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List of contributions
Logistic Saturated Avalance Model
Presented by: G. Aielli
G. Aielli, P. Camarri, R. Cardarelli, A. Di Ciaccio, B. Liberti, A. Paoloni, R. Santonico
Università di Roma ""Tor Vergata"" INFN Sez. ROMA 2
The simple exponential model can describe the electronic multiplication phenomena in the gas with acceptable accuracy until the external electric field is not perturbed by the growing avalanche. We present here a simple model in which the saturated growth induced by the space charge effects is explained in a natural way by a simple constant coefficient non linear differential equation, strictly connected to the Logistic function, which was originally introduced to describe the evolution of a biological population in a limited resources environment.Due to the uniform and intense field, RPCs are an ideal device to study the saturated discharge. Furthermore the introduction of SF6 in the mixture as a powerful streamer suppressor, made the study of deeply saturated avalanche regime possible.We present here also a set of experimental tests supporting the model
Detailed Models for Timing and Crosstalk in Resistive Plate Chambers
Presented by: W. Riegler
Werner Riegler
CERN EP Geneve 23
We discuss detailed models for detector physics processes in Resistive Plate Chambers, in particular including the effect of attachment and large electric fields on the avalanche statistics. In addition we present analytic formulas for average charges, signals and intrinsic RPC time resolution. Using a Monte Carlo simulation including all the steps from primary ionization to the front-end electronics we discuss the dependence of efficiency and time resolution on detector physics parameters like primary ionization, avalanche statistics as well as electronics parameters like peaking time, noise and threshold. We discuss crosstalk in RPCs with long readout electrodes by regarding the RPC as a multi-conductor transmission line. Using a simple matrix formalism we find very general results for the absolute crosstalk numbers as well as the dependence of crosstalk on amplifier input impedance, propagation delay and amplifier bandwidth. In addition we discuss the complex issue of termination of a multi-conductor line.
Space Charge Effects and Induced Signals in Resistive Plate Chambers
Presented by: C. Lippmann
Christian Lippmann (1) , Bernhard Schnizer (2)
(1) CERN EP, Geneve
(2) Institut fuer Theoretische Physik, Technische Universtitaet Graz, Austria
We present analytic solutions for the static electric field of a point charge in a three layer geometry with different permittivities (a RPC). Special integral representations of the solutions allow easy numerical evaluation for simulation applications. Using these solutions we calculate the effect of the space charge on the electric field in the gas gap, hence the Townsend coefficient and the evolution of the avalanche. In addition to longitudinal diffusion we include transverse diffusion by distributing the charge in discs vertical to the direction of the movement of the electrons following a Gaussian distribution with a sigma increasing towards the anode. This procedure allows a careful study of avalanche saturation for different detector physics parameters. A detailed Monte Carlo simulation was developed which allows calculation of the actual charge spectrum. The field solutions of a point charge in the resistive layer of an RPC is used to calculate the effect ofthe draining off charge on the electric field in the gas gap, which is directly related to the rate capability of the RPC.Results of this simulation are presented, using the example of a Trigger-RPC with 2mm gas gap, similar to the ones used by ATLAS, (ATLAS TDR 10, CERN-LHCC-97-22) and a Timing RPC with 300 micron gas gap (Fonte et. al. NIM A449 (2000) 295-301).Finally we also present analytic solutions for the weighting fields of RPC readout strips and pads for the geometry mentioned above, which allow to calculate the directly induced crosstalk.
The Time Response Function of Spark Counters
Presented by: A.Mangiarotti
A.Gobbi*, A.Mangiarotti**
*Gesellschaft fuer Schwerionenforschung, Darmstadt, Germany
**Universita` degli Studi di Firenze, Firenze, Italy
Spark counters of the type developed by Yu.Pestov are attractive for time of flight measurements, because they can reach resolutions of ~50 ps and can operate inside a magnetic field.However the response function shows, on the side of delayed events, a tail(~10% for delays > 300 ps), which can be very disturbing in experiments were rare particles have to be identified.The tail and the resolution were seen to show, while changing the strength of the electric field or the type of noble gas, a correlated increase with the mean time delay of the spark.The response function of a spark counter can be calculated analytically starting from the well known Furry and Polya laws for fluctuations in multiplication at constant length using a threshold hypothesis (Raether condition) for the transition from the avalanche to the streamer. Such a theory reproduces very well the shape of the experimental spectra and gives as a fundamental time scale for fluctuations 1/aVd where a is the Townsend first ionization coefficient and Vd is the electrons drift velocity.The basic ingredients to calculate the time fluctuations are the same as the one for the fluctuations in multiplication which have already been studied extensively in the past. In such a theory however the absolute magnitude of the luctuations can be reproduced only if the space charge effects are taken into account at large multiplications (>105 %106); this situation is not unexpected since the avalanche streamer transition is known to be driven by such effects.A field drop at breakdown of 25-30% is found to be enough to increase the fluctuation time scale 1/aVd of the factor 6 needed to reproduce the experimental observations.The strongest evidence in favor of the presented approach and interpretation is its ability to reproduce the correlated increase of the resolution and the amount of tail with the mean time delay of the spark while changing voltage and noble gas in the mixture. As compared to spark counters, the operation of RPC (Resistive Plate Chambers) counters has the advantage to measure the time at a threshold in multiplication, given by the discriminator, of about 105 (as opposed to the value of approx 108 of the Raether condition) so that for RPC's the large fluctuations in the region of the space charge effects are not contributing to the overall time resolution.
Laser beam studies of RPC behaviour in avalanche mode
Author: V. Golovatyuk
V.Golovatyuk, F.Grancagnolo, R.Perrino
Sezione di Lecce, Lecce, Italy
Primary ionization inside the gas gap of a small size (10 x 20 cm2) RPC, analagous to the RPC of the ATLAS muon detector is created by focusing (transversed diameter ~15 mm ) a pulsed (rise time <1 ns) nitrogen laser beam. With this setup we have studied the effects of small additions of SF6 to C2H2F4 - 3 % isobutane gas mixture on drift velocity and gas amplification. Limitations due to space charge are quantified in terms of high rate capability of the RPC.
Optical study of the features of the streamer images in RPC
Presented by: T. Takahashi
K.Abe (1), Y.Hoshi (1), T.Nagamine (2), K.Neichi (3), K.Onodera (1), T.Takahashi (1), A.Yamaguchi (2), H.Yuta (4)
(1) Dept. of Applied Physics, Tohoku Gakuin University, Tagajo,
JAPAN
(2) Dept. of Physics, Tohoku University, Sendai,JAPAN
(3) Dept. of Commerce, Tohoku Gakuin University, Sendai, JAPAN
(4) Dept. of Engineering, Aomori University, Aomori, JAPAN
Optical images of the streamer in a RPC have been observed for self-triggered in vertical and horizontal view, operated in the streamer mode with various gas mixtures (Ar + Butane with/without HFC134a). Streamer images were taken by using an image intensifier and a CCD camera system. The analysis of the streamer image might be useful for us to design the pickup strip width for the readout. In this workshop we report on a shape of the streamer in vertical and horizontal view as a function of gas mixing ratio.
Effect of oiling and gas composition on the stability of the RPC operation
Presented by: M. Cwiok
Mikolaj Cwiok(1), Maciej Gorski (2), Wojciech Dominik (1), Jan Krolikowski (1)
(1) Institute of Experimental Physics, Warsaw University, Warsaw,
Poland
(2) Soltan's Institute for Nuclear Studies, PL-00-681, Warsaw, Poland
An Inverted Double Gap RPC made of bakelite of 5*10^9 Ohm*cm specific resistivity was tested in the Gamma Irradiation Facility at CERN in years 2000 and 2001. For the 2001 measurements the inner surfaces of the chamber electrodes were cladded using linseed oil varnish. Several factors determining long term operation stability of the RPC such as gas composition and temperature effect will be discussed.
RPC operation at high temperature
Presented by: A. Paoloni
G. Aielli, P. Camarri, R. Cardarelli, A. Di Ciaccio, L. Di Stante, B. Liberti, A. Paoloni, E. Pastori, R. Santonico
University of Rome ""Tor Vergata"" and I.N.F.N. sezione Roma 2
The resistive electrodes of RPCs utilised in several current experiments (ATLAS, CMS, ALICE, BABAR and ARGO) are made of phenolic/melaminic polymers, with room temperature resistivities ranging from 1010 Wxcm, for detectors working at high rate typically in avalanche mode, to 5x1011 Wxcm, for streamer mode operation at low rate. The resistivity has however a strong temperature dependence, decreasing exponentially with increasing temperature. We have tested several RPCs with different electrode resistivity in avalanche as well as in streamer operation. The behaviours of the operating current and of the counting rate have been studied at different temperatures. Long term operation has also been performed at T=45 C and T=35 C, respectively for high and low resistivity electrode RPCs.
Study of the effect of water vapor on a glass RPC with and without freon
Presented by: Y. Teramoto
T. Kubo, H. Sakaue, Y. Teramoto, E. Nakano, and T. Takahashi
Institute for Cosmic Ray Physics, Faculty of Science, Osaka City University
Efficiencies of glass RPCs (two 1 mm gas gap and two 2 mm gas gap RPCs) have been measured, operated with water vapor (~1000 ppm) in the chamber gas with and without freon (C2H2F4).During the three months operation, efficiencies with the freon mixture dropped from ~90% (~90%) to ~10% (~40%) for the 2 mm (1 mm) gas gap chamber.With the freonless mixture, however, the drops of efficiencies were not significant: from ~80% (~85%) to ~70% (~85%) for the 2 mm (1 mm) gas gap chamber.
Freonless gas mixtures for glass RPC operated in streamer mode
Presented by: A.Yamaguch
Y.Hoshi (2), Y.Mikami (1), T.Nagamin (1), N,Takahashi (1), K.Watanabe (1), A.Yamaguchi (1), Y.Yusa (1)
(1) Tohoku University
(2) Tohoku-Gakuin University
We have operated successfully glass Resistive Plate Counters (RPC)in the streamer mode at the BELLE experiment by using a non .ammable gas mixture of argon 30%, butane-silver 8%and freon,C2H2F4 (HFC-134a)62%.The single RPC e .ciency was 93%,and the superlayer module has been checked to achieve the design value of 99%.This freon is non-ozone depleting freon,but a freon has a high global warming potential in general.Thus a gas mixture for RPC might be desired to be freonless in the near future.We have searched for an alternative gas mixture for a streamer mode operation of a glass RPC with a volume resistivity of 7x10^12 cm. A freonless gas mixture of argon,butane, CO2 and/or O2 gases ,shown in Table 1.
Composition of the gas mixtures uesd in this test.HFC-134a |
C4H10/Ar |
C4H10/O2 =8/0 |
C4H10/O2 =6/5 |
C4H10/O2 =4/10 |
134a/C4H10/Ar |
C4H10/Ar |
C4H10/O2/Ar/CO2 |
C4H10/O2/Ar/CO2 |
C4H10/O2/Ar/CO2 |
62/8/30 |
70/30 |
8/0/30/62 |
6/50/30/59 |
4/10/30/56 |
50/50 |
8/0/20/72 |
6/5/20/69 |
4/10/20/66 |
|
30/70 |
8/0/10/82 |
6/5/10/79 |
4/10/10/76 |
|
8/0/5/87 |
6/5/5/84 |
4/10/5/81 |
Presented by: C. Finck
Ch. Finck (1), P. Fonte(2), A. Gobbi(1)
(1)GSI, 64291 Darmstadt, Germany
(2)LIP, laboratorio de Instrumentacao e Fisica Experimental de Particulas, Coimbra,
Portugal
Time of flight (ToF) systems are used with tracking devices in order to improve particle separation especially identifying strange mesons in sub-threshold heavy ion collisions. The development of timing Resistive Plate Chambers (RPC) have made significant progress during the last few years. The rather reduced cost and simple construction make the RPC technique very attractive for large ToF arrays compared to scintillator technology. Timing Glass-RPC prototypes were build and tested at CERN-PS with the aim to obtain an optimum time response function all over the counter area, edges included. Possible edge effects and how to minimize them, are discussed. It is shown that such effects can be reduced to a level where the amount of tails is below 1 % and the resolution is 50 to 60 ps. The possibility of a surface emission of electron from the cathode is studied by measurements of the GRPC counter efficiency as a function of the gas pressure. The obtained results will be discussed. Layouts of new ToF arrays are presented in view of future applications.
Single-Gap Timing RPCs with Bidimensional Position Sensitive Readout for Very Accurate TOF systems
Presented by: P. Fonte
A. Blanco (1,2), R. Ferreira Marques (1,3), Ch. Finck (4), P. Fonte (1,5), A. Gobbi (4), A. Policarpo (1,5)
1 LIP, Coimbra, Portugal.
2 GENP, Dept. Fisica de Particulas, Univ. Santiago de Compostela, Spain.
3 Departamento de Fisica da Universidade de Coimbra, Portugal.
4 GSI, Darmstadt, Germany.
5 ISEC, Coimbra, Portugal.
In this work we report the development and performance of single-gap timing RPCs equipped with a 3 mm FWHM resolution bidimensional position sensitive readout and a simultaneous timing resolution of 55 ps sigma at an efficiency of 75% for MIPs. These counters are aimed to be applied in a multilayer geometry, forming small, very accurate, TOF systems.The millimetric avalanche localisation capability provides information for accurate flight-path determination and allows the offline correction of any position dependent effects in the counter, like gap inhomogeneities or edge effects. The multilayer geometry provides redundant timing information, which, besides improving the timing resolution, can be used for controlling the timing tails and for the self-calibration of the device. From the experimental single-counter data it can be easily and reliably calculated that a 4-layer configuration of such counters would yield a time resolution of 33 ps sigma at a 95% efficiency, essentially free of timing tails.The application of this readout concept to the bidimensional avalanche localisation in very large timing RPC counters will be also discussed.
Presented by: M.Petrovici
M.Petrovici, N.Herrmann, K.D.Hildenbrand, M.Ciobanu, I.Cruceru, M.Duma, O.Hartmann, T.Kress, D.Moisa, M.Petris, V.Simion, G.Stoicea
National Institute for Nuclear Physics and Engineering,Bucharest,
Romania
Gesellschaft für Schwerionenforschung, Darmstadt, Germany
Physikalisches Institut der Universität Heidelberg,Heidelberg, Germany
A completely new configuration of a two times double gap large area resistive plate counter, based on an intermediate strip structure read-out printed circuit (ISRPC), was built and tested. Results of measurements using 60Co source and p, d particles of 1.5 A.GeV are reported. A time resolution better than 80 psec and efficiency larger than 95% were obtained using the available in house fast electronics. These results open the perspectives to access high resolution and high granularity large area TOF detectors using compact modules with negligible edge effects.
Study of Thin Glass RPCs as Prototypes of HARP TOF Detectors
Presented by: Yu.Sviridov
V.Ammosov, V.Ermolaev, V.Gapienko, A.Ivanilov, A.Semak, Yu.Sviridov, E.Usenko, V.Zaets
Institute for High Energy Physics, Protvino Moscow region Russia
Two-double-gap glass RPCs with 0.3 mm gap and read-out electrodes position between two double-gaps were tested in hadron beam as prototypes of TOF detector for HARP experiment at CERN. Counters worked in avalanche mode at atmospheric pressure. The time resolution of about 80 ps was achieved for a small pad read-out. Investigations of the time resolution as a function of pad size, applied HV, beam rate and FEE structure were performed. Comparison with double-gap counter of similar design and 0.6 mm wide subgaps was also made.
Test results from a prototype RPC setup for the OPERA Target Tracker
Presented by: D. Autiero
D. Autiero (1), E.Borsato (4), R.Brugnera (4), L.Camilleri (1), F.Dal Corso (4), L. Di Lella (1), S.Dusini (4), A.Ereditato (3), C. Heritier (1), C.Fanin (4), A.Garfagnini (4), K.Jacovcic (5), A.Longhin (4), S.Mengucci (2), P.Parascandolo (3), R. Petti (1), G.Sorrentino (3), M.Spinetti (2), L.Stanco (4), M.Turcato (4), M.Ventura (2), L.Votano (2)
1. CERN, Geneva, Switzerland
2. Laboratori Nazionali di Frascati, INFN Frascati, Italy
3. INFN and ""Federico II"" University, Naples, Italy
4. INFN and Padova University, Padova, Italy
5. Ruder Boskovic Institute, Zagreb, Croatia
Resistive Plate Chamber (RPC) detectors with analog readout of the strips were considered as an option for the Target Tracker (TT) of the OPERA experiment, with the task of identifying the location of neutrino interactions and performing a first muon tracking. In order to study this option, the performance of a small scale prototype of the TT built with RPCs was determined with muon, pion and electron beams in the momentum range 1-15 GeV/c. General response features of the RPCs were studied, as well as their specific performance as Target Trackers. Data were collected with high statistics in the T9 and T7 beam lines at the CERN PS. We present here results on the detector spatial resolution and on the electron identification capabilities. The results are compared with a full Monte Carlo simulation. The same setup was also placed in the Gran Sasso underground laboratory, where the OPERA detector will be installed, in order to measure the RPC noise rate under operating conditions, an important parameter for the design of the Target Tracker.
Spatial resolution of RPC in streamer mode
Presented by: V. Barret
A.Baldit, V.Barret, N.Bastid, G.Blanchard, P.Crochet, P.Dupieux,
B.Espagnon, B.Forestier, C.Insa, F.Jouve, L.Lamoine, F.Manso, L.Royer, P.Saturnini (1)
A.Genoux-Lubain, Ph.Rosnet (2)
G.Dellacasa, E.Scalas (3)
R.Arnaldi, E.Chiavassa, P.Cortese, N.De Marco, A.Ferretti, M.Gallio,P.Mereu, A.Musso,
C.Oppedisano, A.Piccotti, E.Scomparin, F.Sigaudo, E.Vercellin (4)
C.Drancourt, F.Lefevre (5)
(1) LPC Clermont Ferrand - IN2P3/CNRS and Université Blaise Pascal
(2) LPC Clermont Ferrand - IN2P3/CNRS and I.U.T. de Montluçon del'Université Blaise
Pascal
(3) Universita del Piemonte Orientale, Dipartimento Scienze e Tecnologie Avanzate
(4) Sezione INFN di Torino
(5) Ecole des Mines de Nantes, Subatech nantes
The ALICE dimuon trigger is based on RPC, working in streamer mode, with X and Y strips of 1 cm, 2 cm or 4 cm width. As a purpose of optimizing the detector with respect to ALICE requirements, the charge profile of the discharge has been studied in cosmic runs with a RPC equipped with 2 mm wide strips. It was observed that the collected charge - hence the spatial resolution - depends obviously on the RPC high voltage and the gas mixture, and shows a gaussian shape with sstreamer = 5 mm in all cases. Other tests were done to determine the spatial resolution with the help of an external tracking system. The tracking system provides a determination of the particle impact on the RPC with a resolution better than 1 mm. The results show a RPC spatial resolution very close to the expected one for only one strip fired per particle: sRPC = w /sqrt(12). The probability distribution to fire a strip at a given distance of the particle impact, taking into account the RPC high voltage and particle angle dependencies, has been extracted from the experimental results.This parametrisation can be used, for instance, in simulations to predict the cluster size distribution for other strip widths.
Presented by: R. Guida
Bari-Pavia RPC CMS Collaboration
Università di Pavia & INFN Pavia
Bakelite Resistive Plate Chambers (RPCs) have been chosen as a part of the muon subdetector for the CMS experiment at the Large Hadronic Collider (LHC). Neutrons, produced in most hadronic interactions, are an important source of background in the CMS experimental environment. RPC neutron sensitivity has been studied during two test at different neutron energy. In the first one, neutron from spontaneous fission of 252Cf has been used. RPC signals were triggered by fission events detected using BaF2 scintillators. A Monte Carlo code, inside GEANT 3.21 framework, has been used to identify the gamma and neutron contributions to the total number of collected RPC signals. A neutron sensitivity of 4.6e-4 (average energy 2 MeV) and a gamma sensitivity of 1.26e-2 (average energy 1.5 MeV) have been measured in the double gap mode. During the second test, neutrons were produced using a 50 MeV deuteron beam, accelerated by the Louvain-la-Neuve cyclotron, on a 1 cm thick berillium target. In this case the average neutron energy was around 20 MeV.
Potencial of RPC's for tracking
Presented by: V. Peskov
V. Peskov, P. Fonte, T. Francke
LIP, Coimbra University
KTH, Stockholm
We have demonstarted that small gap (0.1-0.4mm) RPC's made of small resistivity materials can operate at rates up to 104-105 Hz/mm2 with a position resolution better than 50 micron. We will discusse a possible applications such types of RPC for tracking and medical imaging.
Perspectives for positron emission tomography (PET) with RPCs
Presented by: A. Blanco
A. Blanco (1,5), P. Fonte (1,4), I. Lopes (1), R. Marques (1,2), V. Peskov (3), A. Policarpo (1,2), V. Tchepel (1)
(1) LIP, laboratorio de Instrumentacao e Fisica Experimental de
Particulas
(2) Departamento de Física da Universidade de Coimbra
(3) KTH, Stockholm
(4) ISEC, Coimbra, Portugal.
(5) GENP, Dept. Fisica de Particulas, Univ. Santiago de Compostela, Spain.
In this study we address the feasibility and main properties of a positron emission tomograph (PET) based on RPCs. The concept, based on the converter-plate principle, takes advantage of the intrinsic layered nature of RPC geometry and of its simplicity of construction. The extremelly good time resolution of RPCs (50 ps sigma) also allows the TOF-PET imaging technique to be used. Monte-Carlo simulations, supported by experimental data, are presented and the main advantages and drawbacks for different applications are discussed.
Ageing tests on the low-resistivity RPC for the ALICE dimuon arm
Presented by: A. Ferreti
R.Arnaldi, E.Chiavassa, N.De Marco, A.Ferretti, M.Gallio, P.Mereu,
A.Musso, C.Oppedisano, A.Piccotti, E.Scomparin, F.Sigaudo, E.Vercellin (1)
P.Cortese, G.Dellacasa, E.Scalas;(2)
A.Baldit, V.Barret, N.Bastid, G.Blanchard, P.Crochet, B.Espagnon, B.Forestier, C.Insa,
F.Jouve, L.Lamoine, F.Manso, L.Royer, P.Saturnini (3)
A.Genoux-Lubain, Ph.Rosnet (4)
C.Drancourt, F.Lefevre (5)
for the ALICE collaboration
(1) Sezione INFN di Torino and Dipartimento di Fisica Sperimentale
dell'Universita
(2) Universitá del Piemonte Orientale, Dipartimento Scienze e Tecnologie Avanzate
(3) LPC Clermont-Ferrand- IN2P3/CNRS and Université Blaise Pascal
(4) LPC Clermont-Ferrand- IN2P3/CNRS and I.U.T. de Montlucon de l'Université Blaise
Pascal
(5) Ecole des Mines de Nantes, SUBATECH Nantes
The trigger for the Dimuon Forward Spectrometer of the forthcoming ALICE experiment at CERN will be given by means of low-resistivity, single gap Resistive Plate Chambers working in streamer mode. During the data taking of the experiment, the detectors will be exposed to counting rates of 5 Hz/cm2 in Pb-Pb collisions and of 40 Hz/cm2 in Ar-Ar interactions. In order to check the ability of the chambers to withstand these fluxes all along the life-time of the experiment, different aging test were performed. In order to understand the effects of continuous gas flow upon the bakelite resistivity, dummy chambers have been built: the effects on rate capability of our standard gas mixture (49% Ar, 40% Forane, 7% Isobutane and 4% SF6) will be reported, and compared with the same mixture in which 1% of water vapor is added. Moreover, two aging test of one month each (corresponding to several years of operation at LHC) have been carried out at the Gamma Irradiation Facility at CERN during 2001. The efficiency for cosmic rays of chambers with different thicknesses of linseed oil coating was continuously measured during irradiation. Although no decrease of efficiency was observed, after protracted operation the detectors have shown an increase of the current absorbed and of the single rate. The increase is slower in the chamber with a thicker oil coating, and also the reduction of SF6 from 4% to 1% seems to play a role in slowing down the current increase.
Performance of the RPCs for the ARGO detector operated at the YangBaJing laboratory (4300 m a.s.l).
Presented by: M. Iacovacci
ARGO Collaboration
University of Napoli
Bakelite RPCs, assembled according to the ARGO design, have been operated in the high altitude Laboratory of YBJ using dedicated electronics to pick-up the streamer signal. Here we report on the results concerning absorbed current, single counting rate, efficiency and time resolution.
Assembling Facility of the ATLAS RPCs
Presented by: R. Perrino
R. Perrino et all.
Istituto Nazionale di Fisica Nucleare, Sezione di Lecce
The dedicated facility built for the assembling of the ~1000 RPC units of the ATLAS mu-spectrometer is described in detail. The necessity of keeping the gravitational sagitta below 10 mm for the 5 m long RPC units has driven the careful design of the extruded Al lateral profiles and of the Al suspension end-plates.
A special assembly table allows to mantain the mechanical tolerances of each unit well below +/- 1 mm in all deimensions. Both gas gaps inside each unit are kept at a constant pressure of 103 Pa over the whole surface, in order to ensure the uniformity of the gap.
Test of ATLAS RPCs Front-End Electronics
Presented by: B. Liberti
G. Aielli, P. Camarri, R. Cardarelli, A. Di Ciaccio, L. Di Stante, B. Liberti, A. Paoloni, E. Pastori, R. Santonico
University of Rome ""Tor Vergata"" and I.N.F.N. sezione Roma2
The Front-End Electronics performing the ATLAS RPCs readout is a full custom 8 channels GaAs circuit, which integrates in a single die both the analog and the digital signalprocessing. The die is bonded on the Front-End board which is mounted on the pick-up strips panel and therefore completely closed inside the detector Faraday cage. About 50000 FE boards are foreseen for the experiment. The complete functionality of the FE boards will be certificated before the detector assembly. We describe here the selection criteria applied by means of a systematic test devoted to check the dynamic functionality of each single channel. It measures and registers all relevant electronics parameters to build up a complete database for the experiment. The statistical results from more than 1100 channels are presented.
A new discrimination technique for better timing performances of single gap RPCs in streamer mode
Presented by: P.Dupieux
A.Baldit , V.Barret, N.Bastid, G.Blanchard, P.Crochet, P.Dupieux,
B.Espagnon, B.Forestier, C.Insa, F.Jouve, L.Lamoine, F.Manso, L.Royer, P.Saturnini (1)
A.Genoux-Lubain, Ph.Rosnet (2)
G.Dellacasa, E.Scalas (3)
R.Arnaldi, E.Chiavassa, P.Cortese, N.De Marco, A.Ferretti, M.Gallio, P.Mereu, A.Musso,
C.Oppedisano, A.Piccotti, E.Scomparin, F.Sigaudo, E.Vercellin (4)
C.Drancourt, F.Lefevre (5)
(1) LPC Clermont Ferrand - IN2P3/CNRS and Université Blaise Pascal
(2) LPC Clermont Ferrand - IN2P3/CNRS and I.U.T. de Montluçon de l'Université Blaise
Pascal
(3) Universita del Piemonte Orientale, Dipartimento Scienze e tecnologie Avanzate
(4) Sezione INFN di Torino
(5) Ecole des Mines de Nantes, Subatech nantes
Single gap Resistive Plate Chambers (RPCs) operated in streamer mode have been chosen
for the trigger of the ALICE dimuon arm at LHC. The requirements in term of rate
capability and spatial resolution are fulfilled by such detectors. Using conventional
discrimination techniques, the timing performances were not fully satisfactory except at
quite high running voltages which are, on the other hand, not suitable for the detector
operation and ageing.
A new discrimination technique, called ADULT (A DUaL Threshold), has been recently
proposed to improve the situation. A good time resolution is obtained with ADULT as soon
as the applied voltage is sufficient for the RPC to reach full efficiency.
The time distributions show a narrow peak (speak <1 ns) which contains more than 97% of
the events. This new method has been implanted in a custom chip using the AMS BiCMOS
technology. Results of tests carried on at the PS and GIF (Gamma Irradiation
Facility) at
CERN will be shown.
Study of the performance of standard RPC chambers as a function of bakelite temperature.
Presented by: S. Mari
Mario De Vincenzi, Giulia Hull, Stefano M. Mari, Gabriele Pellizzoni
Dipartimento di Fisica, Univerita' di Roma Tre and INFN sezione di Roma, Rome Italy
A sistematic study of the performance of the Resistive Plate Chambers as a function of the
bakelite temperature is presented, the relative humidity was monitored.The current, the
rate, the charge and the efficiency were measured in the temperature range 22 - 40 Celsius
degrees and in the humidity range 20 - 27 %,The time resolution was also measured.
Measurements show a strong dependence of efficiency and time resolution on bakelite
temperature.
The RPC Detector of the LHCb Muon System
Presented by: R. Messi
A. Bizzeti, G. Carboni, G. Collazuol, S. De Capua, D. Domenici, G. Ganis, M. Lenti, R. Messi, L. Paoluzi, G. Passaleva, E. Santovetti, M. Veltri
Università di Firenze and INFN, Università degli Studi di Roma "Tor Vergata" and INFN
A substantial part (48%) of the LHCb Muon System is equipped with Resistive Plate Chambers (RPC). We describe the overall design and discuss the performances of the prototypes, with emphasis on efficiency, cluster size and rate capability.
Ageing studies for the RPCs of the CMS Muon Trigger detector
Presented by: G.Pugliese
M.Abbrescia, A.Colaleo, G.Iaselli, F.Loddo, M.Maggi, B.Marangelli, S.Natali, S.Nuzzo, G.Pugliese, A.Ranieri, F.Romano, S.Altieri, G.Belli, G.Bruno, R.Guida, S.P. Ratti,C.Riccardi,P.Torre,P.Vitulo
Dip.Interateneo di Fisica and Sez. INFN Bari,
Dip. di Fisica Nucleare e Teorica and Sez. INFN Pavia
The CMS Resistive Plate Chambers (RPCs) muon trigger detectors will work in presence of
an intense gamma and neutron background. The total accumulated dose and charge for 10
years of LHC operation have been estimated to be about 1 Gy and 0.05 C/cm2gap,
respectively. In order to realistically reproduce the background conditions of the CMS
experiment and to study possible aging effects, two dedicated irradiation tests have been
performed at the CERN Gamma Irradiation Facility and Louvain-la-Neuve neutron facility.
Detectors with and without linseed oil treatment have both been tested, in order to verify
a possible different
behaviour from the aging point of view. The counting rates and the efficiency of the
chambers have been monitoring during the irradiation.
Cosmic ray tests of RPCs for the ATLAS experiment
Presented by: G. Sehkniaidze
G. Sehkniaidze
INFN Naples
The RPCs for the ATLAS experiment require a full quality control test before being mounted on the detector. This test will be done using a cosmic ray stand with tracking capabilities that will allow to measure uniformity of the chamber response and monitor all parametres of the detectors during the test period. A description of the test stand and results from the first mass produced detectors under test will be presented.
Time resolution of four 0.3mm gap RPC with constant fraction discriminator.
Presented by: A. Semak
V. Ammosov, V. Gapienko, A. Ivanilov, A. Semak, Yu. Sviridov, E. Usenko, V. Zaets
Institute for High Energy Physics, Protvino Moscow region, Russia
Time resolution of four 0.3mm gap RPC with a constant fraction discriminator was measured at CERN T10 beam. The value of ~70ps was achieved. It is compatible with the time resolution obtained using a time-charge correction. The used RPC approach with CFD can be used for high resolution TOF trigger systems.
Neutron Single Event Upset cross section on CMS FE chips from thermal energy to 60 MeV
Presented by: P. Vitulo
Bari-Pavia RPC CMS COllaboration
Dip. di Fisica Nucleare e Teorica & INFN PAVIA
Neutrons from a Reactor and from a Cyclotron were used to measure the sensitivity of the CMS RPC Frontend chips against Single Event Upsets (SEUs), i.e. neutrons induced damaging events.By counting the neutrons induced events within the FE chips we were able to measure the SEU cross sections. Neutrons energy ranged from thermal (0.025 eV) up to 60 MeV. At the reactor we integrated a fast fluence ( 3 MeV< E < 10 MeV) of 1.7 x 1010 cm-2 and a thermal fluence of 9.5 x 1011 cm-2 while at the cyclotron a fluence of 1012 cm-2 has been accumulated.Data indicate the existence of a chip SEU sensitivity already at neutrons thermal energies and a saturated SEU cross section from 3 to about 60 MeV.
Performance of Glass RPC with industrial silk-screening coated electrodes
Presented by: M. Ambrosio
M. Ambrosio, A.Candela, M.De Deo, M.D'Incecco, D. Gamba, A.Giuliano, C.Gustavino, S. Morganti, N. Redaello, A. Tonazzo, G.C.Trinchero
Laboratori Nazionali del Gran Sasso, INFN, Assergi, Italy
CNR, Istituto di Cosmogeofisica and INFN, Torino, Italy
In this paper we describe the performance of several Glass RPCs, where the water-based graphite coating is replaced by a syntetic coating applied by using the silk screening tecniques. As expected, the performance of the detectors is good and reproducible due to the accurate control of the coating resistivity value. The resistance of the coating to the action of mechanical and chemical agents permits an easy electrode cleaning and mounting respect to the RPC coated with the graphite varnish. This coating, togeter with the use of float glass as electrode material, allows an industrial production, where the detector characteristic can be tailored as a function of the experiment requirements.
A Study of New Techniques for Large Scale Glass RPC production
Presented by: G.C. Trinchero
G.C. Trinchero [1,2], A. Giuliano [1,2], P. Picchi [1,3,4]
[1] Istituto di Cosmogeofisica del CNR, Torino,Italy
[2] INFN Sezione di Torino, Italy
[3] Universit\'a degli Studi di Torino, Italy
[4] Laboratori Nazionali di Frascati and INFN, Frascati, Italy
Glass RPCs (GSC Glass Spark Chambers) have been chosen as active elements for the MONOLITH detector. They are derived from resistive plate chambers by substituting the bakelite electrodes with commercial float glass electrodes of high resistivity. Taking into account the MONOLITH detector overall dimensions (total active area ~54000 m2) GSC has to be designed for large scale production. Moreover industrial mass production has to be standardized in order to have homogeneous affordable and reproducible detectors. A wide range of industrial glass treatments are already exploited by both glass and automobile industries . Our efforts are aimed to import and adapt such existing techniques for GSC large scale production. On the other hand we will modify GSC design to fit into standard industrial production techniques. A first attempt in this direction has been successful, and we have found a way to produce glass with the appropriate resistive coating by using industrial silk screen printing techniques with an ad hoc developed synthetic varnish.
Performance of a readout system for MONOLITH
Presented by: C.Gustavino
(1) A.Candela ,(1) M.De Deo, (1) M.D'Incecco, (1) C.Gustavino
(1) Laboratori Nazionali del Gran Sasso, INFN, Assergi, Italy
In this paper we describe the performance of the readout system for MONOLITH developed at the LNGS. This system is based on the use of flat cables as readout elements, instead of the conventional copper strips.Each electronic channel of the X-coordinate readout system (X-system) is connected to a 15 m long 2.8 wide Flat Cable Strips (FCS). Each channel of the Y-coordinate readout system (Y-system) is connected, through a bus line, to eigth 1.8 m long, 2.8 cm wide FCS. This system minimize the number of channels and does not require electronics inside the apparatus Its mounting is safe and fast, as no soldering but rather commercial wiremount socket connectors are used to couple the front end electronics (FEE) to the pickup elements.Beside the digital pattern, the X-system provide the time measurement to reconize the particle direction. The distribution of the time difference between the streamer signals transmitted at both the ends of the X-system FCS has a sigma resolution of the order of 100 ps due to the excellent signal transmission along the FCS. This resolution can be exploited to measure the Y-coordinate, without the Y-system, with a resolution on the order of 1 cm.
Mechanisms affecting Performance of the BaBar RPC Chambers
and Searches for Remediation
Presented by: C. LU
BaBar IFR collaboration
F. Anulli(2), S. Bagnasco(3), R. Baldini(2), H.R. Band(11), R. Bionta(7), J.E. Brau(10), V. Brigljevic(7), A. Buzzo(3), A. Calcaterra(2), M. Carpinelli(5), T. Cartaro(4), N. Cavallo(4), G. Crosetti(3), R. de Sangro(2), G. De Nardo(4), A. Eichenbaum(11), F. Fabozzi(4), D. Falciai(2), F. Ferrarotto(6), F. Ferroni(6), G. Finocchiaro(2), F. Forti(5), R. Frey(10), C. Gatto(4), E. Grauges(10), M. Iwasaki(10), J.R. Johnson(11), D.J. Lange(7), Y.P. Lau(8), L. Lista(4), M. Lovetere(3), C. Lu(8),
M. Macri(3), T.B. Moore(12), S. Morganti(6), N. Neri(5), H. Neal(12), A. Palano(1), E. Paoloni(5), P. Paolucci(4), S. Passaggio(3), F. Pastore(3), P. Patteri(2), I. Peruzzi(2), M. Piccolo(2), D. Piccolo(4), G. Piredda(6), E. Robutti(3), A. Roodman(9), A. Santroni(3), C. Sciacca(4), N.B. Sinev(10), D. Strom(10), A. Soha(9), S. Tosi(3), J. Va'vra(9), W.J. Wisniewski(9), D.M. Wright,(7), Y. Xie(2), A. Zallo(2)
(1)Universita` di Bari, Dipartimento di Fisica and INFN,
Bari,Italy,
(2)Laboratori Nazionali di Frascati dell'INFN, Frascati, Italy,
(3)Universita` di Genova, Dipartimento di Fisica and INFN,Genova, Italy,
(4)Universita` di Napoli Federico II, Dipartimento di Scienze Fisicheand INFN,
Napoli, Italy,
(5)Universita` di Pisa, Scuola Normale Superiore, and INFN, Pisa, Italy,
(6)Universita` di Roma La Sapienza, Dipartimento di Fisica and INFN, Roma, Italy,
(7)Lawrence Livermore National Laboratory, Livermore, USA,
(8)Princeton University, Princeton, USA,
(9)Stanford Linear Accelerator Center, Stanford, USA,
(10)University of Oregon, Eugene, USA,
(11)University of Wisconsin, Madison, USA,
(12)Yale University, New Haven, USA
The BaBar experiment at PEPII relies on the Instrumentation of the Flux Return (IFR) for both muon identification and K-long detection. The active detector is composed with RPCs operated in streamer mode. Since the start of operation the RPC chambers have suffered persistent efficiency deterioration and dark current increase problems. The "autopsy" of bad BaBar RPC chambers revealed that in many cases uncured Linseed oil droplets had formed on the inner surface of the Bakelite plates, leading to current paths from oil "stalagmites" bridging the 2 mm gap. In this paper a possible model of this "stalagmite" formation and its effect on the dark current and efficiency of RPC chambers is presented. Laboratory test results strongly support this model.
Based upon this model we are searching for solutions to eliminate the unfavorable effect of the oil stalagmites. The lab tests show that the resistivity of the oil stalagmite increases dramatically if exposed to the air, an observation that points to a possible way to remediate the damage and increase the efficiency. We have seen that flowing an oxygen gas mixture into the chamber helps to polymerize the uncured Linseed oil. Consequently the resistivity of the bridged oil stalagmites increases, as does that of the oil coating the frame edges and spacers, significantly reducing the RPC dark currents and low-efficiency regions. We have tested this idea on two RPC chambers removed from BaBar because of their low efficiency and high dark current. After flowing a N2/O2 (40/60) gas mixture for a certain period their efficiency and dark current improved dramatically. However, after several days their efficiency began to deteriorate again, but the dark current remained low. We continue to study this problem, and try to understand the mechanisms at
work.
A study of Energy lose and Radiation for RPC detector at Belle/KEKB
Presented by: J. G. Wang
J. G. Wang
Virginia Polytechnic Institute and State University
The K_L and muon detector subsystem (KLM) at Belle/KEKB is described shortly. The paper will present the result of study about energy loss in KLM system in Barrel region and Endcap region and the relation of muon detecting efficiency with radiation. To obtain a clear picture about energy losing and understand the dependence of different matures with energy losing, we used about 20 fb-1 integral luminosity experiment data (two photo to two muon) and equivalent Monte Carlo data for such analysis. The result of our study shows a proximately linear relation of energy losing with number of layers RPC passed in Barrel region. A much more complicate relation has also been obtained from Endcap region. The result of study abut beam radiation and RPC detecting efficiency in barrel region and endcap region will also been discussed in this paper. The radiation effect to detecting efficiency in different layer of RPC will be presented.
Test beam Results of the Forward RPC Prototype Chamber for the CMS Muon Detector
Presented by: Z. Aftab
Z. Aftab, H. Hoorani, J.A. Jan, M.S. Khan, T. Solaija, I. Crotty
National Centre for Physics, Islamabad, Pakistan.
A full size prototype of the second forward RPC station (RE2/2) for the CMS detector has
been tested during the 2000 beam test. The prototype was exposed to high irradiation flux
using the CERN Gamma Irradiation Facility (GIF) and the 200 GeV muon beam from X5
beamline. We have studied number of chamber parameters which are relevant for the trigger
such as: time resolution, efficiency, cluster size and rate capability. We have used two
different gas mixtures to understand the effect of SF6 on the efficiency plateau and the
rate capability of the chamber. We have also studied the intrinsic chamber rate for
different discrimination thresholds.
The RPC system for the CMS experiment at the LHC
Presented by: G.Bruno
Giacomo Bruno for the CMS collaboration
Dipartimento di Fisica Nucleare e Teorica Universita' di Pavia, Pavia, Italy
The CMS detector at the LHC has a redundant muon system. Two independent trigger systems
are foreseen. One of them is based on wire chambers, the other on RPC detectors. Properly
combining the answers of the two systems results in a highly efficient first level trigger
with high flexibility from the point of view of rate control. Use of RPC is not only
limited to the first level trigger. Indeed despite their worse space resolution with
respect to the wire chambers, they are very useful in the higher level triggers and at
reconstruction level. Results on the performance of the first and higher level CMS muon
trigger are reported with emphasis on the role played by RPCs.
First results on the MB2 barrel muon station for the CMS detector.
Presented by: A. Colaleo
Bari-Pavia CMS-RPC Group
University and I.N.F.N Bari.
The first completely assembled CMS MB2 station, where Resistive Plate Chambers (RPC) are integrated to the Drift Tube Chambers (DT) in the second barrel muon station, has been extensively tested both with cosmic muons and with muon beam under high intensity photon flux at the CERN Gamma Irradiation Facility during the 2001 tests. Preliminary results on spatial resolution, signal to noise ratio, rate capability for the RPC subdetectors inside the muon station are given here.
Final Design and the Beam test of the Forward Resistive Plate Chamber for CMS/LHC Experiments
Presented by: S. Park
S. H. Ahn(a), S. Y. Bahk(b), E. J. Choi(a), B. Hong(a), D. H. Kang(a), K. H. Kim(a), T. J. Kim(a), Y. J. Kim(c), Y. U. Kim(d), D. G. Goo(e), H. W. Lee(a), K. S. Lee(a), S. J. Lee(f), S. K. Nam(g), S. W. Lee(a), J. K. Oh(a), J. W. Park(a), M. K. Park(a), S. Park(a), W. J. Park(a), J. T. Rhee(h), M. S. Ryu(a), H. H. Sim(a), S. W. Youn(a)
(a) Korea Detector Laboratory, Korea Univesity, Seoul, Korea
(b) Wonkwang University, Iksan, Korea
(c) Cheju National University, Cheju, korea
(d) Chungbuk National University, Chungju, Korea
(e) Seoul National University of Education, Seoul, Korea
(f) Seonam University, Namwon, Korea
(g) Konkuk University, Seoul, Korea
The final design of the Forward Resistive Plate Chamber (FRPC) of the CMS/LHC experiments is reported in this paper. The gas gaps of the RPCs at high ( regions were optimized to obtain both high rate capability and low intrinsic noise rate. A real size prototype chamber for the RE2/1 RPCs manufactured with the final design was tested at the Gamma Irradiation Facility (GIF) at CERN in an environment of the background gamma rate, ranging up to 1.5 kHz/ cm2. The bulk resistivity of the bakelite for the prototype is 1 ( 1010 Wcm at temperature of 25oC and relative humidity of 50 %. The typical intrinsic noise rate is 15 Hz/cm2 at 200 V above the knee of the efficiency plateau. The prototype RPC shows uniform RPC characteristics which well satisfy the experimental condition of the Forward Region Trigger of the CMS detector up to the maximum gamma background rate provided in the beam test.
The RPC time-of-flight system of the HARP experiment
Presented by: J.Wotschack
M.Bogomilov (1), D.Dedovich (2), R.Dumps (1), F.Dydak (1), V.Gapienko (3), A.Semak (3), Y.Sviridov (3), E.Usenko (3), J.Wotschack (1), V.Zaits (3)
(1) CERN
(2) JINR Dubna
(3) IHEP Protvino
The HARP RPC time-of-flight system was designed for particle identification in the
150-350 MeV momentum range over path lengths of 0.5-2 m requiring a time resolution of
better than 200 ps. For R&D, design, and construction less than eight months were
available.
The system consists of 46 4-gap glass RPCs with dimensions 1930x106x7.8 mm3; it covers an
area of about 10 m2. The glas plates are 0.7 mm thick and the gap width is 0.3 mm per gap.
HV is applied on the two outer glas plates and the signal is read out via 64 30x104 mm2
copper pads located in the mid plane. Each RPC has eight readout channels; each readout
channel sums over eight pads. The RPCs are operated at with a mixture of freon-124 (90%),
isobutane (5%), and SF6 (5%) at a HV of -6 kV.
Chamber design and assembly are described and first experience with the chamber operation
and performance in the HARP detector since May 2001 is reported.
Presented by: D. Della Volpe
D. Della Volpe
INFN Naples
The RPC chambers in the L3 forward-backward muon spectrometer have been operational from 1994 to the end of LEP running. After dismantilng of the L3 detector some of the detectors have been trasported to Naples where their performance has been re-measured with cosmic rays. Results of long term performance in the LEP environment and of laboratory tests with cosmic rays will be presented.
Preliminary results from an aging test of a prototype RPC for the LHCb muon system
Presented by: G. Ganis
A. Bizzeti (a), G. Carboni(b), G. Collazuol(a),S. De Capua(b),D. Domenici(b),G. Ganis(b), M. Lenti(a), R. Messi(b), L. Paoluzi(b), G. Passaleva(a),E. Santovetti(b),M. Veltri(a)
a) Universitá and INFN, Firenze, Italy
b) Universitá and INFN, Roma II, Italy
A substantial part (48%) of the LHCb Muon System is equipped with Resistive Plate Chambers (RPC). We describe the overall design and discuss the performances in terms of efficiency, cluster size and rate capability of the prototypes. We present the preliminary results of an aging test being performed at the CERN Gamma Irradiation Facility with a half scale prototype. The results are based on an accumulated charge of about 0.5 C/cm2, corresponding to about 5 years in the worst LHCb running conditions. We found that the dark rate and noise increased after irradiation. We observed a degradation of the rate capability above about 1-2 kHz/cm2. However the chamber still meets the LHCb operation requirements.
Analysis of the performance of the MONOLITH prototype at LNGS
Presented by: C. Gustavino
G.Bari, A.Candela, M.De Deo, M.D'Incecco, M.Garbini, P.Giusti, C.Gustavino, M.Lindozzi, H.Menghetti, G.Sartorelli, L.Satta, M.Selvi
Laboratori Nazionali del Gran Sasso, INFN, Assergi, Italy
Laboratori Nazionali di Frascati, INFN, Frascati, Italy
Bologna University and INFN, Bologna, Italy
MONOLITH Massive (Observatory for Neutrino Oscillation or LImits on THeir existence)
is the project of an experiment to study atmospheric neutrino oscillations with a massive
magnetized iron detector. A 8 ton prototype equipped with 20 m2 of Glass RPCs has been
realized and tested at LNGS with cosmic ray muons. The prototype is made of 20 iron planes
(100X100 cm2) 5cm thick, interleaved
with 2cm gaps housing Glass RPCs equipped with X and Y flat cable strips 1cm wide. In our
measurements about 106 downward going muons were collected, to study the MONOLITH
capability of determining the muon direction using the time-of-flight technique. As this
prototype allows the reconstruction of crossing muons with a granularity of 1cm2, the
local effect of 2mm wide stick spacers is clearly visible in the efficiency, in the timing
performance and in the released charge.
Design and prototype tests of the RPC system for the OPERA spectrometers
Presented by: S. Dusini
S. Dusini (4), D.Autiero (1), E.Borsato(4), R.Brugnera (4), L.Camilleri (1), F.Dal Corso (4), L.Di Lella (1), A.Ereditato (3), C. Heritier (1), C.Fanin (4), A.Garfagnini (4), K.Jacovcic (5), A.Longhin (4), S.Mengucci (2), P. Parascandolo (3), R.Petti (1), G.Sorrentino (3), M.Spinetti (2), L.Stanco (4), M.Turcato (4), M.Ventura (2), L. Votano (2)
1. CERN, Geneva, Switzerland
2. Laboratori Nazionali di Frascati, INFN Frascati, Italy
3. INFN and ""Federico II"" University, Naples, Italy
4. INFN and Padova University, Padova, Italy
5. Ruder Boskovic Institute, Zagreb, Croatia
The Inner Tracker system of the spectrometers of the OPERA experiment makes use of Resistive Plate Chambers (RPC) in a large scale application. We present here the definition of the project and the full design of the Inner Tracker. Specific performances for the OPERA-RPC in the spectrometer are also reported. Particle detection, muon identification and trigger capability are discussed, in particular. Results on beam and laboratory test measurements with prototype detectors are presented. Data were collected in the T9 and T7 beam lines at the CERN PS and in different local laboratories (CERN, Frascati, Padova), as well as in the Gran Sasso underground site. Results are compared with a full Monte Carlo simulation of the experimental setup.
Presented by: J. Lamas valverde
B.Bonner (a), H.Chen (b), G. Eppley (a), F. Geurts (a), J. Lamas valverde (a,c,1), Ch. Li(b), W.J. Llope (a), T. Nussbaum(a), E.Platner (a), J. Roberts (a)
(a) Rice University, Bonner Nuclear Lab, Houston, U.S.A
(b) University of Science and Technology of China, Hefei, China
(c) CERN, EP Division, Geneva, Switzerland
The STAR experiment at RICH plans to implement a 60 m2 Time-Of-Flight (TOF) system, which will cover the outer surface of the STAR Time Projection Chamber, and will be arranged in 120 trays. the MRPC is a suitable candidate for the STAR TOF system due to its start-subtracted time resolution of order of 60 ps with efficiencies in excess of 95%. We obtained this result with modules composed of 6 gas gaps of 220 mm. In this paper we report on the performance of MRPCs. We present the current status of the construction and instalation into STAR of a prototype tray, which contains 34, 6-channel modules.
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