Design and construction of the fast photon detection system for COMPASS RICH-1

Abbon, P.; Alexeev, M.; Angerer, H.; Birsa, R.; Bordalo, P.; Bradamante, F.; Bressan, A.; Chiosso, M.; Ciliberti, P.; Colantoni, M.; Dafní, T.; Torre, S. Dalla; Delagnes, É.; Денисов, О.; Deschamps, H.; Diaz, V.; Dibiase, N.; Duic, V.; Eyrich, W.; Ferrero, A.; Finger, M.; Fischer, H.; Gerassimov, S.; Giorgi, M. A.; Gobbo, B.; Hagemann, R.; Harrach, D. von; Heinsius, F. H.; Joosten, R.; Ketzer, B.; Kolosov, V.N.; Königsmann, K.; Konorov, I.; Kramer, Daniel; Kunne, F.; Lehmann, A.; Levorato, S.; Maggiora, A.; Magnon, A.; Mann, A.; Martin, A.; Menon, G.; Mutter, A.; Nähle, O.; Nerling, F.; Neyret, D.; Panzieri, D.; Paul, S.; Pesaro, G.; Pizzolotto, C.; Polák, Jaroslav; Rebourgeard, P.; Robinet, F.; Rocco, E.; Schiavon, P.; Schill, C.; Schoenmeier, P.; Schröder, W.; Silva, L.; Slunečka, M.; Sozzi, F.; Steiger, L.; Šulc, M.; Svec, M.; Takekawa, S.; Tessarotto, F.; Teufel, Andreas; Wollny, H.

doi:10.1016/j.nima.2010.02.069

Cited by 40 publications

(14 citation statements)

References 41 publications

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“…The RICH-1 detector [1][2][3] of the COMPASS experiment [4,5] is a Ring Imaging Cherenkov detector with a 3 m long gaseous C 4 F 10 radiator, 21 m 2 wide focusing VUV mirror surface and Photon Detectors (PD) covering a total active area of 5.5 m 2 . In the 2015-2016 winter shut-down of the COMPASS experiment, around 1.4 m 2 of the active area of the photon detectors was upgraded by novel detectors based on MPGD technologies [6].…”

Section: Introductionmentioning

confidence: 99%

The high voltage system with pressure and temperature corrections for the novel MPGD-based photon detectors of COMPASS RICH-1

Agarwala

Bari

Bradamante

et al. 2019

Nuclear Instruments and Methods in Physics Research Section A:

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The novel MPGD-based photon detectors of COMPASS RICH-1 consist of large-size hybrid MPGDs with multilayer architecture including two layers of Thick-GEMs and a bulk resistive MicroMegas. The top surface of the first THGEM is coated with a CsI film which also acts as photo-cathode. These detectors have been successfully in operation at COMPASS since 2016. Concerning bias-voltage supply, the Thick-GEMs are segmented in order to reduce the energy released in case of occasional discharges, while the MicroMegas anode is segmented into pads individually biased with positive voltage while the micromesh is grounded. In total, there are about ten different electrode types and more than 20000 electrodes supplied by more than 100 HV channels, where appropriate correlations among the applied voltages are required for the correct operation of the detectors. Therefore, a robust control system is mandatory, implemented by a custom designed software package, while commercial power supply units are used. This sophisticated control system allows to protect the detectors against errors by the operator, to monitor and log voltages and currents at 1 Hz rate, and automatically react to detector misbehaviour. In addition, a voltage compensation system has been developed to automatically adjust the biasing voltage according to environmental pressure and temperature variations, to achieve constant gain over time. This development answers to a more general need. In fact, voltage compensation is always a requirement for the stability of gaseous detectors and its need is enhanced in multi-layer ones.In this paper, the HV system and its performance are described in details, as well as the stability of the novel MPGD-based photon detectors during the physics data taking at COMPASS.

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Section: Introductionmentioning

confidence: 99%

The high voltage system with pressure and temperature corrections for the novel MPGD-based photon detectors of COMPASS RICH-1

Agarwala

Bari

Bradamante

et al. 2019

Nuclear Instruments and Methods in Physics Research Section A:

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“…A total of 612 MAPMTs have been submitted to a complete quality control protocol [25,31] including visual inspection, measurements of dark currents and of gain at 5 different voltages. The typical gain is about 10 7 at 900 V, with excellent uniformity; no gain reduction is observed up to a single photoelectron rate of at least 5 MHz per channel.…”

Section: The Mapmt-based Photon Detectors the Readout And Daqmentioning

confidence: 99%

“…It consists of individual optical telescopes [25,32] -15 - for each MAPMT, made of two fused silica lenses (see figure 21): a plano-convex field lens, placed in the focal plane of the mirrors and a biconvex condenser lens with one aspherical surface, providing the large demagnification with reduced image distortions. The image is projected to the plane of the MAPMT photo-cathode with a total spot size r.m.s.…”

Section: The Mapmt-based Photon Detectors the Readout And Daqmentioning

confidence: 99%

“…Each lens and each telescope have been tested [25,33] in a custom setup employing the Hartmann method [34,35] to provide individual characterization of wavefront distortions with respect to ideal optics; the final image displacement introduced by optics imperfections is below 50 µm for 70% of the telescopes, and in all cases below 150 µm. A careful mechanical design of the lens support frames (see figure 22) allowed to reduce the dead areas below 2% of the surface.…”

Section: The Mapmt-based Photon Detectors the Readout And Daqmentioning

confidence: 99%

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Long term experience and performance of COMPASS RICH-1

et al. 2014

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JINST 9 C09011ABSTRACT: COMPASS RICH-1 is a large size gaseous Imaging Cherenkov Detector providing hadron identification in the range from 3 to 55 GeV/c, in the wide acceptance spectrometer of the COMPASS Experiment at CERN SPS.It uses a 3 m long C 4 F 10 radiator, a 21 m 2 large VUV mirror surface and two kinds of photon detectors: MAPMTs and MWPCs with CsI photocathodes, covering a total of 5.5 m 2 . It is in operation since 2002 and its performance increased thanks to progressive optimization and to a major upgrade of its photon detection system, implemented in 2006; a new upgrade is foreseen for 2016, with the use of MPGD-based photon detectors.The main characteristics of COMPASS RICH-1 components are described and the most critical aspects related to the C 4 F 10 radiator gas system, to the mirrors and their alignment, as well as the performance of the photon detectors are presented and discussed. The response of the MWPCs and the observed evolution of the effective quantum efficiency of the CsI photocathodes is analyzed. The properties and performance of the MAPMTs with individual fused lens telescopes are presented together with the readout characteristics. The PID performance of COMPASS RICH-1 is discussed and the future upgrade program is mentioned.

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“…For example, experiments such as COMPASS [18] and ALICE [19] at CERN both have implemented a reflective CsI thin films photocathode with a MWPC. However, PHENIX at RHIC [20] has used a cascade of GEMs with a reflective CsI thin films for particle identification.…”

Section: Introductionmentioning

confidence: 99%

Structural and optical properties of CsI thin films: Influence of film thickness and humidity

Jammal

Rai

Pandit

et al. 2018

Physica B: Condensed Matter

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Structural and optical studies have been performed on the thermally-evaporated "as-deposited" and "humid air aged" CsI thin films. The structural analysis for both "as-deposited" and "humid air aged" films shows a well-oriented peaks position of (110) and (220) lattice planes with a compressive stress in the films. The crystal quality has been investigated through the structural parameters. The increase in peak intensity as well as sharpness with film thickness implies the improvement of crystallinity. The optical absorbance of CsI films has been analyzed in the wavelength range of 190 nm -900 nm in order to estimate the band gap energy of the films. Slater's model has also been used to explain the degradation of band gap energy with the increase in crystallite size. been tested successfully under liquid xenon atmosphere for its use in dark matter search experiment [21]. The detectors used for these experiments generally work in two modes; reflective (opaque) and semitransparent mode. The Quantum Yield (QY) of reflective films has been observed to be higher in comparison with the semitransparent films. This is because the semitransparent films have a small escape length (L≤ 10 nm) [16]. Also, it has been revealed that the reflective films have more chemical stability against the moisture compared to the semitransparent films [17].Keeping these facts in mind, the main issue related to CsI photocathode is the aging which causes a degradation in the photoemission properties and thus limits their life. In order to develop and optimize large area photocathodes based detector, the study of the optical and structural properties of the "as-deposited" and "aged" CsI photocathodes is ultimately required. In literature, there are several studies on CsI ageing, but its mechanism does not have a clear understanding yet. A. S. Tremsin et al. [23] have used TEM technique to study the structural properties of polycrystalline CsI thin film of 100 nm thickness under the impact of humid air and UV irradiation. M. A. Nitti et al. [24] have examined the bulk structure and the surface of freshly and humid air exposed 100 nm CsI film by XRD and XPS measurements. Recently, Triloki et al. [25] have studied the structural properties of thermally-evaporated CsI thin films of different thicknesses by using XRD and TEM techniques. C. Lu and K.T. McDonald [16] have previously reported the optical properties of freshly CsI thin films up to 31 nm thickness. This work is an extension of the previous works, where we have systematically studied the structural and optical properties of semitransparent and reflective CsI thin films grown under similar vacuum-environment in case of "as-deposited" and "humid air aged". Experimental Details Deposition of CsI thin filmsThe deposition of reflective (500 nm and 300 nm) and semitransparent (50 nm and 30 nm) CsI thin films was done in a stainless steel 18" diameter spherical vacuum chamber. Prior to the deposition process, the substrates were cleaned by treating with distilled water, acetone, and alcohol to...

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Design and construction of the fast photon detection system for COMPASS RICH-1

Cited by 40 publications

References 41 publications

The high voltage system with pressure and temperature corrections for the novel MPGD-based photon detectors of COMPASS RICH-1

The high voltage system with pressure and temperature corrections for the novel MPGD-based photon detectors of COMPASS RICH-1

Long term experience and performance of COMPASS RICH-1

Structural and optical properties of CsI thin films: Influence of film thickness and humidity

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