Muography applied to nuclear waste storage sites

Legacy storage sites for nuclear waste can pose a serious environmental problem. In fact, since certain sites date from the middle of the last century when safety protocols had not been properly established and strict bookkeeping was not enforced, a situation has evolved where the content of storage silos is basically known only with a large uncertainty both on quantity and quality. At the same time maintenance work on old storage structures is becoming ever more urgent and yet this work requires exactly that information which is now lacking on the type of waste that was stored inside. Because of the difficulty in accessing the storage silos and the near impossibility of making visual inspections inside, techniques have to be developed which can determine the presence or absence of heavy elements (i.e. uranium) within the structures. Muography is a very promising technique which could allow the survey of previously inaccessible structures. We have begun an evaluation performing feasibility studies using simulations based on real case scenarios. This paper will outline the storage site scenarios and then present some of the results obtained from the Monte Carlo simulations

The MURAVES muon telescope: technology and expected performances

The MURAVES project aims to study the inner structure of the upper part of the Mt. Vesuvius volcano by muon radiography (muography) technique. Very high energy muons, produced by cosmic rays in the at- mosphere, can penetrate large thickness of rocks. By measuring the at- tenuation of the muons flux trough the volcano cone is possible to obtain a 2D image of the density structure. Internal discontinuities, with a spa- tial resolution of about 10 m, can be, in principle, resolved. An absolute average density measurement can be provided too. The project, funded by the Italian Ministry of University, Research and Education (MIUR), is led by INGV and INFN. In this article the mechanical structure of the de- tectors and background suppression techniques are reported

The Impact of Crystal Light Yield Non-Proportionality on a Typical Calorimetric Space Experiment: Beam Test Measurements and Monte Carlo Simulations

Calorimetric space experiments were employed for the direct measurements of cosmic-ray spectra above the TeV region. According to several theoretical models and recent measurements, relevant features in both electron and nucleus fluxes are expected. Unfortunately, sizable disagreements among the current results of different space calorimeters exist. In order to improve the accuracy of future experiments, it is fundamental to understand the reasons of these discrepancies, especially since they are not compatible with the quoted experimental errors. A few articles of different collaborations suggest that a systematic error of a few percentage points related to the energy-scale calibration could explain these differences. In this work, we analyze the impact of the nonproportionality of the light yield of scintillating crystals on the energy scale of typical calorimeters. Space calorimeters are usually calibrated by employing minimal ionizing particles (MIPs), e.g., nonshowering proton or helium nuclei, which feature different ionization density distributions with respect to particles included in showers. By using the experimental data obtained by the CaloCube collaboration and a minimalist model of the light yield as a function of the ionization density, several scintillating crystals (BGO, CsI(Tl), LYSO, YAP, YAG and BaF2) are characterized. Then, the response of a few crystals is implemented inside the Monte Carlo simulation of a space calorimeter to check the energy deposited by electromagnetic and hadronic showers. The results of this work show that the energy scale obtained by MIP calibration could be affected by sizable systematic errors if the nonproportionality of scintillation light is not properly taken into account

Development and validation of HERWIG 7 tunes from CMS underlying-event measurements

This paper presents new sets of parameters (“tunes”) for the underlying-event model of the HERWIG7 event generator. These parameters control the description of multiple-parton interactions (MPI) and colour reconnection in HERWIG7, and are obtained from a fit to minimum-bias data collected by the CMS experiment at s=0.9, 7, and 13Te. The tunes are based on the NNPDF 3.1 next-to-next-to-leading-order parton distribution function (PDF) set for the parton shower, and either a leading-order or next-to-next-to-leading-order PDF set for the simulation of MPI and the beam remnants. Predictions utilizing the tunes are produced for event shape observables in electron-positron collisions, and for minimum-bias, inclusive jet, top quark pair, and Z and W boson events in proton-proton collisions, and are compared with data. Each of the new tunes describes the data at a reasonable level, and the tunes using a leading-order PDF for the simulation of MPI provide the best description of the dat

Atmospheric muons as an imaging tool

Imaging methods based on the absorption or scattering of atmospheric muons, collectively named under the neologism “muography”, exploit the abundant natural flux of muons produced from cosmic-ray interactions in the atmosphere. Recent years have seen a steep rise in the development of muography methods in a variety of innovative multidisciplinary approaches to study the interior of natural or human-made structures, establishing synergies between usually disconnected academic disciplines such as particle physics, geology, and archaeology. Muography also bears promise of immediate societal impact through geotechnical investigations, nuclear waste surveys, homeland security, and natural hazard monitoring. Our aim is to provide an introduction to this vibrant research area, starting from the physical principles at the basis of the methods and describing the main detector technologies and imaging tools, including their combination with conventional techniques from other disciplines, where appropriate. Then, we discuss critically some outstanding issues that affect a broad variety of applications, and the current state of the art in addressing them. Finally, we review several recent developments in the application of muography methods to specific use cases, without any pretence of exhaustiveness

Muography of the Puy de Dôme

Muon radiography is an imaging technique that relies on the transmis- sion of cosmic muons through matter. It allows the measurement of den- sity maps of large structures such as volcanoes. During the second half of 2013 the MURAY detector prototype carried out a data taking at the Puy de Dôme in the framework of the scientific collaboration with the experiment TOMUVOL in order to compare the results and performance of the two different detectors. Both experimental apparatuses measure a muon transmission of some orders of magnitude higher than that ex- pected highlighting a background that perturbs these measures

Status of the LHCf experiment

International audienceA precise understanding of hadronic interactions is essential to interpreting the mass composition of ultra-high energy cosmic rays from the results of air shower experiments. The Large Hadron Collier forward (LHCf) experiment aims to measure forward neutral particles for validation of hadronic interaction models adopted in air shower simulations. We already published the production cross sections of forward photons and neutrons for proton-proton collisions at √s=13 TeV. Recently, we showed a preliminary result of the energy spectrum of forward η mesons for proton-proton collisions at √s=13 TeV. Moreover, in September 2022, we had another data-taking for proton-proton collisions at √s=13.6 TeV. In data taking, we planned to obtain a number of π0 and η candidates ten times larger for precise measurements and to perform the joint operation with ATLAS Roman pots and zero-degree calorimeters. Thanks to the joint operation with the ATLAS Roman pots, we can measure diffractive mass and neutral particles from diffractive dissociation simultaneously. Furthermore, energy resolution for neutrons is expected to be improved from 40% to 20% by combining the LHCf and the ATLAS zero-degree calorimeters. In this work, we report the status and prospects of the LHCf experiment

Tracker-in-Calorimeter (TIC) Project: A Calorimetric New Solution for Space Experiments

A space-based detector dedicated to measurements of γ-rays and charged particles has to achieve a balance between different instrumental requirements. A good angular resolution is necessary for the γ-rays, whereas an excellent geometric factor is needed for the charged particles. The tracking reference technique of γ-ray physics is based on a pair-conversion telescope made of passive material (e.g., tungsten) coupled with sensitive layers (e.g., silicon microstrip). However, this kind of detector has a limited acceptance because of the large lever arm between the active layers, needed to improve the track reconstruction capability. Moreover, the passive material can induce fragmentation of nuclei, thus worsening charge reconstruction performances. The Tracker-In-Calorimeter (TIC) project aims to solve all these drawbacks. In the TIC proposal, the silicon sensors are moved inside a highly-segmented isotropic calorimeter with a couple of external scintillators dedicated to charge reconstruction. In principle, this configuration has a good geometrical factor, and the angle of the γ-rays can be precisely reconstructed from the lateral profile of the electromagnetic shower sampled, at different depths in the calorimeter, by silicon strips. The effectiveness of this approach has been studied with Monte Carlo simulations and validated with beam test data of a small prototype

Performance evaluation of LHCf-ATLAS ZDC joint measurement using proton beam

International audienceMeasurements of forward neutrons in pp collisions will allow us to investigate π-p cross-section via one-pion exchange process, which are important for air shower development. However, the precision of these measurements is limited by the energy resolution of the LHCf detectors. To improve it, a joint measurement with the ATLAS ZDC was planned. In 2021, a beam test was conducted to evaluate the performance of the joint measurement of the LHCf-Arm1 and ZDC detectors using proton beams of 350 GeV at SPS. Combining the LHCf data with the ZDC data, we confirmed that the energy resolution improved from about 40% to 21.4%