Improving radioactive contaminant identification through the analysis of delayed coincidences with an $$\alpha $$-spectrometer

In the framework of rare event searches, the identification of radioactive contaminants in ultra-pure samples is a challenging task, because the signal is often at the same level of the instrumental background. This is a rather common situation for $$\alpha $$ α -spectrometers and other detectors used for low-activity measurements. In order to obtain the target sensitivity without extending the data taking live-time, analysis strategies that highlight the presence of the signal sought should be developed. In this paper, we show how to improve the contaminant tagging capability relying on the time-correlation of radioactive decay sequences. We validate the proposed technique by measuring the impurity level of both contaminated and ultra-pure copper samples, demonstrating the potential of this analysis tool in disentangling different background sources and providing an effective way to mitigate their impact in rare event searches.

The Impact of 242Pu Speciation on the Bioaccumulation of Plutonium by Babylonia spirata from Jakarta Bay

The research of bioaccumulation Plutonium of Babylonia spirata from Jakarta Bay using 242Pu radiotracer has been conducted. The aquaria experiments were applied by two oxidation states of Pu speciation with three replications. The experiment was carried out by 2 steps, such as uptake and depuration. The bioavailability of 242Pu in the (III) and (IV) oxidation states from sea has been studied for Babylonia spirata. Biokinetics parameters, such as concentration factors (CFss), uptake rate constants (ku), elimination rate constants (ke), bioconcentration factors (BCF), and biological half-life (tb1/2), were investigated. The dissection is carried out to separate the parts of the gastropod's body so that the target organs for Plutonium contamination can be identified. Each part of the gastropod's body was prepared radiochemically and analyzed using an alpha spectrometer. The research shows that Pu4+ is potentially accumulated in greater value than Pu3+ by B. spirata, in which Pu is more rapidly distributed and retained longer in proboscis and gastrointestinal tract.

Estimasi Dosis Radiasi 210Po pada Ikan Laut Konsumsi dari Perairan Banda Aceh

The main idea of this study is to calculate 210Po activity in marine biota from Banda Aceh waters and calculate dose estimates for marine biota consumers. Polonium analysis was carried out for Kaka Tua fish, Layur fish, Talang-talang fish, Kawet fish, and sharks using alpha spectrometer. The highest 210Po activity was found in sharks at 16.90 Bq/kg and Kaka tua fish at 16.24 Bq/kg. This activity is slightly above the recommended value for seafood, which is 15 Bq / kg. Based on the calculation, the daily intake for adults is around 0.18-0.41 Bq, for children, it is 0.12-0.27 Bq, and infant are 0.06-0.14 Bq. The daily intake of adults and children exceeds the recommended annual intake limit. However, the annual intake of many countries in the Asian region, including Japan and China, also far exceeds the recommended value. The amount of marine fish consumed significantly influences this annual dose estimate. The estimated dosage of 210Po yearly for adult consumers is 32.3-71.42 µSv/year for children, it ranges from 46.65-103.16 µSv/year, and for infants, it ranges from 78.95-174.58 µSv/year. These values are similar to the UNSCEAR recommended values: around 70, 100, and 180 µSv/year for adults, children, and infants. Ide utama dari penelitian ini adalah untuk menghitung aktivitas 210Po pada biota laut dari perairan Banda Aceh dan menghitung estimasi dosis terhadap konsumen ikan laut. Analisis polonium dilakukan terhadap sampel ikan ikan kaka tua, ikan layur, ikan talang-talang, ikan kawet, dan ikan hiu menggunakan alfa spektrometer. Hasil penelitian menemukan aktivitas 210Po tertinggi pada ikan hiu yaitu 16,90 Bq/kg, dan ikan Kaka tua sebesar 16,24 Bq/kg. Aktivitas ini sedikit diatas nilai yang direkomendasikan untuk makanan laut, yaitu sebesar 15 Bq/kg. Berdasarkan perhitungan, asupan harian terhadap orang dewasa sekitar 0,18–0,41 Bq, untuk anak anak sebesar 0,12–0,27 Bq dan bayi sebesar 0,06-0,14 Bq. Asupan harian dewasa dan anak melebih batas tahunan asupan yang direkomendasikan, namun asupan tahunan dari banyak Negara di kawasan Asia termasuk Jepang dan China juga jauh melebih nilai yang direkomendasikan Jumlah konsumsi ikan laut sangat berpengaruh terhadap estimasi dosis tahunan ini. Penghitungan estimasi dosis 210Po tahunan terhadap konsumen dewasa adalah sebesar 32,3–71,42 µSv/tahun, untuk anak anak berkisar antara 46,65–103,16 µSv/tahun dan untuk bayi berkisar antara 78,95–174,58 µSv/tahun. Nilai ini mirip dengan nilai rekomendasi UNSCEAR, yaitu sekitar 70, 100 dan 180 µSv/tahun untuk dewasa, anak anak dan bayi.

Radioactivity of some natural and artificial radionuclides in coastal seawater at Ninh Thuan, Ba Ria - Vung Tau and Ca Mau provinces in 2018

Radioactivities of some natural (Ra-226, Th-232, U-238, Po-210) and artificial (Cs-137, Sr-90 and Pu-239,240) radionuclides in coastal seawater at monitoring points of Ninh Thuan, Ba Ria - Vung Tau and Ca Mau provinces were analyzed quarterly in the year of 2018. Radioactivities of Ra-226, Th-232, U-238, and Cs-137 had been determined by simultaneous precipitation method and measured on low-level background gamma spectrometer; the radioactivities of Po-210 and Pu- 239,240 had been analyzed by radiochemical separation method and measured on alpha spectrometer; the radioactivity of Sr-90 had been analyzed by radiochemical separation method and measured on low-level background beta counting system. The ranges of radioactivities of Ra-226, Th-232, U-238, Po-210, Cs-137, Sr-90, and Pu-239,240 were 2.71 ÷ 15.91, 3.45 ÷ 35.93, 3.02 ÷ 21.47, 1.51÷ 6.74, 0.88 ÷ 1.68, 1.08 ÷ 1.86 and 0.0026 ÷ 0.0062 mBq/L, with the average values of 6.37, 12.67, 8.34, 3.29, 1.36, 1.46 and 0.0043 mBq/L, respectively. The results shown that the radioactivities of theabove-mentioned radionuclides varied between the seawaters at Ninh Thuan, Ba Ria - Vung Tau and Ca Mau seawater. Additionally, physicochemical parameters in seawater were also surveyed to assess their impact on the fluctuations of the above radionuclides.

FSUE SRI IMM: Evolution of Devices for Radon Control and its DPR

Preparation and implementation of measures to reduce radiation doses to personnel of enterprises engaged in the extraction and processing of uranium-containing ores, and the population of the territories adjacent to uranium deposits, require an increase in the accuracy of estimates of absorbed and effective doses to the personnel of enterprises and the population with the inhalation of radon and its progeny. This can only be done by taking into account the contribution of the aerosol-unattached fraction of the radon decay progeny to the effective and absorbed radiation doses, which are evaluated on the basis of direct measurements. Alpha spectrometer SAT-03 – a means of measurement of the third generation, has been developed in the Research Institute of Industry and Maritime Medicine for these purposes. Widespread domestic radiometers of the previous generation (RAA-10, RRA-01M) do not have the technical capabilities to perform such studies.

Sedimentation Rate and Sediment Accumulation at the Estuary of Rokan River, Indonesia

The objective of the study was to analyse the sedimentation rate and sediment accumulation at the estuary of the Rokan River. Sediment samples were collected from 3 sampling points, i.e. Southern, Western and Northern of Berkey Island. The samples were then analysed using 210Pb radioisotope of the alpha spectrometer. The bottom of the Rokan River estuary is dominated by fine silt. It was recorded that sedimentation rate in Southern, Western, and Northern of Berkey Island were 0.3, 0.22, and 0.28 cm/year, respectively. The accumulation of sediment in each station was as follows; 3.13, 2.88, and 3.42 ton/ha/year. The age of sediment in the Southern Berkey Island was 23,71 years at depth 14 cm, Western Berkey Island was 64,26 years, and in Northern Berkey Island was 26,59 years. Sedimentation rate inside was higher than outside of the estuary. Higher sediment accumulation was noted at the outer part of the estuary compared to the inner part. The sediments found in the central part of the estuary are older than those inside and outside.

Design by numerical simulation of an in situ alpha spectrometer operating at ambient air pressure

Alpha emitters are usually identified and quantified by alpha spectrometry measurements in a vacuum chamber performed in laboratory environments. This study shows that transuranic elements can be distinguished under ambient conditions using a grid collimator. The aim of this work was to use numerical simulations with the MCNP6 code to design a grid with a resolution high enough to differentiate the same radionuclide combinations as alpha spectrometry in a vacuum chamber, namely 239Pu + 240Pu, 241Am + 238Pu and 244Cm. Results show that a compromise is required to obtain the best performances in terms of energy resolution and detection efficiency, leading to the choice of two hexagonal grid collimators. The first has a collimation height of 0.5 cm and an apothem of 1 mm. Laboratory tests on electrodeposited sources show that the target radionuclides can be identified without prior deconvolution, with an energy resolution of about 70 keV and a detection efficiency of 0.74% at incident energies of 5–6 MeV. The second grid has the same collimation height but a coarser mesh with an apothem of 2 mm. In this case, the alpha peaks are still distinguishable, but with a lower resolution of 125 keV. The detection efficiency is three times higher however.