MAROC: Multi-Anode ReadOut Chip for MaPMTs

International audienceFor the ATLAS luminometer, made of Roman pots, a complete readout ASIC has been designed in 0.35 SiGe technology. It is used to readout 64 channels multi anode photomultipliers and supplies 64 trigger outputs and a multiplexed charge. Since its delivery in November 2005, the MAROC chip has been tested at LAL. Despite a substrate coupling effect which affects the performance when all channels are used in high gain, the chip has shown nice global behavior and it has been used during beam tests at CERN in October 2006

Development of an Anger camera in Lanthanum Bromide for gamma-ray space astronomy in the MeV range

International audienceLanthanum bromide is a very promising scintillator material for the next generation of g-ray telescopes. We present in this paper first g-ray imaging results obtained by coupling a LaBr3 crystal with a position-sensitive 8×8 multianode photomultiplier tube to form a simple Anger camera module. The readout of the 64 signals is carried out with the most recent evolution of the MultiAnode ReadOut Chip (MAROC) which was initially designed for the luminometer of the ATLAS detector. Measured charge distributions are compared with detailed GEANT4 simulations that include the tracking of the optical photons produced in the scintillation crystal. The depth of interaction (d.o.i.) of 662-keV g-rays inside the crystal is derived from the charge distributions using an artificial neural network. We obtain for an irradiation at detector centre a mean standard deviation of the d.o.i. of 1.69 mm. Such a position-sensitive g-ray detector can form an innovative building block for a future space calorimete

PMF the front end electronic for the ALFA detector

International audienceThe PMF (Photo Multiplier Front end) is the front end electronics designed for the ATLAS luminometer ALFA (Absolute Luminosity For ATLAS) made of 20 staggered U-V scintillating fiber layers inserted in Roman Pots (eight in total). Each of these plans is made of 64 fibers. The PMF consists of a 64 channels photomultiplier (MAPMT) and a very compact stack of three different PCBs (3x3 cm2), mounted directly on the back and in the shadow of the MAPMT: a board which brings the high voltage to the MAPMT, an intermediate board used to send the signals to connectors located on the edge and, finally, a board with the readout chip MAROC (Multi Anode Read Out Chip), directly bonded on the PCB, on one side and a FPGA on the other. The 64 inputs MAROC ASIC allows correcting for the gain spread of MAPMT channels thanks to a 6 bits variable gain preamplifier. For each channel the signal is shaped (fast shaper, 15ns) and discriminated to produce a trigger output. A multiplexed charge output is also produced both in analog and digital thanks to a Wilkinson ADC. The main requirements are the following: 100 % trigger efficiency for a signal greater than 1/3 of a photoelectron, a charge measurement up to 30 photoelectrons with a linearity of 2 % or better and a cross talk of 1 % or less. The performances of the second version of MAROC were checked successfully during the year 2007 at LAL-Orsay. A nice dispersion of the trigger output (± 5 fC) was, in particular, observed. A sample of PMFs was produced during autumn 2007 as a prototype. Laboratory tests were performed both at LAL and CERN respectively on the third PCB (the one with MAROC) and on a full PMF equipped with a MAPMT illuminated by a LED. They were carried out using dedicated test board and acquisition software and have allowed the approval of the design and the green light for the final production and integration with the detector. Beam tests of a complete Roman Pot, equipped with 23 PMFs, will take place during summer 2008 for two periods and will conclude the test phase and mark the beginning of the final production

Hadron beam test of a scintillating fibre tracker system for elastic scattering and luminosity measurement in ATLAS

A scintillating fibre tracker is proposed to measure elastic proton scattering at very small angles in the ATLAS experiment at CERN. The tracker will be located in so-called Roman Pot units at a distance of 240 m on each side of the ATLAS interaction point. An initial validation of the design choices was achieved in a beam test at DESY in a relatively low energy electron beam and using slow off-the-shelf electronics. Here we report on the results from a second beam test experiment carried out at CERN, where new detector prototypes were tested in a high energy hadron beam, using the first version of the custom designed front-end electronics. The results show an adequate tracking performance under conditions which are similar to the situation at the LHC. In addition, the alignment method using so-called overlap detectors was studied and shown to have the expected precision.Comment: 12 pages, 8 figures. Submitted to Journal of Instrumentation (JINST

Position resolution and particle identification with the ATLAS EM calorimeter

In the years between 2000 and 2002 several pre-series and series modules of the ATLAS EM barrel and end-cap calorimeter were exposed to electron, photon and pion beams. The performance of the calorimeter with respect to its finely segmented first sampling has been studied. The polar angle resolution has been found to be in the range 50-60 mrad/sqrt(E (GeV)). The neutral pion rejection has been measured to be about 3.5 for 90% photon selection efficiency at pT=50 GeV/c. Electron-pion separation studies have indicated that a pion fake rate of (0.07-0.5)% can be achieved while maintaining 90% electron identification efficiency for energies up to 40 GeV.Comment: 32 pages, 22 figures, to be published in NIM

An evaluation of the exposure in nadir observation of the JEM-EUSO mission

We evaluate the exposure during nadir observations with JEM-EUSO, the Extreme Universe Space Observatory,on-board the Japanese Experiment Module of the International Space Station. Designed as a mission to explore the extreme energy Universe from space, JEM-EUSO will monitor the Earth's nighttime atmosphere to record the ultraviolet light from tracks generated by extensive air showers initiated by ultra-high energy cosmic rays. In the present work, we discuss the particularities of space-based observation and we compute the annual exposure in nadir observation. The results are based on studies of the expected trigger aperture and observational duty cycle, as well as, on the investigations of the effects of clouds and different types of background light. We show that the annual exposure is about one order of magnitude higher than those of the presently operating ground-based observatories.Fil: Adams, J. H.. University of Alabama in Huntsville; Estados UnidosFil: Ahmad, S.. Universite Paris Sud; FranciaFil: Albert, J. N..Fil: Allard, D.. Universite Paris Diderot - Paris 7; FranciaFil: Ambrosio, M.. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Anchordoqui, L.. Medical College Of Wisconsin; Estados UnidosFil: Anzalone, A.. INAF; ItaliaFil: Arai, Y.. High Energy Accelerator Research Organization (KEK); JapónFil: Aramo, C..Fil: Asano, K.. Interactive Research Center of Science, Tokyo Institute of Technology; JapónFil: Ave, M.. Universidad de Santiago de Compostela; EspañaFil: Barrillon, P.. Universite de Paris; FranciaFil: Batsch, T.. National Centre for Nuclear Research; PoloniaFil: Bayer, J.. University of Tubingen; AlemaniaFil: Belenguer, T.. j Instituto Nacional de Técnica Aeroespacial (INTA); EspañaFil: Bellotti, R.. Universita’ degli Studi di Bari Aldo Moro and INFN; ItaliaFil: Berlind, A. A.. Vanderbilt University; Estados UnidosFil: Bertaina, M.. Universita di Torino; ItaliaFil: Biermann, P. L.. Karlsruhe Institute of Technology (KIT); AlemaniaFil: Biktemerova,. Joint Institute for Nuclear Research; RusiaFil: Blaksley, C.. Universite de la Sorbona Nouvelle; FranciaFil: Blecki, J.. Space Research Centre of the Polish Academy of Sciences (CBK); PoloniaFil: Blin-Bondil, S.. Universite de Paris; FranciaFil: Blumer, J.. Karlsruhe Institute of Technology (KIT),; AlemaniaFil: Bobik, P.. Institute of Experimental Physics; EslovaquiaFil: Bogomilov, M.. St. Kliment Ohridski University of Sofia; BulgariaFil: Bonamente, M.. University of Alabama in Huntsville; Estados UnidosFil: Briz, S.. Universidad Carlos III de Madrid,; EspañaFil: Supanitsky, Alberto Daniel. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentin

Characteristics of a prototype matrix of Silicon PhotoMultipliers (SiPM)

International audienceThis work reports on the electrical (static and dynamic) as well as on the optical characteristics of a prototype matrix of Silicon Photomultipliers (SiPM). The prototype matrix consists of 4 × 4 SiPM's on the same substrat fabricated at FBK-irst (Trento, Italy). Each SiPM of the matrix has an area of 1 × 1mm2 and it is composed of 625 microcells connected in parallel. Each microcell of the SiPM is a GM-APD (n+/p junction on P+ substrate) with an area of 40 × 40 μm2 connected in series with its integrated polysilicon quenching resistance. The static characteristics as breakdown voltage, quenching resistance, post-breakdown dark current as well as the dynamic characteristics as gain and dark count rate have been analysed. The photon detection efficiency as a function of wavelength and operation voltage has been also estimated

Global Description of EUSO-Balloon Instrument

For the JEM-EUSO CollaborationThe EUSO-Balloon is a pathfinder of the JEM-EUSO mission, designed to be installed on-board the International Space Station before the end of this decade. The EUSO-Balloon instrument, conceived as a scaleddown version of the main mission, is currently developed as a payload of a stratospheric balloon operated by CNES, and will, most likely, be launched during the CNES flight campaign in 2014. Several key elements of JEM-EUSO have been implemented in the EUSO-Balloon. The instrument consists of an UV telescope, made of three Fresnel lenses, designed to focus the signal of the UV tracks, generated by highly energetic cosmic rays propagating in the earth's atmosphere, onto a finely pixelized UV camera. In this contribution, we review the main stages of the signal processing of the EUSO-Balloon instrument: the photodetection, the analog electronics, the trigger stages, which select events while rejecting random background, the acquisition system performing data storage and the monitoring, which allows the instrument control during operation

Science of atmospheric phenomena with JEM-EUSO

The main goal of the JEM-EUSO experiment is the study of Ultra HighEnergy Cosmic Rays (UHECR, 10^19 - 10^21 eV ), but the method which will be used (detection of the secondary light emissions induced by cosmic rays in the atmosphere) allows to study other luminous phenomena. The UHECRs will be detected through the measurement of the emission in the range between 290 and 430 m, where some part of Transient Luminous Events (TLEs) emission also appears. This work discusses the possibility of using the JEM-EUSO Telescope to get new scientific results on TLEs. The high time resolution of this instrument allows to observe the evolution of TLEs with great precision just at the moment of their origin. Thepaper consists of four parts: review of the present knowledge on the TLE, presentation of the results of the simulations of the TLE images in the JEM-EUSO telescope, results of the Russian experiment Tatiana-2 and discussion of the possible progress achievable in this field with JEM-EUSO as well as possible cooperation with other space projects devoted to the study of TLE-TARANIS and ASIM. In atmospheric physics, the study of TLEs became one of the main physical subjects of interest after their discovery in 1989. In the years 1992 - 1994 detection was performed fromsatellite, aircraft and space shuttle and recently from the International Space Station. These events have short duration (milliseconds) and small scales (km to tens of km) and appear at altitudes 50 - 100 km. Their nature is still not clear and each new experimental data can be useful for a better understanding of these mysterious phenomena.Fil: Adams, J. H.. University of Alabama in Huntsville; Estados UnidosFil: Ahmad, S.. Ecole Polytechnique; FranciaFil: Albert, J. N.. Univ Paris-Sud; FranciaFil: Allard, D.. Univ Paris Diderot; FranciaFil: Anchordoqui, L.. University of Wisconsin-Milwaukee; Estados UnidosFil: Andreev, V.. University of California; Estados UnidosFil: Anzalone, A.. INAF - Istituto di Astrofisica Spaziale e Fisica Cosmica di Palermo; ItaliaFil: Arai, Y.. High Energy Accelerator Research Organization (KEK); JapónFil: Asano, K.. Tokyo Institute of Technology; JapónFil: Ave Pernas, M.. Universidad de Alcala (UAH); EspañaFil: Barrillon, P.. Univ Paris-Sud; FranciaFil: Batsch, T.. Skobeltsyn Institute of Nuclear Physics; RusiaFil: Bayer, J.. University of Tubingen; AlemaniaFil: Bechini, R.. Universita’ di Torino; ItaliaFil: Belenguer, T.. Instituto Nacional de Tecnica Aeroespacial (INTA); EspañaFil: Bellotti, R.. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Belov, K.. University of California; Estados UnidosFil: Berlind, A. A.. Vanderbilt University; Estados UnidosFil: Bertaina, M.. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Biermann, P. L.. Karlsruhe Institute of Technology (KIT); AlemaniaFil: Biktemerova, S.. Joint Institute for Nuclear Research; RusiaFil: Blaksley, C.. Univ Paris Diderot; FranciaFil: Blanc, N.. Swiss Center for Electronics and Microtechnology (CSEM); SuizaFil: Blecki, J.. Space Research Centre of the Polish Academy of Sciences (CBK; PoloniaFil: Blin-Bondil, S.. Ecole Polytechnique; FranciaFil: Blumer, J.. Karlsruhe Institute of Technology (KIT),; AlemaniaFil: Bobik, P.. Institute of Experimental Physics; EslovaquiaFil: Bogomilov, M.. University of Sofia; BulgariaFil: Bonamente, M.. University of Alabama in Huntsville; Estados UnidosFil: Supanitsky, Alberto Daniel. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: The JEM-EUSO Collaboration