arXiv subjects

P. Strolin

Publications and source records attributed to P. Strolin.

13 recordsLinked to original sources

arXiv2022

The MURAVES experiment: study of the Vesuvius Great Cone with Muon Radiography

The MURAVES experiment aims at the muographic imaging of the internal structure of the summit of Mt. Vesuvius, exploiting muons produced by cosmic rays. Though presently quiescent, the volcano carries a dramatic hazard in its highly populated surroundings. The challenging measurement of the rock density distribution in its summit by muography, in conjunction with data from other geophysical techniques, can help the modeling of possible eruptive dynamics. The MURAVES apparatus consists of an array of three independent and identical muon trackers, with a total sensitive area of 3 square meters. In each tracker, a sequence of 4 XY tracking planes made of plastic scintillators is complemented by a 60 cm thick lead wall inserted between the two downstream planes to improve rejection of background from low energy muons. The apparatus is currently acquiring data. Preliminary results from the analysis of a first data sample are presented.

physics.ins-det↗

arXiv2017

Discovery potential for directional Dark Matter detection with nuclear emulsions

Direct Dark Matter searches are nowadays one of the most fervid research topics with many experimental efforts devoted to the search for nuclear recoils induced by the scattering of Weakly Interactive Massive Particles (WIMPs). Detectors able to reconstruct the direction of the nucleus recoiling against the scattering WIMP are opening a new frontier to possibly extend Dark Matter searches beyond the neutrino background. Exploiting directionality would also prove the galactic origin of Dark Matter with an unambiguous signal-to-background separation. Indeed, the angular distribution of recoiled nuclei is centered around the direction of the Cygnus constellation, while the background distribution is expected to be isotropic. Current directional experiments are based on gas TPC whose sensitivity is limited by the small achievable detector mass. In this paper we present the discovery potential of a directional experiment based on the use of a solid target made of newly developed nuclear emulsions and of optical read-out systems reaching unprecedented nanometric resolution.

astro-ph.CO↗

arXiv2016

NEWS: Nuclear Emulsions for WIMP Search

Nowadays there is compelling evidence for the existence of dark matter in the Universe. A general consensus has been expressed on the need for a directional sensitive detector to confirm, with a complementary approach, the candidates found in conventional searches and to finally extend their sensitivity beyond the limit of neutrino-induced background. We propose here the use of a detector based on nuclear emulsions to measure the direction of WIMP-induced nuclear recoils. The production of nuclear emulsion films with nanometric grains is established. Several measurement campaigns have demonstrated the capability of detecting sub-micrometric tracks left by low energy ions in such emulsion films. Innovative analysis technologies with fully automated optical microscopes have made it possible to achieve the track reconstruction for path lengths down to one hundred nanometers and there are good prospects to further exceed this limit. The detector concept we propose foresees the use of a bulk of nuclear emulsion films surrounded by a shield from environmental radioactivity, to be placed on an equatorial telescope in order to cancel out the effect of the Earth rotation, thus keeping the detector at a fixed orientation toward the expected direction of galactic WIMPs. We report the schedule and cost estimate for a one-kilogram mass pilot experiment, aiming at delivering the first results on the time scale of six years.

astro-ph.IM↗

arXiv2015

Intrinsic neutron background of nuclear emulsions for directional Dark Matter searches

Recent developments of the nuclear emulsion technology led to the production of films with nanometric silver halide grains suitable to track low energy nuclear recoils with submicrometric length. This improvement opens the way to a directional Dark Matter detection, thus providing an innovative and complementary approach to the on-going WIMP searches. An important background source for these searches is represented by neutron-induced nuclear recoils that can mimic the WIMP signal. In this paper we provide an estimation of the contribution to this background from the intrinsic radioactive contamination of nuclear emulsions. We also report the induced background as a function of the read-out threshold, by using a GEANT4 simulation of the nuclear emulsion, showing that it amounts to about 0.06 neutrons per year per kilogram, fully compatible with the design of a 10 kg$\times$year exposure.

astro-ph.IM↗

arXiv2011

Measurement of charm production in neutrino charged-current interactions

The nuclear emulsion target of the CHORUS detector was exposed to the wide-band neutrino beam of the CERN SPS of 27 GeV average neutrino energy from 1994 to 1997. In total about 100000 charged-current neutrino interactions with at least one identified muon were located in the emulsion target and fully reconstructed, using newly developed automated scanning systems. Charmed particles were searched for by a program recognizing particle decays. The observation of the decay in nuclear emulsion makes it possible to select a sample with very low background and minimal kinematical bias. 2013 charged-current interactions with a charmed hadron candidate in the final state were selected and confirmed through visual inspection. The charm production rate induced by neutrinos relative to the charged-current cross-section is measured to be sigma(nu_mu N -> mu- C X)/sigma(CC) = (5.75 +-0.32 stat +-0.30 syst)%. The charm production cross-section as a function of the neutrino energy is also obtained. The results are in good agreement with previous measurements. The charm-quark hadronization produces the following charmed hadrons with relative fractions (in %): f_Dzero = 43.7+-4.5, f_Lambda_c^plus = 19.2+-4.2, f_Dplus = 25.3+-4.2, and f_D_splus = 11.8+-4.7.

hep-ex↗

arXiv2009

Sensitivity on Earth Core and Mantle densities using Atmospheric Neutrinos

Neutrino radiography may provide an alternative tool to study the very deep structures of the Earth. Though these measurements are unable to resolve the fine density layer features, nevertheless the information which can be obtained are independent and complementary to the more conventional seismic studies. The aim of this paper is to assess how well the core and mantle averaged densities can be reconstructed through atmospheric neutrino radiography. We find that about a 2% sensitivity for the mantle and 5% for the core could be achieved for a ten year data taking at an underwater km^3 Neutrino Telescope. This result does not take into account systematics related to the details of the experimental apparatus.

astro-ph.EP↗

arXiv2007

Detectors and flux instrumentation for future neutrino facilities

This report summarises the conclusions from the detector group of the International Scoping Study of a future Neutrino Factory and Super-Beam neutrino facility. The baseline detector options for each possible neutrino beam are defined as follows: 1. A very massive (Megaton) water Cherenkov detector is the baseline option for a sub-GeV Beta Beam and Super Beam facility. 2. There are a number of possibilities for either a Beta Beam or Super Beam (SB) medium energy facility between 1-5 GeV. These include a totally active scintillating detector (TASD), a liquid argon TPC or a water Cherenkov detector. 3. A 100 kton magnetized iron neutrino detector (MIND) is the baseline to detect the wrong sign muon final states (golden channel) at a high energy (20-50 GeV) neutrino factory from muon decay. A 10 kton hybrid neutrino magnetic emulsion cloud chamber detector for wrong sign tau detection (silver channel) is a possible complement to MIND, if one needs to resolve degeneracies that appear in the $δ$-$θ_{13}$ parameter space.

physics.ins-det↗

arXiv2007

Emulsion Cloud Chamber technique to measure the fragmentation of a high-energy carbon beam

Beams of Carbon nuclei are used or planned to be used in various centers for cancer treatment around the world because of their therapeutic advantages over proton beams. The knowledge of the fragmentation of Carbon nuclei when they interact with the human body is important to evaluate the spatial profile of their energy deposition in the tissues, hence the damage to the tissues neighboring the tumor. In this respect, the identification of the fragmentation products is a key element. We present in this paper the charge measurement of about 3000 fragments produced by the interaction of $^{12}$C nuclei with an energy of 400 MeV/nucleon in a detector simulating the density of the human body. The nuclear emulsion technique is used, by means of the so-called Emulsion Cloud Chamber. In order to achieve the large dynamical range required for the charge measurement, the recently developed techniques of the emulsion controlled fading are used. The nuclear emulsions are inspected using fast automated microscopes recently developed. A charge assignment efficiency of more than 99% is achieved. The separation of Hydrogen, Helium, Lithium, Berillium, Boron and Carbon can be achieved at two standard deviations or considerably more, according to the track length available for the measurement.

physics.med-ph↗

arXiv2007

Track reconstruction in the emulsion-lead target of the OPERA experiment using the ESS microscope

The OPERA experiment, designed to conclusively prove the existence of $\rm ν_μ\to ν_τ$ oscillations in the atmospheric sector, makes use of a massive lead-nuclear emulsion target to observe the appearance of $\rm ν_τ$'s in the CNGS $\rm ν_μ$ beam. The location and analysis of the neutrino interactions in quasi real-time required the development of fast computer-controlled microscopes able to reconstruct particle tracks with sub-micron precision and high efficiency at a speed of 20 cm^2 / h. This paper describes the performance in particle track reconstruction of the European Scanning System, a novel automatic microscope for the measurement of emulsion films developed for OPERA.

physics.ins-det↗

arXiv2007

Electron/pion separation with an Emulsion Cloud Chamber by using a Neural Network

We have studied the performance of a new algorithm for electron/pion separation in an Emulsion Cloud Chamber (ECC) made of lead and nuclear emulsion films. The software for separation consists of two parts: a shower reconstruction algorithm and a Neural Network that assigns to each reconstructed shower the probability to be an electron or a pion. The performance has been studied for the ECC of the OPERA experiment [1]. The $e/π$ separation algorithm has been optimized by using a detailed Monte Carlo simulation of the ECC and tested on real data taken at CERN (pion beams) and at DESY (electron beams). The algorithm allows to achieve a 90% electron identification efficiency with a pion misidentification smaller than 1% for energies higher than 2 GeV.

physics.data-an↗

arXiv2006

Hardware performance of a scanning system for high speed analysis of nuclear emulsions

The use of nuclear emulsions in very large physics experiments is now possible thanks to the recent improvements in the industrial production of emulsions and to the development of fast automated microscopes. In this paper the hardware performances of the European Scanning System (ESS) are described. The ESS is a very fast automatic system developed for the mass scanning of the emulsions of the OPERA experiment, which requires microscopes with scanning speeds of about 20 cm^2/h in an emulsion volume of 44 micron thickness.

physics.ins-det↗

arXiv2006

Future neutrino oscillation facilities

The recent discovery that neutrinos have masses opens a wide new field of experimentation. Accelerator-made neutrinos are essential in this program. Ideas for future facilities include high intensity muon neutrino beams from pion decay (`SuperBeam'), electron neutrino beams from nuclei decays (`Beta Beam'), or muon and electron neutrino beams from muon decay (`Neutrino Factory'), each associated with one or several options for detector systems. Each option offers synergetic possibilities, e.g. some of the detectors can be used for proton decay searches, while the Neutrino Factory is a first step towards muon colliders. A summary of the perceived virtues and shortcomings of the various options, and a number of open questions are presented.

hep-ph↗

arXiv2003

Heavy quark studies with nuclear emulsions

Emulsions have started particle physics with the discovery of natural radioactivity by Becquerel in 1896. The development of the ``nuclear emulsions'' made it possible to detect tracks of single particle and to perform detailed measurements of their interactions. The discovery of the pion in 1947 was the first, spectacular demonstration of their unique features for the direct observation of the production and decay of short-lived particles, with negligible or very low background. In particular, these features are now exploited for studies of heavy quark physics in experiments where nuclear emulsions are combined with electronic detectors and profit is taken of the remarkable technological progress in automated analysis. In these experiments, neutrinos provide a selective probe for specific quark flavors. Interesting results on charm production and decay are expected in the very near future.

hep-ph↗