The treatment of deep-seated tumours with electrons of very high energies (VHEE, 70–150 MeV) has already been explored in the past, suggesting that a dosimetric coverage comparable with ...state-of-the-art proton (PT) or photon radiotherapy (RT) could be achieved with a large (
>
10) number of fields and high electron energy. The technical and economical challenges posed by the deployment of such beams in treatment centres, together with the expected small therapeutic gain, prevented the development of such technique. This scenario could radically change in the light of recent developments that occurred in the compact, high-gradient, electron acceleration technology and, additionally, of the experimental evidence of the sparing of organs at risk achieved in ultra-high dose rate irradiation, also referred to as FLASH. Electrons with the energy required to treat intracranial lesions could be provided, at dose rates compatible with what is needed to trigger the FLASH effect, by accelerators that are a few metres long, and the organ sparing could be exploited to significantly simplify the irradiation geometry, decreasing the number of fields needed to treat a patient. In this paper, the case of two patients affected by a chordoma and a meningioma, respectively, treated with protons in Trento (IT) is presented. The proton plans have been compared with VHEE plans and X-ray intensity-modulated radiotherapy (IMRT) plans. The VHEE plans were first evaluated in terms of physical dose distribution and then assuming that the FLASH regimen can be achieved. VHEE beams demonstrated their potential in obtaining plans that have comparable tumour coverage and organs at risk sparing when benchmarked against current state-of-the-art IMRT and PT. These results were obtained with a number of explored fields that was in the range between 3 and 7, consistent with what is routinely performed in IMRT and PT conventional irradiations. The FLASH regimen, in all cases, showed its potential in reducing damage to the organs placed nearby the target volume, allowing, particularly in the chordoma case where the irradiation geometry is more challenging, a better tumour coverage with respect to the conventional treatments.
The growing interest in clarifying the controversial situation in the Dark Matter sector has driven the experimental efforts towards new ways to investigate the long-standing DAMA/LIBRA result. Among ...them, low-temperature calorimeters based on Na-containing scintillating crystals offer the possibility to clarify the nature of the measured signal via particle identification. Here we report the first preliminary measurement of Na-containing crystals, based on a material different from NaI, i.e. Na2Mo2O7 and Na2W2O7, pointing out their performance in terms of energy resolution, light yield, and particle identification.
The growing interest in clarifying the controversial situation in the Dark Matter sector has driven the experimental efforts towards new ways to investigate the long-standing DAMA/LIBRA result. Among ...them, low-temperature calorimeters based on Na-containing scintillating crystals offer the possibility to clarify the nature of the measured signal via particle identification. Here we report the first measurement of Na-containing crystals, based on material different from NaI, i.e. Na\(_2\)Mo\(_2\)O\(_7\) and Na\(_2\)W\(_2\)O\(_7\), pointing out their excellent performance in term of energy resolution, light yield, and particle identification.
The CUPID-Mo experiment is searching for neutrinoless double beta decay in \(^{100}\)Mo, evaluating the technology of cryogenic scintillating Li\(_{2}^{100}\)MoO\(_4\) detectors for CUPID (CUORE ...Upgrade with Particle ID). CUPID-Mo detectors feature background suppression using a dual-readout scheme with Li\(_{2}\)MoO\(_4\) crystals complemented by Ge bolometers for light detection. The detection of both heat and scintillation light signals allows the efficient discrimination of \(\alpha\) from \(\gamma\)&\(\beta\) events. In this proceedings, we discuss results from the first 2 months of data taking in spring 2019. In addition to an excellent bolometric performance of 6.7\(\,\)keV (FWHM) at 2615\(\,\)keV and an \(\alpha\) separation of better than 99.9\% for all detectors, we report on bulk radiopurity for Th and U. Finally, we interpret the accumulated physics data in terms of a limit of \(T_{1/2}^{0\nu}\,> 3\times10^{23}\,\)yr for \(^{100}\)Mo and discuss the sensitivity of CUPID-Mo until the expected end of physics data taking in early 2020.
CUPID-Mo is a bolometric experiment to search for neutrinoless double-beta decay (\(0\nu\beta\beta\)) of \(^{100}\)Mo. In this article, we detail the CUPID-Mo detector concept, assembly, installation ...in the underground laboratory in Modane in 2018, and provide results from the first datasets. The demonstrator consists of an array of 20 scintillating bolometers comprised of \(^{100}\)Mo-enriched 0.2 kg Li\(_2\)MoO\(_4\) crystals. The detectors are complemented by 20 thin cryogenic Ge bolometers acting as light detectors to distinguish \(\alpha\) from \(\gamma\)/\(\beta\) events by the detection of both heat and scintillation light signals. We observe good detector uniformity, facilitating the operation of a large detector array as well as excellent energy resolution of 5.3 keV (6.5 keV) FWHM at 2615 keV, in calibration (physics) data. Based on the observed energy resolutions and light yields a separation of \(\alpha\) particles at much better than 99.9\% with equally high acceptance for \(\gamma\)/\(\beta\) events is expected for events in the region of interest for \(^{100}\)Mo \(0\nu\beta\beta\). We present limits on the crystals' radiopurity (\(\leq\)3 \(\mu\)Bq/kg of \(^{226}\)Ra and \(\leq\)2 \(\mu\)Bq/kg of \(^{232}\)Th). Based on these initial results we also discuss a sensitivity study for the science reach of the CUPID-Mo experiment, in particular, the ability to set the most stringent half-life limit on the \(^{100}\)Mo \(0\nu\beta\beta\) decay after half a year of livetime. The achieved results show that CUPID-Mo is a successful demonstrator of the technology - developed in the framework of the LUMINEU project - selected for the CUPID experiment, a proposed follow-up of CUORE, the currently running first tonne-scale cryogenic \(0\nu\beta\beta\) experiment.
Rainfall-induced flow landslides in coarse-grained soils pose significant threats to populations and structures due to their high velocities, long travel distance and the absence of definite warning ...signs during the pre-failure stage. The triggering phase of these phenomena is frequently related to rainfall events which significantly reduce matric suction in the shallower soil layers. In this paper the processes leading to the onset of such phenomena are illustrated and some observations on their modelling are briefly recalled. The failure stage at different scales is then modelled with reference to a case study from southern Italy which draws on high-quality experimental data sets from extensive in situ and laboratory investigation.
► Describing rainfall-induced landslides of flow-type. ► Mechanical characterisation of pyroclastic unsaturated soils via lab advanced tests. ► Monitoring in situ matric suction and soil water contents. ► Modelling soil atmosphere interaction and flow-slide triggering.
Hazard and risk assessment of landslides with potentially long run-out is becoming more and more important. Numerical tools exploiting different constitutive models, initial data and numerical ...solution techniques are important for making the expert’s assessment more objective, even though they cannot substitute for the expert’s understanding of the site-specific conditions and the involved processes. This paper presents a depth-integrated model accounting for pore water pressure dissipation and applications both to real events and problems for which analytical solutions exist. The main ingredients are: (i) The mathematical model, which includes pore pressure dissipation as an additional equation. This makes possible to model flowslide problems with a high mobility at the beginning, the landslide mass coming to rest once pore water pressures dissipate. (ii) The rheological models describing basal friction: Bingham, frictional, Voellmy and cohesive-frictional viscous models. (iii) We have implemented simple erosion laws, providing a comparison between the approaches of Egashira, Hungr and Blanc. (iv) We propose a Lagrangian SPH model to discretize the equations, including pore water pressure information associated to the moving SPH nodes.
PDF
