The Gassiplex0.7-2 Integrated Front-End Analog Processor for the HMPID and the Dimuon Spectrometer of ALICE

The most recent member of the Gasplex family of ASICs has been designed in a 0.7 µm n-well CMOS process to meet specifications for the ALICE applications: 500 fC linear dynamic range and a peaking time of 1.2 µs. Its internal circuitry is optimized for the readout of gaseous detectors. A dedicated filter compensates the long hyperbolic signal tail produced by the slow drift of the ions and allows the shaper to achieve perfect return to the base line after 5 µs. Measurement of fabricated chips showed a noise performance of 530 e - rms at 0 pF external input capacitance and 1.2 µs peaking-time, with a noise slope of 11.2 e - rms/pF. The gain is 3.6 mv/fC over a linear dynamic range of 560 fC

Dilogic-2: A Sparse Data Scan Readout Processor for the HMPID Detector of ALICE

The processing of analog information is always spoiled by additional DC level and noise given by the sensors or their additional readout electronics. The Dilogic-2 ASICcircuit has been developed in a 0.7um n-well CMOS technologyto process the data given by Analog to Digital Converters, in order to eliminate the empty channels, to subtract the base line (pedestal) and to locally store the true analog information.(Abstract only available, full text willfollow

A threshold imaging Cerenkov detector with CsI photocathodes

A Threshold Imaging Cherenkov (TIC) detector, in conjunction with a tracking device and a time-of-flight system, has been developed to allow pion, kaon and proton identification in the 3--8 GeV/$c$ range of momenta. The system allows spatial identification of the photons of particles above the Cherenkov threshold and their correlation to a particular track. The TIC detector uses a MWPC detector with a CsI coated photocathode for photon conversion. The results obtained in ultrarelativistic lead--lead collisions at the CERN SPS accelerator are presented

Nov sistem za identifikaciju čestica u području 3 − 8 GeV/c

A threshold imaging Cherenkov (TIC) detector, in conjunction with a tracking device, has been developed to allow pion/kaon, proton identification in the 3–8 GeV/c range of momenta. The most important feature of the system is that it allows spatial identification of the photons of particles above the Cherenkov threshold and their correlation to a particular track. The TIC detector uses a MWPC detector with TMAE for photon conversion into electrons. The first results obtained in ultrarelativistic lead–lead collisions at the CERN SPS accelerator are presented. In a recent development use of a solid CsI cathode instead of TMAE has been successfully tested in proton–lead collisions at the CERN SPS.Razvijen je pozicioni detektor fotona Cerenkovljeva zračenja iznad praga emisije (TIC), koji omogućuje (u sklopu sistema za mjerenje tragova čestica) razlikovanje piona od kaona i protona u području između praga emisije za pione i za kaone t.j između 3 i 8 GeV/c. Najbitnija odlika sistema jest mogućnost dvodimenzijske lokalizacije emitiranih fotona i njihovo jednoznačno pridruživanje određenom tragu čestice koji je odreden drugim detektorima. Detektor TIC primjenjuje višezičane proporcionalne komore s TMAE dodanom brojačkom plinu za konverziju fotona u elektrone. Prikazuju se prvi rezultati dobiveni u ultrarelativističkim sudarima iona olova s metom olova u SPS akceleratoru u CERNu. Nedavno je upotreba čvrstih fotokatoda umjesto TMAE bila uspješno iskušana procesima sudara protona s olovom u SPS akceleratoru

Nov sistem za identifikaciju čestica u području 3 − 8 GeV/c

A threshold imaging Cherenkov (TIC) detector, in conjunction with a tracking device, has been developed to allow pion/kaon, proton identification in the 3–8 GeV/c range of momenta. The most important feature of the system is that it allows spatial identification of the photons of particles above the Cherenkov threshold and their correlation to a particular track. The TIC detector uses a MWPC detector with TMAE for photon conversion into electrons. The first results obtained in ultrarelativistic lead–lead collisions at the CERN SPS accelerator are presented. In a recent development use of a solid CsI cathode instead of TMAE has been successfully tested in proton–lead collisions at the CERN SPS.Razvijen je pozicioni detektor fotona Cerenkovljeva zračenja iznad praga emisije (TIC), koji omogućuje (u sklopu sistema za mjerenje tragova čestica) razlikovanje piona od kaona i protona u području između praga emisije za pione i za kaone t.j između 3 i 8 GeV/c. Najbitnija odlika sistema jest mogućnost dvodimenzijske lokalizacije emitiranih fotona i njihovo jednoznačno pridruživanje određenom tragu čestice koji je odreden drugim detektorima. Detektor TIC primjenjuje višezičane proporcionalne komore s TMAE dodanom brojačkom plinu za konverziju fotona u elektrone. Prikazuju se prvi rezultati dobiveni u ultrarelativističkim sudarima iona olova s metom olova u SPS akceleratoru u CERNu. Nedavno je upotreba čvrstih fotokatoda umjesto TMAE bila uspješno iskušana procesima sudara protona s olovom u SPS akceleratoru

Final tests of the CsI-based ring imaging detector for the ALICE experiment

We report on the final tests performed on a CsI-based RICH detector equipped with 2 C$_6$F$_{14}$ radiator trays and 4 photocathodes, each of 64$\times$38 cm$^2$ area. The overall performance of the detector is described, using different gas mixtures, in view of optimizing the photoelectron yield and the pad occupancy. Test results under magnetic field up to 0.9 T, photocathode homogeneity and stability are presented

A large area CsI RICH Detector in ALICE at LHC

A 1m2 CsI RICH prototype has been successfully tested in a hadron beam at CERN SPS. The prototype, fully equipped with 15k electronic channels, has been used to identify particles coming from pi-Be interactions. Track reconstruction has been performed by using a telescope consisting of four gas pad chambers. A detailed description of the detector will be presented and results from the test will be discussed.List of figuresFigure 1 Expected proton and antiproton yields including jet quenching mechanism in central Pb-Pb collisions at LHC.Figure 2 Schematic view of the HMPID CsI-RICHFigure 3 Experimental layout used at the SPS/H4 test beamFigure 4 Distributions of the mean number, per ring, of pad hits (Npad), electrons (Ntot) and Cherenkov photoelectrons (Nres) as a function of the single-electron mean pulse heightFigure 5 Mean single-electron pulse height as a function of high voltage measured at the centre of each of the four photocathodesFigure 6 Evaluation of the uniformity of the chamber gain for the photocathode PC32Figure 7 Azimuthal distribution of the photon pad hits in the Cherenkov fiducial zone (HV=2050 V)Figure 8 Photon angle (a) and track Cherenkov angle (b) distributions for beam events at the SPSFigure 9 Track density on the HMPID cathode plane in real 350 GeV/c pi--Be eventsFigure 10 Three dimensional display of an SPS 350 GeV/c pi--Be event. Eleven tracks are reconstructed in the telescope by requiring one hit on each pad chamber to reconstruct a track</UL

The Present Development of CsI Rich Detectors for the ALICE Experiment at CERN

The ALICE Collaboration plans to implement a 12m^2 array consisting of 7 proximity focussed C6F^14 liquid radiator RICH modules devoted to the particle identification in the momentum range: 1 GeV/c - 3.5 GeV/c for pions and kaons. A large area CSI-RICH prototype has been designed and built with the aim to validate the detector parameter assumptions made to predict the performance of the High Momentum Particle Identification System (HMPID) of the ALICE Experiment. The main elements of the prototype will be described with emphasis on the engineering solutions adopted. First results from the analysis of multitrack events recorded with this prototype exposed to hadron beams at the CERN SPS will be discussedList of FiguresFigure 1 General view of the ALICE lay-outFigure 2 Schematic layout of the fast CsI-RICHFigure 3 Perspective view of the HMPID layout with the seven RICH modules tilted according to their position with respect to the interaction vertex. The frame that supports the detectors is also shownFigure 4 Top view of the photodetector anode plane with the wire support spacer. One CsI board, out of six forming the pad cathode plane, is also shown.Figure 5 Perspective view of the HMPID honeycomb panel with the three radiator vesselsFigure 6 Cut away view of the HMPID CsI-RICH showing separately each detector component. Kapton buses that carry signals from the pads to the readout electronics are also shownFigure 7 a)number of resolved photoelectrons per event, b)reconstructed Cherenkov angle per photonFigure 8 C6F14 transmission plots before and after the molecular sieve purificationFigure 9 Display plot showing an SPS event. Three tracks are reconstructed by using the tracking chamber telescope, the associated rings are shown in the HMPID prototypeThis publication also appears as INT-98-20

A progress report on the development of the CsI-RICH detector for the ALICE experiment at LHC

The particle identification in ALICE (A Large Ion Collider Experiment) at LHC will be achieved by two complementary systems based on time of flight measurement, at low $p_t$, and on the Ring Imaging Cherenkov (RICH) technique, at $p_t$ ranging from 2 to 5 GeV/$c$, respectively. The High Momentum PID (HMPID) system will cover $\sim$5\% of the phase space, the single arm detector array beeing composed by seven 1.3$\times$1.3 m$^2$ CsI-RICH modules placed at 4.7 m from the interaction point where a density of about 50 particles/m$^2$ is expected.\\ A 1 m$^2$ prototype, 2/3 of HMPID module size, has been successfully tested at the CERN/PS beam where 18 photoelectrons per event have been obtained with 3 GeV/c pions and 10 mm liquid $\mathrm{C}_6\mathrm{F}_{14}$ radiator. Mechanical problems related to the liquid radiator vessel construction have been solved and the prototype, fully equipped, will be tested at the CERN/SPS to investigate the PID capability in high particle density events.\\ In this report, after an introductory discussion on the requirements for PID in ALICE, the HMPID prototype is described and the main results of beam tests on large area CsI photocathodes, operated in RICH detectors, are given

Review of the development of cesium iodide photocathodes for application to large RICH detectors

CsI photocathodes were studied in order to evaluate their potential use as large photo converters in RICH detectors for the PID system of ALICE at LHC in heavy-ion collider mode. It has been demonstrated that a quantum efficiency close to the reference value obtained on small samples can be obtained on CsI layers evaporated on large pad electrodes operated in a MWPC at atmospheric pressure. We present a survey of the results obtained in the laboratory on small samples irradiated with UV-monochromatic beams and with large area RICH detectors of proximity-focusing geometry in a 3 GeV/c pion beam