L. Viliani

The MU-RAY project: detector technology and first data from Mt. Vesuvius

Muon Radiography allows to map the density of a volcanic cone. It is based on the measurement of the attenuation of the flux of muons present in the cosmic radiation on the ground. The MU-RAY project has developed an innovative detector designed for the muon radiography. The main features are the low electric power consumption, robustness and transportability, good spatial resolution and muon time of flight measurement. A 1 m2 detector prototype has been constructed. and collected data at Mt. Vesuvius for approximately 1 month in spring 2013. A second campaign of measurement has been performed at the Puy de Dome, France, in the last four months of 2013. In this article the principles of muon radiography, the MU-RAY detector and the first results from the collected data will be described.

Assessing the feasibility of interrogating nuclear waste storage silos using cosmic-ray muons

Muon radiography is a fast growing field in applied scientific research. In recent years, many detector technologies and imaging techniques using the Coulomb scattering and absorption properties of cosmic-ray muons have been developed for the non-destructive assay of various structures across a wide range of applications. This work presents the first results that assess the feasibility of using muon radiography to interrogate waste silos within the U.K. Nuclear Industry. Two such approaches, using different techniques that exploit each of these properties, have previously been published, and show promising results from both simulation and experimental data for the detection of shielded high-Z materials and density variations from volcanic assay. Both detection systems used are based on scintillator and photomultiplier technologies. Results from dedicated simulation studies using both these proven technologies and image reconstruction techniques are presented for an intermediate-sized legacy nuclear waste storage facility filled with concrete and an array of uranium samples. Both results highlight the potential to identify uranium objects of varying thicknesses greater than 5 cm within real-time durations of several weeks. Increased contributions from Coulomb scattering within the concrete matrix of the structure hinder the ability of both approaches to resolve similar objects of 2 cm dimensions even with increased statistics. These results are all dependent on both the position of the objects within the facility and the locations of the detectors. Results for differing thicknesses of concrete, which reflect the non-standard composition of these complex, legacy structures under interrogation, are also presented alongside studies performed for a series of data collection durations. It is anticipated that with further research and optimisation of detector technologies and geometries, muon radiography in one, or both of these forms, will play a key role in future industrial applications within the U.K. Nuclear Industry.

A projective reconstruction method of underground or hidden structures using atmospheric muon absorption data

Muon absorption radiography is an imaging technique based on the analysis of the attenuation of the cosmic-ray muon flux after traversing an object under examination. While this technique is now reaching maturity in the field of volcanology for the imaging of the innermost parts of the volcanic cones, its applicability to other fields of research has not yet been proved. In this paper we present a study concerning the application of the muon absorption radiography technique to the field of archaeology, and we propose a method for the search of underground cavities and structures hidden a few metres deep in the soil (patent [1]). An original geometric treatment of the reconstructed muon tracks, based on the comparison of the measured flux with a reference simulated flux, and the preliminary results of specific simulations are discussed in details.

Feasibility study of detection of high-Z material in nuclear waste storage facilities with atmosperic muons

Muon radiography is a well-established technique which is widely used in investigating the internal density structure of targets of different size and composition. Some examples of successful applications are the search for hidden chambers in archaeological sites and the monitoring of geological structures like volcanoes. The two main approaches to muon radiography are based on the effects of multiple Coulomb scattering and on absorption inside the target of atmospheric muons. The results of a Monte Carlo feasibility study of using muon radiography to investigate the presence of high-Z material (e.g. uranium) inside nuclear waste storage facilities using both the above mentioned techniques are presented. Albeit muon radiography has already been successfully applied to this kind of investigation in the past, this is the first time that it is benchmarked against the detection of cm-sized, high-Z samples inside building-sized storage facilities. For both multiple scattering and absorption approaches, preliminary results show that uranium samples of typical size greater than 5 cm can be detected inside a storage silo with a size of some meter filled with concrete, with a data taking period of several weeks. Smaller samples with size 2 cm are not detectable due to multiple scattering within the concrete matrix. The dependence of these results on the position of the samples and on the duration of data acquisition have been investigated and are reported as well, together with an estimate of the detection probability for fake signals.

Measurement of the transverse momentum spectrum of the Higgs boson decaying into WW at 8 TeV with the CMS detector

Differential and integrated fiducial cross sections measured using the Higgs to W+Wleptonic decays are presented as a function of the Higgs boson production. The measurements are performed using pp collisions at a centre-of-mass energy of 8 TeV collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 19.4 fb-1. The Higgs boson transverse momentum is reconstructed using the lepton pair transverse momentum and missing transverse momentum, which originates from the presence of two neutrinos in the final state. The differential cross section is measured as a function of the Higgs boson transverse momentum in a fiducial phase space defined to match the experimental acceptance in terms of the lepton kinematics and event topology. The measurements are compared to theoretical calculations. Presented at LHCP2016 Fourth annual Large Hadron Collider Physics Measurement of the transverse momentum spectrum of the Higgs boson decaying into WW at 8 TeV with the CMS detector Lorenzo Viliani∗† INFN Sezione di Firenze, Universita di Firenze, Firenze, Italy Also at CERN, European Organization for Nuclear Research, Geneva, Switzerland E-mail: lorenzo.viliani@cern.ch Differential and integrated fiducial cross sections measured using the Higgs to W+W− leptonic decays are presented as a function of the Higgs boson production. The measurements are performed using proton-proton collisions at a centre-of-mass energy of 8 TeV collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 19.4 fb−1. The Higgs boson transverse momentum is reconstructed using the lepton pair transverse momentum and missing transverse momentum, which originates from the presence of two neutrinos in the final state. The differential cross section is measured as a function of the Higgs boson transverse momentum in a fiducial phase space defined to match the experimental acceptance in terms of the lepton kinematics and event topology. The measurements are compared to theoretical calculations. Fourth Annual Large Hadron Collider Physics 13-18 June 2016 Lund, Sweden ∗Speaker. †On behalf of the CMS Collaboration c