Research Article
Calibration of Radioisotope Level Gauge Detector
Issue:
Volume 11, Issue 3, September 2026
Pages:
30-39
Received:
6 February 2026
Accepted:
19 March 2026
Published:
27 August 2026
Abstract: In accordance with regulatory standards, to meet the requirements of legislation in the field of industrial safety and ensure the quality of fiberglass products, as well as to confirm the correct operation of the measuring instrument, accurate calibration of the radioisotope measuring instrument is necessary.The aim of this work is to develop a method for testing the tightness of the Cesium-137 ionizing radiation source included in the radioisotope level gauge, to develop a method for accurately calibrating the radioisotope level gauge in laboratory conditions and to install the radioisotope level gauge in the preliminary channel of technological line of glass fiber production for continuous measurement of the glass mass level in online mode. The leak tightness of the Cs-137 radioactive ionizing radiation source was tested using three different methods. To calibrate the radioisotope level gauge in a laboratory conditions, a stainless steel calibration stend was used. The stand consisted of a square container with an internal lining of firebrick, and a mixture of bromoform and ethyl alcohol with a density of ρ=1799 g/dm3 was used as a simulant liquid. A gamma source block with a Сs-137 source was installed on one side of the pre-channel, and a detector was installed on the diametrically opposite side. One external firebrick in front of the detector was removed from the pre-channel, and the resulting void was filled with fiberglass to protect the detector from heating due to the high temperature of the fiberglass. The radioisotope level gauge detector (M7213 scintillation probe, Tesakon Messele-lectronics, GmbH Dresden), which has a housing with a water cooling system and a scintillation crystal length of 35 mm (Φ=38 mm, H=38 mm), was calibrated to an acceptable glass mass level of 192.5 mm (±1 mm) from the bottom of the preliminary channel at a maximum γ-radiation flux from a Cs-137 ionizing radiation source with an intensity of 1660 pulses/sec.
Abstract: In accordance with regulatory standards, to meet the requirements of legislation in the field of industrial safety and ensure the quality of fiberglass products, as well as to confirm the correct operation of the measuring instrument, accurate calibration of the radioisotope measuring instrument is necessary.The aim of this work is to develop a met...
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Research Article
Investigating Temporal-Spatial Compatibility of Magnetic Data from Madagascar Repeat Stations
Lady Mireille Razafindranaivo*
,
Ravo Zohary Andrianasolo
Issue:
Volume 11, Issue 3, September 2026
Pages:
40-53
Received:
14 July 2026
Accepted:
27 July 2026
Published:
27 August 2026
Abstract: Accurate regional geomagnetic field modeling is crucial for navigation, resource exploration, and solid-Earth geophysics. In Madagascar, however, field model consistency has been hindered by severe spatio-temporal irregularities in the reoccupation of its twenty-five-station repeat network, including the pivotal Antananarivo observatory, between 1983 and 2001. To overcome these data limitations, this comprehensive study evaluates the spatial and temporal compatibility of the Malagasy repeat station network to establish robust regional geomagnetic field models. Assuming negligible altitude variance across the island region, the parameterization framework relies exclusively on geographic latitude and longitude coordinates. Gauss coefficients were derived using two complementary modeling methods specifically suited for sparse, non-uniformly distributed datasets: regional harmonic analysis and surface polynomial modeling. Both techniques produced highly consistent and robust field representations for periods characterized by stable network geometry, notably 1983 through 1985. In sharp contrast, the 1986 dataset exhibited pronounced anomalous coefficients and residuals stemming from observational inconsistencies, necessitating its complete exclusion from subsequent calculations. A rigorous comparative evaluation revealed that regional harmonic models maintain far greater mathematical stability under non-uniform station distributions. Conversely, polynomial models suffer from boundary artifacts and produce unreliable extrapolation across unmonitored regions lacking observational data. Consequently, while both approaches perform comparably under dense spatial sampling, regional harmonic analysis proves markedly superior within data-sparse regimes. These findings highlight the absolute necessity of maintaining broad, uniformly distributed monitoring networks across the island. Furthermore, they provide a methodological framework for annual field interpolation, guide future cartographic mapping efforts, and strongly advocate for continued, systematic geomagnetic surveys across Madagascar to continually refine these essential regional field representations.
Abstract: Accurate regional geomagnetic field modeling is crucial for navigation, resource exploration, and solid-Earth geophysics. In Madagascar, however, field model consistency has been hindered by severe spatio-temporal irregularities in the reoccupation of its twenty-five-station repeat network, including the pivotal Antananarivo observatory, between 19...
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