Articoli di riviste: "Prompt γ-spectroscopy"

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Guessous, A., N. Schulz, M. Bentaleb, E. Lubkiewicz, J. L. Durell, C. J. Pearson, W. R. Phillips et al. "Prompt γ-ray spectroscopy of theMo104andMo108fission fragments". Physical Review C 53, n. 3 (1 marzo 1996): 1191–96. http://dx.doi.org/10.1103/physrevc.53.1191.

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DANU, L. S., D. C. BISWAS, B. K. NAYAK e R. K. CHOUDHURY. "Fission fragment mass distributions via prompt γ-ray spectroscopy". Pramana 85, n. 3 (24 luglio 2015): 379–84. http://dx.doi.org/10.1007/s12043-015-1052-2.

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Wilson, Jonathan, Damien Thisse, Matthieu Lebois, Nikola Jovancevic, Rhiann Canavan, Mathias Rudigier, David Étasse e Rosa-Belle Gerst. "High resolution gamma-ray spectroscopy of fast-neutron induced fission". EPJ Web of Conferences 256 (2021): 00019. http://dx.doi.org/10.1051/epjconf/202125600019.

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Experiments to perform precision spectroscopy of fast neutron induced fission were carried out during the ν-Ball experimental campaign at the ALTO facility of IJC Laboratory Orsay. Low energy fission of 232Th(n,f), 238U(n,f) and spontaneous fission of 252Cf were studied using this hybrid highresolution spectrometer and calorimeter. New observables such as γ-ray multiplicity distributions correlated with specific fission fragments are presented and discussed. A new method using fast-timing techniques to detect prompt fission neutrons in coincidence with prompt fission γ-rays is described.

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Toh, Y., M. Oshima, M. Koizumi, A. Osa, A. Kimura, J. Goto e Y. Hatsukawa. "Analysis of cadmium in food by multiple prompt γ-ray spectroscopy". Applied Radiation and Isotopes 64, n. 7 (luglio 2006): 751–54. http://dx.doi.org/10.1016/j.apradiso.2006.02.087.

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Rubert, J., O. Dorvaux, B. J. P. Gall, P. T. Greenlees, Z. Asfari, J. Piot, L. L. Andersson et al. "First prompt in-beam γ-ray spectroscopy of a superheavy element: the256Rf". Journal of Physics: Conference Series 420 (25 marzo 2013): 012010. http://dx.doi.org/10.1088/1742-6596/420/1/012010.

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Underwood, M. C., e J. S. Petler. "High resolution prompt (n,γ) spectroscopy using a down hole logging tool". Journal of Radioanalytical and Nuclear Chemistry Articles 114, n. 2 (settembre 1987): 379–85. http://dx.doi.org/10.1007/bf02039813.

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Kerveno, Maëlle, Greg Henning, Catalin Borcea, Philippe Dessagne, Marc Dupuis, Stéphane Hilaire, Alexandru Negret et al. "How to produce accurate inelastic cross sections from an indirect measurement method?" EPJ Nuclear Sciences & Technologies 4 (2018): 23. http://dx.doi.org/10.1051/epjn/2018020.

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Inelastic reactions ((n,xn) for x ≥ 1) play a key role in reactor cores as they influence the slowing down of the neutrons. A reactor neutron energy spectrum depends thus on this process which is in strong competition with elastic scattering and fission; a nice example is the case of 238U. Inelastic scattering (x = 1) impacts keff and radial power distribution in the nuclear reactor. For several years, it has been shown that the knowledge of the inelastic cross sections in nuclear databases is not good enough to accurately simulate reactor cores and a strong demand for new measurements has emerged with very tight objectives (only a few percent) for the uncertainties on the cross section. To bypass the well-known experimental difficulty to detect neutrons, the prompt γ-ray spectroscopy method is a powerful but indirect way to obtain inelastic cross sections. Our collaboration has used this method for more than ten years and have produced a lot of (n,n′γ) cross sections for nuclei from 7Li to 238U. In this article, we will first discuss the issues of the prompt γ-ray spectroscopy regarding the control of all the uncertainties involved in the (n,n′γ) cross section estimation. Secondly, we will focus on the role of theoretical modeling which, in certain cases, is crucial to reach the objectives of a few percent uncertainty on the (n,n′) cross sections.

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Régis, J. M., G. S. Simpson, H. Mach, A. Blanc, M. Jentschel, U. Köster, P. Mutti et al. "The γ-γ fast-timing technique and the EXILL&FATIMA campaign". EPJ Web of Conferences 193 (2018): 04008. http://dx.doi.org/10.1051/epjconf/201819304008.

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At the Institut Laue-Langevin in Grenoble, germanium-gated γ-γ fast-timing lifetime measurements of nuclear excited states in neutron-rich nuclei have been performed within a prompt γ-ray spectroscopy experimental campaign. We report on results obtained from the cold-neutron induced fission of 235U. The excited secondary fission products were stopped almost instantaneously within the thick target and the γ rays emitted were collected triggerlessly using the EXILL&FATIMA mixed array of HPGe and LaBr3(Ce) detectors. Precise lifetimes could be determined by analysing the γ-γ time difference spectra using the generalized centroid difference method. This picosecondsensitive method provides many advantages and is briefly explained. Still, the major source of systematic errors is related to the contribution of time-correlated Compton background. The EXILL&FATIMA results are discussed with respect to the typical energy-dependent timing behaviour of the background. According to the time response of the background, appropriate methods and a time correction for the sub-nanosecond regime are proposed.

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Kerveno, Maëlle, Catalin Borcea, Marian Boromiza, Roberto Capote, François Claeys, Nicolas Dari Bako, Cyrille De Saint Jean et al. "GRAPhEME: Performances, achievements (@EC-JRC/GELINA) and future (@GANIL/SPIRAL2/NFS)". EPJ Web of Conferences 284 (2023): 01005. http://dx.doi.org/10.1051/epjconf/202328401005.

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GRAPhEME is a γ-spectrometer developed by CNRS/IPHC Strasbourg (France), in collaboration with EC-JRC Geel (Belgium) and IFIN-HH Bucharest (Romania). With its 6 High Purity Planar Germanium detectors and one fission chamber, GRAPhEME, installed at the EC-JRC GELINA facility, was optimized for measurements of accurate (n, xnγ) cross sections on actinides. The experimental methodology is based on the prompt γ-ray spectroscopy coupled to time-of-flight measurements. In this paper, we present an overview of fifteen years of experiments with GRAPhEME at EC-JRC GELINA facility, illustrated by main achievements to highlight the performances reached by our spectrometer. Beyond the experimental work, a close collaboration with theoreticians has emerged allowing the use of the data produced with GRAPhEME to test and constraint nuclear reaction codes like TALYS, CoH and EMPIRE. In a near future, GRAPhEME will be available to start measurement campaigns at the new neutron beam facility SPIRAL2/NFS. There, studies of (n, 2n) and (n, 3n) reactions will be possible and will complete the work done at EC-JRC GELINA on (n, n ) reactions. Despite the amount of cross section data provided by GRAPhEME up to now, the prompt γ-ray spectroscopy method presents some weaknesses that our collaboration tries to overcome. This goes through new calculation schemes based on theoretical modeling constrained on experimental data to infer the total (n, xn) cross section, new instrument to measure conversion electrons but also by being proactive in dissemination activities to make the nuclear structure community aware of our needs about new accurate nuclear structure information on actinides.

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NAKAMURA, Shoji, Hideo HARADA, Subramanian RAMAN e Paul E. KOEHLER. "Thermal Neutron Capture Cross Sections of Zirconium-91 and Zirconium-93 by Prompt γ-ray Spectroscopy". Journal of Nuclear Science and Technology 44, n. 1 (gennaio 2007): 21–28. http://dx.doi.org/10.1080/18811248.2007.9711252.

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Cieplicka-Oryńczak, Natalia, Silvia Leoni, Bogdan Fornal, Dino Bazzacco, Aurelien Blanc, Giovanna Benzoni, Simone Bottoni et al. "The γ-ray spectroscopy studies of low-spin structures in 210Bi and 206Tl using cold neutron capture reactions". EPJ Web of Conferences 193 (2018): 05007. http://dx.doi.org/10.1051/epjconf/201819305007.

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The γ-coincidence studies of low-spin structures of 210Bi and 206Tl are presented. The 210Bi nucleus, populated in thermal neutron capture reaction, was investigated using EXILL HPGe array at Institut Laue-Langevin in Grenoble. The experimental results were compared to the shell-model calculations allowing to draw the conclusions on the nature of the low-spin excitations populated below the neutron binding energy in 210Bi (4.6 MeV). It has been found that some levels cannot be described by the valence proton and neutron couplings, but may arise from couplings of valence particles to the 3- octupole phonon of the doubly magic 208Pb core. Moreover, preliminary results of a low-spin structure measurements of 206Tl by the γ-coincidence technique, making use of the 205Tl(n,γ)206Tl reaction at the FIPPS prompt γ-ray spectroscopy facility of ILL are shown. The population of a large number of excited states of 206Tl above the ground state up to the neutron binding energy (at 6.5 MeV), within a few units of spin is expected. The analysis involving double and triple γ-coincidences and γγ-angular correlations will allow to significantly extend the experimental information on the energy and spin-parity of the levels in 206Tl. This will help shedding light on the proton-hole and neutron-hole couplings near the doubly magic core 208Pb.

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Dari Bako, Nicolas, Maëlle Kerveno, Philippe Dessagne, Catalin Borcea, Marian Boromiza, Roberto Capote, François Claeys et al. "From ²³²Th(n, n’γ) cross sections to level production and total neutron inelastic scattering cross sections". EPJ Web of Conferences 284 (2023): 08005. http://dx.doi.org/10.1051/epjconf/202328408005.

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To probe the neutron inelastic scattering off 232Th, an experiment took place at the EC-JRC Geel conducted with the experimental setup GRAPhEME to detect emitted γ-rays. The prompt γ-ray spectroscopy method was used and 70 experimental 232Th(n, n’γ) cross sections were obtained from the experimental data. Combining these cross sections, nuclear-structure data available in databases and hypotheses to complete the latter, neutron inelastic level production cross sections in 232Th and the total inelastic cross section were calculated. For the first time, the total inelastic cross section of an actinide nucleus was derived on the total neutron energy range from experimental data only. Comparisons of (n, n’) cross section data with evaluated data reveal a good agreement between them all above 300 keV of neutron energy. TALYS calculations are compatible but lower than the evaluated data.

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Gupta, R., S. B. Pandey, A. J. Castro-Tirado, A. Kumar, A. Aryan e S. N. Tiwari. "OBSERVATIONAL PROPERTIES OF TEV DETECTED GRB 180720B, GRB 190114C AND GRB 190829A". Revista Mexicana de Astronomía y Astrofísica Serie de Conferencias 53 (1 settembre 2021): 113–23. http://dx.doi.org/10.22201/ia.14052059p.2021.53.23.

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TeV emissions from γ-ray bursts are very important to study their origin and the radiation mechanisms in detail. Recent observations of TeV photons in some of the GRBs are challenging to be explained by the traditional Synchrotron radiation mechanism. In this work, we present the results of a detailed investigation of the prompt and afterglow emissions of recently discovered TeV GRBs (GRB 180720B, GRB 190114C, and GRB 190829A) based on the publicly available prompt and afterglow data including 10.4m GTC and 1.3m DFOT telescopes observations of the first HESS and MAGIC bursts, respectively. Timeresolved spectroscopy of prompt emission of GRB 180720B and GRB 190114C shows an intensity tracking nature of peak energy. In the case of GRB 190829A, peak energy evolution shows a hard to soft tracking trend followed by a very soft and chaotic trend. GRB 190829A is a peculiar intermediate luminous two episodic burst with first emission episode outlier to Amati correlation. We analyzed the late time Fermi-LAT emission that encapsulates the H.E.S.S. and MAGIC observations. Some of the LAT photons are likely to be associated with these GRBs and they could have an Inverse Compton radiation mechanism.

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Kerveno, Maëlle, Marc Dupuis, Catalin Borcea, Marian Boromiza, Roberto Capote, Philippe Dessagne, Greg Henning et al. "What can we learn from (n,xnγ) cross sections about reaction mechanism and nuclear structure?" EPJ Web of Conferences 239 (2020): 01023. http://dx.doi.org/10.1051/epjconf/202023901023.

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Inelastic (n,n') cross section is a key quantity to accurately simulate reactor cores, and its precision was shown to need significant improvements. To bypass the experimental difficulties to detect neutrons from (n,xn) reaction and to discriminate inelastically scattered neutrons from those following the fission process in case of fissile targets, an indirect but yet powerful method is used: the prompt γ-ray spectroscopy. Along this line, our collaboration has developed the GRAPhEME setup, optimized for actinides, at the GELINA facility to measure partial (n,xn γ) cross sections, from which the total (n,xn) cross section can be inferred. (n,xn γ) experiments with actinides are still particularly challenging, as their structure presents a high level density at low energy, and the competing neutron-induced fission reaction contaminates the γ-energy distribution. New precise measurements of the partial (n,xn γ) cross sections provide a stringent test to theoretical model and offer a way to improve them. This is a path to a better determination of the total inelastic scattering cross sections. In this contribution we discuss modeling aspects of the 238U and 182W (n,n' γ) reactions, also measured with GRAPhEME, using the three codes TALYS, EMPIRE and CoH. We will highlight the needed/expected improvements on reaction modeling and nuclear structure input.

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Henning, Greg, Maëlle Kerveno, Philippe Dessagne, François Claeys, Nicolas Dari Bako, Marc Dupuis, Stéphane Hilaire et al. "On the need for precise nuclear structure data for high quality (n, n’γ) cross-section measurements". EPJ Web of Conferences 284 (2023): 01022. http://dx.doi.org/10.1051/epjconf/202328401022.

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The necessary improvement of evaluated nuclear data for nuclear applications development is possible through new and high-quality measurements, often combined with appropriate nuclear-reaction modelling. In particular, improving inelastic cross-section evaluations requires new and high-quality data. We measure (n, n’γ) cross-sections using prompt γ-ray spectroscopy and neutron energy determination by time-of-flight. To extract, from these partial data, the total inelastic cross-section, we rely on theoretical model as well as nuclear structure data such as γ ray emission probabilities. This structure information, tabulated in databases, comes with uncertainty. This directly affects the precision of our results, regardless of how good the measurement is. In this paper, we will present the issue of limited precision structure data and its impact on nuclear reaction data quality in the case of neutron inelastic scattering measurements. We will also discuss how to foresee and mitigate the issue.

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Luo, Y. X., J. H. Hamilton, J. O. Rasmussen, A. V. Ramayya, S. Frauendorf, E. Wang, J. K. Hwang et al. "Triaxial deformations in neutron-rich nuclei with Z = 41 – 46, A ~ 100 – 116 based on prompt fission γ spectroscopy". EPJ Web of Conferences 178 (2018): 02021. http://dx.doi.org/10.1051/epjconf/201817802021.

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Henning, Greg, Antoine Bacquias, Catalin Borcea, Mariam Boromiza, Roberto Capote, Philippe Dessagne, Jean-Claude Drohé et al. "MEASUREMENT OF 182,184,186W (N, N’ γ) CROSS SECTIONS AND WHAT WE CAN LEARN FROM IT". EPJ Web of Conferences 247 (2021): 09003. http://dx.doi.org/10.1051/epjconf/202124709003.

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Today’s development of nuclear installations rely on numerical simulation for which the main input are evaluated nuclear data. Inelastic neutron scattering (n, xn) is a reaction of importance because it modifies the neutron population, the neutron energy distribution and may create new isotopes. The study of this reaction on tungsten isotopes is interesting because it is a common structural material. Additionally, tungsten isotopes are a good testing field for theories. The IPHC group started an experimental program with the GRAPhEME setup installed at the neutron beam facility GELINA to measure (n, xn γ) reaction cross sections using prompt gamma spectroscopy and neutron energy determination by time-of-flight. The obtained experimental data provide constraints on nuclear reaction mechanisms models for 182,184,186W. Indeed, to reproduce correctly the experimental (n, n’ γ) cross-sections, the reaction codes must include accurate models of the reaction mechanism, nuclear de-excitation process and use correct nuclear structure information.

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Vedyagin, Aleksey A., Pavel E. Plyusnin, Roman M. Kenzhin, Vladimir O. Stoyanovskii, Andrey V. Zadesenets e Yury V. Shubin. "Partial Miscibility of Metals as a Key for Improved Properties". Materials Science Forum 998 (giugno 2020): 151–56. http://dx.doi.org/10.4028/www.scientific.net/msf.998.151.

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Platinum and iridium are known to belong to a family of partly miscible metals. On the other hand, these metals are high demanded as active components of the catalysts for a variety of industrially important processes. In the present work, a series of bimetallic Pt-Ir catalysts supported on alumina were prepared using a “single source precursor” concept. The ratio of metals in the alloy was varied from 1:3 to 3:1. The thermal stability and catalytic activity in CO oxidation of the samples were studied in a prompt thermal aging regime. Monometallic Pt/γ-Al2O3 and Ir/γ-Al2O3 samples were used as references. All the studied catalysts were characterized by UV-vis spectroscopy in initial state and after the aging treatment. It was found that the bimetallic nanoparticles being subjected to the high temperature aging at 600 and 800 °C undergo redistribution with further stabilization in a noticeably more active state. The observed increase in the catalytic activity is explained by an enrichment of the particles’ surface with platinum.

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Egorov, A. I., Yu E. Loginov e S. Eh Malyutenkova. "Measurement of absolute intensities of some prompt γ-lines from the 91Zr, 143Nd, 177Hf and 116,118–120,122,124Sn(n,γ) reactions and isomeric cross-sections of 123m,125mSn by in-beam γ-spectroscopy method". Applied Radiation and Isotopes 65, n. 11 (novembre 2007): 1290–92. http://dx.doi.org/10.1016/j.apradiso.2007.06.010.

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Germogli, Salvador, Bacci, Bagli, Bandiera, Camattari, Carturan et al. "Radioisotope Production through Accelerators in Crystalline Targets". Proceedings 26, n. 1 (5 settembre 2019): 51. http://dx.doi.org/10.3390/proceedings2019026051.

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The production techniques of radioisotopes for medical purposes is a valuable and important field in nuclear medicine. In particular, the expensive cost of the prime materials for the production via cyclotron obliges the search for new solutions to enhance the production rate with minor upgrades of the current instrumentation. Oriented ordered structure can modify particle trajectories inside a medium leading to a sensible variation of the interaction rate with atomic nuclei. Under specific orientations of the target with respect to the incident beam, the probability of inelastic interaction with nuclei can be enhanced with respect to the standard rate. This effect is called anti-channeling and leads to an increase of the radioisotope production yield. A dedicated set of experimental measurements were carried out at the CN accelerator of the INFN Legnaro Laboratories to investigate nuclear reactions under channeling experiments. In particular, the production of the Arsenic-74 radioisotope through a proton beam delivered to a natural single-crystal Germanium target was monitored via γ-spectroscopy of the prompt γ-rays upon de-excitation of produced nuclei, in order to quantify the production rate variation as a function of the incident angle.

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SKOULAKIS, A., G. C. ANDROULAKIS, E. L. CLARK, S. M. HASSAN, P. LEE, J. CHATZAKIS, M. BAKAREZOS et al. "A PORTABLE PULSED NEUTRON GENERATOR". International Journal of Modern Physics: Conference Series 27 (gennaio 2014): 1460127. http://dx.doi.org/10.1142/s2010194514601276.

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The design and construction of a pulsed plasma focus device to be used as a portable neutron source for material analysis such as explosive detection using gamma spectroscopy is presented. The device is capable of operating at a repetitive rate of a few Hz. When deuterium gas is used, up to 105 neutrons per shot are expected to be produced with a temporal pulse width of a few tens of nanoseconds. The pulsed operation of the device and its portable size are its main advantage in comparison with the existing continuous neutron sources. Parts of the device include the electrical charging unit, the capacitor bank, the spark switch (spark gap), the trigger unit and the vacuum–fuel chamber / anode–cathode. Numerical simulations are used for the simulation of the electrical characteristics of the device including the scaling of the capacitor bank energies with total current, the pinch current, and the scaling of neutron yields with energies and currents. The MCNPX code is used to simulate the moderation of the produced neutrons in a simplified geometry and subsequently, the interaction of thermal neutrons with a test target and the corresponding prompt γ-ray generation.

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Claeys, François, Philippe Dessagne, Maëlle Kerveno, Cyrille De Saint Jean, Catalin Borcea, Marian Boromiza, Roberto Capote et al. "Measurement of partial (n, n’γ) reaction cross-sections on highly radioactive nuclei of interest for energy production". EPJ Web of Conferences 284 (2023): 01014. http://dx.doi.org/10.1051/epjconf/202328401014.

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In the context of the development of Gen. IV nuclear reactors, the GIF (Generation IV. International Forum) has selected six innovative technologies. Among them, one can highlight the concept of breeding for 232Th/233U and 238U/239Pu fuel cycles. But those nuclei, crucial for such cycles, suffer from a lack of precise knowledge (nuclear structure, reaction cross sections). In particular, it has been demonstrated that neutron inelastic scattering reaction cross sections are not known with sufficient precision for the isotopes 238U and 239Pu, and not known at all experimentally for 233U. In order to perform simulations of innovative reactor cores for the development of those technologies, the knowledge of the reaction cross section has to be improved which implies that new measurements have to be done. The GRAPhEME (GeRmanium array for Actinides PrEcise MEasurements) experimental setup, developed by the IPHC laboratory from CNRS and installed at the EC-JRC-Geel GELINA facility is a powerful tool to answer this need [1, 2]. Combining the prompt γ-ray spectroscopy and the time-of-flight methods, it measures partial (n, xnγ) reaction cross sections. This paper reports on the improvements made on the GRAPhEME setup and data analysis methodology to tackle the challenge of (n, xnγ) cross section measurements on high activity actinides. Results obtained so far on 233U are presented compared to TALYS calculations.

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Schiavone, Maria-Maddalena, David Hermann Lamparelli, Yue Zhao, Fengfeng Zhu, Zsolt Revay e Aurel Radulescu. "The Effects of Temperature and Humidity on the Microstructure of Sulfonated Syndiotactic–polystyrene Ionic Membranes". Membranes 10, n. 8 (14 agosto 2020): 187. http://dx.doi.org/10.3390/membranes10080187.

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Polymeric membranes based on the semi-crystalline syndiotactic–polystyrene (sPS) become hydrophilic, and therefore conductive, following the functionalization of the amorphous phase by the solid-state sulfonation procedure. Because the crystallinity of the material, and thus the mechanical strength of the membranes, is maintained and the resistance to oxidation decomposition can be improved by doping the membranes with fullerenes, the sPS becomes attractive for proton-exchange membranes fuel cells (PEMFC) and energy storage applications. In the current work we report the micro-structural characterization by small-angle neutron scattering (SANS) method of sulfonated sPS films and sPS–fullerene composite membranes at different temperatures between 20 °C and 80 °C, under the relative humidity (RH) level from 10% to 70%. Complementary characterization of membranes was carried out by FTIR, UV-Vis spectroscopy and prompt–γ neutron activation analysis in terms of composition, following the specific preparation and functionalization procedure, and by XRD with respect to crystallinity. The hydrated ionic clusters are formed in the hydrated membrane and shrink slightly with the increasing temperature, which leads to a slight desorption of water at high temperatures. However, it seems that the conductive properties of the membranes do not deteriorate with the increasing temperature and that all membranes equilibrated in liquid water show an increased conductivity at 80 °C compared to the room temperature. The presence of fullerenes in the composite membrane induces a tremendous increase in the conductivity at high temperatures compared to fullerenes-free membranes. Apparently, the observed effects may be related to the formation of additional hydrated pathways in the composite membrane in conjunction with changes in the dynamics of water and polymer.

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Michelagnoli, Caterina, Aurelien Blanc, Emilio Ruiz-Martinez, Abdelaziz Chebboubi, Herbert Faust, Emmanuel Froidefond, Gregoire Kessedjian et al. "FIPPS (FIssion Product Prompt γ-ray Spectrometer) and its first experimental campaign". EPJ Web of Conferences 193 (2018): 04009. http://dx.doi.org/10.1051/epjconf/201819304009.

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FIPPS is the new nuclear physics instrument of ILL for the spectroscopy of nuclei produced in neutron-induced reactions. The performance of the first implementation of the setup will be shown, together with an overview of the first experimental campaign (December 2016-March 2017). Future perspectives and physics opportunities will then be discussed.

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Mauerhofer, Eric, Zeljko Ilic, Christian Stieghorst, Zsolt Révay, Matthias Rossbach, Jingjing Li, Tsitohaina H. Randriamalala e Thomas Brückel. "Prompt and delayed gamma rays induced by epithermal and fast neutrons with indium". Journal of Radioanalytical and Nuclear Chemistry 331, n. 1 (2 dicembre 2021): 535–46. http://dx.doi.org/10.1007/s10967-021-08102-2.

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AbstractThe emission of prompt and delayed gamma rays from (n,γ) and (n,n´γ) reactions induced by irradiation of indium with epithermal and fast neutrons was investigated with the instrument FaNGaS operated at Heinz-Maier-Leibnitz Zentrum (MLZ) in Garching. The average neutron energy of the neutron spectrum was 2.30 MeV. The measurement was done at an angle of 90° between neutron beam and detector. A total of 136 prompt gamma lines from which 42 are related to the capture of epithermal and fast neutrons and 94 to the inelastic scattering of fast neutrons were detected together with the delayed gamma lines of the activation products 113mIn, 114m2In, 115mIn, 116m2In and 116mIn. Intensities and neutron spectrum averaged isotopic partial cross section of the gamma lines are presented. Additionally the neutron spectrum averaged cross sections of the reactions, 113In(n,n´)113mIn, 113In(n,γ)114m2In, 115In(n,n´)15mIn, 115In(n, γ)116m2In and 115In(n, γ)116mIn were determined from the corresponding delayed gamma rays of the formed isotopes as 143 ± 22, 288 ± 13 194 ± 18, 201 ± 10 and 508 ± 24 mb respectively. The various results obtained were found consistent with the literature data. However, our measurement indicate the need to reevaluate the cross section of the 115In(n,γ)116m2In reaction for thermal neutrons.

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Ohde, S., K. Tanaka, A. Snidvongs e H. Matsue. "Boron in coral skeletons determined by prompt γ-ray analysis". Journal of Radioanalytical and Nuclear Chemistry 289, n. 2 (28 aprile 2011): 401–6. http://dx.doi.org/10.1007/s10967-011-1102-2.

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Anderson, D. L., e E. A. Mackey. "Neutron scattering-induced background enhancement in prompt γ-ray activation analysis". Journal of Radioanalytical and Nuclear Chemistry Articles 167, n. 1 (gennaio 1993): 145–51. http://dx.doi.org/10.1007/bf02035474.

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Anderson, D. L., W. C. Cunningham e G. H. Alvarez. "Multielement analysis of foods by neutron capture prompt γ-ray activation analysis". Journal of Radioanalytical and Nuclear Chemistry Articles 167, n. 1 (gennaio 1993): 139–44. http://dx.doi.org/10.1007/bf02035473.

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Sudarshan, K., R. Tripathi, A. G. C. Nair, R. Acharya, A. V. R. Reddy e A. Goswami. "Analysis of reference materials by prompt γ-ray neutron activation analysis and evaluation of sample-dependent background". Analytica Chimica Acta 535, n. 1-2 (aprile 2005): 309–15. http://dx.doi.org/10.1016/j.aca.2004.11.056.

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Sun, G. M., C. S. Park e H. D. Choi. "Determination of the prompt k0,H factors and partial γ-ray production cross sections for B, N, Si, P, S and Cl". Journal of Radioanalytical and Nuclear Chemistry 264, n. 3 (maggio 2005): 603–16. http://dx.doi.org/10.1007/s10967-005-0760-3.

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31

Yentekakis, Ioannis V., Philippe Vernoux, Grammatiki Goula e Angel Caravaca. "Electropositive Promotion by Alkalis or Alkaline Earths of Pt-Group Metals in Emissions Control Catalysis: A Status Report". Catalysts 9, n. 2 (5 febbraio 2019): 157. http://dx.doi.org/10.3390/catal9020157.

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Recent studies have shown that the catalytic performance (activity and/or selectivity) of Pt-group metal (PGM) catalysts for the CO and hydrocarbons oxidation as well as for the (CO, HCs or H2)-SCR of NOx or N2O can be remarkably affected through surface-induced promotion by successful application of electropositive promoters, such as alkalis or alkaline earths. Two promotion methodologies were implemented for these studies: the Electrochemical Promotion of Catalysis (EPOC) and the Conventional Catalysts Promotion (CCP). Both methodologies were in general found to achieve similar results. Turnover rate enhancements by up to two orders of magnitude were typically achievable for the reduction of NOx by hydrocarbons or CO, in the presence or absence of oxygen. Subsequent improvements (ca. 30–60 additional percentage units) in selectivity towards N2 were also observed. Electropositively promoted PGMs were also found to be significantly more active for CO and hydrocarbons oxidations, either when these reactions occur simultaneously with deNOx reactions or not. The aforementioned direct (via surface) promotion was also found to act synergistically with support-mediated promotion (structural promotion); the latter is typically implemented in TWCs through the complex (Ce–La–Zr)-modified γ-Al2O3 washcoats used. These attractive findings prompt to the development of novel catalyst formulations for a more efficient and cost-effective control of the emissions of automotives and stationary combustion processes. In this report the literature findings in the relevant area are summarized, classified and discussed. The mechanism and the mode of action of the electropositive promoters are consistently interpreted with all the observed promoting phenomena, by means of indirect (kinetics) and direct (spectroscopic) evidences.

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Tang, Nicolas, Marta Bueno, Sylvain Meylan, Yann Perrot, Hoang N. Tran, Amélie Freneau, Morgane Dos Santos et al. "Assessment of Radio-Induced Damage in Endothelial Cells Irradiated with 40 kVp, 220 kVp, and 4 MV X-rays by Means of Micro and Nanodosimetric Calculations". International Journal of Molecular Sciences 20, n. 24 (9 dicembre 2019): 6204. http://dx.doi.org/10.3390/ijms20246204.

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The objective of this work was to study the differences in terms of early biological effects that might exist between different X-rays energies by using a mechanistic approach. To this end, radiobiological experiments exposing cell monolayers to three X-ray energies were performed in order to assess the yields of early DNA damage, in particular of double-strand breaks (DSBs). The simulation of these irradiations was set in order to understand the differences in the obtained experimental results. Hence, simulated results in terms of microdosimetric spectra and early DSB induction were analyzed and compared to the experimental data. Human umbilical vein endothelial cells (HUVECs) were irradiated with 40, 220 kVp, and 4 MV X-rays. The Geant4 Monte Carlo simulation toolkit and its extension Geant4-DNA were used for the simulations. Microdosimetric calculations aiming to determine possible differences in the variability of the energy absorbed by the irradiated cell population for those photon spectra were performed on 10,000 endothelial cell nuclei representing a cell monolayer. Nanodosimetric simulations were also carried out using a computation chain that allowed the simulation of physical, physico-chemical, and chemical stages on a single realistic endothelial cell nucleus model including both heterochromatin and euchromatin. DNA damage was scored in terms of yields of prompt DSBs per Gray (Gy) and per giga (109) base pair (Gbp) and DSB complexity was derived in order to be compared to experimental data expressed as numbers of histone variant H2AX (γ-H2AX) foci per cell. The calculated microdosimetric spread in the irradiated cell population was similar when comparing between 40 and 220 kVp X-rays and higher when comparing with 4 MV X-rays. Simulated yields of induced DSB/Gy/Gbp were found to be equivalent to those for 40 and 220 kVp but larger than those for 4 MV, resulting in a relative biological effectiveness (RBE) of 1.3. Additionally, DSB complexity was similar between the considered photon spectra. Simulated results were in good agreement with experimental data obtained by IRSN (Institut de radioprotection et de sûreté nucléaire) radiobiologists. Despite differences in photon energy, few differences were observed when comparing between 40 and 220 kVp X-rays in microdosimetric and nanodosimetric calculations. Nevertheless, variations were observed when comparing between 40/220 kVp and 4 MV X-rays. Thanks to the simulation results, these variations were able to be explained by the differences in the production of secondary electrons with energies below 10 keV.

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33

Biswas, S., A. Lemasson, M. Rejmund, A. Navin, Y. H. Kim, C. Michelagnoli, I. Stefan et al. "Prompt-delayed γ -ray spectroscopy of neutron-rich In119,121 isotopes". Physical Review C 102, n. 1 (29 luglio 2020). http://dx.doi.org/10.1103/physrevc.102.014326.

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Kim, Y. H., A. Lemasson, M. Rejmund, A. Navin, S. Biswas, C. Michelagnoli, I. Stefan et al. "Prompt-delayed $\gamma$ γ -ray spectroscopy with AGATA, EXOGAM and VAMOS++". European Physical Journal A 53, n. 8 (agosto 2017). http://dx.doi.org/10.1140/epja/i2017-12353-y.

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35

Gerst, R. B., A. Blazhev, N. Warr, J. N. Wilson, M. Lebois, N. Jovančević, D. Thisse et al. "Prompt and delayed γ spectroscopy of neutron-rich Kr94 and observation of a new isomer". Physical Review C 102, n. 6 (24 dicembre 2020). http://dx.doi.org/10.1103/physrevc.102.064323.

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36

Bikchurina, Marina, Timofey Bykov, Ibrahim Ibrahim, Anna Kasatova, Dmitrii Kasatov, Iaroslav Kolesnikov, Victoria Konovalova et al. "Dosimetry for boron neutron capture therapy developed and verified at the accelerator based neutron source VITA". Frontiers in Nuclear Engineering 2 (3 ottobre 2023). http://dx.doi.org/10.3389/fnuen.2023.1266562.

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The method of boron neutron capture therapy for malignant tumors, proposed in 1936, is beginning to enter clinical practice. The development of dosimetry tools for characterization of therapeutic mixed neutron-photon beam and assessing the patient’s response to treatment is becoming relevant. In this work, a number of dosimetric techniques have been developed: a compact neutron detector with a pair of cast scintillators, one of which is enriched with boron, to measure the boron dose and the γ-ray dose; cell dosimeter for measuring the sum of the equivalent dose of fast neutrons and the equivalent nitrogen dose; prompt γ-ray spectroscopy for in situ measurement of boron dose in real time; epithermal neutron flux monitor for measuring the epithermal neutron flux. Their verification carried out on the accelerator based neutron source VITA showed that they can become convenient and reliable tools for characterization of neutron beam and assessing the patient’s response to treatment.

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Liu, H. N., F. Flavigny, H. Baba, M. Boehmer, U. Bonnes, V. Borshchov, P. Doornenbal et al. "STRASSE: a silicon tracker for quasi-free scattering measurements at the RIBF". European Physical Journal A 59, n. 6 (1 giugno 2023). http://dx.doi.org/10.1140/epja/s10050-023-01018-3.

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AbstractSilicon Tracker for RAdioactive nuclei Studies at SAMURAI Experiments is a new detection system under construction for quasi-free scattering (QFS) measurements at 200–250 MeV/nucleon at the RIBF facility of the RIKEN Nishina Center. It consists of a charged-particle silicon tracker coupled with a dedicated thick liquid hydrogen target (up to 150-mm long) in a compact geometry to fit inside large scintillator or germanium arrays. Its design was optimized for two types of studies using QFS: missing-mass measurements and in-flight prompt $$\gamma $$ γ -ray spectroscopy. This article describes (i) the resolution requirements needed to go beyond the sensitivity of existing systems for these two types of measurements, (ii) the conceptual design of the system using detailed simulations of the setup and (iii) its complete technical implementation and challenges. The final tracker aims at a sub-mm reaction vertex resolution and is expected to reach a missing-mass resolution below 2 MeV in $$\sigma $$ σ for (p, 2p) reactions when combined with the CsI(Na) CATANA array.

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38

Lu, Wenbin, e Eliot Quataert. "Late-time accretion in neutron star mergers: Implications for short gamma-ray bursts and kilonovae". Monthly Notices of the Royal Astronomical Society, 4 maggio 2023. http://dx.doi.org/10.1093/mnras/stad1336.

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Abstract We study the long-term ($t\gg 10\rm \, s$) evolution of the accretion disk after a neutron star(NS)-NS or NS-black hole merger, taking into account the radioactive heating by r-process nuclei formed in the first few seconds. We find that the cumulative heating eventually exceeds the disk’s binding energy at t ∼ 102 s (α/0.1)−1.8(M/2.6 M⊙)1.8 after the merger, where α is the viscosity parameter and M is the mass of the remnant object. This causes the disk to evaporate rapidly and the jet power to shut off. We propose that this corresponds to the steep flux decline at the end of the extended emission (EE) or X-ray plateau seen in many short γ-ray bursts (GRBs). The shallow flux evolution before the steep decline is consistent with a plausible scenario where the jet power scales linearly with the disk mass. We suggest that the jets from NS mergers have two components – a short-duration narrow one producing the prompt γ-rays and a long-lasting wide component producing the EE. This leads to a prediction that ‘orphan EE’ (without short GRB) may be a promising electromagnetic counterpart for NS mergers observable by future wide-field X-ray surveys. The long-lived disk produces a slow ejecta component that can efficiently thermalize the β-electrons’ energy up to $t\sim 100\rm \, d$ and contributes $\sim \!10~{{\ \rm per\ cent}}$ of the kilonova’s bolometric luminosity at these late epochs. We predict that future ground-based and JWST near-IR spectroscopy of nearby ($\lesssim 100\rm \, Mpc$) NS mergers will detect narrow (Δv ∼ 0.01c) line features a few weeks after the merger.

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Pereira-López, X., M. A. Bentley, R. Wadsworth, P. Ruotsalainen, S. M. Lenzi, U. Forsberg, K. Auranen et al. "In-beam $$\gamma $$-ray spectroscopy of $$^{94}$$Ag". European Physical Journal A 59, n. 3 (15 marzo 2023). http://dx.doi.org/10.1140/epja/s10050-023-00950-8.

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AbstractA recoil-beta-tagging experiment has been performed to study the excited $$T=0$$ T = 0 and $$T=1$$ T = 1 states in the odd–odd $$N=Z$$ N = Z nucleus $$^{94}$$ 94 Ag, populated via the $$^{40}$$ 40 Ca($$^{58}$$ 58 Ni,1p3n)$$^{94}$$ 94 Ag reaction. The experiment was conducted using the MARA recoil separator and JUROGAM3 array at the Accelerator Laboratory of the University of Jyväskylä. Through correlating fast, high-energy beta decays at the MARA focal plane with prompt $$\gamma $$ γ rays emitted at the reaction target, a number of transitions between excited states in $$^{94}$$ 94 Ag have been identified. The timing characteristics of these transitions confirm that they fall within decay sequences that feed the short-lived $$T=1$$ T = 1 ground state of $$^{94}$$ 94 Ag. The transitions are proposed to proceed within and between the sets of states with $$T=0$$ T = 0 and $$T=1$$ T = 1 . Possible correspondence between some of these transitions from analog states in $$^{94}$$ 94 Pd has been discussed, and shell-model calculations including multipole and monopole electromagnetic effects have been presented, in order to enable predictions of the decay patterns between the $$T=0$$ T = 0 and $$T=1$$ T = 1 states and to allow a theoretical set of Coulomb energy differences to be calculated for the $$A = 94$$ A = 94 $$T=1$$ T = 1 analog states.

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40

Kinoshita, Norikazu, Takuma Noto, Hitoshi Nakashima, Kazuaki Kosako, Takahiro Kato, Yoichi Kuroiwa, Misako Kurabe et al. "Water contents in aggregates and cement pastes determined by gravimetric analysis and prompt γ-ray analysis". Journal of Radioanalytical and Nuclear Chemistry, 14 gennaio 2023. http://dx.doi.org/10.1007/s10967-023-08776-w.

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