HAL-IN2P3
Not a member yet
78719 research outputs found
Sort by
Shape evolution in neutron-rich odd-even Nb isotopes
No full textInternational audienceNeutron-rich nuclei around exhibit multiple shape transitions. This region shows one of the sharpest transitions in the nuclear chart, from a spherical vibrator at to a strongly deformed prolate shape at , with largest deformations seen for Sr and Zr. Below , a spherical-to-oblate transition is predicted, while above and , the shape evolves from axial to triaxial. Even- nuclei have been well studied, but odd- isotopes such as Nb offer additional insights into these mechanisms. The Nb isotopes lie at the boundary between axially deformed Zr and triaxially deformed Mo nuclei. This work explores the structure of neutron-rich Nb nuclei up to , aiming to understand shape evolution with isospin and the onset of triaxiality. Two complementary fission experiments were used: (i) U+Be at GANIL in inverse kinematics with AGATA, EXOGAM, and VAMOS++, allowing prompt and delayed -ray spectroscopy with isotopic identification; (ii) spontaneous fission of Cf with the Gammasphere array providing high-fold -coincidence data. The level scheme of Nb was significantly extended with two new negative-parity bands. A revised scheme is proposed for Nb, differing from previous results, and new structures are reported in Nb. The signature splitting analysis indicates triaxial deformation for positive-parity bands, while negative-parity bands show axial symmetry, similar to Zr. This reveals a shape coexistence in neutron-rich Nb nuclei
Fast switching of various ions from 11 to 23 MeV/u for space applications at GANIL
No full textInternational audienceIn recent years, the demand for radiation hardness testing of electronic components for space applications has grown significantly across Europe. In response, the Grand Accélérateur National d’Ions Lourds (GANIL) is developing a dedicated test beamline downstream of the Cyclotron for Ions of Medium Energy (CIME), optimized for delivering fast-switchable heavy-ion cocktail beams suitable for irradiation in both air and vacuum environments. These beams include ions ranging from carbon to xenon, covering energies from 11 to 23 MeV/u. They span Linear Energy Transfers (LET) at the surface up to 50 MeV mg−1 cm2, with ranges in silicon up to 530 μm. The intensities of the various beams produced from the Electron Cyclotron Resonance (ECR) ion source can be adjusted from 102 to 105 particles⋅s−1⋅cm−2, ensuring uniform irradiation over a 6 cm2 area. Thanks to mass-to-charge (m/q) selection of the cyclotron and fast magnetic tuning, about ten ion species can be delivered successively in a single session, with switching times under 10 min. These capabilities enhance European heavy-ion Single Event Effect (SEE) testing capacity and complement other cyclotron-based infrastructures
Exploring the science of radon adsorption: Materials, methodologies, and emerging directions
No full textInternational audienceRadon, a radioactive noble gas, poses significant health risks due to its link to lung cancer and presents a major challenge in low-background physics experiments, where its decay products contribute to background noise. Developing efficient adsorbent materials for radon mitigation is therefore crucial for both environmental safety and scientific research. However, designing effective radon adsorbents remains challenging due to the low concentration of the gas, its inert nature, and associated health risks. This review provides a comprehensive analysis of radon adsorption on porous materials, with a focus on experimental methodologies, structure-property relationships, and emerging trends in material design. We highlight key material classes, including activated carbons, zeolites, metal-organic frameworks, and other carbon-based adsorbents, evaluating their adsorption performance and practical considerations. Additionally, we explore future directions in radon adsorbent development, discuss improved experimental approaches, and examine insights from xenon adsorption studies as a predictive tool for radon capture. By consolidating current knowledge and identifying critical gaps, this review aims to guide the design of next-generation materials for efficient radon mitigation in environmental, industrial, and scientific applications
Effect of local environment on Ly line profile in DESI/ODIN LAEs
No full textInternational audienceLyman-Alpha Emitters (LAEs) are star-forming galaxies with significant Ly emission and are often used as tracers of large-scale structure at high redshift. We explore the relationship between the Ly line profile and environmental density with spectroscopy from the Dark Energy Spectroscopic Instrument (DESI) of LAEs selected with narrow-band photometry through the One-hundred-deg DECam Imaging in Narrowbands (ODIN) survey. We use LAE surface density maps in the N419 (z 2.45) and N501 (z 3.12) narrow bands to probe the relationship between local environmental density and the Ly line profile. In both narrow bands, we stack the LAE spectra in bins of environmental density and inside and outside of protocluster regions. The N501 data shows 15% higher Ly line luminosity for galaxies in protoclusters, suggesting increased star formation in these regions. However, the line luminosity is not appreciably greater in protocluster galaxies in the N419 band, suggesting a potential redshift evolution of this effect. The shape of the line profile itself does not vary with environmental density, suggesting that line shape changes are caused by local effects independent of a galaxy's environment. These data indicate a potential relationship between LAE local environmental density, ionized gas distribution, and Ly line luminosity
photoD with Rubin's Data Preview 1: first stellar photometric distances and deficit of faint blue stars. Stellar distances with Rubin's DP1
No full textInternational audienceAims: We investigate the utility of Rubin's Data Preview 1 for estimating stellar number density profile in the Milky Way halo. Methods: Stellar broad-band near-UV to near-IR photometry released in Rubin's Data Preview 1 is used to estimate distance and metallicity for blue main sequence stars brighter than in three 1.1. sq.~deg. fields at southern Galactic latitudes. Results: Compared to TRILEGAL simulations of the Galaxy's stellar content by (Dal Tio, 2022), we find a significant deficit of blue main sequence turn-off stars with . We interpret this discrepancy as a signature of a much steeper halo number density profile at galactocentric distances kpc than the cannonical profile assumed in TRILEGAL simulations. Conclusions: This interpretation is consistent with earlier suggestions based on observations of more luminous, but much less numerous, evolved stellar populations, and a few pencil beam surveys of blue main sequence stars in the northern sky. These results bode well for the future Galactic halo exploration with Rubin's Legacy Survey of Space and Time
Art, deuil et culture : les nouveaux territoires de la cognition chez les primates
No full textInternational audienceFor centuries, the question of human uniqueness has fueled scientific and philosophical debates. Humans have often been portrayed as singular beings endowed with abstract abilities such as tool use ( Homo habilis ), economic reasoning and theory of mind ( Homo economicus ), aesthetic sensibility ( Homo aestheticus ), or awareness of death and spirituality ( Homo deus ). However, advances in ethology and evolutionary anthropology have uncovered in non-human species behaviors once thought to be exclusively human. This paper explores three of these domains − culture, mourning, and art − through a comparative approach across human and non-human primates. By examining mechanisms of social transmission, behavioral expressions related to death, and graphic productions such as drawing, we discuss cognitive continuities between species, methodological challenges (notably anthropomorphism), and the broader implications for redefining the boundary between nature and culture. Our findings suggest that rather than representing absolute distinctions, these capacities reveal shared evolutionary roots of cognition, emotion, and creativity across the primate lineage.Depuis des siècles, la question de l’unicité humaine alimente les débats scientifiques et philosophiques. L’Homme s’est souvent défini comme un être à part, doté de capacités abstraites telles que l’usage d’outils ( Homo habilis ), la pensée économique et la théorie de l’esprit ( Homo economicus ), la sensibilité esthétique ( Homo aestheticus ) ou la conscience de la mort et la spiritualité ( Homo deus ). Pourtant, les avancées en éthologie et en anthropologie évolutive ont révélé chez d’autres espèces des comportements jadis considérés comme spécifiquement humains. Cet article explore trois de ces domaines – la culture, le deuil et l’art – à travers une approche comparative entre primates humains et non humains. En analysant les mécanismes de transmission sociale, les manifestations comportementales liées à la mort, et les productions graphiques observées chez les grands singes, nous discutons des continuités cognitives entre espèces, des biais méthodologiques (notamment l’anthropomorphisme) et des implications pour la redéfinition de la frontière entre nature et culture
Probing millisecond magnetar formation in binary neutron star mergers through X-ray follow-up of gravitational wave alerts
No full textInternational audienceThe nature of the remnant of a binary neutron star (BNS) merger is uncertain. Though certainly a black hole (BH) in the cases of the most massive BNSs, X-ray lightcurves from gamma-ray burst (GRB) afterglows suggest a neutron star (NS) as a viable candidate for both the merger remnant as well as the central engine of these transients. When jointly observed with gravitational waves (GWs), X-ray lightcurves from BNS merger events could provide critical constraints on the remnant's nature. We aim to assess the current and future capabilities to detect a NS remnant through X-ray observations following GW detections. To this end, we simulate GW signals from BNS mergers and the subsequent X-ray emission from newborn millisecond magnetars. The GW detectability is modeled for both current and next-generation interferometers, while the X-ray emission is reproduced using a dedicated numerical code that models magnetar spin-down and ejecta dynamics informed by numerical-relativity simulations. In our simulations, 2% - 16% of BNS mergers form millisecond magnetars. Among these, up to 70% could be detectable, amounting to up to 1 millisecond magnetar detection per year with SVOM/MXT-like instruments during the LIGO Virgo KAGRA LIGO India (LVKI) O5 run, with optimal detectability occurring about 2 hours post-merger. For next-generation GW interferometers, this rate could increase by up to three orders of magnitude, with peak detectability 3 to 4 hours post-merger. We also explore how the magnetar's magnetic field strength and observer viewing angle affect detectability and discuss optimized observational strategies. Although more likely with upcoming GW interferometers, detecting the spin-down emission of a millisecond magnetar may already be within reach, warranting sustained theoretical and observational efforts given the profound implications for mergers, GRBs, and NS physics of a single detection
Marked statistics across the cosmic web: Environmental dependent clustering in modified gravity simulations
No full textInternational audienceWe study environment-dependent clustering using the marked correlation function applied to Hu-Sawicki modified gravity simulations. This gravity theory enriches the structure formation by enhancing gravity in a scale-dependent form. By employing a multi-scale cosmic structure finder algorithm, we define the cosmic environments divided in: nodes, filaments, walls and voids. We find a stronger impact of modified gravity in nodes and filament, which together dominate the information content by more than a factor of four relative to other environments. Combining environmental information further enhances the expected signal-to-noise ratio for CMASS- and DESI-like mock samples, particularly in configurations including filaments. Overall, marked correlation functions that incorporate environmental structure increase the information content by about a factor of two compared to standard density-based marks applied to the full galaxy sample. These results demonstrate the importance of environmental information, especially from filaments, in improving the constraining power of galaxy clustering tests of modified gravity
Element sorption on thiolate-functionalized Au-coated Si detectors in isothermal online gas-phase experiments
No full textInternational audience•Atom-at-a-time chemistry using products of nuclear reactions.•Self-assembly of 1-(11-mercaptoundecyl)imidazole and 12-mercaptododecanoic acid.•Radionuclide sorption on thiolate-functionalized gold-coated silicon detectors.•New simple recoil transfer chamber to study the chemistry of the produced elements. Developing a novel detector setup for the rapid superheavy element detection in the gas phase has been a current research topic for many scientists. The findings of our previous work showed that 1-(11-mercaptoundecyl)imidazole and 12-mercaptododecanoic acid self-assembled monolayers on Au-coated Si and glass chips are stable and effective materials for the Ir(IV) adsorption from HCl solutions [1]. As the next step, this paper reports the first attempt to sorb 152,153Er, 199-201At, and 173-176Ir radionuclides on thiolate-functionalized Au-coated Si detectors during online cyclotron-based experiments performed at the Cyclotron Institute at Texas A&M University using the AGGIE (Albert Ghiorso’s Gas-filled Ion Equipment) separator. A simple recoil transfer chamber equipped with four consecutive alpha-detectors was designed and used to thermalize nuclear reaction products and study their chemical behavior. The surfaces of three out of four detectors were Au-coated, two of which were functionalized with different thiol molecules. The design of the detector chamber allowed for an easy change of the detectors’ order. The detector position and the surface material were found to influence the sorption of the studied nuclides within the isothermal detector setup. The detector resolution stayed in the same order after the gold coating and the detector usage in online experiments
Searching for Cosmological Collider in the Planck CMB Data II: collider templates and Modal analysis
No full textInternational audienceSignatures of massive particles during inflation are highly informative targets for cosmological experiments. With recent progress on both theoretical and observational frontiers, we have reached the point where these novel signals of primordial non-Gaussianities (PNG) can be systematically tested with increasingly precise data. In this paper, we present the results of improved CMB data analysis for cosmological collider signals using Planck CMB data. To set the stage, we first construct a set of simplified but characteristic collider templates which are accurate over a broad range of particle masses, spins and sound speeds. In order to break degeneracies with single-field PNG, we propose an orthogonalization scheme such that the collider templates are uncorrelated with the highly constrained equilateral and orthogonal shapes. On this basis, we deploy the Modal bispectrum estimator for the Planck analysis and perform a systematic scan of parameters to search for the most significant collider signal. The maximum signal-to-noise ratio is found to be for massive spin-0 exchange after taking into account the look-elsewhere effect. In addition, we cross-validate the Modal analysis with the CMB-BEST pipeline, which demonstrates the consistency of results across the benchmark examples of collider templates. Given the low signal-to-noise ratio regime we find at the current stage of PNG observations, we believe the orthogonalization procedure provides an optimized strategy for future tests of the cosmological collider with the ability to rule out single field inflation