THGEM based photon detector for Cherenkov imaging applications Alexeev, M.; Birsa, R.; Bradamante, F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2010, Letnik:
617, Številka:
1
Journal Article
Recenzirano
We are developing a single photon detector for Cherenkov imaging counters. This detector is based on the use of THGEM electron multipliers in a multilayer design. The major goals of our project are ...ion feedback suppression down to a few per cent, large gain, fast response, insensitivity to magnetic fields, and a large detector size.
We report about the project status and perspectives. In particular, we present a systematic study of the THGEM response as a function of geometrical parameters, production techniques and the gas mixture composition. The first figures obtained from measuring the response of a CsI coated THGEM to single photons are presented.
Micropattern gaseous photon detectors for Cherenkov imaging counters Alexeev, M.; Birsa, R.; Bradamante, F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2010, Letnik:
623, Številka:
1
Journal Article
Recenzirano
We are developing a detector of single photons for application in Cherenkov imaging counters, based on the use of a multilayer architecture of THGEM electron multipliers coupled to a solid state CsI ...photocathode. The main goals of our project are ion feedback suppression down to a few per cent level, large gain, fast response, good time resolution, insensitivity to magnetic field and large detector size. We report about the project status and perspectives.
Particle identification with COMPASS RICH-1 Abbon, P.; Alexeev, M.; Angerer, H. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2011, Letnik:
631, Številka:
1
Journal Article
Recenzirano
RICH-1 is a large size RICH detector in operation at the COMPASS experiment since 2001 and recently upgraded implementing a new photon detection system with increased performance.
A dedicated ...software package has been developed to perform RICH-1 data reduction, pattern recognition and particle identification as well as a number of accessory tasks for detector studies.
The software package, the algorithms implemented and the detector characterisation and performance are reported in detail.
On-line mirror alignment monitoring method for COMPASS RICH-1 Alexeev, M.; Birsa, R.; Bradamante, F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2008, Letnik:
595, Številka:
1
Journal Article
Recenzirano
COMPASS RICH-1 is a large size gaseous Cherenkov detector. Two reflecting spherical surfaces, covering a total area of about
21
m
2
hosted in the radiator vessel provide image focusing. The segmented ...surfaces are formed by 116 mirrors, with individual degrees of freedom for angular adjustment. An original method has been developed and applied for the on-line monitoring of the mirror alignment. Relative tilts between neighbouring mirror elements create discontinuities in the image of continuous lines reflected by the mirror wall. The measurement of the discontinuities can also provide information about the absolute tilt with a resolution of 0.1
mrad. An independent check and calibration of this method has been performed in laboratory using, as reference, a laser interferometer.
We present the technical solutions adopted to implement the dedicated setup, the results of the method calibration by laser interferometer, and the preliminary results obtained measuring the alignment of the RICH-1 mirror wall.
Particle identification with the fast COMPASS RICH-1 detector Abbon, P.; Alexeev, M.; Angerer, H. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2010, Letnik:
623, Številka:
1
Journal Article
Recenzirano
A new photon detection system for the COMPASS RICH-1 detector has been designed and installed. In the central region, the project is based on multi-anode photo-multiplier technology accompanied by ...charge sensitive, high resolution and dead-time free time digitization. In the outer area, only the readout electronics for the existing photon detectors has been replaced. Details on the detector upgrade and its performance are presented.
A major upgrade of the Cherenkov photon detection system of COMPASS RICH-1 has been performed and it has been in operation since the 2006 physics run. The inner part of the photon detector has been ...replaced by a different technology in order to measure Cherenkov photons at high photoelectron rates, up to several times 10
6 per second and per channel. Cherenkov photons from 200 to 750
nm are detected by 576 multianode photomultiplier tubes (MAPMTs) with 16 channels each, coupled to individual fused silica lens telescopes and fast, high sensitivity and high time resolution electronics read-out. To guarantee an optimal performance of the complete system, parameters like dark current, gain, uniformity, relative quantum efficiency have been measured for a totality of more than 600 MAPMTs (about 10
000 channels) in a fully automated test-stand, developed for this purpose. The ideal working point for each individual pixel could be ascertained by these measurements. In 2006 the newly equipped detector exhibited an excellent performance: about 56 detected photons per ring at saturation and a time resolution of better than 1
ns.
We report about the MAPMT characterisation and the quality control set-up, protocol and results.
The
p
̄
Ne
annihilation cross section is measured for the first time in the momentum interval (53÷63) MeV/c. About 9000 pictures collected by the Streamer Chamber Collaboration (PS179) at LEAR-CERN ...have been scanned. Four events are found, corresponding to
σ
ann=2210±1105 mb. The result is compared to the set of measurements presently available in the region of low p̄ momentum.
Design and status of COMPASS FAST-RICH Abbon, P.; Alekseev, M.; Angerer, H. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2006, Letnik:
567, Številka:
1
Journal Article
Recenzirano
In the context of the upgrade of COMPASS RICH-1, we are developing a fast photodetection system for RICH counters, based on UV extended Multi-Anode PhotoMultiplier Tubes (MAPMT) and a custom, low ...dead-time electronic readout system. Photons are concentrated on the MAPMT photocathode by an optical system that preserves the position information. The ratio between the collection and the photosensitive surfaces is
∼
7.5
in our design, larger than in previous applications. A new front-end electronics, based on a modified version of the MAD4 discriminator chip, is being realized to digitize the MAPMT signals. We report about the design of the photodetection system and of the associated electronic readout system, and on the preliminary test beam results.
Double-spin asymmetries for production of charged pions and kaons in semi-inclusive deep-inelastic muon scattering have been measured by the COMPASS experiment at CERN. The data, obtained by ...scattering a 160 GeV muon beam off a longitudinally polarised NH
3 target, cover a range of the Bjorken variable
x between 0.004 and 0.7. A leading order evaluation of the helicity distributions for the three lightest quarks and antiquark flavours derived from these asymmetries and from our previous deuteron data is presented. The resulting values of the sea quark distributions are small and do not show any sizable dependence on
x in the range of the measurements. No significant difference is observed between the strange and antistrange helicity distributions, both compatible with zero. The integrated value of the flavour asymmetry of the helicity distribution of the light-quark sea,
Δ
u
¯
−
Δ
d
¯
, is found to be slightly positive, about 1.5 standard deviations away from zero.
PDF
