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Dosimetric environment of preclinical FLASH hadrontherapy studies at the ARRONAX cyclotron
No full textNational audienc
XeLab: a test platform for xenon TPC instrumentation
No full textInternational audienceXenon double phase TPCs have shown the best sensitivities for dark matter direct searches over a large parameter space.However difficulties in the construction large scale TPC have already arisen in the current detectors and will be even more challengingin the next generation one. Of critical importance are the construction of meter scale electrodes with negligible sagging and high optical transparencybut also the control of instrumental background such as single electron emission. Xelab is a system equipped with a small double phase xenon TPCcooled with liquid nitrogen and a xenon recuperation module primarily designed for the test of innovative concept of floating electrodesbut will also serve as a platform for instrumental development for xenon based TPC.We present the design and realisation of XeLab and the baseline of electrodes that we plan to test
First evidence of in vivo effect of FLASH radiotherapy with helium ions in zebrafish embryos
No full textInternational audienceThe ability to reduce toxicity of ultra-high dose rate (UHDR) helium ion irradiation has not been reported in vivo. Here, we tested UHDR helium ion irradiation in an embryonic zebrafish model. Our results show that UHDR helium ions spare body development and reduce spine curvature, compared to conventional dose rate
Dynamical position and orientation calibration of the KM3NeT telescope
No full textInternational audienceKM3NeT is an underwater neutrino telescope which detects the Cherenkov radiation created by the products of neutrino interactions. To accurately reconstruct neutrino events, a precise determination of the position and orientation of the optical modules, which detect the Cherenkov radiation, is required. As the detector elements sway with the deep sea currents, a continuous tracking of the positions and orientations is necessary. A network of acoustic emitters and receivers is used to position the optical modules. Their orientation is determined by compasses placed in each optical module. This contribution presents the methods to perform the position and orientation calibration of the KM3NeT telescope. The positions of the optical modules need to be resolved with an accuracy of better than 20 cm in order to achieve the envisaged angular resolution of the KM3NeT/ARCA telescope of 0.05 degrees. The orientations of the optical modules need to be resolved with an accuracy of about 3 degrees in order to not compromise the quality of the event reconstruction
Interaction of Nitrite Ions with Hydrated Portlandite Surfaces: Atomistic Computer Simulation Study
No full textInternational audienceThe nitrite admixtures in cement and concrete are used as corrosion inhibitors for steel reinforcement and also as anti-freezing agents. The characterization of the protective properties should account for the decrease in the concentration of free NO2− ions in the pores of cement concretes due to their adsorption. Here we applied the classical molecular dynamics computer simulation approach to quantitatively study the molecular scale mechanisms of nitrite adsorption from NaNO2 aqueous solution on a portlandite surface. We used a new parameterization to model the hydrated NO2− ions in combination with the recently upgraded ClayFF force field (ClayFF-MOH) for the structure of portlandite. The new NO2− parameterization makes it possible to reproduce the properties of hydrated NO2− ions in good agreement with experimental data. In addition, the ClayFF-MOH model improves the description of the portlandite structure by explicitly taking into account the bending of Ca-O-H angles in the crystal and on its surface. The simulations showed that despite the formation of a well-structured water layer on the portlandite (001) crystal surface, NO2− ions can be strongly adsorbed. The nitrite adsorption is primarily due to the formation of hydrogen bonds between the structural hydroxyls on the portlandite surface and both the nitrogen and oxygen atoms of the NO2− ions. Due to that, the ions do not form surface adsorption complexes with a single well-defined structure but can assume various local coordinations. However, in all cases, the adsorbed ions did not show significant surface diffusional mobility. Moreover, we demonstrated that the nitrite ions can be adsorbed both near the previously-adsorbed hydrated Na+ ions as surface ion pairs, but also separately from the cations.</jats:p
The Giant Radio Array for Neutrino Detection (GRAND) Collaboration -- Contributions to the 38th International Cosmic Ray Conference (ICRC 2023)
No full textInternational audienceThe Giant Radio Array for Neutrino Detection (GRAND) is an envisioned observatory of ultra-high-energy particles of cosmic origin, with energies in excess of 100 PeV. GRAND uses large surface arrays of autonomous radio-detection units to look for the radio emission from extensive air showers that are triggered by the interaction of ultra-high-energy cosmic rays, gamma rays, and neutrinos in the atmosphere or underground. In particular, for ultra-high-energy neutrinos, the future final phase of GRAND aims to be sensitive enough to discover them in spite of their plausibly tiny flux. Presently, three prototype GRAND radio arrays are in operation: GRANDProto300, in China, GRAND@Auger, in Argentina, and GRAND@Nancay, in France. Their goals are to field-test the design of the radio-detection units, understand the radio background to which they are exposed, and develop tools for diagnostic, data gathering, and data analysis. This list of contributions to the 38th International Cosmic Ray Conference (ICRC 2023) presents an overview of GRAND, in its present and future incarnations, and a look at the first data collected by GRANDProto13, the first phase of GRANDProto300
EPOS LHC-R : up-to-date hadronic model for EAS simulations
No full textInternational audienceThe hadron production in the simulation of extensive air showers is a long standing problem and the origin of large uncertainties in the reconstruction of the mass of the high energy primary cosmic rays. Hadronic interaction models re-tuned after early LHC data give more consistent results among each other compared to the first generation of models, but still can't reproduce extended air shower data (EAS) consistently. Ten years after the first LHC tuned model release, much more detailed data are available both from LHC, SPS and hybrid air shower measurements allowing to understand some deficiencies in the model. Properly taken into account in the new EPOS LHC-R, it leads to a change in both Xmax and the muon production by air showers. A better treatment of the hadronization according to LHC data is important for the muon production while an update of cross-section and nuclear fragmentation is changing the Xmax distribution. The detailed changes introduced in EPOS LHC-R will be addressed and their consequences on EAS observable
Quarkonium production in high energy collisions
No full textInternational audienceWe investigate the charmonium and bottomonium production in collisions using the Wigner densities formalism. The Wigner density of the quarkonia is approximated by analytical 3-D isotropic harmonic oscillator Wigner densities with the same root-mean-square radius given by the solution of the Schrödinger equation. This approach reproduces quite well the available experimental transverse momentum and rapidity distributions
A digital real-time high-resolution imaging system to quantify and identify all emitted charged particles
No full textInternational audienceThis paper describes an instrumentation imaging system that provides, at real-time, localization, quantification and identification of a radioactive source with a precision up to 20μm. The localization of each decay position is obtained with using a parallel ionization multiplier gaseous detector and a reconstruction algorithm. The spatial identification of the composition of the radioactive source is performed by an original specific set of temporal and energy spectrometry techniques. The system allows with a single detector to combine the measurement of the spatial distribution with the ability to separate and quantify at real time each radionuclide. From an application point of view, this system opens up possibilities for theragnostic applications that typically use two radionuclides. Further upstream, it can optimize the production and distribution challenge of α radionuclides by allowing the identification and characterization of individual radionuclides in radionuclide chains such as 225Ac. Moreover, the measurement system and the associated method could strongly contribute to facilitate research on the biodistribution of α radionuclides that are by their nature difficult to characterize by standard methods
Common femtoscopic hadron-emission source in pp collisions at the LHC
No full textInternational audienceThe femtoscopic study of pairs of identical pions is particularly suited to investigate the effective source function of particle emission, due to the resulting Bose-Einstein correlation signal. In small collision systems at the LHC, pp in particular, the majority of the pions are produced in resonance decays, which significantly affect the profile and size of the source. In this work, we explicitly model this effect in order to extract the primordial source in pp collisions at TeV from charged - correlations measured by ALICE. We demonstrate that the assumption of a Gaussian primordial source is compatible with the data and that the effective source, resulting from modifications due to resonances, is approximately exponential, as found in previous measurements at the LHC. The universality of hadron emission in pp collisions is further investigated by applying the same methodology to characterize the primordial source of K-p pairs. The size of the primordial source is evaluated as a function of the transverse mass () of the pairs, leading to the observation of a common scaling for both - and K-p, suggesting a collective effect. Further, the present results are compatible with the scaling of the p-p and p primordial source measured by ALICE in high multiplicity pp collisions, providing compelling evidence for the presence of a common emission source for all hadrons in small collision systems at the LHC. This will allow the determination of the source function for any hadron--hadron pairs with high precision, granting access to the properties of the possible final-state interaction among pairs of less abundantly produced hadrons, such as strange or charmed particles