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A. DiMauro,
Y. Andres,
B. Belin,
A. Braem,
K. Chileev,
M. Davenport,
G. DeCataldo,
D. DiBari,
A. Franco,
U. Fratino, [......],
A. Kurepin,
P. Martinengo,
E. Nappi,
G. Paic,
C. Pastore,
F. Piuz,
J.C. Santiard,
E. Schyns,
I. Sgura,
A. Tauro
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ABSTRACT: The ALICE (A Large Ion Collider Experiment) high momentum particle identification (HMPID) detector, presently under construction, consists of seven identical proximity focusing ring imaging Cherenkov (RICH) counters exploiting large area CsI photocathodes for Cherenkov light imaging. With a total area of 11 $ m^2$ , it represents the largest CsI-RICH system ever used in High Energy Physics. The detector layout, assembly and quality checks will be presented, with particular emphasis on CsI photocathodes mass production. A validation procedure has been established combining the results of the photocathode response mapping obtained in a dedicated VUV scanner with test beam data. The long-term stability has also been studied by irradiation with a Sr-90 source of a final size CsI photocathode inside a detector prototype.
IEEE Transactions on Nuclear Science 09/2005; · 1.45 Impact Factor
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STAR-RICH Collaboration: A. Braem,
D Cozza,
M Davenport,
G De Cataldo,
L. Dell Olio,
D. DiBari, A. DiMauro,
J. C. Dunlop,
E. Finch,
D. Fraissard, [......],
J Raynaud,
S. Salur,
J. Sandweiss,
J. C. Santiard,
J. Satinover,
E. Schyns,
N Smirnov,
J. Van Beelen,
T D Williams,
Z Xu
[show abstract]
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ABSTRACT: The STAR-RICH detector extends the particle identification capapbilities of the STAR experiment for charged hadrons at mid-rapidity. This detector represents the first use of a proximity-focusing CsI-based RICH detector in a collider experiment. It provides identification of pions and kaons up to 3 GeV/c and protons up to 5 GeV/c. The characteristics and performance of the device in the inaugural RHIC run are described.
12/2002;
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ABSTRACT: Using the X-ray spectromicroscopy technique, we studied the primary and secondary electron photoemission of cesium iodide (CsI) films deposited on different substrates, such as copper, aluminum, stainless-steel, and gold-coated quartz. We found an increase of more than a factor of 2 in the secondary emission after exposing, for a few seconds in ultra-high-vacuum (3 X 10(-10) mbar), the sample surface to an X-ray dose-rate of about 5 X 10(11) photons/s cm2 at the Al Kalpha photon energy (1486.7 eV). The activation effect, that lasts for about two days, is related to a change in the surface morphology: after the X-ray exposure the surface presents a single phase with respect to the presence of two phases in the as-deposited or aged samples (lower Quantum Efficiency (QE) condition). Furthermore, the 25 mum lateral resolution of our spectromicroscope allowed us to show that the secondary electron photoemission is strongly inhomogeneous on the plane of the surface, and that this inhomogeneity is more closely related to the spatial inhomogeneity of the Cs photoemission yield than to that of 1. Finally, we found a decomposition effect induced by the X-ray exposure. This photoetching is less effective for the CsI deposited on the copper substrate, probably due to the presence of Cu-I compounds at the interface with the substrate, which is revealed by X-ray diffraction measurements.
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H. Berger,
P Besson,
P. Bourgeois,
A. Braem,
A. Breskin,
A. Buzulutskov,
R. Chechik,
E. Chesi,
C. Coluzza,
R. Ferreiramarques, [......],
J Schukraft,
T Scognetti,
S. Sgobba,
O. Svensson,
T. Tustonic,
A. Valentini,
D Vartsky,
G Vasileiadis,
F. Divenere,
K. Zeitelhack
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ABSTRACT: We report here on the results obtained by the CERN RD26 collaboration on the production and characterization of large area photocathodes, susceptible to equip fast UV-photon imaging devices. Such detectors are planned for some Ring Imaging Cherenkov (RICH) detector projects, in particular HADES at SIS Darmstadt, BABAR at the SLAG asymmetric B-factory, and ALICE at the LHC (CERN).
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J. Almeida,
A. Amadon,
P Besson,
P. Bourgeois,
A. Braem,
A. Breskin,
A. Buzulutskov,
R. Chechik,
C. Coluzza, A. DiMauro, [......],
E. Nappi,
T. Dellorto,
G Paic,
F. Piuz,
F Posa,
J. C. Santiard,
P Sartori,
S. Sgobba,
G Vasileiadis,
T D Williams
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ABSTRACT: CsI photocathodes were studied in order to evaluate their potential use as large photoconverters in RICH detectors for the PID system at ALICE (LHC in heavy ion collider mode). It has been demonstrated that a quantum efficiency comparable 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 RICH detectors of proximity-focusing geometry at a 3 GeV/c pion beam.
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ABSTRACT: CsI photocathodes of 30 × 30 cm2 size have been operated in a fast RICH detector composed of a NaF radiator and a multiwire proportional chamber with a cathode pad readout. Results are presented from tests with a proton beam. A Cherenkov angular resolution of 8 mrad is obtained by detecting a mean of 8 photoelectrons per ring. Methods are described for counting the Cherenkov photons and evaluating the differential quantum efficiency of the CsI photocathode. The results obtained with photons impinging at a large angle on the CsI layer are presented and discussed in comparison with higher quantum efficiencies observed under different experimental conditions.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment.
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Y. Andres,
A. Braem,
D. Cozza,
M. Davenport,
G. De Cataldo,
L. Dell Olio,
D. DiBari, A. DiMauro,
J.C. Dunlop,
E. Finch, [......],
J. Raynaud,
S. Salur,
J. Sandweiss,
J.C. Santiard,
J. Satinover,
E. Schyns,
N. Smirnov,
J. Van Beelen,
T.D. Williams,
Z. Xu
[show abstract]
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ABSTRACT: A RICH detector with a CsI photo-cathode and liquid perfluorohexane radiator has been installed in the STAR experiment at RHIC. The liquid is continuously cleaned and distributed to a quartz containment vessel within the detector by a closed recirculation system. A VUV spectrometer is connected to the system which monitors the optical transparency of the liquid. This measurement provides one of the pieces of information necessary to model the number of Cherenkov photons which reach the pad plane. A description of the liquid recirculation system and the cleaning procedure for the liquid as well as the spectrometer is presented along with results of their performance.
Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 486(3):590-609. · 1.21 Impact Factor
