Low-background Gamma-ray Spectrometry Research Articles

Изучение радиоактивности вод горных рек Кабардино-Балкарской Республики с использованием детектора NaI в низкофоновой защите

The results of studies of the radioactivity of the waters of the mountain rivers of the Kabardino-Balkarian Republic using the NaI detector in low-background protection are presented. The paper presents a method of low-background gamma-ray spectrometry for detecting radioactivity in drinking water, which is an effective method, has high sensitivity to radioactive radiation and allows you to accurately determine the level of radioactivity. The MULTIRAD MKS-01A spectrometric installation was used to measure radiation in samples under low background conditions. The identification and calculation of the volumetric activity of radionuclides was carried out using special software "Progress". Concentration levels and specific activity distribution of natural radionuclides 137Cs, 232Th, 40K, 226Ra and 222Rn were studied. Water samples were taken from the rivers of the Baksan, Cherek gorges and the Malka River of the Kabardino-Balkarian Republic. Studies have shown that radiation levels were within the norm set for drinking water.

Underground radioactivity measurements of meteorites: Development of methods suitable to determine precise terrestrial age of recent falls

The L6 chondritic meteorite, HaH-346, fell in Libya. However, neither the exact date of the fall nor the exact size of the original meteoroid or asteroid is known. A specimen of the meteorite, weighing 488 g, was measured using ultra low-background gamma-ray spectrometry in the 225 m deep underground facility HADES. Activation products 22Na, 26Al, 60Co, 57Co, 54Mn and 44Ti were detected. The detection efficiency was determined by 3D scanning the meteorite and introducing this in the computer model of the detector and sample implemented in the MCNP6.2 Monte Carlo code. The activities of 22Na and 26Al support the hypothesis that the fall took place on 26 August 2018. Furthermore, the 60Co and 26Al activities indicate that the original radius of meteoroid was between 50 and 80 cm, which suggests the mass prior to atmospheric entry was between 2400 and 7300 kg.

Study of Naturally Occurring Radioactive Material Present in Deep Soil of the Malwa Region of Punjab State of India Using Low Level Background Gamma-Ray Spectrometry

Background: Epidemiological observations such as mental retardation, physical deformities, etc., in children besides different types of cancer in the adult population of the Malwa region have been reported. The present study is designed to get insight into the role of naturally occurring radioactive material (NORM) in causing detrimental health effects observed in the general population of this region.Materials and Methods: Deep soil samples were collected from different locations in the Malwa region. Their activity concentrations were determined using low-level background gammaray spectrometry. High efficiency and high purity germanium detector capped in a lead-shielded chamber having a resolution of 1.8 keV at 1,173 keV and 2.0 keV at the 1,332 keV line of 60Co was used in the present work. Data were evaluated with Genie-2000 software.Results and Discussion: Mean activity concentrations of 238U, 232Th, and 40K in deep soil were found to be 101.3 Bq/kg, 65.8 Bq/kg, and 688.6 Bq/kg, respectively. The mean activity concentration of 238U was found to be three and half times higher than the global average prescribed by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). It was further observed that the activity concentration of 232Th and 40K has a magnitude that is nearly one and half times higher than the global average prescribed by UNSCEAR. In addition, the radioisotope 137Cs which is likely to have its origin in radiation fallout was also observed. It is postulated that the NORM present in high quantity in deep soil somehow get mobilized into the water aquifers used by the general population and thereby causing harmful health problems.Conclusion: It can be stated that the present work has been able to demonstrate the use of low background gamma-ray spectrometry to understand the role of NORM in causing health-related effects in a general population of the Malwa region of Punjab, India.

Study of uranium toxicity using low-background gamma-ray spectrometry

The natural activity of 238U, 232Th and 40K present in soil, fertilizer and palaeosols besides animal fossils was determined using low background gamma ray spectrometry. The highest uranium activity level were found in animal fossils of geogenic origin compared to palaeosols, soils and fertilizers, a result of post-mortem uranium assimilation in these fossils via diagenetic processes. Hence, geogenic mobilization is likely a major cause of elevated uranium levels in Malwa region of Punjab, also known for higher than normal cancer incidence.

Low-background gamma-ray spectrometry for the international monitoring system

PNNL has developed two low-background gamma-ray spectrometers in a new shallow underground laboratory, thereby significantly improving its ability to detect low levels of gamma-ray emitting fission or activation products in airborne particulate in samples from the IMS (International Monitoring System). The combination of cosmic veto panels, dry nitrogen gas to reduce radon and low background shielding results in a reduction of the background count rate by about a factor of 100 compared to detectors operating above ground at our laboratory.

The Dortmund Low Background Facility — Low-background gamma ray spectrometry with an artificial overburden

The Dortmund Low Background Facility is an instrument for low-level gamma ray spectrometry with an artificial overburden of ten meters of water equivalent, an inner shielding, featuring a neutron absorber, and an active muon veto. An integral background count rate between 40keV and 2700keV of (2.528±0.004)counts/(kgmin) enables low-background gamma ray spectrometry with sensitivities in the range of some 10mBq/kg within a week of measurement time.

Study of uranium mobilization from Himalayan Siwaliks to the Malwa region of Punjab state in India

Fossils, palaeosols and associated sedimentary rock samples from well-dated Siwalik sediments have been measured for their uranium content by low background gamma ray spectrometry with a view to study the role of geo-genic mobilization in enhancing the levels of uranium in ground water bodies of Malwa region in Punjab state, North Western India. Uranium activity in pure palaeosol and palaeosol associated samples i.e. calcrete and nodules varied between 46 and 214 Bq/kg whereas the same in pure fossil samples varied between 208 and 4837 Bq/kg. The data indicates a geo-genic contribution in the enhancement of uranium concentration in groundwater of the region.

Application of low-background gamma-ray spectrometry to monitor radioactivity in the environment and food

The results are described of an upgrade of the low-background gamma-ray spectrometry laboratory at New York State Department of Health by acquiring sensitivity to low-energy gamma rays. Tuning of the spectrometer and its low-energy response characteristics are described. The spectrometer has been applied to monitor the environment by measuring aerosols and water in New York State contaminated by the 2011 Fukushima accident plume. In addition, the spectrometer has been used to monitor radioactivity in food by performing a study of cesium in Florida milk.

Air radioactivity levels following the Fukushima reactor accident measured at the Laboratoire Souterrain de Modane, France

The radioactivity levels in the air of the radionuclides released by the Fukushima accident were measured at the Laboratoire Souterrain de Modane, in the South-East of France, during the period 25 March–18 April 2011. Air-filters from the ventilation system exposed for one or two days were measured using low-background gamma-ray spectrometry. In this paper we present the activity concentrations obtained for the radionuclides 131I, 132Te, 134Cs, 137Cs, 95Nb, 95Zr, 106Ru, 140Ba/La and 103Ru. The activity concentration of 131I was of the order of 100 μBq/m3, more than 100 times higher than the activities of other fission products. The highest activities of 131I were measured as a first peak on 30 March and a second peak on 3–4 April. The activity concentrations of 134Cs and 137Cs varied from 5 to 30 μBq/m3. The highest activity concentration recorded for Cs corresponded to the same period as for 131I, with a peak on 2–3 April. The results of the radioactivity concentration levels in grass and mushrooms exposed to the air in the Modane region were also measured. Activity concentrations of 131I of about 100 mBq/m2 were found in grass.

Comparison of gamma-ray coincidence and low-background gamma-ray singles spectrometry

Aerosol samples have been studied under different background conditions using gamma-ray coincidence and low-background gamma-ray singles spectrometric techniques with High-Purity Germanium detectors. Conventional low-background gamma-ray singles counting is a competitive technique when compared to the gamma-gamma coincidence approach in elevated background conditions. However, measurement of gamma-gamma coincidences can clearly make the identification of different nuclides more reliable and efficient than using singles spectrometry alone. The optimum solution would be a low-background counting station capable of both singles and gamma-gamma coincidence spectrometry.

Determination of the natural radioactivity in Qatarian building materials using high-resolution gamma-ray spectrometry

Abstract This study is aimed at the determination of the activity concentrations of naturally occurring and technically enhanced levels of radiation in building materials used across the State of Qatar. Samples from a range of common building materials, including Qatarian cement, Saudi cement, white cement, sand and washed sand, have been analyzed, in addition to other samples of cement's raw materials and additives collected from the main suppliers in Qatar. In order to establish the activity concentrations associated with the 235,8U and 232Th natural decay chains and 40K, the samples have been studied using a high-resolution, low-background gamma-ray spectrometry set-up. Details of the sample preparation and the gamma-ray spectroscopic analysis techniques are presented, together with the preliminary results of the activity concentrations associated with the naturally occurring radionuclide chains for the building materials collected across the Qatarian peninsula.

Relationship between variations of 7Be, 210Pb and 212Pb concentrations and sub-regional atmospheric transport: Simultaneous observation at distant locations

In order to investigate the applicability of 212Pb as a tracer for atmospheric transport in the sub-regional scale (few hundred kilometers in horizontal direction and up to ∼1 km by height), we measured the air concentrations of the short-lived radionuclide 212Pb along with the long-lived 7Be and 210Pb near the ground surface. For this purpose, simultaneous observations were continued for several days at three locations: a reference point representative for standard land surface atmosphere conditions, a second location at an altitude 650 m near the reference point, and on a solitary island ∼180 km from the reference point. Measurements of radioactivity in aerosol particle samples collected at intervals of 2–3 h with a high-volume air sampler were performed by extremely low background gamma-ray spectrometry with the use of Ge detectors located at the Ogoya Underground Laboratory. Concentration of 7Be or 210Pb and their variation patterns was found to be similar among the three points during the whole observation period except for moment of the passage of a cold front. The results indicate that distributions of concentrations of the long-lived nuclides were uniform in this range. On the other hand, concentration levels and the variation patterns of the short-lived 212Pb differed greatly from one location to another, reflecting differences in geographical location and altitude of the observation points. Additionally, there were certain indications that observed concentration of 212Pb contained two components: an autogenous component from sources nearby and a heterogenous one from faraway sources carried by atmospheric horizontal transport. Results of this study provide experimental proof that 212Pb can be used as a tracer of sub-regional atmospheric transport.

Smallest KnownQValue of Any Nuclear Decay: The Rareβ−Decay ofIn115(9/2+)→Sn115(3/2+)

The ground-state-to-ground-state Q_{beta;{-}} value of ;{115}In was determined to 497.68(17) keV using a high-precision Penning trap facility at the University of Jyväskylä, Finland. From this, a Q_{beta;{-}} value of 0.35(17) keV was obtained for the rare beta;{-} decay to the first excited state of ;{115}Sn at 497.334(22) keV. The partial half-life was determined to 4.1(6) x 10;{20} yr using ultra low-background gamma-ray spectrometry in an underground laboratory. Theoretical modeling of this 2nd-forbidden unique beta;{-} transition was also undertaken and resulted in Q_{beta;{-}} = 57_{-12};{+19} eV using the measured half-life. The discrepancy between theory and experiment could be attributed to atomic effects enhanced by the low Q value. The present study implies that this transition has the lowest Q value of any known nuclear beta decay.

ATOMIC BOMB INDUCED 152Eu: RECONCILIATION OF DISCREPANCY BETWEEN MEASUREMENTS AND CALCULATION

In order to resolve the discrepancy between the measured and calculated 152Eu activity induced by the atomic bomb at Hiroshima, extremely low background gamma-ray spectrometry was performed for 17 granite samples collected from 134 m to more than 3 km from the hypocenter. Measurements agreed well with theoretical calculations based on DS02 up to 1.4 km from hypocenter.

海藻試料への極低バックグラウンドγ線測定の適用―微量人工放射性核種に対する検出限界改善の試み―

海藻試料への極低バックグラウンドγ線測定の適用―微量人工放射性核種に対する検出限界改善の試み―

Application of low background gamma-ray spectrometry to environmental monitoring samples: Water leaching treatment for 40K-removal

In the usual measurements of radionuclides in the environmental samples by g-ray spectrometry, Compton scattering of 1461 keV g-rays from 40K severely interferes with the detection of artificial radionuclides in marine and agricultural products. In order to eliminate the interference of 40K, we have developed a simple and convenient “water leaching treatment” method applicable to seaweed (sargasso) samples. By this treatment, over 98% of the potassium in seaweed samples is removed without notable losses of artificial and/or natural radionuclides. In combination with the low-level g-ray counting in the Ogoya underground laboratory, the detection limit could be improved by ~1 order of magnitude.

Low-level measurement of the cosmogenic 22Na radionuclide in fresh water by ultra low-background gamma-ray spectrometry after simple radiochemical separation

A simple analytical method was developed for the determination of cosmogenic 22Na radionuclide in fresh water samples by ultra low-background g-ray spectrometry after radiochemical separation. The method consists in pre-concentration of 22Na(Na) by a ion exchange resin column from a large volume of ca. 500-liter water samples, elution with 4M HCl from the resin, and removal of the main metal components such as Ca and Mg as carbonate precipitates and of 40K(K) as potassium tetraphenylborate K[B(C6H5)4]. The obtained 22Na fraction was successfully measured by an ultra low-background Ge detector installed in the Ogoya Underground Laboratory.

Determination of low-level 54Mn in soils by ultra low-background gamma-ray spectrometry after radiochemical separation

An analytical method was developed for the measurement of low-level 54Mn in soil sample by ultra low-background g-ray spectrometry after radiochemical separation. The method consists of decomposition of sample by a mixture of HNO3 and HF, dissolution by HNO3, precipitation as hydroxide, solvent extraction with diisopropyl ether and anion exchange. Finally, for purification of Mn it was precipitated as MnO2 by adding KClO3. 54Mn in the precipitate was measured by ultra low-background well-type Ge detector at Ogoya Underground Laboratory. Measurements of 54Mn using 30-200 g of soil samples from the JCO grounds were successfully performed by the present method. The minimum detectable activity of 54Mn was about 0.01 dpm (0.2 mBq) for a 7-day counting period.

Correlation of natural and artificial radionuclides in soils with pedological, climatological and geographic parameters

Various types of soil samples were collected in the southern part of Brazil, with depth intervals of 5 cm, down to 50 cm, using a specially designed sampler. Pedological analysis of these soils were performed. Nuclear activities of137Cs (expressed in Bq m−2) and radioactive natural element (226Ra,228Ra and40K) concentrations were determined by low background gamma-ray spectrometry.137Cs concentrations were correlated with radioactive natural element concentrations and pedological, climatological and geographic parameters related to the soil samples collected.

Radioactivité induite par le rayonnement cosmique dans la météorite bogou

Low background gamma-ray spectrometry has been used to determine the activities of gamma emitters contained in a 0.185 kg sample sliced out of the Bogou iron meteorite that fell on 14 August 1962, near Bogou, Republic of the Upper Volta. The following results were obtained: 54Mn 483 ± 40 dpm.kg −1, at time of fall 22 Na 0 ± 4 60 Co 14 ± 7 44Ti 3.8 ± 3 26Al 4.3 ± 3 40K ⩽9 ± 6 These results are discussed and compared with those obtained by different authors on Bogou and on other iron meteorites. An upper limit for the exposure age (0.9 × 10 9 y) has been computed from the 40K and 44Ti contents and the ratio of 40K to 44Ti production rates.