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Prompt/non-prompt J/psi separation in pp at sqrt(s) = 13.6 TeV with ALICE
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Study of collective phenomena via the production of heavy quarks and quarkonia in hadronic collisions with ALICE
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The carbon footprint of external beam radiotherapy and its impact in health technology assessment
No full textInternational audienceBackgroundThe major drivers of carbon dioxide (CO2eq) emissions of external beam radiation therapy (EBRT) are not well known and limit our ability to initiate mitigation strategies.Material and methodsWe describe the carbon footprint of four typical centers. We explore direct EBRT associated factors such as the impact of fractionation and use of MRI-LINAC, as well as indirect factors (e.g. patient rides). Treatment strategy related CO2eq emissions are included in a health technology assessment analysis that takes into account CO2eq emissions.ResultsA typical EBRT treatment emits from 185 kgCO2eq to 2066 kgCO2eq. CO2eq emissions are mostly driven by (i) accelerator acquisition and maintenance (37.8 %), (ii) patients and workers rides (32.7 %), (iii) drugs and medical devices (7.3 %), (iv) direct energy consumption (6.1 %), and (v) building and bunker construction (5.6 %) with a substantial heterogeneity among centers. Hypofractionation has a strong impact to mitigate emissions. MRI-LINAC is associated with a substantial increase in CO2eq emissions per fraction and requires ultra hypofractionation in 5 fractions to achieve a similar carbon footprint compared to 20 fractions treatment schemes. The expected limited small increase in toxicities due to hypofractionation (when existing) are in the same range as avoided detrimental effects to future people’s health thanks to CO2eq mitigation.ConclusionCarbon footprint of EBRT is not neglectable and could be mitigated. When safely feasible, hypofractionation is one of the main factors to decrease this impact. Taking into account CO2eq emissions has a substantial impact on the health technology assessment of EBRT, favoring hypofractionated regimens
First Measurement of Solar B Neutrinos via Coherent Elastic Neutrino-Nucleus Scattering with XENONnT
No full textInternational audienceWe present the first measurement of nuclear recoils from solar B neutrinos via coherent elastic neutrino-nucleus scattering with the XENONnT dark matter experiment. The central detector of XENONnT is a low-background, two-phase time projection chamber with a 5.9 t sensitive liquid xenon target. A blind analysis with an exposure of 3.51 ty resulted in 37 observed events above 0.5 keV, with () events expected from backgrounds. The background-only hypothesis is rejected with a statistical significance of 2.73 . The measured B solar neutrino flux of is consistent with results from dedicated solar neutrino experiments. The measured neutrino flux-weighted CENS cross-section on Xe of is consistent with the Standard Model prediction. This is the first direct measurement of nuclear recoils from solar neutrinos with a dark matter detector
Rapidity dependence of antideuteron coalescence in pp collisions at = 13 TeV with ALICE
No full textInternational audienceThe production yields of antideuterons and antiprotons are measured in pp collisions at a center-of-mass energy of TeV, as a function of transverse momentum () and rapidity (), for the first time up to . The measured spectra are used to study the and rapidity dependence of the coalescence parameter , which quantifies the coalescence probability of antideuterons. The and rapidity dependence of the obtained is extrapolated for GeV/ and using the phenomenological antideuteron production model implemented in PYTHIA 8.3 as well as a baryon coalescence afterburner model based on EPOS 3. Such measurements are of interest to the astrophysics community, since they can be used for the calculation of the flux of antinuclei from cosmic rays, in combination with coalescence models
Chemical and mechanical decontamination of scales from geothermal shell and tube heat exchangers in operation before anti-scaling treatment
No full textInternational audienceHeat exchangers used in the Upper Rhine Graben (URG) area to generate heat or electricity are subject during their life cycle to scale accumulation. The main mineral precipitations related to scales in the URG are sulfates (barite, celestite), sulfides (galena, pyrite), nanocrystalline intermetallic mixed compound (Sb, As), elemental metals (Pb, As, Sb), metal oxides and carbonates. During plant operation, radionuclides from uranium and thorium decay chains, that are naturally dissolved in the geothermal fluid circulating in granitic fractured reservoirs, could be accumulated by precipitation or incorporation into the scales as observed on geothermal equipment. The direct treatment in these tubes showed an effectiveness of mechanical decontamination ( >95%) and multiple cycle chemical decontamination (-90% HNO3 : HCl 1:3, -70% DTPA, -30% NOXOL100+NOXOL771). However, the choice of chemical treatments is important to consider in relation to the waste acceptance criteria. In particular, the concentrations of chelating agents such as DTPA and EDTA are regulated and cannot exceed the threshold concentrations per waste package recommended by the national waste acceptance criteria. This research work also showed the importance of a good characterization of scales to model as closely as possible the geometry of the tubes, implemented in ISOCS/LabSOCS processing software for gamma spectrometry, in order to evaluate the radioactive level of radionuclides difficult to measure such as (210) Pb
First measurements with a new -electron detector for spectral shape studies
No full textInternational audienceThe shape of the spectrum corresponding to the electrons emitted in decay carries a wealth of information about nuclear structure and fundamental physics. In spite of that, few dedicated measurements have been made of -spectrum shapes. In this work we present a newly developed detector for 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 -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 -decay experiments at the Ion Guide Isotope Separator On-Line facility in Jyväskylä, aimed at improving our understanding of reactor antineutrino spectra
First measurement of the -dependence of incoherent J/ photonuclear production
No full textInternational audienceThe first measurement of the cross section for incoherent photonuclear production of J/ vector meson as a function of the Mandelstam variable is presented. The measurement was carried out with the ALICE detector at midrapidity, , using ultra-peripheral collisions of Pb nuclei at a centre-of-mass energy per nucleon pair TeV. This rapidity interval corresponds to a Bjorken- range . Cross sections are reported in five intervals in the range ~GeV and compared to the predictions of different models. Models that ignore quantum fluctuations of the gluon density in the colliding hadron predict a -dependence of the cross section much steeper than in data. The inclusion of such fluctuations in the same models provides a better description of the data
Advancing the understanding of energy-energy correlators in heavy-ion collisions
No full textInternational audienceWe investigate the collinear limit of the energy-energy correlator (EEC) in a heavy-ion context. First, we revisit the leading-logarithmic (LL) resummation of this observable in vacuum following a diagrammatic approach. We argue that this route allows to naturally incorporate medium-induced effects into the all-orders structure systematically. As an example, we show how the phase-space constraints imposed by the medium on vacuum-like emissions can be incorporated into the LL result by modifying the anomalous dimensions. On the fixed-order side, we calculate the expansion of the in-medium EEC for a splitting using, for the first time, the exact matrix element. When comparing this result to previously used approximations in the literature, we find up to deviations in the regime of interest for jet quenching signatures. Energy loss effects are also quantified and further suppress the EEC at large angles. These semi-analytic studies are complemented with a phenomenological study using the jet quenching Monte Carlo JetMed. Finally, we argue that the imprint of medium-induced effects in energy-energy correlators can be enhanced by using an alternative definition that takes as input Lund primary declusterings instead of particles