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Abstract We examined the vertical 134Cs and 137Cs concentration profiles in the southwestern Okhotsk Sea in 2011, 2013, and 2017. In June 2011, atmospheric deposition-derived 134Cs from the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) was detected at depths of 0–200 m (0.06–0.6 mBq/L). In July 2013, 134Cs detected at depths of 100–200 m (∼0.05 mBq/L) was ascribed to the transport of low-level 134Cs-contaminated water and/or the convection of radioactive depositions (<0.03 mBq/L at depths of 0–50 m). In July 2017, 134Cs was detected in water samples at depths above 300 m (0.03–0.05 mBq/L), and the inventory, decay-corrected to the FDNPP accident date, exhibited its maximum value (85 Bq/m2) during this period. Combining temperature-salinity data with the concentrations of global fallout-derived 137Cs led to a plausible explanation for this observation, which is a consequence of re-entry of FDNPP-derived radiocesium through the Kuril Strait from the northwestern North Pacific Ocean to the Okhotsk Sea and subsequent mixing with the south Okhotsk subsurface layer until 2017. Highlights • Radiocesium vertical profiles in the southwestern Okhotsk Sea were investigated. • 134Cs was affected by physical oceanographic processes such as advection and mixing. • Atmospheric deposition-derived 134Cs from the FDNPP was detected in June 2011. • The 134Cs inventory, based on the FDNPP accident date, showed a maximum value in 2017. • FDNPP-derived radiocesium was re-delivered from the North Pacific Ocean until 2017. [ABSTRACT FROM AUTHOR]

Abstract Superplasticizers added into cementitious materials can degrade due to hydrolytic, thermal, radiolytic and microbial effects. Short-chain organic compounds such as acetate, phthalate, oxalate, phenol, urea, etc., have been confirmed as possible degradation products of superplasticizers. This work presents a review of the degradation process of superplasticizers and a thermodynamic study on the effect that model compounds considered as proxy for their degradation products have on the solubility of several radionuclides (Ni, Eu, U). Our results indicate that the complexation capacity of the proxy superplasticizers degradation products considered (i.e. acetate, phthalate, phenol and urea) towards Ni Eu and U is almost negligible in alkaline conditions, but relatively important in the near-neutral pH range. Highlights • Alteration of superplasticizers lead to the formation of small organic compounds. • Degraded superplasticizers interactions with Ni-Eu-U are negligible in alkaline media. • In slightly alkaline media, phthalate and acetate, control the chemistry of Ni-Eu. [ABSTRACT FROM AUTHOR]

The dose to kidneys of newborns and 1-year old children was calculated using the MIRD methodology. In order to perform renal studies radiopharmaceutical like 99m Tc-DTPA, 99m Tc-MAG3 and 99m Tc-DMSA are used. Here, besides the anatomic and structure information of kidneys another data are provided in benefit of patient, however during the radioisotope decay emitted radiations delivers, totally or partially, their energy. Therefore is important to estimate the internal radiation dose of the organs. The largest dose to kidneys comes from the self-dose and it is due to the charged particles emitted during 99m Tc decay. From the three radiopharmaceutical here used the largest dose to kidneys is due to 99m Tc-DMSA, and the smaller dose is due to 99m Tc-MAG3. [ABSTRACT FROM AUTHOR]

Vertical distributions of total and particulate 210Po and 210Pb activities in the water column were measured at eleven stations in the North Atlantic during the GEOTRACES GA01 GEOVIDE cruise in May–June 2014. Total 210Po activity was on average 24 % lower than 210Pb activity in the upper 100 m, and was closer to unity in the mesopelagic (100–1000 m). The partitioning coefficients (Kd) along the transect suggest the preferential association of 210Po relative to 210Pb onto particles. The prominent role of small particles in sorption was confirmed by the observation that over 80 % of the particulate radionuclide activity was on small particles. To account for the observed surface water 210Po / 210Pb disequilibria, particulate radionuclide activities and export of both small (1–53 μm) and large (> 53 μm) particles must be considered. A comparison between the GEOVIDE total particulate 210Po / 210Pb activity ratios (AR) and the ratios in previous studies revealed a distinct geographic distribution, with lower particulate AR in the high-latitude North Atlantic (including this study) and Arctic in relation to all other samples. For the samples where apparent oxygen utilization (AOU) was calculated at the same depth and time as the 210Po / 210Pb AR (40 stations including this study), there was a two-phase correlation between the total particulate AR and AOU demonstrating the competing forces of remineralization and radionuclide decay from particles as they age. [ABSTRACT FROM AUTHOR]

In order to automate sample preparation processes, a precision pattern dispenser was designed to reproducibly dispense radioactive solutions at pre-defined positions. It is composed of an automatic liquid sample handling unit coupled to an XYZ table. Qualification tests were conducted to evaluate the performance of the instrument and to assess the compliance with the requirements, in particular trueness (< 2%) and repeatability (< 1%). The instrument allows preparing sources in different source holders and on air filters, in a fast and accurate way. [ABSTRACT FROM AUTHOR]

The Provisional Technical Secretariat (PTS) of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) Organization organizes Proficiency Test Exercises (PTE) annually for the 16 radionuclide laboratories supporting its network of radionuclide air monitoring stations since 2000. These laboratories re-analyze samples from radionuclide stations for quality control. The PTEs, in turn, are a means of checking the quality of analytical results provided by laboratories. Laboratories implement corrective actions for PTE discrepant results. These actions are checked in subsequent PTEs or during surveillance assessment. [ABSTRACT FROM AUTHOR]

We theoretically investigate the propagation properties of cosh-Airy beams, which can be considered as a superposition of two Airy beams with different decay factors. We find that the field distribution of cosh-Airy beams is the same as that of Airy beams. Moreover, we find that the evolution of cosh-Airy beams is determined by the parameters of the cosh modulation function, in addition to the transverse scale factor and decay factor of the Airy beams. Our results demonstrate a possible method of manipulating Airy beams in free space. They can also be extended to the study of the propagation properties of cosine-Airy beams (or sine-Airy beams). [ABSTRACT FROM PUBLISHER]

This article is devoted to obtaining the α-emitter Tb for radioimmunotherapy. A method for producing Tb based on the reaction Eu(He, 5n)Tb is proposed. It is proposed that europium with native isotopic composition (Eu - 47.81%, Eu - 52.19%) or enriched Eu be used as the target. The 29 MeV threshold of the indicated reaction makes it possible to use accelerators with the initial He energy 40-70 MeV. [ABSTRACT FROM AUTHOR]

The 176 Lu– 176 Hf isotopic system is widely used for dating and tracing cosmochemical and geological processes, but still suffers from two uncertainties. First, Lu–Hf isochrons for some early Solar System materials have excess slope of unknown origin that should not be expected for meteorites with ages precisely determined with other isotopic chronometers. This observation translates to an apparent Lu decay constant higher than the one calculated by comparing ages obtained with various dating methods on terrestrial samples. Second, unlike the well constrained Sm/Nd value (to within 2%) for the chondritic uniform reservoir (CHUR), the Lu/Hf ratios in chondrites vary up to 18% when considering all chondrites, adding uncertainty to the Lu/Hf CHUR value. In order to better understand the Lu–Hf systematics of chondrites, we analyzed mineral fractions from the Richardton H5 chondrite to construct an internal Lu–Hf isochron, and set up a numerical model to investigate the effect of preferential diffusion of Lu compared to Hf from phosphate, the phase with the highest Lu–Hf ratio in chondrites, to other minerals. The isochron yields an age of 4647 ± 210 million years (Myr) using the accepted 176 Lu decay constant of 1.867 ± 0.008 × 10 − 11 yr − 1 . Combining this study with the phosphate fractions measured in a previous study yields a slope of 0.08855 ± 0.00072 , translating to a 176 Lu decay constant of 1.862 ± 0.016 × 10 − 11 yr − 1 using the Pb–Pb age previously obtained, in agreement with the accepted value. The large variation of the Lu/Hf phosphates combined with observations in the present study identify phosphates as the key in perturbing Lu–Hf dating and generating the isochron slope discrepancy. This is critical as apatite has substantially higher diffusion rates of rare earth elements than most silicate minerals that comprise stony meteorites. Results of numerical modeling depending of temperature peak, size of the grains and duration of the metamorphic event, show that diffusion processes in phosphate can produce an apparently older Lu–Hf isochron, while this effect will remain negligible in perturbing the Sm–Nd chronology. Our results suggest that only type 3 chondrites with the lowest metamorphic grade and large minerals with minimal diffusive effects are suitable for determination of the Lu–Hf CHUR values and the Lu decay constant respectively. [ABSTRACT FROM AUTHOR]

The ability of black carbonaceous siltstones and silt sandstones, lime sandstones, gray limestones, carbon-silicon carbonate schists with pyrite, and other rocks that most widely occur on the Novaya Zemlya Archipelago to sorb Cs, Sr, Pu, and Am was studied. The distribution coefficients K (cm g) are as follows: for Pu, 2.7 × 10-7.7 × 10; for 241Am, 2.5 × 10-1.8 × 10; and for Cs, 1.1 × 10-2.0 × 10. Strontium-85(90) it not noticeably sorbed (within the measurement uncertainty) by any of the rocks studied. Pu, Am, and Cs are strongly sorbed onto the rocks studied and are not noticeably desorbed from them with distilled water. The data obtained are required for predicting the migration of long-lived radionuclides generated by nuclear explosion with surface waters from test sites on the Novaya Zemlya Archipelago. [ABSTRACT FROM AUTHOR]

Distribution of Po in thalli of soil and wood (epiphytic) lichens was studied. Four fractions containing the corresponding Ро forms were obtained by sequential extraction: (1) intercellular, (2) extracellular, (3) intracellular, and (4) insoluble thallus residue. The Ро uptake by lichens is mainly passive, as the total content of the radionuclide in fractions 1, 2, and 4 reaches 88-97%. From 3 to 12% of Ро is taken up actively (fraction 3), and for soil lichens this parameter is approximately 2.75 times higher than for epiphytic lichens. Presumably, Ро is supplied into soil and epiphytic lichens in the form of different chemical compounds and is therefore characterized by different bioavailability. [ABSTRACT FROM AUTHOR]

The test of production of the 198Au radioisotope by means of Varian medical linear accelerators used in teleradiotherapy was carried out. The targets made of the natural gold (100% of the 197Au isotope) were irradiated with high-energy therapeutic 20 MV X-ray beam. 198Au was produced in the simple capture reaction 197Au(n;)198Au. The obtained specific activities in the saturation state are relatively low, not exceeding the value of 510.4 kBq/g, because only the high-energy part of the spectrum of 20 MV X-ray beam covers the energy range of the neutron production cross section. Low activity of the 198Au radioisotope produced by medical linear accelerators makes this technique not suitable for a massive production of 198Au for nuclear medicine, but the produced amount of 198Au is sufficient for laboratory tests of new drugs for possible clinical applications. [ABSTRACT FROM AUTHOR]

The Qβ-window has been studied within the Skyrme HF-BCS calculations including the blocking effect of unpaired neutron and proton in cases of the even-odd and odd-odd nuclei. Using the energy-density functional T45 containing the tensor terms, we analyze this effect on the β-transition rates of the neutron-rich nuclei 72-80Ni. [ABSTRACT FROM AUTHOR]

The β-delayed neutron emission probability, Pn, of very neutron-rich nuclei allows us to achieve a better understanding of the nuclear structure above the neutron separation energy, Sn. The emission of neutrons can become the dominant decay process in neutron-rich astrophysical phenomena such as the rapid neutron capture process (r-process). There are around 600 accessible isotopes for which β-delayed one-neutron emission (β1n) is energetically allowed, but the branching ratio has only been determined for about one third of them. β1n decays have been experimentally measured up to the mass A ~ 150, plus a single measurement of 210Tl. Concerning two-neutron emitters (β2n), ~ 300 isotopes are accessible and only 24 have been measured so far up to the mass A = 100. In this contribution, we report recent experiments which allowed the measurement of β1n emitters for masses beyond A > 200 and N > 126 and identified the heaviest β2n emitter measured so far, 136Sb. [ABSTRACT FROM AUTHOR]

Total absorption spectroscopy is a technique that helps obtain reliable β-feeding patterns of complex decays important for nuclear structure and astrophysics modeling as well as decay heat analysis in nuclear reactors. The need for improved measurements of β-feeding patterns from fission decay products has come to the forefront of experiments that use nuclear reactors as a source of antineutrinos. Here we present more detailed results, in particular the β-decay measurements of 96gsY, and demonstrate the impact of the β-delayed γ multiplicity on the overall efficiency of Modular Total Absorption Spectrometer used at Oak Ridge National Laboratory to study the decays of fission products abundant during a nuclear fuel cycle. [ABSTRACT FROM AUTHOR]

Fast radioanalytical methods are essential for a rapid response of decision makers. A fast method for the simultaneous determination of the pure beta emitting radionuclides Sr/Sr and Tc in food samples was developed. It includes the precipitation of fat and proteins with trichloroacetic acid for milk and dairy products and microwave digestion for other food products, followed by an anion exchange step to separate strontium from technetium. The purification steps for strontium and technetium are done using Sr-resin and TEVA-resin, respectively. Typical chemical yields are around 70 % for both radionuclides. The whole determination takes only around 20 h. [ABSTRACT FROM AUTHOR]

As a complement to a resent high-resolution spectrometric investigation of the decay of 194 Au to levels of 194 Pt, a similar study has been undertaken of the decay of 19-h 194 Ir to 194 Pt. The two decays populate a similar set of levels in 194 Pt, and so the complementary investigations with similar resolution and efficiency permit a direct comparison of the two data sets. Overall there is excellent agreement between the energies of the common γ -ray transitions and also between the deduced energies of the excited states in 194 Pt. The 194 Ir half-life has been remeasured to be 19.20(2) h. [ABSTRACT FROM AUTHOR]

As part of the verification component of the Comprehensive Nuclear-Test-Ban Treaty (CTBT), environmental gas samples originating from nuclear fission are analyzed for the presence of Xe, Xe, Xe, and Xe. In this work, the non-traditional radioxenon isotope Xe was investigated. The isotope was produced as an isotopically pure sample via neutron activation of Xe at the University of Texas at Austin Nuclear Engineering Teaching Lab's TRIGA MARK II Reactor. The sample was then measured using a HPGe detector as well as an ARSA-style β-γ coincidence detector. Potential sources and sensitivities for production of Xe are also considered for relevance to the CTBT verification mission. [ABSTRACT FROM AUTHOR]

Studies and calibrations of short-lived radionuclides, for example 15 O, are of particular interest in nuclear medicine. Yet counting experiments on such species are vulnerable to an error due to the combined effect of decay and dead time. Separate decay corrections and dead-time corrections do not account for this issue. Usually counting data are decay-corrected to the start time of the count period, or else instead of correcting the count rate, the mid-time of the measurement is used as the reference time. Correction factors are derived for both those methods, considering both extending and non-extending dead time. Series approximations are derived here and the accuracy of those approximations are discussed. [ABSTRACT FROM AUTHOR]

From a review of the available literature, a database of experimental shape factors from measured beta spectra was created in previous work. Classical assumptions applied in beta spectra calculations which avoid the determination of the electron and nuclear wave functions were tested by comparison with each measured spectrum present in the database. From this systematic comparison, it was demonstrated that the typical assumption λ k =1 is inappropriate for all forbidden unique transitions. Moreover, the equally common ξ -approximation was also proved to be incorrect for about half of the listed first forbidden non-unique transitions and for all second non-unique ones. In present work, this study has been performed once again using an improved analytical screening correction. General results from previous study still remain the same. Except for allowed transitions, the mean energies in current nuclear databases are expected to be erroneous. Some selected beta spectra are also given to illustrate these results. [ABSTRACT FROM AUTHOR]

Soil organic carbon (SOC) dynamics result from different interacting processes and controls on spatial scales from sub-aggregate to pedon to the whole ecosystem. These complex dynamics are translated into models as abundant degrees of freedom. This high number of not directly measurable variables and, on the other hand, very limited data at disposal result in equifinality and parameter uncertainty. Carbon radioisotope measurements are a proxy for SOC age both at annual to decadal (bomb peak based) and centennial to millennial time scales (radio decay based), and thus can be used in addition to total organic C for constraining SOC models. By considering this additional information, uncertainties in model structure and parameters may be reduced. To test this hypothesis we studied SOC dynamics and their defining kinetic parameters in the ZOFE experiment, a >60-years old controlled cropland experiment in Switzerland, by utilising SOC and SO14C time-series. To represent different processes we applied five model structures, all stemming from a simple mother model (ICBM): I) two decomposing pools, II) an inert pool added, III) three decomposing pools, IV) two decomposing pools with a substrate control feedback on decomposition, V) as IV but with also an inert pool. These structures were extended to explicitly represent total SOC and 14C pools. The use of different model structures allowed us to explore model structural uncertainty and the impact of 14C on kinet ic parameters. We considered parameter uncertainty by calibrating in a formal Bayesian framework. By varying the relative importance of total SOC and SO14C data in the calibration, we could quantify the effect of the information from these two data streams on estimated model parameters. The weighing of the two data streams was crucial for determining model outcomes, and we suggest including it in future modelling efforts whenever SO14C data are available. The measurements and all model structures indicated a dramatic decline in SOC in the ZOFE experiment after an initial land use change in 1949 from grass- to cropland, followed by a constant but smaller decline. According to all structures, the three treatments (control, mineral fertilizer, farmyard manure) we considered were still far from equilibrium. The estimates of mean residence time (MRT) of the C pools defined by our models were sensitive to the consideration of the SO14C data stream. Model structure had a smaller effect on estimated MRT, which ranged between 5.91 and 4.22 years and 78.93 and 98.85 years for young and old pool, respectively, for structures without substrate interactions. The simplest model structure performed the best according to information criteria, validating the idea that we still lack data for mechanistic SOC models. Although we could not exclude any of the considered processes possibly involved in SOC decomposition, it was not possible to discriminate their relative importance. [ABSTRACT FROM AUTHOR]

Several directions of the demand for decay data in nuclear astrophysics are discussed for radionuclides near the valley of nuclear stability. The current half-life and gamma-ray intensity evaluation results are presented for some radionuclides of astrophysical interest. An extended list of such nuclides is offered for their nuclear characteristics to be further evaluated by the Decay Data Evaluation Project collaboration participants. [ABSTRACT FROM AUTHOR]

In this study, measurement of natural radioactivity and analyses of physical properties of soil were carried on great soil groups around the Seferihisar Geothermal Region. The radioactivity levels in soils were analyzed using scintillation gamma spectroscopy. The activity concentrations for Ra, Th, and K range from 7.1 to 32.0 Bq kg, 15.2 to 35.9 Bq kg and 223.1 to 802.2 Bq kg, respectively. Obtained data was compared with average values given by UNSCEAR and the other studies. The radium equivalent activity (Ra) in soil samples ranges from 42.2 to 144.7 Bq kg which are lower than the suggested maximal admissible value of 370 Bq kg recommended by OECD. In addition, the value of external exposure dose has been determined from the content of natural radionuclides in soil. The absorbed dose rates change between 20.6 and 70.9 nGy h with a mean value of 46.7 nGy h which is lower than the global average value of 55 nGy h. The annual effective dose rates varied from 25.2 to 87.0 μSv year with an average value of 57.3 μSv year. Obviously, all the calculated values were lower than this value, and therefore the environment of Tuzla Fault can be regarded as an area with normal natural background radiation. [ABSTRACT FROM AUTHOR]

Zirconium 89 (89Zr) is a promising radionuclide for development of new PET agents due to its convenient half life of 78.4 h, β+ emission rate of 23%, low maximum energy of 0.9 MeV resulting in good spatial resolution, a stable daughter isotope of yttrium-89 (89Y) and favorable imaging characteristics, with only one significant γ-line of 909 keV emitted during decay alongside the 511 keV positron photons. Our aim was to share over 2 years of experience of producing isotopically pure 89Zr via the 89Y(p,n)89Zr nuclear reaction with a COSTIS Solid Target System (STS) and CYCLONE 18/9 cyclotron. We optimized the yields without producing either of the long-lived impurities 88Zr or 88Y. The degradation of the beam energy with 400 and 500 μm thick niobium foils was tested without overheating problems within 2-6 h of irradiation. From repeated measurements of activity, it was clear that there is a bi-exponential decay of radioactivity due to the short lived 89mZr and 89Zr. The measured half life of the longer lived radionuclide was consistent with value for 89Zr. The energy spectrum from 89Zr had energy peaks at 511 keV and 909 keV and was consistent with 89Zr. Production of 89Zr with 400 (Ep = 9:8 MeV) and 500 μm (Ep = 11:6 MeV) thick niobium beam degrader was achieved, without producing either 88Zr or Y88. It was necessary to wait at least 4 hours before measuring the activity and decay correct in order to calculate the 89Zr activity at the end of cyclotron production. Degrading the proton beam to 10 MeV produces radionuclidically pure 89Zr with yields from 8 to 9 MBq/μAh. Whilst this is enough for pre-clinical use, the yield is not enough for either clinical use or commercial supply. Use of thinner beam degraders (400 μm) increases the proton beam energy and increases the radionuclidic yield to 15.5 MBq/μAh whilst maintaining radionuclidic purity. [ABSTRACT FROM AUTHOR]

Prompt-gamma imaging during ion therapy has proven its ability to control the ion range in real time. The achievable precision is of the order of the millimeter for a single spot in proton pencil beam scanning. Collimated gamma cameras have been developed, that are close to clinical application. The Compton cameras are also under development in various laboratories. Time of flight enables the reduction of the background due to other prompt radiations. [ABSTRACT FROM AUTHOR]

We show that the X-ray line flux of the Mn Kα line at 5.9 keV from the decay of 55Fe is a promising diagnostic to distinguish between Type Ia supernova (SN Ia) explosion models. Using radiation transport calculations, we compute the line flux for two three-dimensional explosion models: a near-Chandrasekhar mass delayed detonation and a violent merger of two (1.1 and 0.9 M⊙) white dwarfs. Both models are based on solar metallicity zero-age main-sequence progenitors. Due to explosive nuclear burning at higher density, the delayed-detonation model synthesizes ~3.5 times more radioactive 55Fe than the merger model. As a result, we find that the peak Mn Kα line flux of the delayed-detonation model exceeds that of the merger model by a factor of ~4.5. Since in both models the 5.9-keV X-ray flux peaks five to six years after the explosion, a single measurement of the X-ray line emission at this time can place a constraint on the explosion physics that is complementary to those derived from earlier phase optical spectra or light curves. We perform detector simulations of current and future X-ray telescopes to investigate the possibilities of detecting the X-ray line at 5.9 keV. Of the currently existing telescopes, XMM-Newton/pn is the best instrument for close (≲ 1-2 Mpc), non-background limited SNe Ia because of its large effective area. Due to its low instrumental background, Chandra/ACIS is currently the best choice for SNe Ia at distances above ~2 Mpc. For the delayed-detonation scenario, a line detection is feasible with Chandra up to ~3 Mpc for an exposure time of 106 s. We find that it should be possible with currently existing X-ray instruments (with exposure times ≲ 5 x 105 s) to detect both of our models at sufficiently high S/N to distinguish between them for hypothetical events within the Local Group. The prospects for detection will be better with future missions. For example, the proposed Athena/X-IFU instrument could detect our delayed-detonation model out to a distance of ~5 Mpc. This would make it possible to study future events occurring during its operational life at distances comparable to those of the recent supernovae SN 201 1fe (~6.4Mpc) and SN 2014J (~3.5Mpc). [ABSTRACT FROM AUTHOR]

The use of the tools of formal chemical kinetics for calculating the total α-, β-, and γ-ray spectra in decay of radioactive isotopes is suggested. Principles of constructing a reaction scheme modeling the radioactive decay of the initial isotope and chain of its daughter nuclides are described. The reaction scheme allows calculation of the total current radiation spectra, total decay energy, and gas (He) formation along with variation of the isotope composition. [ABSTRACT FROM AUTHOR]

The collapse of the Soviet Union ushered in an era of interest in the security of the radiological and nuclear material holdings of the Russian Federation and other countries of the Former Soviet Union. Additionally, the increasing sophistication of international criminal and terrorist organizations highlighted the need to secure these materials and prevent them from being smuggled from their point of origin and across international boundaries. To combat the growing threat of radiological and nuclear smuggling, radiation portal monitors (RPMs) are deployed at ports of entry (POEs) around the world to passively detect gamma and neutron radiation signatures from cargo and pedestrian traffic. In some locations, RPMs are reporting abnormally high gamma-ray background count rates, a situation that has been attributed, in part, to the building materials surrounding the RPMs. The primary objective of this work was to determine the impact of different types of concrete on the gamma-ray background readings in a particular RPM. Secondaiy objectives include developing an adaptable model to estimate the gamma-ray background contribution from any composition of concrete in any RPM configuration and determining the elemental composition of different concrete samples through neutron activation analysis (NAA) techniques. The specific activities of 40K and isotopes from the 238U and 232Th decay series were determined with a high-purity germanium detector and computer-generated calibration files. Through NAA, 34 elemental compositions were determined for six concrete samples from three different parent slabs. The total weight percentages determined were 84% to 100% of the total mass of the samples. The Monte Carlo N-Particle (MCNP) transport code was used to simulate the RPM response to the different concrete slabs. The MCNP model was validated by comparing actual and simulated detector responses to I37Cs check sources of vaiying strengths. For all validation cases, the MCNP estimates were 6% to 16% less than the value obtained from the actual RPM data. This work shows that it is possible to estimate the gamma-ray response of an RPM to the underlying concrete roadway. Knowing the amount of this contribution will allow RPM customers to choose suitable foundation materials before installation and accurately set alarm thresholds. This could ultimately increase the ability of RPMs to detect radiation at POEs, thereby increasing the probability of a seizure of smuggled radiological and nuclear materials. [ABSTRACT FROM AUTHOR]

The new neutron-deficient isotope 205Ac was synthesized in the complete-fusion reaction 169Tm(40Ca, 4n)205Ac. The evaporation residues were separated in-flight by the gas-filled recoil separator SHANS in Lanzhou and subsequently identified by the α-α position and time correlation method. The α-decay energy and half-life of 205Ac were determined to be 7.935(30) MeV and 20+97-9 ms, respectively. Previously reported decay properties of the ground state in 206Ac were confirmed. [ABSTRACT FROM AUTHOR]

Abstract: The idea of using a scintillating bolometer was first suggested for solar neutrino experiments in 1989. After many years of developments, now we are able to exploit this experimental technique, based on the calorimetric approach with cryogenic particle detectors, to investigate rare events such as Neutrinoless Double Beta Decay and interaction of Dark Matter candidates. The possibility to have high resolution detectors in which a very large part of the natural background can be discriminated with respect to the weak expected signal is very appealing. The goal to distinguish the different types of interactions in the detector can be achieved by means of scintillating bolometer. The simultaneous read-out of the heat and scintillation signals made with two independent bolometers enable this precious feature leading to possible background free experiment. In the frame of the LUCIFER project we report on how exploiting this technique to investigate Double Beta Decay for different isotope candidates. Moreover we demonstrate how scintillating bolometers are suited for investigating other rare events such as decays of long living isotopes of lead and bismuth. [Copyright &y& Elsevier]

The preformation factors of alpha clusters for fully-favoured alpha decay of even--even heavy nuclei, 82 < Z <114, 126 < N <170, were determined using the alpha preformation formula taken from the hypothesized cluster-formation model of our previous work. In this model, the formation of an alpha particle inside the parent nuclei was considered as a quantum-mechanical cluster-formation state. The eigenvalues of these states are determined from the differences between the binding energies. The total energy of the considered total system state was investigated by adopting the alpha-decay energy and the energy of the open-shell nucleons. The clustering amount was also calculated on the basis of this model. The results showed a very good consistency with the alpha-decay constants. This model presents a significant step forward in the determination of realistic preformation factors. [ABSTRACT FROM AUTHOR]

Cerenkov luminescence imaging based on light emissionfrom thedecay of radionuclides has recently drawn great interest in molecularimaging. In this paper, we report for the first time the Cerenkovluminescence phenomenon of 198Au isotope, as well as afacile route to the preparation of radioluminescent Au nanocages withoutadditional radiolabeling or dye conjugation. The specific radioactivityof the Au nanocages could be easily and precisely controlled by varyingthe concentration of H198AuCl4precursor usedfor the galvanic replacement reaction. The direct incorporation of 198Au atoms into the structure of Au nanocages enabled theability of accurate analysis and real-time imaging in vivo. Furthermore,under biological conditions the radioactive Au nanocages were shownto emit light with wavelengths in the visible and near-infrared regions,enabling luminescence imaging of the whole mice in vivo, as well asthe organs ex vivo. When combined with their favorable scatteringand absorption properties in the near-infrared region, the radioactiveAu nanocages can serve as a new platform for multimodality imagingand will have a significant impact on both small animal and clinicalimaging. [ABSTRACT FROM AUTHOR]

The decay of the hot and rotating compound nucleus 241Pu* formed in the reaction 9Be + 232Th around the Coulomb barrier ('42.16 MeV), at energies ranging from 37 to 48 MeV, is studied using the dynamical cluster-decay model (DCM) with the effects of static and dynamic deformations included. With the inclusion of dynamical deformations both the preformation probability P0 and the tunneling probability P, and hence the cross sections, change considerably. The only parameter of the model, namely, the neck-length parameter, varies smoothly with excitation energy or temperature of the system both at above- and below-barrier energies, whose value depends strongly on the limiting angular momentum, which in turn depends on the sticking and nonsticking moments of inertia. The relative effect of static and dynamic deformations on the neck-length parameter AR is also studied which indicates the reaction time scale for both static and dynamic choices of deformation. In addition, the exclusive role of angular momentum and "barrier modification" effects at sub-barrier energies are also addressed. Although calculated anisotropies are consistent with the results of Appannababu et al. [Phys. Rev. C 83,067601 (2011 )], no significant contribution of a noncompound nucleus in the form of incomplete fusion is seen on the basis of DCM calculations. [ABSTRACT FROM AUTHOR]

Extensive hydrogeological investigations followed by three-dimensional groundwater flow and contaminant transport modelling were carried out around a proposed uranium tailings pond at Seripalli in Andhra Pradesh, India, to estimate its radiological impact. The hydrogeological parameters and measured groundwater level were used to model the groundwater flow and contaminant transport from the uranium tailings pond using a finite-element-based model. The simulated groundwater level compares reasonably with the observed groundwater level. Subsequently, the transport of long-lived radionuclides such as U, U, Th and Ra from the proposed tailings pond was modelled. The ingrowths of progenies were also considered in the modelling. It was observed that these radionuclides move very little from the tailings pond, even at the end of 10,000 y, due to their high distribution coefficients and low groundwater velocities. These concentrations were translated into committed effective dose rates at different distances in the vicinity of the uranium tailings pond. The results indicated that the highest effective dose rate to members of the public along the groundwater flow pathway is 2.5 times lower than the drinking water guideline of 0.1 mSv/y, even after a long time period of 10,000 y. [ABSTRACT FROM AUTHOR]

The dynamical cluster-decay model (DCM) is used to study the odd-mass nuclear systems 213Fr* (with N = 126) and 217Fr* (with N = 130) formed in 19F + 194,198Pt reactions. The measured anomaly in fission anisotropy for 213Fr* in this reaction is said to be due to either the possible role of the magic N = 126 shell of the compound nucleus (CN) or the presence of a noncompound nucleus component, such as quasifission, in the fission cross section. Our calculations are made within the DCM for the fragments having quadrupole (β2) deformations with orientations of compact, hot configurations, compared with spherical as well as β2-β4 deformed considerations. For quadrupole deformed fragments (with "optimal" orientations), the calculated fission cross-sections (as well as the evaporation residue cross-sections) match the data nearly exactly, without invoking a significant contribution from quasifission. The calculated fission mass distribution for the two systems is quite similar for either of the spherical, β2-alone deformed, and β2-β4 deformed choices of fragments. A small hump or shoulder is seen in fragment preformation yields for the deformed case (β2 or β2-β4) in both the systems due to a deformed closed shell around Z2 = 36 and a spherical magic shell around Z1 = 50, which for 213Fr* (N = 126) decay is somewhat more pronounced as compared to 217Fr* (N = 130). Note that the magic shell of the CN proton/neutron number plays no role in DCM. [ABSTRACT FROM AUTHOR]

Disposal of radioactive materials requires identification of the permissible radionuclide and its inventory limits. This paper addresses the study of some parameters to specify radioactive wastes, which are buried in repository by assessing; 1) the sensitivity of these parameters on the dose received by individual through water ingestion pathway, and 2) approach to evaluate the effect of these specific parameters on the safety of disposal site. Activity, halflife, travel time and dose conversion factor are the selected parameters for this study. Using simple sensitivity method, the effect of these parameters on a human dose shows higher sensitivity index. Additionally, safety of repository in respect to the decay time and activity of radionuclides are evaluated. [ABSTRACT FROM AUTHOR]