This paper describes a small prototype of an in beam PET like detector, named ”Large Acceptance Pixelized Detector” (LAPD), developed to test technical concepts for the ion range control in the ...context of cancer treatments using proton or ion beams. The mechanical characteristics of this detector together with the read-out electronics are first presented. Then, results of a first experiment, performed on a 65 MeV proton beamline, are reported. Finally, we discuss the ability of Geant4 Monte-Carlo to reproduce the experimental data.
A software tool, computing observed and expected upper limits on Poissonian process rates using a hybrid frequentist-Bayesian CLs method, is presented. This tool can be used for simple counting ...experiments where only signal, background and observed yields are provided or for multi-bin experiments where binned distributions of discriminating variables are provided. It allows the combination of several channels and takes into account statistical and systematic uncertainties, as well as correlations of systematic uncertainties between channels. It has been validated against other software tools and analytical calculations, for several realistic cases.
Program Title:OpTHyLiC
Program Files doi:http://dx.doi.org/10.17632/2jv8ytrhcg.1
Licensing provisions: GPLv3
Programming language: C++
Supplementary material:http://opthylic.in2p3.fr
Nature of problem: computation of limits on Poissonian process rates in presence of background when no signal is observed, taking correctly into account statistical and systematic uncertainties, in particular correlations of systematic uncertainties between samples and channels.
Solution method: a C++ library to be used together with the ROOT C++ package, using a hybrid frequentist-Bayesian CLs method; the optimisation of the program typically reduces the limit computation time down to less than a few minutes in realistic cases.
Additional comments including Restrictions and Unusual features: the ROOT software is necessary.
Towards a muon radiography of the Puy de Dôme Cârloganu, C.; Niess, V.; Béné, S. ...
Geoscientific instrumentation, methods and data systems,
02/2013, Letnik:
2, Številka:
1
Journal Article
Recenzirano
Odprti dostop
High-energy (above a few hundred GeV) atmospheric muons are a natural probe for geophysical studies. They can travel through kilometres of rock allowing for a radiography of the density distribution ...within large structures, like mountains or volcanoes. A collaboration between volcanologists, astroparticle and particle physicists, Tomuvol was formed in 2009 to study tomographic muon imaging of volcanoes with high-resolution, large-scale tracking detectors. We report on two campaigns of measurements at the flank of the Puy de Dôme using glass resistive plate chambers (GRPCs) developed for particle physics, within the CALICE collaboration.
The effect of the intrinsic lutetium radioactivity on the detection performances of a LYSO based in-beam PET prototype used for quality control of hadron therapy treatments is studied. This ...radioactivity leads to a background that degrades the measurement of the \(\beta\) + signal. In particular, it prevents the measurement of faint signals originating from low activity \(\beta\) + sources. This paper presents a method to estimate the minimum \(\beta\) + activity that can be measured for any acquisition time taking into account the non-extensible dead time of the detector. This method is illustrated with experimental data collected with the in-beam PET prototype. The results presented in this paper are therefore specific to this detector. The method can however be applied in other contexts, either to other lutetium based PET detectors or even to non-PET detectors affected by lutetium radioactivity. The dead time correction formalism can also be used generally to scale signal and background yields in any non-paralizable detector, even those in which the background is not due to the presence of intrinsic radioactivity.
Muon imaging of volcanoes and of geological structures in general is actively being developed by several groups in the world. It has the potential to provide 3-D density distributions with an ...accuracy of a few percent. At this stage of development, comparisons with established geophysical methods are useful to validate the method. An experiment has been carried out in 2011 and 2012 on a large trachytic dome, the Puy de Dôme volcano, to perform such a comparison of muon imaging with gravimetric tomography and 2-D electrical resistivity tomography. Here, we present the preliminary results for the last two methods. North–south and east–west resistivity profiles allow us to model the resistivity distribution down to the base of the dome. The modelling of the Bouguer anomaly provides models for the density distribution within the dome that are directly comparable with the results from the muon imaging. Our ultimate goal is to derive a model of the dome using the joint interpretation of all sets of data.
The relation between hybrid CLs and bayesian methods used for limit setting is discussed. It is shown that the two methods are equivalent in the single channel case even when the background yield is ...not perfectly known. Only counting experiments are considered in this document.
A software tool, computing observed and expected upper limits on Poissonian process rates using a hybrid frequentist-Bayesian CLs method, is presented. This tool can be used for simple counting ...experiments where only signal, background and observed yields are provided or for multi-bin experiments where binned distributions of discriminating variables are provided. It allows the combination of several channels and takes into account statistical and systematic uncertainties, as well as correlations of systematic uncertainties between channels. It has been validated against other software tools and analytical calculations, for several realistic cases.
One of the main sources of background for the radiography of volcanoes using atmospheric muons comes from the accidental coincidences produced in the muon telescopes by charged particles belonging to ...the air shower generated by the primary cosmic ray. In order to quantify this background effect, Monte Carlo simulations of the showers and of the detector are developed by the TOMUVOL collaboration. As a first step, the atmospheric showers were simulated and investigated using two Monte Carlo packages, CORSIKA and GEANT4. We compared the results provided by the two programs for the muonic component of vertical proton-induced showers at three energies: 1, 10 and 100 TeV. We found that the spatial distribution and energy spectrum of the muons were in good agreement for the two codes.
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