Search

Purpose: A study of indoor radon and thoron has been carried out in the dwelling of Moradabad, Uttar Pradesh, India. Radon is an invisible radioactive gas that occurs naturally in the indoor atmosphere. It comes from the natural breakdown of uranium in soils and rocks. Lung cancer risk depends upon the concentration of radon, thoron and their decay product in the air. Methodology: The measurements of radon and thoron concentration were carried out by using LR-115 type II plastic track detectors (SSNTD Technique). Findings: In the present study the value of radon concentration from10.5 Bq/m3to 30Bq/m3 with an average19.9Bq/m3and thoron concentration from 5.6 Bq/m3 to 24 Bq/m3 with an average of 14.9 Bq/m3. It is observed that radon and thoron concentration is maximum in winter and minimum during summer. The maximum concentration in winter is essentially influenced by the intense temperature inversion, which occurs in the winter season when the wind velocity is low. The maximum concentration in winter is also the result of decreased ventilation because in this season the houses are closed for a long time and radon/thoron accumulated inside the room and a weak positive correlation was observed between radon and thoron. Social Implications: There are some difficulties in assessing the exact risks of radon in the home. Most studies have used data from miners who will have had far more exposure to radon than is likely in any building. Originality/ Novelty: This study is done at Moradabad City and Research Lab present in S.S.P. G. College Shajhanapur. Data of radon and thoron concentration has been taken from twin cup radon-thoron Dosimeter and Spark Counter.

This paper presents an experimental approach to evaluate the effectiveness of unipolar ionizers in indoor environment for the removal of thoron (220Rn) daughter products. Both continuous and instantaneous source conditions were simulated during these experiments. Activity and aerosol related parameters were measured for these experiments and results were interpreted. Activity concentration was found to be reduced by a factor 6.6 and 34 for continuous and instantaneous source conditions, respectively. The particle size dependency of mitigation of particles using ionizer is also discussed. The effect of ionizer on activity size distribution has been directly measured for the first time. The ionizer induced changes in particle size distributions were coupled to Dose Reduction Factor (DRF) model and significant DRF values were obtained for both source conditions. This study discusses open issues which are important for establishing ionizer induced radioactivity mitigation as a technology application.

The temporal variations of the airborne radon decay product dose rate and deposited radon decay product activities, as well as the within-house and house-to-house variations of radon concentrations, were evaluated through repeated field measurements. Long-term average radon and surface-deposited radon decay product concentrations were measured in 76 rooms of 38 houses. Temporal variation of radon, as well as airborne and surface-deposited radon decay products, were measured in 11 of the 38 houses during two different seasons. Environmental factors that have the potential to influence airborne dose rate and deposited radon decay products were also studied. Airborne dose rates were calculated from the unattached and attached potential alpha energy concentrations using two dosimetric models. For one model, the observed dose variations were 103%, 74%, 58%, and 60% for the total, house-to-house, within-house, and within-room temporal variations, respectively. For the other model, the dose variations were 100%, 66%, 61%, and 46%, respectively. Surface-deposited (214)Po showed variations of 79%, 57%, 42%, and 48%, respectively. These substantial radon decay product concentration variations suggest that multiple locations and time-integrated measurements are needed to make an accurate assessment of the chronic radon-related doses in homes. Smoking was the environmental factor that had the largest temporal and spatial effect on airborne radon decay product dose rates.

A wealth of new physics models which are motivated by questions such as the nature of dark matter, the origin of the neutrino masses and the baryon asymmetry in the universe, predict the existence of hidden sectors featuring new particles. Among the possibilities are heavy neutral leptons, vectors and scalars, that feebly interact with the Standard Model (SM) sector and are typically light and long lived. Such new states could be produced in high-intensity facilities, the so-called beam dump experiments, either directly in the hard interaction or as a decay product of heavier mesons. They could then decay back to the SM or to hidden sector particles, giving rise to peculiar decay or interaction signatures in a far-placed detector. Simulating such kind of events presents a challenge, as not only short-distance new physics (hard production, hadron decays, and interaction with the detector) and usual SM phenomena need to be described but also the travel has to be accounted for as determined by the geometry of the detector. In this work, we describe a new plugin to the {\sc MadGraph5\_aMC@NLO} platform, which allows the complete simulation of new physics processes relevant for beam dump experiments, including the various mechanisms for the production of hidden particles, namely their decays or scattering off SM particles, as well as their far detection, keeping into account spatial correlations and the geometry of the experiment., LaTeX, 42 pages, 14 figures

Radon is a noble gas that occurs in nature as a decay product of uranium. Radon is the principal contributor to natural background radiation and is considered to be one of the major leading causes of lung cancer. The main concern revolves around indoor environments where radon accumulates and reaches high concentrations. In this paper, a semiparametric random-effect M-quantile model is introduced to model radon concentration inside a building, and a way to estimate the model within the framework of robust maximum likelihood is presented. Using data collected in a monitoring survey carried out in the Lombardy Region (Italy) in 2003–2004, we investigate the impact of a number of factors, such as geological typologies of the soil and building characteristics, on indoor concentration. The proposed methodology permits the identification of building typologies prone to a high concentration of the pollutant. It is shown how these effects are largely not constant across the entire distribution of indoor radon concentration, making the suggested approach preferable to ordinary regression techniques since high concentrations are usually of concern. Furthermore, we demonstrate how our model provides a natural way of identifying those areas more prone to high concentration, displaying them by thematic maps. Understanding how buildings’ characteristics affect indoor concentration is fundamental both for preventing the gas from accumulating in new buildings and for mitigating those situations where the amount of radon detected inside a building is too high and has to be reduced.

Due to the universality of gravitational interactions, it is generally expected that a stochastic gravitational wave (GW) background could form during the reheating period when the inflaton perturbatively decays with the emission of gravitons. Previously, only models in which the inflaton dominantly decays into a pair of light scalar and/or fermion particles were considered in the literature. In the present paper, we focus on the cases with a vector particle pair in the final decay product. The differential decay rates for the three-body gravitational inflaton decays are presented for two typical couplings between the inflaton and vector fields, from which we predict their respective GW frequency spectra. It turns out that, similar to the scalar and fermion cases, the obtained GW spectra is too high in frequency to be observed by the current and near-future GW detection experiments and calls for a new design of high-frequency GW detectors., Comment: 15 pages, 4 figures

International audience; The superheavy isotope$^{258}$Db was produced in the$^{209}$Bi($^{50}$Ti, 1n)$^{258}$Db reaction at GSI, Germany. A detailed $ \alpha$ -spectroscopy study of this isotope and its $ \alpha$ -decay daughter products was performed. Two long-lived $ \alpha$ -decaying states in$^{258}$Db are observed. A spin-parity of $ 0^{-}$ is tentatively assigned to the ground state for which a half-life of $ 2.17 \pm 0.36$ s is determined. Spins and parities of either $ 5^{+}$ or $ 10^{-}$ are proposed for the isomeric state found at an excitation energy of 51 keV with a half-life of $ 4.41 \pm 0.21$ s. The $ \alpha$ -decay daughter isotope$^{254}$Lr displays a similar behavior. A half-life of $ 11.9 \pm 0.9$ s is determined for the$^{254}$Lr ground state which is tentatively assigned a spin-parity of $ 4^{+}$ . The isomeric level of this isotope placed at 108 keV with a half-life of $ 20.3 \pm 4.2$ s is tentatively assigned a spin-parity of $ 1^{-}$ . Two long-lived $ \alpha$ -decaying states are observed in the granddaughter isotope$^{250}$Md . The ground state has a half-life of $ 59.5 \pm 9.1$ s. A half-life of $ 42.4 \pm 4.5$ s is measured for the isomeric state positioned at an excitation energy of 123 keV. Partial, tentative level schemes for$^{254}$Lr,$^{250}$Md and$^{246}$Es are proposed based on the $ \alpha$ - $ \gamma$ coincidences.

During the 33rd summer expedition to the two Indian Stations at Antarctica, Bharati and Maitri, radon and thoron progeny concentrations in indoors and outdoors were measured along with radon (222Rn)/thoron (220Rn) exhalation rate measurements of soil samples, radionuclide content and 222Rn emanation coefficient. This investigation was based on the reports of the higher gamma radiation levels reported around these stations. The results will give an estimate of the radioactivity level as well as the total dose received by personnel carrying out long-term measurements at these stations. Radon and thoron progeny concentrations were measured using direct radon and thoron progeny sensors (DRPS and DTPS). The soil radionuclide content was measured using HPGe gamma spectrometry while radon/thoron exhalation rates were measured using the accumulation method by scintillation radon/thoron monitor. In contrast to a higher radiation field and radioactivity content, studies showed the radon/thoron exhalation rates and progeny concentration to be similar to that measured in normal background areas of other parts of the world. This could be attributed to the ice deposits and the larger atmospheric dispersion, and also to the soil nature which is mainly loamy sands with low clay content contributing to a lower emanation. The results are discussed.

The distribution of the anthropogenic radionuclide 241Am, a decay product of 241Pu discharged from atmospheric tests of nuclear weapons, was investigated to resolve its horizontal and vertical migration in the Tropical East Pacific. We analyzed 241Am concentrations in seawater samples collected in 2003. On comparing the 241Am concentrations with the previously determined concentrations of 239+240Pu in the same samples, the vertical profiles of 241Am were found to be similar to those of 239+240Pu. At some stations, the maximum concentration of 241Am occurred 100–200 m deeper than that of 239+240Pu. The 241Am/239+240Pu ratios in the North Pacific and South Pacific were comparable to one another, and were the typical ratio for the Pacific. The 241Am distribution was influenced by the water mass at depths below 400 m. The 241Am data support the view there is a current flowing at depths of 400–3000 m from the North Pacific through the Equator to the South Pacific. In addition, the 241Am vertical profile was explained by using a 1-D scavenging model that considers the decay of 241Pu and adsorption and scavenging by suspended particles. The different depths for the maximum concentrations of 241Am and 239+240Pu observed at some stations were well explained by the model and by the distribution of CaCO3 particles. The residence time of 241Am in the Pacific was also estimated by using the model.

The study reports measurements of radon and its decay products and of perceived air quality carried out in an occupied and unoccupied auditorium at the Lublin University of Technology in Lublin, Poland during three air conditioning system operation modes – air conditioning off, air conditioning on and air conditioning on/off. In the air conditioning on/off mode radon and its decay product concentrations and values of perceived air quality were inversely related. During that air conditioning operation mode, the value of the mean equilibrium factor F for the unattached fraction (0.31 ± 0.19) was somewhat higher than for the attached fraction (0.24 ± 0.19) and significant negative correlations were found between F values for attached, unattached and for the sum of both progeny fractions and perceived air quality values. These findings may be of importance as they indicate that in certain air conditioning operation modes indoor air quality deteriorates along with a reduction in the radon health hazard. This, in turn may adversely affect the comfort and productivity of the room users.

This study proposes a novel method for the detection of inert gas radon using a label-free, specific, fluorescence-sensing aptamer in the context of PW17-OG system. This method utilizes the cyanine dye OliGreen (OG) as a signal reactor and the aptamer PW17 as a fluorescent identification probe. When OG integrates into the free curling PW17, a strong fluorescence signal is generated. After radon decays, the long lived naturally occurring radon progeny Pb being disposed and introduced to the system. Lead ions induce PW17 to form a stable G-quadruplex, thereby inhibiting the interaction between OG and PW17 and resulting in a reduction of the fluorescence intensity. The fluorescence intensity show a good linear relationship with lead ion and the radon concentration (D), thereinto, We fitted linear regression of radon concentration in the range of 0.92-4.22 (×10(4) Bqhm(-3)) to receive a good relationship between ΔF and the concentration of radon with the detection limit of 1963 Bqhm(-3). This method has been successfully applied for detecting standard cumulative concentration of radon and the detection limit reached the national standard of China. This sensitive method can exclude radiation damage in field testing, furthermore, it explores a new field in biological analysis using an aptamer to detected inorganic, gaseous, and radioactive materials.

Molybdenum-99 (99Mo) is the most important isotope because its daughter isotope, technetium-99m (99mTc), has been the most widely used medical radioisotope for more than 50 years, accounting for > 80% of total nuclear diagnostics worldwide. In this review, radiochemical routes for the production of 99Mo, and the aspects for selecting a suitable process strategy are discussed from the historical viewpoint of 99Mo technology developments. Most of the industrial-scale 99Mo processes have been based on the fission of 235U. Recently, important issues have been raised for the conversion of fission 99Mo targets from highly enriched uranium to low enriched uranium (LEU). The development of new LEU targets with higher density was requested to compensate for the loss of 99Mo yield, caused by a significant reduction of 235U enrichment, from the conversion. As the dramatic increment of intermediate level liquid waste is also expected from the conversion, an effective strategy to reduce the waste generation from the fission 99Mo production is required. The mitigation of radioxenon emission from medical radioisotope production facilities is discussed in relation with the monitoring of nuclear explosions and comprehensive nuclear test ban. Lastly, the 99Mo production process paired with the Korea Atomic Energy Research Institute's own LEU target is proposed as one of the most suitable processes for the LEU target.

We have recently established a new method for measuring the mass of unstable particles produced at hadron colliders based on the analysis of the energy distribution of a massless product from their two-body decays. The central ingredient of our proposal is the remarkable result that, for an unpolarized decaying particle, the location of the peak in the energy distribution of the observed decay product is identical to the (fixed) value of the energy that this particle would have in the rest-frame of the decaying particle, which, in turn, is a simple function of the involved masses. In addition, we utilized the property that this energy distribution is symmetric around the location of peak when energy is plotted on a logarithmic scale. The general strategy was demonstrated in several specific cases, including both beyond the SM particles, as well as for the top quark. In the present work, we generalize this method to the case of a massive decay product from a two-body decay; this procedure is far from trivial because (in general) both the above- mentioned properties are no longer valid. Nonetheless, we propose a suitably modified parametrization of the energy distribution that was used successfully for the massless case, which can deal with the massive case as well. We establish the accuracy of this parametrization using concrete examples of energy spectra of Z bosons from the decay of a heavier stop into a Z boson and a lighter stop. We then study a realistic application for the same process, but now including dominant backgrounds and using foreseeable statistics at LHC14, in order to determine the performance of this method for an actual mass measurement. The upshot of our present and previous work is that, in spite of energy being a Lorentz-variant quantity, its distribution emerges as a powerful tool for mass measurement at hadron colliders., 37 pages, 8 figures

The aim of this paper is to contribute to a more rapid determination of a series of samples containing Sr-90 by making the Cherenkov measurement of the daughter nuclide Y-90 more time efficient. There are many instances when an optimization of the measurement method might be favorable, such as; situations requiring rapid results in order to make urgent decisions or, on the other hand, to maximize the throughput of samples in a limited available time span. In order to minimize the total analysis time, a mathematical model was developed which calculates the time of ingrowth as well as individual measurement times for n samples in a series. This work is focused on the measurement of Y-90 during ingrowth, after an initial chemical separation of strontium, in which it is assumed that no other radioactive strontium isotopes are present. By using a fixed minimum detectable activity (MDA) and iterating the measurement time for each consecutive sample the total analysis time will be less, compared to using the same measurement time for all samples. It was found that by optimization, the total analysis time for 10 samples can be decreased greatly, from 21 h to 6.5 h, when assuming a MDA of 1 Bq/L and at a background count rate of approximately 0.8 cpm.

An electron spectrometry set-up was built at IRMM consisting of a vacuum chamber with a moveable source holder and windowless Peltier-cooled silicon drift detector (SDD). The SDD is well suited for measuring low-energy x rays and electrons emitted from thin radioactive sources with low self-absorption. The attainable energy resolution is better than 0.5keV for electrons of 30keV. It has been used to measure the conversion electron spectra of three plutonium isotopes, i.e. (238)Pu, (239)Pu, (240)Pu, as well as (241)Am (being a decay product of (241)Pu). The obtained mixed x-ray and electron spectra are compared with spectra obtained with a close-geometry set-up using another SDD in STUK and spectra measured with a Si(Li) detector at IRMM. The potential of conversion electron spectrometry for isotopic analysis of mixed plutonium samples is investigated. With respect to the (240)Pu/(239)Pu isotopic ratio, the conversion electron peaks of both isotopes are more clearly separated than their largely overlapping peaks in alpha spectra.

The half-life of (234)U has been measured using a novel approach. In this method, a uranium material was chemically purified from its thorium decay product at a well-known time. The ingrowth of the (230)Th daughter product in the material was followed by measuring the accumulated (230)Th daughter product relative to its parent (234)U nuclide using inductively coupled plasma mass spectrometry. Then, the (234)U decay constant and the respective half-life could be calculated using the radioactive decay equations based on the n((230)Th)/n((234)U) amount ratio. The obtained (234)U half-life is 244 900 ± 670 years (k = 1), which is in good agreement with the previously reported results in the literature with comparable uncertainty. The main advantages of the proposed method are that it does not require the assumption of secular equilibrium between (234)U and (238)U. Moreover, the calculation is independent from the (238)U half-life value and its uncertainty. The suggested methodology can also be applied for the remeasurement of the half-lives of several other long-lived radionuclides.

Assay methods for measuring 238U, 232Th, and 210Pb concentrations in refined lead are presented. The 238U and 232Th concentrations are determined using isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS) after anion exchange column separation of dissolved lead samples. The 210Pb concentration is inferred through {\alpha}-spectroscopy of a daughter isotope, 210Po, after chemical precipitation separation on dissolved lead samples. Subsequent to the 210Po {\alpha}-spectroscopy assay, a method for evaluating 210Pb concentrations in solid lead samples was developed via measurement of bremsstrahlung radiation from \b{eta}-decay of a daughter isotope, 210Bi, by employing a 14-crystal array of high purity germanium (HPGe) detectors. Ten sources of refined lead were assayed. The 238U concentrations were

The measurements of radon and its attached decay product activity concentrations were carried out in an occupied and unoccupied auditorium during three air-conditioning modes i.e. air-conditioning system switched off (air-conditioning off), air-conditioning system switched off during the night and switched on during the day (air-conditioning on/off) and air-conditioning system switched on (air-conditioning on). Higher average concentrations of radon and its decay products were recorded in the auditorium when the air-conditioning system was switched off. The average particle mass and CO2 concentrations and indoor air thermal parameters were elevated during the air-conditioning on/off mode. A statistically significant ( p 2 concentrations in the air-conditioning off mode ( r = −0.86 and r = −0.47, respectively). The obtained results confirmed the impact of the air-conditioning system operation on the decrease of health risks related to the presence of radon and its decay products in air conditioned premises.

Radioisotopes, produced in stars and ejected into the Interstellar Medium, are important for constraining stellar and early Solar System (ESS) models. In particular, the half-life of the radioisotope, Fe-60, can have an impact on calculations for the timing for ESS events, the distance to nearby Supernovae, and the brightness of individual, non-steady-state Fe gamma ray sources in the Galaxy. A half-life measurement has been undertaken at the University of Notre Dame and measurements of the Fe-60/Fe-56 concentration of our samples using Accelerator Mass Spectrometry has begun. This result will be coupled with an activity measurement of the isomeric decay in Co-60, which is the decay product of Fe. Preliminary half-life estimates of (2.53 +/- 0.24) x 10(6) years seem to confirm the recent measurement by Rugel et al. (2009). (C) 2015 Elsevier B.V. All rights reserved.

We report on the results of spectroscopic studies of the HeNeI2 van der Waals trimer using the two-step two-color HeNeI2(E0g+, vE = 0–3 ←hν2 B0u+, vB = 19 ←hν1 X0g+, vX = 0) excitation scheme. The excitation spectra of the HeNeI2(B, E) decay product luminescence and the luminescence spectra of I2 ion-pair states formed after HeNeI2(E) decay have been recorded and analyzed. The HeNeI2(X, B, E) binding energies have been estimated to be less than 111.8 cm−1, 101.6 cm−1, and 117.9 cm−1, respectively. The HeNeI2(B, vB) state decay has been found to be sequential with the formation of the HeI2(B, vB − 1) and NeI2(B, vB − 1) complexes without intermolecular excitation at the first step. An analysis of the HeNeI2(E) decay process based on the relative probabilities of the I2(D0u+) and I2(β1g) formation after decay, as well as vibrational populations of these states obtained from luminescence spectra, has also been performed. Calculations of the HeNeI2(X, B) vibrational energies using potential energy surfaces (PESs) of HeNeI2(X, B) constructed as a sum of the HeNe, HeI2, and NeI2 potentials have been carried out. The values obtained agree well with the experimental estimations, and the observed transitions can be ascribed to the HeNeI2 trimer of a tetrahedral geometry. Besides, a comparison of the PES constructed as a sum of the coupled-cluster single double triple [CCSD(T)] potentials with the PES based on the “direct” CCSD(T) calculations has been performed for the HeNeI2(X) trimer to verify the applicability of this representation to the trimer under study.

231Pa is the longest-lived decay product in the 235U decay chain and precise standards of this radionuclide are required to enable accurate, traceable measurements in nuclear dating applications such as geochronometry and nuclear forensics. Three independent techniques were used at NPL to determine the activity per unit mass of a freshly separated 231Pa solution as part of an international CCRI(II) comparison: CCRI(II)-K2.Pa-231.The first method was defined solid angle α counting and is the first result reported in a BIPM comparison with this instrument. The second method was 4πα liquid scintillation (LS) counting combined with the CIEMAT/NIST method using commercially available LS counters. The third technique used was 4π(LS)α-γ coincidence counting on an NPL-built system comprising an LS counter with dual photomultiplier tubes (PMTs) coupled to a 70% relative efficiency HPGe γ-spectrometer. Excellent agreement between the three methods was obtained.

Auger electron therapy is an attractive modality for targeting microscopic tumors. Rhodium-103 m (103mRh, T½ = 56.1 min) is a promising Auger electron emitter that can be obtained as the decay product of palladium-103 (103Pd, T½ = 16.99 days). 103Pd was chelated in a lipophilic derivative of the 16aneS4 macrocycle and the complex was trapped on a C18 cartridge. Elution with dilute hydrochloric acid gave radiochemically pure 103mRh. We hypothesize this to be through a combination of the Szilard-Chalmers effect and transient ionization.

The unique magnetic structure of the terrestrial aurora as a conduit of information between the ionosphere and magnetosphere can be utilized as a laboratory for physical processes at similar magnetic configurations and applied to various evolutionary phases of the solar (stellar) system. The most spectacular heliospheric abundance enhancement involves the 3He isotope and selective heavy elements in impulsive solar flares. In situ observations of electromagnetic waves on active aurora are extrapolated to flaring corona in an analysis of solar acceleration processes of 3He, the only element that may resonate strongly with the waves, as well as heavy ions with specific charge-to-mass ratios, which may resonate weaker via their higher gyroharmonics. These results are applied to two observed anomalous astrophysical abundances: (1) enhanced abundance of 3He and possibly 13C in the late stellar evolutionary stages of planetary nebulae; and (2) enhanced abundance of the observed fossil element 26Mg in meteorites as a decay product of radioactive 26Al isotope due to interaction with the flare-energized 3He in the early solar system.

To measure the size distribution of radioactive aerosols in the widest possible range, a complex system operating on different physical principles was designed. The system consists of a twelve-stage diffusion battery, a five-stage cascade impactor, and a set of three analytical aerosol filters with established permeability functions. The diffusion battery allows obtaining data on the distribution of aerosols in the range of 0.5–50 nm, the cascade impactor in the range of 0.8–20 μm, and the standard analytical filters in the range of 0.05–0.8 μm. This system was tested in a standard radon box. At a low aerosol concentration (less than 1000 cm−3), nearly 45–75% of radon decay product activity was associated with ultrafine particles with an AMTD of ~1 nm (the so-called unattached fraction). Additionally, a mode with a diameter of ~ 5–8 nm was registered. Larger aerosol particles were not caught by the cascade impactor, instead being deposited on the final filters. This shows that the particles are less than 800 nm in size (the first cut-off diameter of the impactor), which is in good agreement with the literature. When a high concentration of aerosol particles is created by an additional aerosol source, the unattached fraction is absent and maximum activity is observed in the cascade impactor and finishing filters.

In this paper we show the construction of 32 infinite series based on the law of decay of radioactive isotopes, which indicates that a radioactive parent isotope is reduced by 1/2 and 1/e of its initial value during each half-life and mean life, respectively. We found that the ratios among the values of the radioactive parent isotope and the radiogenic daughter isotope for each half-life’s and mean life’s decay can be used to construct 16 half-life related (or 2-related) and 16 mean life related (or e-related) infinite series. There are 8 divergent series, 4 previously known convergent series and 2 series converging to the Erdös-Borwein constant. The remaining 18 series are found to converge to 18 mathematical constants and the divergent and alternating mean life related series leads to another 2 mathematical constants. A few interesting mathematical relations exist among these convergent series and 5 sequences are also attained from the convergent half-life related series.

Behaviour of radionuclides released into environment is crucial for further evaluation of any kind of possible effects. Possibility of observation how does a radionuclide behave in natural environment is limited to very few post accidental areas. However, valuable observation can be collected at areas where enhanced concentration of natural radionuclides is presented caused by activity of non-nuclear industry. One example is area affected by release of radium rich brines from coal mines (Upper Silesia, south of Poland) that let one observe radium and its decay product behaviour in freshwater ecosystem from long-term perspective. Selected as long-term observatory site former mine water reservoir allowed identification of processes leading to accumulation of radium in bottom sediments and observation of its further behaviour from 17-years-time perspective. New data were collected during two-years monitoring campaign and compared with archive data on radioactivity in water and sediments collected in 1999. Radium-barium co-precipitation process was identified as main source of sediments heavy contamination, however, radium chemical form resulted from this process is insoluble and not easy migrate to other environmental compartments, what was proved by low 226Ra and 210Pb transfer to water measured under laboratory condition and to biota observed on site. As barium is not always present in mine radium rich brines a discussion is launched what would happen when such waters are released into environment based on simple laboratory experiment. In main conclusion is underlined that the current radium activity concentration in sediments is lower than expected only considering radioactive decay. Distribution of 226Ra, 228Ra and 210Pb in sediment profiles suggest that bio- or mechanical turbation (e.g. local flood) is responsible for significant 226Ra deficiency observed.

Analyses searching for diboson resonances are very powerful tools to investigate many beyond the Standard Model scenarios such as extension of the Higgs sector, Heavy Vector triplets ($W^{'}$ and $Z^{'}$) or excited states of Gravitons. These searches exploit many decay channels of the two bosons allowing to select topologies with varied signal to background ratios and statistics. Among these searches the one looking for $WW$/$WZ$ in the semileptonic final state finds a compromise between the high signal statistics allowed by the high branching ratio of the hadronic decay of the gauge boson while profiting of the good trigger and analysis signature of the lepton, decay product of the second gauge boson. The $WW$/$WZ$ search for TeV scale resonances in the $\ell\nu qq$ channel with $36.1~\mathrm{fb}^{\mathrm{-1}}$ of data collected with the ATLAS detector at $\sqrt{s} = 13~\mathrm{TeV}$ will be detailed. No significant excess is observed in data with respect to the Standard Model backgrounds. Limits on the production cross section are set for various benchmark scenarios.

Medium-energy electron beam-dump experiments provide an intense source of secondary muons. These particles can be used to search for muon-coupling light dark scalars that may explain the (g−2)μ anomaly. We applied this idea to the SLAC E137 experiment deriving new exclusion limits and evaluated the expected sensitivity for the planned Jefferson Lab BDX experiment (in case of a null result report). The calculation is based on numerical simulations that include a realistic description of secondary muons generation in the dump, dark scalar production, propagation, and decay, and, finally, the decay product (electrons, positrons, or photons) interaction with the detector. For both experiments, exclusion limits were extended to cover a broader area in the scalar-to-muon coupling vs scalar mass parameter space. This study demonstrates that electron beam-dump experiments have an enhanced sensitivity to new physics in processes that are usually studied using proton beams.

Analyzing uranium isotopic and activity ratios can give valuable information for hydrologic and environmental studies such as insights to weathering processes, estimating water mixing ratios, and identifying water sources. The authors employed an inductively coupled plasma mass spectrometer (ICP-MS) to perform environmental level concentration measurements of isotopic uranium on 380 groundwater samples from various locations within the state of Idaho. The U:U uranium activity ratios (UAR) for these samples range between 0.91 and 6.21, which suggests that the parent U is not in equilibrium with its decay product U. The U:U isotopic ratio was also measured for each sample to confirm that there was no depleted or enriched uranium present. All 380 samples exhibited the natural isotopic ratios of U and U isotopes. Therefore, it was concluded that the U:U UARs reflect natural variations in the Idaho groundwater systems.

In India, High Background Radiation Areas (HBRAs) due to enhanced levels of naturally occurring radionuclides in soil (thorium and, to a lesser extent, uranium), are located along some parts of the coastal tracts viz, the coastal belt of Kerala, Tamilnadu and Odisha. It is conjectured that these deposits will result in higher emissions of radon isotopes (Rn-222 and Rn-220) and their daughter products as compared to Normal Background Radiation Areas (NBRAs). While the annual external dose rates contributed by gamma radiations in these areas are about 5-10 times higher, the extent of increase in the inhalation dose rates attributable to Rn-222 and Rn-220 and their decay products is not well quantified. Towards this, systematic indoor surveys were conducted wherein simultaneous measurements of time integrated Rn-222 and Rn-220 gas and their decay product concentrations was carried out in around 800 houses in the HBRAs of Kerala and Odisha to estimate the inhalation doses. All gas measurements were carried out using pin-hole cup dosimeters while the progeny measurements were with samplers and systems based on the Direct radon/thoron Progeny sensors (DRPS/DTPS). To corroborate these passive measurements of decay products concentrations, active sampling was also carried out in a few houses. The results of the surveys provide a strong evidence to conclude that the inhalation doses due to Rn-222 and Rn-220 gas and their decay products in these HBRAs are in the same range as observed in the NBRAs in India. (C) 2015 Elsevier Ltd. All rights reserved.

The PIENU experiment at TRIUMF is aimed at a measurement of the branching ratio R e / μ = Γ ( ( π + → e + ν e ) + ( π + → e + ν e γ ) ) / Γ ( ( π + → μ + ν μ ) + ( π + → μ + ν μ γ ) ) with precision 0.1 % . Incident pions, delivered at the rate of 60 kHz with momentum 75 MeV/c, were degraded and stopped in a plastic scintillator target. Pions and their decay product positrons were detected with plastic scintillators and tracked with multiwire proportional chambers and silicon strip detectors. The energies of the positrons were measured in a spectrometer consisting of a large NaI(Tl) crystal surrounded by an array of pure CsI crystals. This paper provides a description of the PIENU experimental apparatus and its performance in pursuit of R e / μ .

The importance of measuring the decay products of 222Rn (radon) and 220Rn (Thoron) is being realized by researchers as these are the major inhalation dose givers to the general population. Basically the decay products are radioisotopes of Polonium, Bismuth and Lead, which are solid particles. Upon inhalation, these particles deposit in different parts of the respiratory tract, undergo radioactive decay and irradiate the nearby tissues. So, the study of the behavior of the decay products in indoor air is important for assessing the natural background radiation exposures received by general populations through the inhalation route. Although the inhalation doses are predominantly due to decay products yet it had been the usual practice to measure the gas concentration rather than the decay products because of the complexities involved in their detection. The most common method is to derive the progeny concentration from the measured gas concentration using an assumed equilibrium factor. While this is fairly justified for radon in view of the short-lived nature of the progeny as compared to the gas, this approach is beset with serious limitations in thoron-rich environments. However, the development of passive detection system for the decay products known as deposition-based Direct Radon and Thoron Progeny Sensors, has provided a solution to the long standing problem of measuring the time integrated decay product activity concentration. These deposition sensors are calibrated against active measurement techniques, and provide an easy to use method for passive and simultaneous time integrated decay product measurement. In addition, for multi-parametric study, the different modes of these passive sensors, like flow-mode and wire-mesh capped mode, are also used. These are further discussed in the manuscript.

A follow-up study was taken up in a mineralised zone situated in Hamirpur district, Himachal Pradesh, India, to investigate high values of radon concentrations reported in past studies as well to update the old radon data based on bare SSNTD technique. In the present investigation, the concentrations of indoor radon, thoron and their decay products have been measured using the newly developed radon/thoron discriminating diffusion chamber with single entry face, direct radon and thoron progeny sensors (DRPS/DTPS), respectively. The measurements have been carried out in 75 dwellings of 14 different villages where the previous studies were carried out using bare SSNTD technique. It was observed that high values of earlier reported radon concentrations were mainly due to thoron interference in the Solid State Nuclear Track Detector (LR-115 type II) exposed in bare mode. Now, the average concentration values and the estimated annual inhalation dose in these villages have been found to be within the reference level as recommended by the ICRP. The annual average indoor radon and thoron concentrations observed in these dwellings have been found to vary from 44±12 to 157±73 Bq m(-3) and 44±11 to 240±125 Bq m(-3), respectively. The equilibrium equivalent concentrations of radon and thoron decay products have been observed to be in the range of 10 to 63 and 1 to 5 Bq m(-3), respectively.

Uranium is a naturally occurring radioactive element present in trace amount throughout the earth's crust. Radon is a progeny of uranium decay series formed from the radioactive decay of radium in the ground water, soil, environment, oil and gas deposits. The lung cancer risk depends on the above recommendation level concentration of radon, thoron and their decay product in the air.The measurement of indoor radon and thoron decay product concentration in houses of Shahjahanpur and Hardoi have been carried out using deposition based direct radon progeny sensors (DRPS) and direct thoron progeny sensors (DTPS) technique. The concentration of radon and thoron is observed to be higher in mud houses as compared to the cemented houses.

A procedure is described for isolation and purification of 225Ac as a 229Th daughter decay product using ion exchange. The process includes the following steps: separation of 229Th from a mixture of 225Ac and 225Ra (225Ac precursor) using an anion-exchange resin; separation of 225Ac and 225Ra using a cation-exchange resin; purification of 225Ac to remove inactive impurity cations (primarily Fe) using an anion-exchange resin; final purification of the product on a column with a cation-exchange resin.

This numerical study provides the first simulation of the anthropogenic tritium invasion and its decay product helium-3 (3He) in the Mediterranean Sea. The simulation covers the entire tritium (3H) transient generated by the atmospheric nuclear-weapon tests performed in the 1950s and early 1960s and run till 2011. Tritium, helium-3 and their derived age estimates are particularly suitable for studying intermediate and deep-water ventilation and spreading of water masses at intermediate/deep levels. The simulation is made using a high resolution regional model NEMO-MED12 forced at the surface with prescribed tritium evolution derived from observations. The simulation is compared to measurements of tritium and helium-3 performed along large-scale transects in the Mediterranean Sea during the last few decades on cruises of Meteor M5/6, M31/1, M44/4, M51/2, M84/3, and Poseidon 234. The results show that the input function used for the tritium, generates a realistic distribution of the main hydrographic features of the Mediterranean Sea circulation. In the eastern basin, the results highlight the weak formation of Adriatic Deep Water in the model, which explains its weak contribution to the Eastern Mediterranean Deep Water in the Ionian sub-basin. It produces a realistic representation of the Eastern Mediterranean Transient signal, simulating a deep-water formation in the Aegean sub-basin at the beginning of the 1993, with a realistic timing of deep-water renewal in the eastern basin. In the western basin, the unusual intense deep convection event of winter 2005 in the Gulf of Lions during the Western Mediterranean Transition is simulated. However the spreading of the recently ventilated deep water toward the South is too weak. The ventilation and spreading of the Levantine Intermediate Water from the eastern basin toward the western basin is simulated with realistic tracer-age distribution compared to observation-based estimates.

The 238 U– 230 Th internal isochron method has great potential for determining eruption ages of young volcanic materials if the separated groundmass phases have a sufficiently wide range of U/Th ratios. We examined the fractionation behavior of U and Th in aged (i.e., > 0.5 Ma) basaltic samples by 6 M hydrochloric acid leaching to evaluate the applicability of acid-leaching treatment for the 238 U– 230 Th internal isochron method. Acid leaching of aged basaltic rocks in 238 U– 234 U– 230 Th secular equilibrium at the bulk-rock scale results in 230 Th– 238 U and 234 U– 238 U radioactive disequilibria for both leachates and residues. These radioactive disequilibria can be explained by redistribution of 234 Th (parent of 234 U) and 230 Th between acid-soluble and acid-resistant phases due to α-recoil. The number of 230 Th atoms redistributed by α-recoil can be calculated by using a mass conservation equation for 234 U atoms and by the relative amount of recoiled 230 Th and 234 Th, the latter proportional to the kinetic energy of the recoiled nuclide. When the fraction of daughter nuclide 234 U remaining in either the residue or leachate, after α-recoil redistribution of 238 U, is large enough (> 95%), the corrected ( 230 Th/ 238 U) values of leachate and residue show radioactive equilibria. This result demonstrates that preferential fractionation between U and Th does not occur during acid leaching for basaltic samples if there is no selective etching of the α-recoil track. This study implies that acid-leaching can be used in conjunction with the 238 U– 230 Th internal isochron method for dating young volcanic rocks by evaluating the degree of the α-recoil redistribution of 234 U.

nEXO is a 5-ton liquid enriched-xenon time projection chamber (TPC) to search for neutrinoless double-beta decay, designed to have the sensitivity to completely probe the inverted mass hierarchy of Majorana neutrinos. The detector will accommodate—as a background reduction technique—a system to recover and identify the barium decay product. This upgrade will allow a background-free measurement of neutrinoless double-beta decay and increase the half-life sensitivity of the experiment by at least one order of magnitude. Ongoing research and development includes a system to test barium extraction from liquid xenon using surface adsorption and Resonance Ionization Spectroscopy (RIS).

Summary This study presents an analytical approach to simulate nuclide migration through a channel in a fracture accounting for an arbitrary-length decay chain. The nuclides are retarded as they diffuse in the porous rock matrix and stagnant zones in the fracture. The Laplace transform and similarity transform techniques are applied to solve the model. The analytical solution to the nuclide concentrations at the fracture outlet is governed by nine parameters representing different mechanisms acting on nuclide transport through a fracture, including diffusion into the rock matrices, diffusion into the stagnant water zone, chain decay and hydrodynamic dispersion. Furthermore, to assess how sensitive the results are to parameter uncertainties, the Sobol method is applied in variance-based global sensitivity analyses of the model output. The Sobol indices show how uncertainty in the model output is apportioned to the uncertainty in the model input. This method takes into account both direct effects and interaction effects between input parameters. The simulation results suggest that in the case of pulse injections, ignoring the effect of a stagnant water zone can lead to significant errors in the time of first arrival and the peak value of the nuclides. Likewise, neglecting the parent and modeling its daughter as a single stable species can result in a significant overestimation of the peak value of the daughter nuclide. It is also found that as the dispersion increases, the early arrival time and the peak time of the daughter decrease while the peak value increases. More importantly, the global sensitivity analysis reveals that for time periods greater than a few thousand years, the uncertainty of the model output is more sensitive to the values of the individual parameters than to the interaction between them. Moreover, if one tries to evaluate the true values of the input parameters at the same cost and effort, the determination of priorities should follow a certain sequence.

The High Energy X-ray spectrometer (HEX) on Chandrayaan-1 was designed to study the photon emission in the range of 30–270 keV from naturally occurring radioactive decay of 238 U and 232 Th series nuclides from the lunar surface. The primary objective of HEX was to study the transport of volatiles on the lunar surface using radon as a tracer and mapping the 46.5 keV line from 210 Pb, a decay product of 222 Rn. HEX was tested for two days during the commissioning phase of Chandrayaan-1 and performance of all sub systems was found to be as expected. HEX started collecting science data during the first non-prime imaging season (February–April, 2009) of Chandrayaan-1. Certain anomalies persisted in this data set and the early curtailment of Chandrayaan-1 mission in August, 2009, did not allow any further operation of HEX. Despite these issues, HEX provided the first data set for 30–270 keV continuum emission, averaged over a significant portion of the lunar surface, including the polar region.

The radiation dose due to inhalation of radon, thoron and their progenies constitute a major part (50 %) of the total natural background dose received by a man. Thus measurement of indoor radon in dwellings is very important. In the present study, radon, thoron and their decay product measurements were carried out using passive detector systems, namely the pinholes dosimeters and Direct Radon (Thoron) progeny sensors. These measurements were carried out in indoor environments (different dwelling types) during January–April 2013 for 90 days, in the Gogi region. The time-averaged mean radon, thoron and decay product concentrations were found to be within the permissible UNSCEAR limits.

In the present study, the deposition velocities of 222Rn/220Rn decay products were measured experimentally using SSNTD based passive detectors, direct radon progeny sensor (DRPS) and direct thoron progeny sensor (DTPS) and the results were compared with obtained values by Monte-Carlo simulations. In both cases, deposition velocities were found to be log-normally distributed and also the experimentally measured geometric mean (GM) and geometric standard deviation (GSD) of (0.12, 1.85) m h−1 for radon decay products and (0.07, 1.75) m h−1 for thoron decay products were found to be in good agreement with the simulated values.

Experiments have been carried out using the deposition-based Direct Thoron Progeny Sensors (DTPS) in a thoron experimental house. The objective was to study the thoron decay product characteristics such as the deposition velocities, spatial variability and dependence on aerosol particle concentrations. Since the deposition velocity is an important characteristic in the calibration of the DTPS, it is very important to study its dependence on aerosol concentration in a controlled environment. At low aerosol concentration (1500 particles/cm(3)) the mean effective deposition velocity was measured to be 0.159 +/- 0.045 m h(-1); at high aerosol concentration (30 000 particles/cm3) it decreased to 0.079 +/- 0.009 m h(-1). The deposition velocity for the attached fraction of the thoron decay products did not change with increasing aerosol concentration, showing measurement results of 0.048 +/- 0.005 m h(-1) and 0.043 +/- 0.014 m h(-1), respectively. At low particle concentration, the effective deposition velocity showed large scattering within the room at different distances from center. The attached fraction deposition velocity remained uniform at different distances from the wall. The measurements in the thoron experimental house can be used as a sensitivity test of the DTPS in an indoor environment with changing aerosol concentration. The uniform spatial distribution of thoron decay products was confirmed within the experimental house. This indicates that direct measurement of thoron decay product concentration should be carried out instead of inferring it from thoron gas concentration, which is very inhomogeneous within the experimental house.

We investigate the possibility whether the tensions with SM expectations observed in several b -> sll transitions, including hints for lepton flavour non-universality, could be due to the decay of B into a new light resonance. We find that qualitative agreement with the data can be obtained with a light vector resonance dominantly decaying invisibly. This scenario predicts a shift in the muon anomalous magnetic moment that could explain the long-standing discrepancy. The most stringent constraint comes from searches for B decays with missing energy. A striking prediction is a strong q^2 dependence of the lepton flavour universality ratios R_K and R_K* that should allow to clearly confirm or rule out this possibility experimentally. We also comment on the possible connection of the invisible decay product with Dark Matter., 5 pages, 2 figures. v2: typos corrected, references and clarifications added

Background Radiotheragnostics makes use of the same molecular targeting vectors, labeled either with a diagnostic or therapeutic radionuclide, ideally of the same chemical element. The matched pair of scandium radionuclides, 44Sc and 47Sc, satisfies the desired physical aspects for PET imaging and radionuclide therapy, respectively. While the production and application of 44Sc was extensively studied, 47Sc is still in its infancy. The aim of the present study was, therefore, to investigate and compare two different methods of 47Sc production, based on the neutron irradiation of enriched 46Ca and 47Ti targets, respectively. Methods 47Sc was produced by thermal neutron irradiation of enriched 46Ca targets via the 46Ca(n,γ)47Ca → 47Sc nuclear reaction and by fast neutron irradiation of 47Ti targets via the 47Ti(n,p)47Sc nuclear reaction, respectively. The product was compared with regard to yield and radionuclidic purity. The chemical separation of 47Sc was optimized in order to obtain a product of sufficient quality determined by labeling experiments using DOTANOC. Finally, preclinical SPECT/CT experiments were performed in tumor-bearing mice and compared with the PET image of the 44Sc labeled counterpart. Results Up to 2 GBq 47Sc was produced by thermal neutron irradiation of enriched 46Ca targets. The optimized chemical isolation of 47Sc from the target material allowed formulation of up to 1.5 GBq 47Sc with high radionuclidic purity (>99.99%) in a small volume (~700 μL) useful for labeling purposes. Three consecutive separations were possible by isolating the in-grown 47Sc from the 46/47Ca-containing fraction. 47Sc produced by fast neutron irradiated 47Ti targets resulted in a reduced radionuclidic purity (99.95–88.5%). The chemical purity of the separated 47Sc was determined by radiolabeling experiments using DOTANOC achievable at specific activities of 10 MBq/nmol. In vivo the 47Sc-DOTANOC performed equal to 44Sc-DOTANOC as determined by nuclear imaging. Conclusion The production of 47Sc via the 46Ca(n,γ)47Ca nuclear reaction demonstrated significant advantages over the 47Ti production route, as it provided higher quantities of a radionuclidically pure product. The subsequent decay of 47Ca enabled the repeated separation of the 47Sc daughter nuclide from the 47Ca parent nuclide. Based on the results obtained from this work, 47Sc shows potential to be produced in suitable quality for clinical application. Electronic supplementary material The online version of this article (doi:10.1186/s41181-017-0024-x) contains supplementary material, which is available to authorized users.

We propose a method of transferring an equilibrium equivalent decay product activity concentration in the large radon chamber of VNIIFTRI using measuring instruments with a mathematical model that simulates the processes of deposition and decay of natural radioactive aerosols in an aerosol filter. We develop a model that takes into account all the metrological and technical parameters that affect the measurement result. We estimate uncertainties, discuss the applicability of the model for transferring the EEDC of decay products of thoron using appropriate means of measurement.

A self-shielded, sterile and cartridge-based radioisotope concentrator device coupled to 99mTc/188Re generators to increase the 99mTc/188Re-concentration of the generator eluate was developed based on new aminoalkyl-functionalized silica sorbent which conditionally catches and release 99mTc/188Re to concentrate the daughter nuclide of the generator eluates. The cartridge can be used for multiple elutions with an overall concentration factor of >100 and daughter nuclide recovery yield of >85 %. This device can be used for 10 days extension of 99mTc-generator life-time, saving about 20 % of the generator activity and for “early” generator-elution programs, under which the generator is eluted at an optimized build-up time for increasing the effectiveness of 99mTc/99Mo utilisation.

Measurements for determining the activity of Sr-89 and Sr-90 in reactor coolant water are associated with limitations due to interferences from radionuclides with similar chemical properties and beta(-)-energies. From a measurement bias point-of-view these interferences would result mainly in an overestimated activity concentration of Sr-90. In order to address the interference problem, a common and well-known method was used in order to show the need for sufficient decontamination. An improvement was achieved by taking the sample through two initial strontium separations in order to increase the decontamination factor. This method determines the activity concentration of Sr-89 and Sr-90, via its daughter nuclide Y-90, by Cherenkov counting. This work is primarily based on theoretical calculations of strontium-, yttrium- and other potential interfering radionuclide ratios after instant fission. The work done to confirm the theoretical calculations were carried through on spiked strontium standard solutions and fresh reactor coolant water. The reactor coolant water was known to contain interferences at a composition resembling that of instant fission. The detection limit for double separation was calculated to 0.17 Bq/kg for Sr-90 and 0.38 Bq/kg for Sr-89. When using methods that solely rely on strontium resins, this paper shows that the decontamination factor (DF) is significantly higher when using double separation than that of a single separation. The paper also shows that the DF of an initial double strontium separation is as effective when it comes to removing high ratio interferences as separations done with both Sr- and Ln-resin (EiChrom Technologies, Inc., 2003; Tovedal at at, 2009b). However, 'old' samples, where e.g. Ba-140 and Sr-89 has decayed, does not benefit from double separation. Furthermore, samples with low ratios of interfering radionuclides does not benefit from using this method either, seeing as this is a more time consuming method due to the double separations.

The fission-track method has been applied for decades to quantify rates and timing of processes in the shallow crust. The most widely used approach, the external detector method, involves counting fission-tracks, a decay product resulting from the spontaneous fission of 238 U, and a paired set of induced tracks (parent proxy) from the thermal neutron irradiation of 235 U. We propose an alternate method of dating zircons that utilizes an electron microprobe to directly measure uranium concentration [U] and image the number of spontaneous fission-tracks or etch figures that intersect the surface of the crystal using an electron backscatter detector. The electron microprobe fission-track (EP-FT) method is used to date six zircon samples, four of which are widely used as standards: Fish Canyon Tuff, Peach Springs Tuff, Buluk Member of the Bakata Formation (tuff), Tardee Rhyolite, Mt. Dromedary Complex (hypabyssal granite), and Browns Park Formation (tuff). All samples yield ages that overlap within two standard deviations of published reference ages determined using other radiometric techniques (i.e., K/Ar, 40 Ar/ 39 Ar, and U/Pb) and also by the traditional fission-track external detector method. To correct for poorly constrained parameters such as the spontaneous fission decay constant, weight to volume percent conversions, etching efficiency, and selection bias, we calculate a preliminary Z proportionality factor of 4469 ± 661 (1σ). The EP-FT technique avoids the hazard and expense of thermal neutron irradiation, allows simultaneous chemical compositions to be determined, removes the step of counting an external detector manually, and will likely allow much higher track densities to be counted than would be normally possible with optical microscopy. The technique is ideal for dating moderate to high U zircons (>100 ppm U).

Various techniques are available for the estimation of uranium concentration in geological rock samples. In the uranium exploration program in India, the beta–gamma technique is widely used by the Atomic Minerals Directorate for Exploration and Research (Department of Atomic Energy) to estimate uranium concentration in natural rock or soil samples. Uranium concentration cannot be estimated accurately by the beta–gamma technique if the sample has high concentrations of thorium. Because the ratio of thorium to uranium concentration varies between 15 and 30 in monazite samples, uranium concentration in monazite samples cannot be estimated accurately by the conventional beta–gamma technique. Uranium concentration in monazite samples can be estimated by measuring the 1.001 MeV gamma ray peak of Pa-234 (which is a decay product of uranium having a half-life of 1.17 min) using a P-type HPGe semiconductor detector. In this paper, uranium concentrations in 10 samples of Indian monazites were estimated using the P-type HPGe semiconductor detector, in which the average thorium concentration was 9.5%.