of the experiment, and can be made easily from inexpensive and readily available parts. (C) 1999 American Institute of Physics. [S0034-6748(99)01101-6].