Si(Li)-NaI(Tl) sandwich detector array for measurements of trace radionuclides in soil samples
An ultra-sensitive x-/..gamma..-ray detector system for assaying trace radioactivity in actinide contaminated soil and ash samples has been developed. The new system consists of an array of 6 large Si(Li) x-ray detectors sensitive on both faces and mounted on edge in a paddle-shaped cryostat with a 14 cm dia Be window on each side. The paddle, with a sample of the soil placed at each window, is sandwiched between 2 large NaI(Tl) scintillators which suppress the ..gamma.. background. With x rays being measured simultaneously from soil in 2 sample holders and background reduced by 50% using anticoincidence, the sensitivity of this detector is 4 times higher than that of conventionally mounted Si(Li) detectors. A soil sample containing 50 pCi/g /sup 239/Pu was measured in 5 min with an uncertainty of <20% and a sample containing 7 pCi/g was measured in 1 hr. With FWHM resolution of 400 eV at 17 keV, the UL..beta../sub 1/ and NpL..beta../sub 1/ x-ray peaks are resolved thus permitting measurement of trace Pu in the presence of Am-241. This is the most sensitive and selective detector known for nondestructive assay of radioactivity in soil and other samples. 15 refs., 8 figs.
- Research Organization:
- Argonne National Lab., IL (USA); Lawrence Berkeley Lab., CA (USA)
- DOE Contract Number:
- W-31-109-ENG-38
- OSTI ID:
- 5419289
- Report Number(s):
- CONF-850533-10; ON: DE85013865
- Resource Relation:
- Conference: 6. symposium on X- and gamma-ray sources and applications, Ann Arbor, MI, USA, 21 May 1985; Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
54 ENVIRONMENTAL SCIENCES
LI-DRIFTED SI DETECTORS
DESIGN
SENSITIVITY
NAI DETECTORS
SOILS
RADIOASSAY
BACKGROUND RADIATION
ENERGY RESOLUTION
NATURAL RADIOACTIVITY
NONDESTRUCTIVE TESTING
PLUTONIUM 239
QUALITATIVE CHEMICAL ANALYSIS
X-RAY DETECTION
X-RAY SPECTROMETERS
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ALPHA DECAY RADIOISOTOPES
CHEMICAL ANALYSIS
DETECTION
EVEN-ODD NUCLEI
HEAVY NUCLEI
ISOTOPES
LI-DRIFTED DETECTORS
MATERIALS TESTING
MEASURING INSTRUMENTS
NUCLEI
PLUTONIUM ISOTOPES
RADIATION DETECTION
RADIATION DETECTORS
RADIATIONS
RADIOACTIVITY
RADIOISOTOPES
RESOLUTION
SCINTILLATION COUNTERS
SEMICONDUCTOR DETECTORS
SI SEMICONDUCTOR DETECTORS
SOLID SCINTILLATION DETECTORS
SPECTROMETERS
TESTING
YEARS LIVING RADIOISOTOPES
440102* - Radiation Instrumentation- Radiation Dosemeters
510301 - Environment
Terrestrial- Radioactive Materials Monitoring & Transport- Soil- (-1987)