A RADIOISOTOPE X-RAY FLUORESCENCE SPECTROMETER WITH A HIGH-RESOLUTION SEMICONDUCTOR DETECTOR: DETERMINATION OF ANALYTICAL SENSITIVITY,
Abstract
The analytical sensitivity of an x-ray fluorescence spectrometer utilizing a radioisotope exciter source and a high-resolution, lithium-drifted silicon detector was evaluated. The spectrometer system which was studied used I125 as the exciter source and contained a 30 sq mm detector with a resolution of 512 eV full-width at half-maximum (FWHM) at 6.40 keV. Known molybdenum samples ranging from 10 nanograms to 1 milligram and nickel samples ranging from 0.1 microgram to 1 milligram were prepared and analyzed. It was found that the detection limit for molybdenum was 35 nanograms with a ca 5 mc exciter source; precision in the submicrogram range was 10-20%. The detection limit for nickel was considerably poorer and was found to be 1 microgram for an exciter source strength of ca 10 mc. An examination of the various factors that affect the analytical sensitivity of the system showed that the sensitivity was limited primarily by (1) poor detector geometry resulting from the small size of the high-resolution Si(Li) detector, and (2) background. A principal contributor to background was backscatter of the exciter source radiation by materials surrounding the source and detector. It was found that the radiation was being scattered mainly by air. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 12, 1968
- Accession Number
- AD0674418
Entities
People
- Sachio Yamamoto
Organizations
- Naval Radiological Defense Laboratory