Hyper-filter-fluorescer spectrometer for x-rays above 120 keV
AssigneeThe United States of America as represented by the United States Department of Energy
InventorChing L. Wang
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Abstract
An apparatus utilizing filter-fluorescer combinations is provided to measure short bursts of high fluence x-rays above 120 keV energy, where there are no practical absorption edges available for conventional filter-fluorescer techniques. The absorption edge of the prefilter is chosen to be less than that of the fluorescer, i.e., E.sub.PRF <E.sub.F, contrary to the prior art technique E.sub.PRF >E.sub.F. In this way, the response function is virtually zero between E.sub.PRF and E.sub.F and well defined and enhanced in an energy band of less than 1000 keV above the 120 keV energy.
Claims9
In a spectrometer system to provide measurements of x-rays, wherein these x-rays emitted from a source are transmitted through a pre-filter, directed by a first collimator to a fluorescer, re-emitted from the fluorescer as K-fluorescence lines toward a post-filter and directed again by a second collimator to an x-ray detector, the improvement which comprises:
- said pre-filter for transmitting x-rays, having a predetermined absorption edge;
- said post-filter for transmitting x-rays to said detector, having a predetermined absorption edge which is more than the absorption edge of said pre-filter;
- and
- said fluorescer for emitting K-fluorescence lines toward said post-filter, having a predetermined absorption edge substantially equal to the absorption edge of said post-filter.
A method for measuring x-rays above 120 keV energy, in a spectrometer system comprising a pre-filter, two collimators, a fluorescer, a post-filter and a detector, including the steps of:
- transmitting said x-rays by said pre-filter having a predetermined absorption edge;
- transmitting said x-rays to said detector by said post-filter having a predetermined absorption edge which is more than the absorption edge of said pre-filter;
- re-emitting said x-rays as K-fluorescence lines toward said post-filter, by a fluorescer having a predetermined absorption edge equal to the absorption edge of said post-filter.
Dependencies are inferred from the claim text.