Determination of photopeak efficiency for a NaI (Tl) well scintillation detector
Description
The photopeak efficiency for a NaI (Tl) well-type detector was experimentally determined. The results obtained by calculating the total peak area, showed that the efficiency reaches its maximum at 140 KeV (gamma radiation energy) decreasing for energies higher than this value. Considering that 33.2 KeV corresponds to photoelectric absorption of the iodine K layer in the detector, it would be expected that the efficiency would decrease towards this value of the incident radiation energy; nevertheless, it was observed that the drop in efficiency occurs around 60 KeV. This phenomenon could then be explained by the compton effect caused by the degradation of gamma energy due to source packing, also provolking absorption of gamma radiation by the iodine K layer in the NaI detector. (C.L.B.)
Availability note (English)
MF available from INIS under the Report Number.Abstract (Portuguese)
Determina-se, experimentalmente, a eficiencia de fotopico para o detetor a cristal de NaI (Tl) tipo poco. Os resultados obtidos, empregando o metodo do calculo da area total de pico, mostraram que a eficiencia apresenta um maximo para a energia da radiacao gama da ordem de 140 KeV decrescendo para energias superiores a este valor. Considerando que 33,2 KeV corresponde a energia de absorcao fotoeletrica na camada K do iodo, esperava-se que a eficiencia diminuisse para este valor da energia da radiacao incidente; entretanto, observou-se queda na eficiencia em torno de 60 KeV. Explica-se este fato pelo espalhamento compton no encapsulamento da fonte, provando degradacao da radiacao gama e sua absorcao pela camada K do iodo no detetor NaI. (C.L.B.)Files
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Additional details
Additional titles
- Original title (Portuguese)
- Determinacao da eficiencia de fotopico para um detetor cintilador de NaI (Tl) de poco
Publishing Information
- Imprint Pagination
- 41 p.
- Report number
- INIS-BR--161
INIS
- Country of Publication
- Brazil
- Country of Input or Organization
- Brazil
- INIS RN
- 15073121
- Subject category
- S46: INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY;
- Descriptors DEI
- EFFICIENCY; GAS SCINTILLATION DETECTORS; LIQUID SCINTILLATORS; PHOTOMULTIPLIERS; RESPONSE FUNCTIONS; SCINTILLATION COUNTERS; SOLID SCINTILLATION DETECTORS
- Descriptors DEC
- FUNCTIONS; MEASURING INSTRUMENTS; PHOSPHORS; PHOTOTUBES; RADIATION DETECTORS