| Summary: | The aims of this research are to use and validate the k0 standardization
method in the neutron activation analysis (k0-NAA) at Kartini reactor in
Yogyakarta. These works involved detection efficiency calibration of three
semiconductor detectors, calibration of neutron flux parameters include
determination of reactor parameter (� and α), and determination of parameters,
such as Z-score, U-test, accuracy and precision of k0-NAA results for some
elements in the samples.
The determination of detection efficiency (εp) in the case of measurement
restricted to one single distance of sample-detector based on an iterative
procedure, linking the measurement of calibration multi-γ point sources at this
particular detector distance with measurement of some coincidence free single-γ
point source. The obtained εp versus Eγ curve for point source geometry can be
converted to the extended sample geometry, based on the effective solid angle
concept. The determination of � and α in this research using bare-triple monitor
method and Cd-ratio method, while calculation of � and α applying a simple
iterative linear regression using available spreadsheets. The experimental data
were obtained by the irradiation of a set of suitable monitors in three Lazy Susan
irradiation positions and one irradiation position of the reactor pneumatic system.
Calibration and calculation of k0-NAA results were employed by the Kayzero for
Windows programs.The k0-NAA validation with analyzed some reference
materials has been done. The reference materials consists of NIST 8702 Buffalo
River Sediment, NIST 1632c Trace Elements in Coal and NIST 1648a Urban
Particulate Matter.
The optimization results of three detectors are known that GEM35P4-83
HPGe detector within the best of optimal conditions so GEM35P4-83 HPGe
detectors used in this study. From the results of the study at three positions in the
Lazy Susan irradiation system and pneumatic systems, � and α values obtained
with the lowest uncertainty present in position 5 of Lazy Susan. The results
showed that the deviations between experimental and certified values were mostly
less than 20% with most Z-score in the range of -2�x�2. In general, a good
agreement between results of this work and values in the certificates of the
standard reference materials was obtained.
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