We report on the R&D results for a Very High Momentum Particle Identification (VHMPID) detector, which was proposed to extend the charged hadron track-by-track identification in the momentum range ...from 5 to 25 GeV/c in the ALICE experiment at CERN. It is a RICH detector with focusing geometry using pressurized perfluorobutane (C sub(4)F sub(8)O) as a Cherenkov radiator. A MWPC with a CsI photocathode was investigated as the baseline option for the photon detector. The results of beam tests performed on RICH prototypes using both liquid C sub(6)F sub(14) radiator (in proximity focusing geometry for reference measurements) and pressurized C sub(4)F sub(8)O gaseous radiator will be shown in this paper. In addition, we present studies of a CsI based gaseous photon detector equipped with a MWPC having an adjustable anode-cathode gap, aiming at the optimization of the chamber layout and performance in the detection of single photoelectrons.
We report on studies of layout and performance of a new Ring Imaging Cherenkov detector using for the first time pressurized C4F8O radiator gas and a photon detector consisting of a MWPC equipped ...with a CsI photocathode. In particular, we present here the results of beam tests of a MWPC having an adjustable anode–cathode gap, aiming at the optimization of single photoelectron detection and Cherenkov angle resolution. This system was proposed as a Very High Momentum Particle Identification (VHMPID) upgrade for the ALICE experiment at LHC to provide charged hadron track-by-track identification in the momentum range 5–25GeV/c.
•The concept and design of a novel RICH counter operated with pressurized gaseous Cherenkov radiator have been validated.•We used for the first time C4F8O gaseous Cherenkov radiator pressurized up to 3.5atm in a RICH counter.•The refractive index of C4F8O in the UV range is similar to the per-mil level to that of C4F10.•A variable gap MWPC has been used to optimize the layout of the gaseous photon counter, based on CsI photocathodes and MWPC, for the detection of single photoelectrons.
An innovative photosensitive gaseous detector, consisting of a GEM-like amplification structure with double-layered electrodes (instead of commonly used metallic ones) coated with a CsI reflective ...photocathode, is described. In one of our latest designs, the inner electrode consists of a metallic grid and the outer one is made of resistive strips; the latter are manufactured by a screen-printing technology on the top of the metallic strips's grid The inner metallic grid is used for 2-D position measurements whereas the resistive layer provides an efficient spark-protected operation at high gains close to the breakdown limit. Detectors with active areas of 10×10 and 10×20
cm
2 were tested under various conditions including the operation in photosensitive gas mixtures containing ethylferrocene or TMAE vapors.
The new technique could have many applications requiring robust and reliable large-area detectors for UV visualization, as for example, in Cherenkov imaging devices.
We report on the design and construction of a CsI-RICH detector composed of four CsI photocathodes of 64×40 cm
2 each, and two C
6F
14 radiator trays of 133×41 cm
2. A detailed description of the ...novel elements is given and the performance of the detector is illustrated with some basic results obtained during the tests at the beam.
The production of the strange and double-strange baryon resonances (Formula: see text, Formula: see text) has been measured at mid-rapidity (Formula: see textFormula: see text) in proton-proton ...collisions at Formula: see text Formula: see text 7 TeV with the ALICE detector at the LHC. Transverse momentum spectra for inelastic collisions are compared to QCD-inspired models, which in general underpredict the data. A search for the Formula: see text pentaquark, decaying in the Formula: see text channel, has been carried out but no evidence is seen.
Aging of large-area CsI photocathodes for the ALICE HMPID prototypes Braem, A; Davenport, M; Di Mauro, A ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2003, Volume:
515, Issue:
1
Journal Article
Peer reviewed
Open access
The ALICE High-Momentum Particle IDentification RICH detector is equipped with CsI photocathodes (PCs) in a MWPC for the detection of Cherenkov photons. The long-term operational experience with ...large-area CsI PCs is described. The RICH prototypes have shown a very high stability of operation and performance at a gain of 10
5 and with rates up to 2×10
4
cm
−2
s
−1. When exposure to air is avoided, no degradation of the CsI quantum efficiency has been observed on PCs periodically exposed to test beams over 7 years, corresponding to local integrated charge densities of ∼1
mC/cm
2. The results of limited exposures to oxygen and humidity are also presented.
Protons identification up to
10
GeV
/
c
and more is a challenge. We present here an exhaustive study of the possibilities offered by a combination of a gaseous radiator having low index of refraction ...(C
5F
12) with the proven concept of large area CsI photocathodes, instrumenting either a multiwire chamber or a GEM detector. We present two geometries. One of them is proximity-focusing, nevertheless allows identification in a large momentum range. The second one deals with a focusing geometry with a spherical mirror. Simulations of the performance of both types are presented.
PDF
