High rate, fast timing Glass RPC for the high η\eta CMS muon detectors

The HL-LHC phase is designed to increase by an order of magnitude the amount of data to be collected by the LHC experiments. To achieve this goal in a reasonable time scale the instantaneous luminosity would also increase by an order of magnitude up to $6 \cdot 10^{34}$ cm$^{-2}$s$^{-1}$. The region of the forward muon spectrometer ($|\eta| > 1.6$) is not equipped with RPC stations. The increase of the expected particles rate up to 2 kHz/cm$^2$ ( including a safety factor 3 ) motivates the installation of RPC chambers to guarantee redundancy with the CSC chambers already present. The actual RPC technology of CMS cannot sustain the expected background level. A new generation Glass-RPC (GRPC) using low resistivity glass (LR) is proposed to equip at least the two most far away of the four high eta muon stations of CMS. The design of small size prototypes and the studies of their performances under high rate particles flux is presented.Comment: 5 pages, 5 figures, proceeding for the conference VCI 201

Fast plastic scintillator and SiPM based devices for FLASH beams monitoring

International audienceNew cancer treatment modalities are being developed in order to further improve the dose delivery to the tumor while sparing healthy tissues. Such a gain could be obtained by further optimizing the spatial dose distribution for example using mini-beams. Another technique based on temporal optimization, called FLASH therapy, which uses ultra high dose rates, is currently under development. For these particular beams instantaneous dose-rates or doses-per-pulse are up to several orders of magnitude greater than those produced by conventional radiation sources. Conventional active dosimeters (diode or ionization chamber) saturate in the ultra high dose rates (UHDR) irradiation, consequently on-line dosimetry of the beam cannot easily be performed with such devices. CEA-LIST, in the frame of ASTROLABE project (funded by INSERM) and in collaboration with Institut Curie, is developing a dedicated dosimeter for FLASH beams, based on optimised fast plastic scintillator coupled to a silicon photomultiplier (SiPM) sensor. A set-up made of a homemade formulated plastic scintillator, tuned in response time and wavelength emission, a wave guide, a SiPM and its electronic readout is produced. This device is tested on standard therapy beams at DOSEO plateform in CEA-Saclay and with electrons FLASH beams at Institut Curie in Orsay. The Cerenkov contribution is corrected for all measurements by using twin set-up without plastic scintillator. In this work, we will present for the first time experimental results obtained with this optimised fast plastic scintillator coupled to SiPM sensor in FLASH beams : modification of the choice of scintillator used and the assembling phase is presented with the characterisation in laboratory using radioactives sources and standard therapy beams. Following this step, first characterisation results obtained with FLASH electron beams are presented and compared to standard devices

Collision induced dissociation of protaned water clusters studies with the COINTOF mass spectrometry technique : development of a target of rare gas droplets

L'étude de l'irradiation dans le système moléculaire à l'échelle du nanomètre est un domaine d'investigation innovant des sciences des radiations. Le Dispositif d'Irradiation d'Agrégats Moléculaires (DIAM) est conçu en vue les conséquences de l'irradiation dans des petits systèmes moléculaires modèles comme les agrégats d'eau protonés. L'irradiation provoque la fragmentation en plusieurs fragments neutres ou chargés. La technique de spectrométrie de masse COINTOF (Correlated Ion and Neutral Time of Flight) permet la détection corrélées des fragments neutres et chargés issus de la dissociation d'un système moléculaire préalablement sélectionné en masse et en vitesse. Les données collectées sont traitées et structurées pour permettre l'analyse statistique des corrélations sur un grand nombre d'événements de fragmentation. Parallèlement à l'identification des canaux de fragmentation, la technique COINTOF permet la mesure de leur rapport de branchement et de leur section efficace. La méthode est présentée pour la dissociation induite par collision sur un atome d'argon, d'agrégats d'eau protonés H+(H2O)n:[2;7], accélérés à 8keV. L'efficacité de détection, information déterminante pour la production de données quantitatives, est mesurée à partir des données et étudiée en fonction de la distribution l'amplitude des signaux de détection. Enfin, un nouveau système de cible constituée de nanogouttes de gaz rares a été développéThe study of irradiation in molecular systems at the nanometer scale is an innovative field of research in radiation sciences. The DIAM set-up (Dispositif d'Irradiation d'Agrégats Moléculaires) is designed in order to observe and to characterize the consequences of radiation action on model molecular nanosystems such as protonated water clusters. Irradiation induces the fragmentation of the nanosystem in several neutral and charged fragments. The COINTOF (Correlated Ion and Neutral fragments Time of Flight) mass spectrometry techniques allows the correlated detection of the neutral and charged fragments resulting from the dissociation of a mass and velocity selected molecular system. The data processing is performed before the statistical analysis of the fragment production over a large number of fragmentation events. In parallel with the fragmentation channel identification, branching ratio and cross sections are measured with the COINTOF technique. The method is presented here for the collision induced dissociation on argon atoms of protonated water clusters H+(H2O)n, n=2-7, accelerated at 8keV. The detection efficiency, key parameter for the production of quantitative results, is measured from the set of data itself and studied as a function of the amplitude distribution of the detection signal. Finally, a new set-up for production of rare-gas nanodroplets target has been develope

Application de la spectrométrie de masse COINTOF à l'étude de la dissociation de petits agrégats d'eau protonés par collision sur un atome d'argon : développement d'une cible de nano-gouttes de gaz rare

The study of irradiation in molecular systems at the nanometer scale is an innovative field of research in radiation sciences. The DIAM set-up (Dispositif d'Irradiation d'Agrégats Moléculaires) is designed in order to observe and to characterize the consequences of radiation action on model molecular nanosystems such as protonated water clusters. Irradiation induces the fragmentation of the nanosystem in several neutral and charged fragments. The COINTOF (Correlated Ion and Neutral fragments Time of Flight) mass spectrometry techniques allows the correlated detection of the neutral and charged fragments resulting from the dissociation of a mass and velocity selected molecular system. The data processing is performed before the statistical analysis of the fragment production over a large number of fragmentation events. In parallel with the fragmentation channel identification, branching ratio and cross sections are measured with the COINTOF technique. The method is presented here for the collision induced dissociation on argon atoms of protonated water clusters H+(H2O)n, n=2-7, accelerated at 8keV. The detection efficiency, key parameter for the production of quantitative results, is measured from the set of data itself and studied as a function of the amplitude distribution of the detection signal. Finally, a new set-up for production of rare-gas nanodroplets target has been developedL'étude de l'irradiation dans le système moléculaire à l'échelle du nanomètre est un domaine d'investigation innovant des sciences des radiations. Le Dispositif d'Irradiation d'Agrégats Moléculaires (DIAM) est conçu en vue les conséquences de l'irradiation dans des petits systèmes moléculaires modèles comme les agrégats d'eau protonés. L'irradiation provoque la fragmentation en plusieurs fragments neutres ou chargés. La technique de spectrométrie de masse COINTOF (Correlated Ion and Neutral Time of Flight) permet la détection corrélées des fragments neutres et chargés issus de la dissociation d'un système moléculaire préalablement sélectionné en masse et en vitesse. Les données collectées sont traitées et structurées pour permettre l'analyse statistique des corrélations sur un grand nombre d'événements de fragmentation. Parallèlement à l'identification des canaux de fragmentation, la technique COINTOF permet la mesure de leur rapport de branchement et de leur section efficace. La méthode est présentée pour la dissociation induite par collision sur un atome d'argon, d'agrégats d'eau protonés H+(H2O)n:[2;7], accélérés à 8keV. L'efficacité de détection, information déterminante pour la production de données quantitatives, est mesurée à partir des données et étudiée en fonction de la distribution l'amplitude des signaux de détection. Enfin, un nouveau système de cible constituée de nanogouttes de gaz rares a été développ

Development of a hybrid radiation monitor based on NaI(Li+Tl) and PVT scintillators for homeland security

International audienceThe current geopolitical context and the national requirements of a continuous survey in strategical high frequency civil zones such as airports, seaports and train stations conduct to a growing need to develop performant radiation monitors. In this framework, LIST Institute from CEA Paris-Saclay is currently investigating the development of a novel system based on the coupling of inorganic/organic scintillators, respectively NaILTM from Saint-Gobain Crystals and EJ-200 and plastic scintillators from Eljen technology. Traditional technologies are mainly based on either gamma-ray sensible detectors such as for instance NaI(Tl) like the DIRAD radiological monitor, either on neutron detectors such as classical Radiation Portal Monitors (RPM) based on 3He counters. Recent generation RPM based on plastic scintillators only, proposed for instance by Bertin Technologies or Symetrica Inc., allows both gamma and neutron signatures detection. Nevertheless, their radiological identification capabilities are limited due to the low energy resolution of PVT. To counter this drawback, we hereby propose to deploy NaILTM scintillators, which present similar energy resolution capabilities than traditional NaI(Tl), allowing the identification of distinct radiological threats. Moreover, these detectors discriminate radiological from nuclear threats by means of Pulse Shape Discrimination (PSD) using 6Li component and associated 6Li(n,α)3H reaction. Additional PVT organic scintillators surrounding the NaILTM detectors enable an optimal thermalization of the incident neutron flux in presence of a nuclear threat. In addition, the collected signal of interest (total energy spectra and incident particles detected in coincidence) provides additional information on the threat's nature and increases the systems sensitivity. First proof-of-concept experiments with a 3× 3 NaILTM detector surrounded by cylindrical shaped EJ-200 scintillators and a CAEN® DT5730B digitizer are reported in this paper

NaTIF Radiation Portal Monitor performances optimization by means of multi-parametric analysis

International audienceNaTIF (NaIL-based Threats radIation emitters Finder) is a patented new generation Radiation Portal Monitor (RPM) under current development in CEA LIST Institute. This technology aims at proposing a RPM to be deployed in highly frequented civil zones and national borders in order to ensure their control and protection against radiological and nuclear threats. The technology is based on the use of inorganic scintillators [NaI:Tl(6Li)], denoted hereafter as NaILTM. These detectors are price attractive and relevant for the identification of both radiological and nuclear signatures. Indeed, in terms of gamma spectrometry, the state of the art shows that these scintillators have an energy resolution close to classical NaI:Tl detectors close to 6-8% for the Cs-137 gamma ray at 661.7 keV. Moreover, those scintillators are doped with 6Li. This allows to detect gamma and neutron signatures and to separate each contribution by means of Pulse Shape Discrimination (PSD), with important discrimination capabilities given by a Figure of Merit (FoM) estimated at 3.8 in the scope of the current work. The small scale RPM currently studied mainly consists in the combination of two NaILTM detectors with three EJ-200 plastic scintillators [Fig.1A]. Each detector has an active scintillation volume of 1000 cm3. The use of EJ-200 detectors enhances the neutron sensitivity of the global RPM as they are used as neutron detectors as well as moderators. All detectors are biased independently using a DT8033M CAEN® power supply delivering both positive and negative high voltage. Associated output signals are collected and treated with a CAEN® DT5730SB digitizer coupled to CoMPASS software. Signal processing is done according to the settings implemented on the software such as: Charge integration short and long gates for PSD computations, Constant Fraction Discrimination (CFD) set of parameters, signal smoothing and corresponding threshold, etc. The present study aims at optimizing technical and operating performances in accordance with specifications for the global RPM, using multi-parametric analysis. This, firstly done on NaILTM detection systems, includes the tuning of hardware parameters such as the high voltage and associated gain and threshold with the software set parameters of CoMPASS in order to minimize the energy resolution [Fig.1B], to maximize the FoM for gamma/neutron discrimination [Fig.1C], and to detect the low energy gamma rays of interest emitted by radiological threats such as the 59.5 keV gamma rays from Am-241 [Fig.1D]. Reported results associated to parametric performances optimization were processed in a laboratory environment with Cs-137, AmBe, and Am-241 radiological simulants

Fast plastic scintillator and SiPM based devices for FLASH beams monitoring

International audienceRecent developments on new cancer treatment modalities show an improvement of the dose delivery to the tumor while sparing healthy tissues. Among those, FLASH therapy based on the use of low energy electron beams at very high dose rates is a promising technique. However, for these beams, doses-per-pulse are up to several orders of magnitude higher than those produced by conventional radiation sources. In these conditions, conventional active dosimeters as diodes or ionization chambers saturate. Consequently, such devices cannot be used to ensure the on-line dosimetry of those beams. Moreover, passive dosimeters as EBT are not very well adapted for clinical uses in routine. In this context, CEA-LIST, in the frame of ASTROLABE (fAst ScinTillatoR based device for On line FLASH BEam dosimetry) project, in collaboration with Institut Curie, is developing a dedicated point dosimeter for FLASH beams monitoring. This alternative technologyis based on the coupling of a homemade fast plastic scintillator (water equivalent), tuned in response time and wavelength emission, with a PMMA waveguide and a silicon photomultiplier sensor (SiPM). Moreover, in order to estimate the Cerenkov contribution, a twin device without plastic scintillator is also produced. This talk aims to present the development steps and results obtained from these both devices. Those include fast plastic scintillator selection after theircharacterization in laboratory, using ¹³⁷Cs radioactive source, point dosimeters assembly phases and measurements performed under electron FLASH beams (7 MeV), in Institut Curie, in Orsay