Accession Number : AD0674418

Title :   A RADIOISOTOPE X-RAY FLUORESCENCE SPECTROMETER WITH A HIGH-RESOLUTION SEMICONDUCTOR DETECTOR: DETERMINATION OF ANALYTICAL SENSITIVITY,

Corporate Author : NAVAL RADIOLOGICAL DEFENSE LAB SAN FRANCISCO CALIF

Personal Author(s) : Yamamoto,Sachio

Report Date : 12 MAY 1968

Pagination or Media Count : 30

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)

Descriptors :   (*NUCLEAR RADIATION SPECTROMETERS, SENSITIVITY), X RAY SPECTROSCOPY, FLUORESCENCE, SCINTILLATION COUNTERS, SEMICONDUCTOR DEVICES, RADIOACTIVE ISOTOPES, IODINE, NICKEL, MOLYBDENUM, MICROANALYSIS

Subject Categories : Test Facilities, Equipment and Methods
      Nuclear Instrumentation

Distribution Statement : APPROVED FOR PUBLIC RELEASE