Search

The neutron-rich rare isotope 190W is discussed as a candidate for a prolate-oblate transitional nucleus with maximum γ-softness. The collectivity of this isotope is assessed for the first time by the measurement of the reduced E2 transition probability of its first 2+ state to the ground state. The experiment employed the FAst TIming Array (FATIMA), comprised of 36 LaBr3(Ce) scintillators, which was part of the DESPEC setup at GSI, Darmstadt. The 41+ and 21+ states of 190W were populated subsequently to the decay of its 127(12) μs isomeric Jπ=10− state. The mean lifetime of the 21+ state was determined to be τ=274(28) ps, which corresponds to a B(E2;21+→01+) value of 95(10) W.u. The results motivated a revision of previous calculations within an energy-density functional-based interacting boson model-2 approach, yielding E2 transition properties and spectroscopic quadrupole moments for tungsten isotopes. From comparison to theory, the new data suggest that 190W is at the transition from prolate to oblate structure along the W isotopic chain, which had previously been discussed as a nuclear shape-phase transition.

In an ideal germanium detector, fully-absorbed monoenergetic γ-rays will appear in the measured spectrum as a narrow peak, broadened into a Gaussian of width determined only by the statistical properties of charge cloud generation and the electronic noise of the readout electronics. Multielectrode detectors complicate this picture. Broadening of the charge clouds as they drift through the detector will lead to charge sharing between neighboring electrodes and, inevitably, low-energy tails on the photopeak spectra. We simulate charge sharing in our germanium cross strip detectors in order to reproduce the low-energy tails due to charge sharing. Our goal is to utilize these simulated spectra to develop an analytical fit (shape function) for the spectral lines that provides a robust and high-quality fit to the spectral profile, reliably reproduces the interaction energy, noise width, and the number of counts in both the true photopeak and the low-energy tail, and minimizes the number of additional parameters. Accurate modeling of the detailed line profiles is crucial for both calibration of the detectors as well as scientific interpretation of measured spectra.

KHALA, the acronym for Korea high-resolution array of LaBr 3 (Ce), has been developed to measure the lifetimes of the nuclear excited states. This system consists of 36 cylindrical LaBr 3 (Ce) scintillator crystals with a diameter and length of 1.5 inches each. It is suitable for measuring γ -ray emission time from a few tens of picoseconds to a few tens of nanoseconds. The data acquisition electronics of KHALA are fully digitized for both energy and timing information, resulting in the quick data processing. Detailed performance specifications, such as the energy resolution, timing response, and photopeak detection efficiency, of KHALA are presented. [ABSTRACT FROM AUTHOR]

This work aims at presenting an alternative approach to the long standing problem of the B(E2) values in Sn isotopes in the vicinity of the N=Z double-magic nucleus 100Sn, until now predominantly measured with relativistic and intermediate-energy Coulomb excitation reactions. The direct measurement of the lifetime of low-lying excited states in odd-even Sn isotopes provides a new and precise guidance for the theoretical description of the nuclear structure in this region. Lifetime measurements have been performed in 105Sn for the first time with the coincidence Recoil Distance Doppler Shift technique. The lifetime results for the 7/21+ first excited state and the 11/21+ state, 2+(104Sn) ⊗ν1g7/2 multiplet member, are discussed in comparison with state-of-the-art shell model and mean field calculations, highlighting the crucial contribution of proton excitation across the core of 100Sn. The reduced transition probability B(E2) of the 11/21+ core-coupled state points out an enhanced staggering with respect to the B(E2; 21+→01+) in the even-mass 104Sn and 106Sn isotopes.

Wobbling motion as an exotic collective mode in nuclei without axial symmetry, was intensively discussed during the last few years. The observation of the newly proposed transverse wobbling, first reported in 135 Pr and soon after in nuclei from other mass regions, was considered as a significant discovery in low-spin nuclear structure. However, both the reported experimental results and the proposed theoretical models were actively questioned in work devoted to the study of the low-spin wobbling mode in the same nuclei. We recently re-measured the electromagnetic character of the Δ I = 1 transitions connecting the one- to zero-phonon and the two- to one-phonon wobbling bands in 135 Pr, showing their predominant M 1 magnetic character, which is in contradiction with the wobbling interpretation. These new experimental results, which were reproduced by either the quasiparticle-plus-triaxial-rotor model and interacting boson-fermion model calculations, are against the previously proposed wobbling nature of the low-spin bands in 135 Pr. On the other hand, we obtained conclusive experimental evidence for the theoretically proposed transverse wobbling bands at medium spin in 136 Nd. The comparison of the experimental data with calculations using the triaxial projected shell model as well as a new particle-rotor model with frozen orthogonal geometry of the active nucleons, supports the description in terms of transverse wobbling of medium-spin bands in triaxial even-even nuclei. [ABSTRACT FROM AUTHOR]

The nuclear structure of 66Se, nucleus beyond the N=Z line on the proton-rich side of the valley of stability, was investigated by the neutron knock-out reaction 67Se(12C,X)66Se using a 12C target. The analysis of the singles spectrum of the γ-rays emitted during the de-excitation of the populated low-lying excited states revealed two previously detected (927(4) keV, 1460(32) keV) and three new (744(6) keV, 1210(17) keV, 1661(23) keV) transitions. The 744-keV, the 1210-keV, and the 1460-keV transitions were found to be in coincidence with the one at 927 keV. The spectrum coincident with the 927-keV transition showed a further possible transition at 299(35) keV, which was obscured by significant atomic background in the singles spectrum. This transition might correspond to a peak previously reported at 273(5) keV that could not be assigned to 66Se unambiguously. Based on a comparison of the experimental data to theoretical calculations, four new excited states are proposed which suggest that 66Se exhibits shape coexistence.

A review of recent advances in the study of the energy splitting between excited isobaric analogue states is presented. Some of the experimental developments, and new approaches, associated with spectroscopy of the most proton-rich members of isobaric multiplets, are discussed. The review focuses on the immense impact of the shell-model in the analysis of energy differences and their interpretation in terms of nuclear structure phenomena.

The GALILEO γ -ray spectrometer has been constructed at the Legnaro National Laboratory of INFN (LNL-INFN). It can be coupled to advanced ancillary devices which allows nuclear structure studies employing the variety of in-beam γ -ray spectroscopy methods. Such studies benefit from reactions induced by the intense stable beams delivered by the Tandem-ALPI-PIAVE accelerator complex and by the radioactive beams which will be provided by the SPES facility. In this paper we outline two experiments performed within the experimental campaign at GALILEO coupled to the EUCLIDES Si-ball and the Neutron Wall array. The first one was aimed at spectroscopic studies in A=31 mirror nuclei and the second one at measurements of lifetimes of excited states in nuclei in the vicinity of 100 Sn.

A review of recent advances in the study of the energy splitting between excited isobaric analogue states is presented. Some of the experimental developments, and new approaches, associated with spectroscopy of the most proton-rich members of isobaric multiplets, are discussed. The review focuses on the immense impact of the shell-model in the analysis of energy differences and their interpretation in terms of nuclear structure phenomena. [ABSTRACT FROM AUTHOR]

The measurement of β-decay rates in plasma, simulating stellar-like conditions, is of high interest for the investigation of radionuclides involved in nuclear astrophysics processes. In the new PANDORA plasma trap, to be built at the INFN—Laboratori Nazionali del Sud of Catania (Italy), the β-decay rates will be estimated by detecting the γ-rays emitted by the daughter nuclei trapped in the confined plasma. The present work describes the high efficiency High Purity Germanium (HPGe) detector array that will be placed around the magnetic trap for this purpose, as well as the front-end electronics and acquisition system suitable for the array operation in presence of a high counting rate background originating from Bremsstrahlung radiation.

• PM 2.5 levels exceeded WHO's limits; significant concentrations of 226Ra and 232Th found. • High particulate matter and radionuclides pose health risks, especially through inhalation. • Detailed methods for sample collection and radionuclide measurement using gamma-ray spectrometry. • Effective inhalation dose calculated for different age groups, indicating health impact. • Assessed lifetime cancer risk due to radiation exposure from radionuclides. This research focused on measuring the concentration of particulate matter (PM 2.5) aerosols and radionuclides (226Ra, 232Th, and 40K) in road dust collected using glass fiber filters from busy roads and populated areas in Islamabad and Rawalpindi, Pakistan. The measured concentrations ranged between 551.0 and 2025.7 µgm−3 for PM 2.5 aerosols, 32.4 and 54.7 mBqm−3 for 226Ra, 15.8 and 26.8 mBqm−3 for 232Th, and 239.0 and 316.4 mBqm−3 for 40K. The study found that PM 2.5 levels surpassed the WHO's recommended limit of 25 µgm−3. Additionally, concentrations of 226Ra and 232Th were considerably higher than the global average values of 1 and 0.5 µBqm−3, respectively, in dust. The total inhalation effective dose in all samples exceeded the ICRP's acceptable limit of 2 mSvy-1, except in the infant and 1-year-old age groups (considering F, M, and S-type modes). Notably, 232Th was identified as the primary contributor, accounting for 36.5 % to 99.4 % of the total inhalation effective dose. [ABSTRACT FROM AUTHOR]

LaBr3:(Ce) exhibits the best energy resolution among scintillation γ-ray detectors. The excellent energy resolution of this detector has made it suitable for many radiation detection applications such as environmental monitoring, medical imaging, nuclear security, nuclear physics experiments, etc. However, LaBr3:(Ce) crystal endures from internal radioactivity which produces a considerable background in the measurements. The problem of internal radiation is particularly acute with large size detectors, measuring low-intensity γ-rays. A considerable part of the internal radiation comes from the α-decay of 227Ac and its daughters which are present as an impurity in the detector’s crystal. Unfortunately, due to the very similar chemical properties of Actinium and Lanthanum, it is very difficult to remove the 227Ac impurity by using purification processes, and therefore, the α-background is present in all the commercial crystals. A practical approach for the reduction of this problem is to identify the α-events through an electronic analysis of the shape of output pulses of the detector and reject them. In the past, several digital pulse-shape discrimination (PSD) methods have been proposed to suppress the internal α background in LaBr3:(Ce) detectors. These methods exploit the small difference in the shape of scintillation pulses from α- and γ-ray interactions. The PSD methods have demonstrated some degree of success, which are limited to only a partial rejection of the α-background while further reduction of the α background is highly desirable for low-background γ-ray measurements. In this work, a novel digital PSD method that significantly improves the rejection of the internal α background was developed. The PSD method is based on the wavelet transform of the scintillation pulses, leading to an almost complete rejection of the α background. This method is very useful for low-level radiation measurements with LaBr3:(Ce) detectors involving high-energy γ rays.

States in the N=35 and 37 isotopes 55,57Ca have been populated by direct proton-induced nucleon removal reactions from 56,58Sc and 56Ca beams at the RIBF. In addition, the (p,2p) quasi-free single-proton removal reaction from 56Ca was studied. Excited states in 55K, 55Ca, and 57Ca were established for the first time via in-beam γ-ray spectroscopy. Results for the proton and neutron removal reactions from 56Ca to states in 55K and 55Ca for the level energies, excited state lifetimes, and exclusive cross sections agree well with state-of-the-art theoretical calculations using different approaches. The observation of a short-lived state in 57Ca suggests a transition in the calcium isotopic chain from single-particle dominated states at N=35 to collective excitations at N=37.

Lead halide perovskite single crystals (LHPSC) are promising for room-temperature γ-ray spectroscopy in radiation detection. While MA(CH 3 NH 3 )-based LHPSCs are the most straightforward and cost-effective to synthesize from solution, their performance in γ-ray spectroscopy is hindered by significant noise and ion migration at high bias, which degrades their energy resolution (ER). The work introduced an n-type/intrinsic/n-type photodiode incorporating passivation layers of MA-based LHPSCs, grown through solution-process epitaxial growth. This single-polarity device demonstrated an outstanding ER of 3.6% for 662 keV γ-ray photons. Overall, this work provides useful information for developing room-temperature γ-ray detectors based on solution-processed lead halide perovskites.

Most buildings use decorative materials that are aesthetically pleasing, that may contain various amounts of radioactive elements. Thus, the human health of dwellers and workers is continuously exposed to ionizing radiation. Natural radioactivity (238U, 232Th, and 40K) is measured in decorative materials collected from different Iraqi local markets by utilizing a shielded high counting efficiency NaI(Tl) system. Some radiological hazard indexes in all samples were calculated. The results obtained showed that the maximum value of specific activity for 238U, 232Th, and 40K is in decorative stone and the minimum is measured in decorative alabaster. This study concluded that the natural radioactivity and radiological hazard in most samples of decorative materials were within the permissible limits by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), the International Commission on Radiological Protection (ICRP), Organization for Economic Co-operation and Development (OECD), and other world reported. Therefore, most samples of decorative materials in the present study can be used without health risks according to radiation scope. [ABSTRACT FROM AUTHOR]

Excited-state lifetimes were measured by direct fast-timing methods in three N=125 isotones — 209Po, 211Rn, and 213Ra — near doubly magic 208Pb. These nuclei have a single neutron hole and successively add pairs of protons relative to 208Pb. The first-excited state to ground-state transition, 5/21−→1/21−, has almost identical energy in each isotone and can be associated with the single neutron-hole transition νf5/2−1→νp1/2−1. The extent to which the protons act as spectators is assessed based on the measured transition rates, which show a systematic increase along the isotone chain, and by comparisons with large-basis shell-model calculations. The shell model accounts for some of the increased transition strength but consistently underestimates the experimental values. It also fails to explain the near-constant transition energies. These results suggest emerging collectivity beyond the shell-model valence space and show that the near-constant transition energies are not a consequence of a pure neutron-hole transition, but rather the outcome of complex nucleon-nucleon correlations that increase quadrupole collectivity.

This paper provides a new approach that simplifies the monitoring of 214Pb activity concentration on aerosols in the atmospheric surface layer. The approach allows obtaining data on 214Pb activity concentration with the discreteness of 2 h. The experimental setup described in the paper made it possible to achieve a minimum detectable activity level of 0.4 Bq m−3. Using this approach, the data on the diurnal variability of 214Pb activity concentration in the atmosphere of Sevastopol city for a period of 18 months were obtained. The 214Pb activity concentration varied from < 0.4 (less than 1% of the data series) to 8.9 Bq m−3, mean value 2.0 ± 1.0 Bq m−3. The analysis of the temporal variability of 214Pb activity concentration on different time scales (diurnal, seasonal) was carried out. Annually averaged diurnal variation curve of 214Pb activity concentration showed a peak at 6:00 local time and a minimum at 18:00. The maximum variability in the seasonal averaged diurnal cycle of 214Pb activity concentration is observed in summer (± 30% of the daily average value) and the minimum in winter (± 13%). The maximum seasonal average value of 214Pb activity concentration is observed in winter (2.5 Bq m−3) and the minimum in summer (1.4 Bq m−3). A quantitative estimate of the annual effective dose due to exposure to outdoor radon was obtained by using 214Pb data, and it was 0.03 mSv a−1. [ABSTRACT FROM AUTHOR]

The nuclear structure of 51Ar, an uncharted territory so far, was studied by the (p,2p) reaction using γ-ray spectroscopy for the bound states and the invariant mass method for the unbound states. Two peaks were detected in the γ-ray spectrum and six peaks were observed in the 50Ar+n relative energy spectrum. Comparing the results to our shell-model calculations, two bound and six unbound states were established. Three of the unbound states could only be placed tentatively due to the low number of counts in the relative energy spectrum of events associated with the decay through the first excited state of 50Ar. The low cross sections populating the two bound states of 51Ar could be interpreted as a clear signature for the presence of significant subshell closures at neutron numbers 32 and 34 in argon isotopes. It was also revealed that due to the two valence holes, unbound collective states coexist with individual-particle states in 51Ar.

Theoretical and computational methods for simulating the creation of ionization tracks by fast ions in solids were applied to the passage of α-particles in CsI, an inorganic scintillator commonly used for radiation detection. The methods were implemented in a Monte Carlo program to simulate the interaction of α-particles, with incident energies of up to 1 MeV, with CsI. The simulations followed the fate of individual electron-hole pairs and included the formation of Frenkel pairs and thus allowed for a detailed description of the microscopic structure of ionization and defect tracks created by incident radiation. Simulations were also performed with γ-rays of the same energy to compare and contrast the ionization tracks obtained with both types of particles. Intrinsic properties such as the mean energy per electron-hole pair, Fano factor, maximum theoretical light yield, and spatial distributions of electron-hole pairs were computed for both α-particles and γ-rays. α-Particles created cylindrical tracks that were initially aligned with the incident direction and with initial radii of a few tens of nanometers, whereas γ-rays showed significant scattering, resulting in probability distributions with lower intensities and much greater radial extents. [ABSTRACT FROM AUTHOR]

The E0 transition depopulating the first-excited 0+ state in 24Mg has been observed for the first time, and the E0 transition strength determined by electron-positron pair and γ-ray spectroscopy measurements performed using the Super-e pair spectrometer. The E0 transition strength is ρ2×103=380(70). A two-state mixing model implies a deformation of the first-excited 0+ state of β2≈1 and a change in the mean-square charge radius of Δ〈r2〉≈1.9fm2, which suggests a significant shape change between the ground state and first-excited 0+ state in 24Mg. The observed E0 strength gives direct evidence of shape coexistence and superdeformation in 24Mg, bringing this nucleus into line with similar behaviour in nearby N=Z nuclei. This result agrees with recent theoretical work on the cluster nature of 24Mg and has potential ramifications for nuclear reactions of astrophysical importance.

The first evidence for β-delayed proton emission from the 16+ spin gap isomer in 96Cd is presented. The data were obtained from the Rare Isotope Beam Factory, at the RIKEN Nishina Center, using the BigRIPS spectrometer and the EURICA decay station. βp branching ratios for the ground state and 16+ isomer have been extracted along with more precise lifetimes for these states and the lifetime for the ground state decay of 95Cd. Large scale shell model (LSSM) calculations have been performed and WKB estimates made for ℓ=0,2,4 proton emission from three resonance-like states in 96Ag, that are populated by the β decay of the isomer, and the results compared to the new data. The calculations suggest that ℓ=2 proton emission from the resonance states, which reside ∼5 MeV above the proton separation energy, dominates the proton decay. The results highlight the importance of core-excited wavefunction components for the 16+ state.

The low-lying dipole strength of the deformed nucleus 156Gd was investigated in the energy region from 3.1 MeV to 6.2 MeV using the method of nuclear resonance fluorescence (NRF). The NRF experiments were performed at the Darmstadt High Intensity Photon Setup (DHIPS) at Technische Universität Darmstadt using unpolarized continuous-energy bremsstrahlung and at the High-Intensity γ -ray Source (HI γ S) at Duke University using quasi-monoenergetic and linearly-polarized photon beams. The combination of both experiments allows to separate electric and magnetic contributions and to determine absolute transition strengths for individual excited states as well as averaged quantities over narrow excitation energy regions. The investigated energy regions cover the region of the scissors mode as well as the low-energy part of the Pygmy Dipole Resonance. This is the first experiment where both of these excitation modes as well as the region in between has been successfully studied in a deformed heavy nucleus using the NRF method. [ABSTRACT FROM AUTHOR]

The cross sections of the 60Ni(p,n)60Cu reaction from threshold energy to ~ 20 MeV have been measured by employing stack foil activation technique and off-line γ-ray spectrometry. The uncertainties for the reaction cross sections have been estimated by applying covariance analysis and least square method. The measured cross-sections are found to be in agreement with most of the literature data available in EXFOR database. The excitation function of the 60Ni(p,n)60Cu reaction was also theoretically calculated by using the TALYS-1.9 code. The excitation functions of 60Ni(p,n)60Cu reaction from TALYS-1.9 and TENDL-2017 follow a similar trend as of the experimental data of present work and literature but are little higher around the peak cross-section region. [ABSTRACT FROM AUTHOR]

Charge trapping in germanium detectors will inevitably impact their excellent spectral performance. Disordered regions in the germanium crystal structure, either created in the material during processing or induced by radiation exposure, will affect the Charge Collection Efficiency (CCE), degrading the spectral resolution. Here we present numerical simulations of charge trapping effects on the anode and cathode signals for cross-strip germanium detectors. We discuss the assumptions behind our model of trapping, which accounts for both the drift length and thermal motion of the charge carriers. We present simulated CCE curves as a function of interaction depth within the detectors, and develop a technique for benchmarking these simulations against measured data. Comparison with measured CCE curves are presented. We are developing these numerical models with a goal of characterizing, and ultimately correcting, the effects of radiation damage on the spectral resolution of germanium cross-strip detectors. [ABSTRACT FROM AUTHOR]

A big part in understanding the nucleosynthesis of heavy nuclei is a proper description of the effective interaction between an α-particle and a target nucleus. Information about the so-called α+nucleus optical-model potential is achieved by precise cross-section measurements at sub-Coulomb energies aiming to constrain the theoretical models for the nuclear physics input-parameters. The cross sections of the 108Cd(α,γ) and 108Cd(α,n) reaction have been measured for the first time close to the astrophysically relevant energy region via the in-beam method at the high-efficiency γ-ray spectrometer HORUS and via the activation technique at the Cologne Clover Counting Setup at the Institute for Nuclear Physics in Cologne, Germany. Comparisons between experimental results and theoretical predictions calculated in the scope of the Hauser–Feshbach statistical model confirm the need for a exponentially decreasing imaginary part of the potential. Moreover, it is shown that the results presented here together with already published data indicate that a systematic investigation of the real part of the potential could help to further improve the understanding of reactions involving α-particles.

The decay properties of the Pygmy Dipole Resonance (PDR) have been investigated in the semi-magic N=82 nucleus 140Ce using a novel combination of nuclear resonance fluorescence and γ–γ coincidence techniques. Branching ratios for transitions to low-lying excited states are determined in a direct and model-independent way both for individual excited states and for excitation energy intervals. Comparison of the experimental results to microscopic calculations in the quasi-particle phonon model exhibits an excellent agreement, supporting the observation that the Pygmy Dipole Resonance couples to the ground state as well as to low-lying excited states. A 10% mixing of the PDR and the [21+×PDR] is extracted.

A number of 3-quasiparticle isomers have been found and characterised in the odd-mass, neutron-rich, 187Re, 189Re and 191Re nuclei, the latter being four neutrons beyond stability. The decay of the isomers populates states in the rotational bands built upon the 9/2−[514] Nilsson orbital. These bands exhibit a degree of signature splitting that increases with neutron number. This splitting taken together with measurements of the M1/E2 mixing ratios and with the changes observed in the energy of the gamma-vibrational band coupled to the 9/2−[514] state, suggests an increase in triaxiality, with γ values of 5°, 18° and 25° deduced in the framework of a particle-rotor model.

Abstract Most theoretical approaches used in nuclear astrophysics to model the nucleosynthesis of heavy elements incorporate the so-called statistical model in order to describe the excitation and decay properties of atomic nuclei. One of the basic assumptions of this model is the validity of the Brink–Axel hypothesis and the related concept of so-called photon strength functions to describe γ -ray transition probabilities. We present a novel experimental approach that allows for the first time to experimentally determine the photon strength function simultaneously in two independent ways by a unique combination of quasi-monochromatic photon beams and a newly implemented γ – γ coincidence setup. This technique does not assume a priori the validity of the Brink–Axel hypothesis and sets a benchmark in terms of the detection sensitivity for measuring decay properties of photo-excited states below the neutron separation energy. The data for the spherical off-shell nucleus 128Te were obtained for γ -ray beam-energy settings between 3 MeV and 9 MeV in steps of 130 keV for the lower beam energies and in steps of up to 280 keV for the highest beam settings. We present a quantitative analysis on the consistency of the derived photon strength function with the Brink–Axel hypothesis. The data clearly demonstrate a discrepancy of up to a factor of two between the photon strength functions extracted from the photoabsorption and photon emission process, respectively. In addition, we observe that the photon strength functions are not independent of the excitation energy, as usually assumed. Thus, we conclude, that the Brink–Axel hypothesis is not strictly fulfilled in the excitation-energy region below the neutron separation threshold (S n = 8.78 MeV) for the studied case of 128Te. [ABSTRACT FROM AUTHOR]

Abstract Internal dosimetry measurements of trans-uranic (TRU) radionuclides within the human body can be accomplished by γ -ray spectroscopy using high-purity germanium detectors. While measurements are typically conducted inside shielded chambers in order to minimize the background detector signal, the presence of radioactive 40K within the body cannot be removed, which produces a high-energy γ ray at 1461 keV. The 40K, in addition to airborne 222Rn, contributes to the radiation field within the chamber that increases to the minimum detectable activity that can be achieved in practice. The objective of the present work is to estimate the contributions from 40K internal to the human body and airborne 222Rn to the background signal in a lung counter germanium detector array using GEANT4 simulations, with a focus on TRU isotope energy region (17–59 keV). The investigations consisted of three main simulations: 1. Simulating the γ -ray flux at the geometric center of the CEMRC counting chamber arising from a 25 nCi source of 40K from (a) a point source, and (b) a source distributed throughout a BOMAB phantom. 2. Simulating the response of the CEMRC BEGe detectors arising from a 25 nCi source of 40K from (a) a point source, and (b) a source distributed throughout a BOMAB phantom. 3. Simulating the response of the CEMRC BEGe detectors to the environmental background in the counting chamber, consisting of airborne 222Rn (0–4 pCi/L) and 40K (0–160 nCi) internal to the human body. The results are used to investigate the 40K background contribution to a routine spectrum recorded by the lung detectors at the CEMRC Internal Dosimetry laboratory over a typical half hour counting interval used in the dosimetry of radiological workers. The minimum detectable activity was calculated for various 222Rn and 40K activities and compared to experimentally determined values. The contribution of cosmic rays was not included in this investigation. Highlights • Simulated response of BEGe detectors to a point source of 40K. • Simulated response of BEGe detectors to a distributed BOMAB source of 40K. • Simulated response of BEGe detectors to airborne 222Rn. • Comparison of simulated and measured MDAs for 238Pu and 241Am using BEGe detectors. [ABSTRACT FROM AUTHOR]

A reference source with the granular active portion was made using 152,154Eu(III) loaded tin tungstate material. Batch equilibration method was used to investigate the interaction of 152,154Eu(III) radiotracer (10−4 M) in acid solutions on tin(IV) tungstate gel matrix. The sorption behavior of 152,154Eu(III) showed high affinity towards tin(IV) tungstate gel matrix at low pH values. Tin tungstate gel matrix was loaded with 152,154Eu from batch at pH 3. Standardization of the source was done spectroscopically with reference to primary certified set of radioactive sources and with the aid of HPGe detector. Random and true coincidence summing was carried out by following-up coincidence in 152Eu and possible interference between γ lines of 152Eu and 154Eu. The relation between the grain size and the activity of samples was studied. Correction factor for capsule attenuation was applied. [ABSTRACT FROM AUTHOR]

The scale material in TENORM waste from petroleum industry was characterized using nuclear and non-nuclear techniques. The scale TENORM samples were collected from the Ras Shukeir area on the west bank of the Suez Gulf in Egypt during gas and oil production. These scales represent the TENORM deposits formed in the pipelines and removed during the periodical maintenance. X-ray fluorescence analysis showed that the main elements in all investigated fractions were Si, Fe, Mg, Ca, Sr, and Ba in addition to traces of some heavy elements, e.g. Pb, Cr, and Zn. The radioactivity concentrations of natural radionuclides 226Ra, 232Th, and 40K in seven particle size fractions were found to be in the range from 14.1 ± 0.4 to 28.9 ± 0.9, from 5.0 ± 0.2 to 9.5 ± 0.4, and from 0.25 ± 0.02 to 0.43 ± 0.02 kBq kg-1, respectively. The radiation hazard parameters were calculated. The values obtained are much greater than the accepted values. The results were compared to the values reported for other countries. [ABSTRACT FROM AUTHOR]

Standard activation analysis technique with γ ray spectroscopy via off-line mode was utilized for reaction cross section estimation. The proton beam was transported from the BARC-TIFR accelerator and targeted on the n a t Cd target. The 16 MeV proton beam irradiated the sample, and Copper foil was utilized as an energy degrader. The activation cross sections were estimated for 110Cd(p, n) reaction for the ground state (J π = 7 +) population of 110In nucleus and 110Cd(p, 2n)109In reaction at 14.14 MeV of proton energy. Along with experimental measurements, the theoretical study has been carried out for ground and metastable states population by utilizing the nuclear model code TALYS-1.95, EMPIRE-3.2.3, and ALICE-2014 for both reaction channels. The estimated cross sections are valuable for the improvement of theoretical nuclear model codes for a comprehensive knowledge of nuclear reaction mechanisms. The produced isotopes 109 , 110 In have significant importance in Positron Emission Tomography (PET) studies. The present study is a dive into the phenomenological and microscopic level density models of different nuclear model codes in predicting excitation functions. • Standard activation analysis technique was utilized for data analysis. • Cross sections were measured for (p, n) and (p, 2n) reactions on 110Cd. • Cd is important for nuclear reactors and medicines-based applications. • Ground to metastable state cross section ratio was calculated for 110Cd(p, n) 110In. • Phenomenological and microscopic-level density models used for data prediction. [ABSTRACT FROM AUTHOR]

Although environmental radioactivity is all around us, the collective public imagination often associates a negative feeling to this natural phenomenon. To increase the familiarity with this phenomenon we have designed, implemented, and tested an interdisciplinary educational activity for pre-collegiate students in which nuclear engineering and computer science are ancillary to the comprehension of basic physics concepts. Teaching and training experiences are performed by using a 4” × 4” NaI(Tl) detector for in-situ and laboratory γ-ray spectroscopy measurements. Students are asked to directly assemble the experimental setup and to manage the data-taking with a dedicated Android app, which exploits a client-server system that is based on the Bluetooth communication protocol. The acquired γ-ray spectra and the experimental results are analyzed using a multiple-platform software environment and they are finally shared on an open access Web-GIS service. These all-round activities combining theoretical background, hands-on setup operations, data analysis, and critical synthesis of the results were demonstrated to be effective in increasing students’ awareness in quantitatively investigating environmental radioactivity. Supporting information to the basic physics concepts provided in this article can be found at http://www.fe.infn.it/radioactivity/educational.

Isomeric yield ratios in 120m,gSb have been measured in (γ, n)-reaction for the several end-point energies of bremsstrahlung photons from 9.6 to 25 MeV. Theoretical values of the isomeric yield ratios in 120m,gSb have been calculated by using code TALYS-1.0. Statistical nature of reactions with γ-rays has been shown both in the around threshold energy region and in the high energy region of the bremsstrahlung photons.

New materials were synthesized for application in sorption of radionuclides from aqueous solutions. The elaboration was performed by conversion of power plant ash using the hydrothermal method under optimum experimental conditions. Sodalite, Na-Y, and analcime were formed from ash precursor during the treatment, exhibiting thermal stability as revealed by the characterization by X-ray diffraction (XRD) and thermogravimetric differential thermal analysis (TG-DTA). The Brunauer–Emmett–Teller (BET) surface area and pore volume were determined and they presented higher values than plant ash. The ability of the new products to retain Ba and Eu radionuclides was studied in aqueous solutions using 133 Ba and 152 Eu as tracers and γ-ray spectroscopy under batch experiments. The experimental data were modeled by the Langmuir and Freundlich equations, whereas sorption kinetics measurements were performed at 293, 308, and 323 K and thermodynamic parameters were calculated. The release of the sorbed ions into the environment was also tested by leaching experiments. The results of these tests indicated that the synthesized materials are very efficient in removing the aforementioned metals from aqueous solutions and can be considered as potential low-cost sorbents in nuclear waste management. [ABSTRACT FROM AUTHOR]

Methods for measuring U, Th, and Pb in refined lead are presented. The U and Th concentrations are determined using isotope dilution inductively coupled plasma mass spectrometry after anion exchange column separation of dissolved lead samples. The Pb concentration is inferred through α-spectroscopy of a daughter isotope, Po, after precipitation separation of dissolved lead samples. Subsequent to the Po α-spectroscopy measurement, a method for evaluating Pb concentrations was developed via measurement of bremsstrahlung radiation from β-decay of a daughter isotope, Bi, using a 14-crystal array of high purity germanium detectors. Ten sources of refined lead were assayed and results are presented. [ABSTRACT FROM AUTHOR]

This paper describes state-of-the-art digital filtering techniques that are part of GEANA, an automatic data analysis software used for the GERDA experiment. The discussed filters include a novel, nonlinear correction method for ballistic deficits, which is combined with one of three shaping filters: a pseudo-Gaussian, a modified trapezoidal, or a modified cusp filter. The performance of the filters is demonstrated with a 762 g Broad Energy Germanium (BEGe) detector, produced by Canberra, that measures γ-ray lines from radioactive sources in an energy range between 59.5 and 2614.5 keV. At 1332.5 keV, together with the ballistic deficit correction method, all filters produce a comparable energy resolution of ~1.61 keV FWHM. This value is superior to those measured by the manufacturer and those found in publications with detectors of a similar design and mass. At 59.5 keV, the modified cusp filter without a ballistic deficit correction produced the best result, with an energy resolution of 0.46 keV. It is observed that the loss in resolution by using a constant shaping time over the entire energy range is small when using the ballistic deficit correction method. [ABSTRACT FROM AUTHOR]

The COBRA collaboration aims to search for neutrinoless double beta-decay of 116 Cd. A demonstrator setup with 64 CdZnTe semiconductor detectors, each with a volume of 1 cm 3 , is currently being operated at the LNGS underground laboratory in Italy. This paper reports on the characterization of a large 2 × 2 × 1.5 cm 3 CdZnTe detector with a new coplanar-grid design for applications in γ-ray spectroscopy and low-background operation. Several studies of electric properties as well as of the spectrometric performance, like energy response and resolution, are conducted. Furthermore, measurements including investigating the operational stability and a possibility to identify multiple-scattered photons are presented. [ABSTRACT FROM AUTHOR]

The FaNGaS instrument was set up at the research reactor FRM II, Garching. It performs measurements of ( n,n ′ γ ) reactions based on the γ-ray spectroscopy technique within the fission neutrons energy region. The optimization studies of the experimental setup were carried out using MCNP simulations. A full characterization of the detector system and the neutron beam is presented. The determination of the neutron energy spectrum was done using the foil activation method. An average neutron energy of about 2 MeV and a neutron flux of 10 8 cm − 2 · s − 1 were measured. [ABSTRACT FROM AUTHOR]