Manufacturing and characterization of Gd targets for the production of terbium radionuclides for nuclear medicine

International audienceThis study explores gadolinium (Gd) target production for nuclear medicine, focusing on Gd targets for producing terbium-155 (Tb-155), which is used in SPECT imaging. Thin targets are required for cross-section measurements, while thicker targets are needed for large-scale production. The molecular plating (MP) technique was applied to create thin targets on titanium (Ti) substrates, with characterization performed using SEM, ICP-OES, and other analyses. This research aims to explore how different parameters affect the MP process, with initial results proving highly promising

Production of doubly charmed hadron Ξcc++\Xi_{cc}^{++} and Tcc+T_{cc}^+ in relativistic heavy ion collisions

International audienceHeavy ion collisions provide a unique opportunity for studying the properties of exotic hadrons with two charm quarks. The production of $T_{cc}^+$ is significantly enhanced in nuclear collisions compared to proton-proton collisions due to the creation of multiple charm pairs. In this study, we employ the Langevin equation in combination with the Instantaneous Coalescence Model (LICM) to investigate the production of $T_{cc}^+$ and $\Xi_{cc}^{++}$ which consists of two charm quarks. We consider $T_{cc}^+$ as molecular states composed of $D$ and $D^*$ mesons. The Langevin equation is used to calculate the energy loss of charm quarks and $D$ mesons in the hot medium. The hadronization process, where charm quarks transform into each $D$ state as constituents of $T_{cc}^+$ production, is described using the coalescence model. The coalescence probability between $D$ and $D^*$ is determined by the Wigner function, which encodes the information of the $T_{cc}^+$ wave function. Our results show that the $T_{cc}^+$ production varies by approximately one order of magnitude when different widths in the Wigner function, representing distinct binding energies of $T_{cc}^+$, are considered. This variation offers valuable insights into the nature of $T_{cc}^+$ through the analysis of its wave function. The $\Xi_{cc}^{++}$ is treated as a hadronic state produced at the hadronization of the deconfined matter. Its production is also calculated as a comparison with the molecular state $T_{cc}^+$

First measurements with a new β\beta-electron detector for spectral shape studies

International audienceThe shape of the spectrum corresponding to the electrons emitted in $\beta$ decay carries a wealth of information about nuclear structure and fundamental physics. In spite of that, few dedicated measurements have been made of $\beta$-spectrum shapes. In this work we present a newly developed detector for $\beta$ electrons based on a telescope concept. A thick plastic scintillator is employed in coincidence with a thin silicon detector. First measurements employing this detector have been carried out with mono-energetic electrons from the high-energy resolution electron-beam spectrometer at Bordeaux. Here we report on the good reproduction of the experimental spectra of mono-energetic electrons using Monte Carlo simulations. This is a crucial step for future experiments, where a detailed Monte Carlo characterization of the detector is needed to determine the shape of the $\beta$-electron spectra by deconvolution of the measured spectra with the response function of the detector. A chamber to contain two telescope assemblies has been designed for future $\beta$-decay experiments at the Ion Guide Isotope Separator On-Line facility in Jyväskylä, aimed at improving our understanding of reactor antineutrino spectra

From Nuclear Waste to Hydrogen Production: From Past Consequences to Future Prospect

International audienceNuclear wastes may not be considered as unusable materials in the sense that they deliver a free source of energyunder the form of ionizing radiations that can be used to produce hydrogen (H2) through water radiolysis. Thecurrent paradigm that define these nuclear wastes as troublesome by-products which no one uses nowadays mustbe shifted into a new opportunity for pure H2 production with no CO2 emission. Here, we propose a low-techmethod to boost H2 production by water radiolysis thanks to the catalytic effect of a suspension of TiO2 nano-particles. We also demonstrate the relevance of this concept by scaling up our laboratory results. From ourcalculations, this radiocatalytic process can supply until 60% of the actual global demand in hydrogen (42.9MtH2.y-1) and open the door, together with the green and white hydrogen productions, to the “Hydrogencentury

Microbially formed Mn(IV) oxide as a novel adsorbent for removal of Radium

International audienceRadioactivity of Ra isotopes in natural waters is of serious concern. Control of 226Ra concentrations in tailings ponds, which store waste from U ore extraction processes, is an important issue in mill tailings management. In this study, we tested microbially formed Mn(IV) oxide as an adsorbent for removal of Ra in water treatment. Biogenic Mn(IV) oxide (BMO) was prepared using a Mn(II)-oxidizing fungus, Coprinopsis urticicola strain Mn-2. First, adsorption experiments of Sr and Ba, as surrogates for Ra, onto BMO were conducted in aqueous NaCl solution at pH 7. Distribution coefficients for Ba and Sr were estimated to be ∼106.5 and ∼104.3 mL/g, respectively. EXAFS analysis indicated that both Sr and Ba adsorbed in inner-sphere complexes on BMO, suggesting that Ra would adsorb in a similar way. From these findings, we expected that BMO would work effectively in removal of Ra from water. Then, BMO was applied to remove Ra from mine water collected from a U mill tailings pond. Just 7.6 mg of BMO removed >98% of the 226Ra from 3 L of mine water, corresponding to a distribution coefficient of 107.4 mL/g for Ra at pH ∼7. The obtained value was convincingly high for practical application of BMO in water treatment. At the same time, the high distribution coefficient indicates that Mn(IV) oxide can be an important carrier and host phase of Ra in the environment

Transport coefficients for heavy quarks and quarkonia

International audienc

Statistical approach to describe the properties of nanoporous carbons from lignin by chemical activation

International audienceBlack liquor (BL), being a residue of pulp and paper industries, composed of lignin, sulphides and carbonates of alkaline metals. BL valorisation into activated carbon is one of the possible solutions to manage waste from the mentioned industry sectors. A number of studies from the literature reported the preparation of activated carbon from lignin through metallic salt and hydroxide activation. Relying on the existing massive experimental data set, this paper proposes regression models that describe the variation of the textural properties of lignin-derived activated carbon as a function of operation conditions, such as temperature, activation time and impregnation ratio for different activators (KOH, NaOH). Statistical significance of model parameters was verified by relying on results of t-test. Using the proposed models, it was highlighted that activation temperature and impregnation ratio parameters are the principal factors controlling the activation process, while activation time has less significant effect on the development of porous structure. Carbons produced by lignin activation in the presence of KOH exhibit higher specific surface area (SSA) and micropore volume (MPV) than NaOH-activated carbons and require shorter activation time to reach high porosity. KOH activation of lignin-derived char requires lower activation temperature in comparison with a direct KOH-activation of lignin

Coherent J/ψ\psi photoproduction at midrapidity in Pb-Pb collisions at sNN=5.02\sqrt{s_{\rm NN}} = 5.02 TeV

International audienceThe coherent J/$\psi$ photoproduction cross section is measured for the first time at midrapidity in peripheral to semicentral Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV. The centrality differential cross section ${\rm d} \sigma/ {\rm d}y$ is reported for the centrality range 40-90%, together with the doubly-differential cross section ${\rm d}^2 \sigma /{\rm d}y {\rm d} p_{\rm T}$, extracted in two peripheral centrality classes. The J/$\psi$ mesons are reconstructed in the dielectron channel, in the rapidity interval $|y| <$ 0.9 using the ALICE central barrel detectors. The J/$\psi$ cross section at midrapidity is statistically compatible to the earlier ALICE measurement at forward rapidity and at the same centre-of-mass energy, and shows only a mild centrality dependence over the covered range. Several sets of theoretical calculations taking into account the hadronic overlap in the collisions but ignoring possible final-state effects from a hot expanding medium are found to give a fairly good description of the current measurements within uncertainties

Design and performance of the field cage for the XENONnT experiment

International audienceThe precision in reconstructing events detected in a dual-phase time projection chamber depends on an homogeneous and well understood electric field within the liquid target. In the XENONnT TPC the field homogeneity is achieved through a double-array field cage, consisting of two nested arrays of field shaping rings connected by an easily accessible resistor chain. Rather than being connected to the gate electrode, the topmost field shaping ring is independently biased, adding a degree of freedom to tune the electric field during operation. Two-dimensional finite element simulations were used to optimize the field cage, as well as its operation. Simulation results were compared to ${}^{83m}\mathrm{Kr}$ calibration data. This comparison indicates an accumulation of charge on the panels of the TPC which is constant over time, as no evolution of the reconstructed position distribution of events is observed. The simulated electric field was then used to correct the charge signal for the field dependence of the charge yield. This correction resolves the inconsistent measurement of the drift electron lifetime when using different calibrations sources and different field cage tuning voltages

Measurement of inclusive charged-particle jet production in pp and p-Pb collisions at sNN=5.02\sqrt{s_{\rm NN}}=5.02 TeV

International audienceMeasurements of inclusive charged-particle jet production in pp and p-Pb collisions at center-of-mass energy per nucleon-nucleon collision $\sqrt{s_{\rm NN}} = 5.02$ TeV and the corresponding nuclear modification factor $R_{\rm pPb}^{\rm ch\,jet}$ are presented, using data collected with the ALICE detector at the LHC. Jets are reconstructed in the central rapidity region $|\eta_{\rm jet}| < 0.5$ from charged particles using the anti-$k_{\rm T}$ algorithm with resolution parameters $R = 0.2$, 0.3, and 0.4. The $p_{\rm T}$-differential inclusive production cross section of charged-particle jets, as well as the corresponding cross-section ratios, are reported for pp and p-Pb collisions in the transverse momentum range $10 < p^{\rm ch}_{\rm T,jet} < 140$ GeV/$c$ and $10 < p^{\rm ch}_{\rm T,jet} < 160$ GeV/$c$, respectively, together with the nuclear modification factor $R_{\rm pPb}^{\rm ch\,jet}$ in the range $10 < p^{\rm ch}_{\rm T,jet} < 140$ GeV/$c$. The analysis extends the $p_{\rm T}$ range of the previously-reported charged-particle jet measurements by the ALICE Collaboration. The nuclear modification factor is found to be consistent with one and independent of the jet resolution parameter with the improved precision of this study, indicating that the possible influence of cold nuclear matter effects on the production cross section of charged-particle jets in p-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV is smaller than the current precision. The obtained results are in agreement with other minimum bias jet measurements available for RHIC and LHC energies, and are well reproduced by the NLO perturbative QCD POWHEG calculations with parton shower provided by PYTHIA8 as well as by JETSCAPE simulations