Development of THGEM-based photon detectors for Cherenkov Imaging Counters

Alexeev, M.; Alfonsi, M.; Birsa, R.; Bradamante, F.; Bressan, A.; Chiosso, M.; Ciliberti, P.; Croci, G.; Colantoni, M.; Torre, S. Dalla; Денисов, О.; Pinto, S. Duarte; Duic, V.; Ferrero, A.; Finger, M.; Fischer, H.; Giacomini, G.; Giorgi, M. A.; Gobbo, B.; Hagemann, R.; Heinsius, F. H.; Herrmann, F.; Jahodova, Vera; Königsmann, K.; Kramer, Daniel; Lauser, L.; Levorato, S.; Maggiora, A.; Martin, A.; Menon, G.; Mutter, A.; Nerling, F.; Panzieri, D.; Pesaro, G.; Polák, Jaroslav; Rocco, E.; Ropeleswki, L.; Sauli, F.; Sbrizzai, G.; Schiavon, P.; Schill, C.; Schopferer, S.; Slunečka, M.; Sozzi, F.; Steiger, L.; Šulc, M.; Takekawa, S.; Tessarotto, F.; Wollny, H.

doi:10.1088/1748-0221/5/03/p03009

Cited by 64 publications

(25 citation statements)

References 21 publications

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“…Another problem addressed here was the THGEM's gain-stability over time. It was already established in the literature that THGEMs without etched rims around the holes have stable gain on the short-range (hours) and the long-range (weeks) time scales [10]. However, the lack of rims enhanced discharge probability due to defects on the hole-edges, resulting in over 10-fold gain reduction compared to holes with etched rims [1].…”

Section: Summary and Discussionmentioning

confidence: 99%

Further evaluation of a THGEM UV-photon detector for RICH – comparison with MWPC

et al. 2010

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The operation of single-, double-and triple-THGEM UV-detectors with reflective CsI photocathodes (CsI-THGEM) in Ne/CH 4 and Ne/CF 4 mixtures was investigated in view of their potential applications in RICH. The studies were carried out with UV, x-rays and βelectrons and focused on the maximum achievable gain, discharge probability, cathode excitation effects and long-term gain stability. Comparative studies under similar conditions were made in CH 4 , CF 4 and Ne/CF 4 , with a MWPC coupled to a reflective CsI photocathode (CsI-MWPC). It was found that at counting rates ≤ 10 Hz/mm 2 the maximum achievable gain of CsI-THGEMs is determined by the Raether limit; at counting rates > 10 Hz/mm 2 it dropped with rate. In all cases investigated the attainable CsI-THGEM gain was significantly higher than that of the CsI-MWPC, under similar conditions. Furthermore, the CsI-THGEM UV-detector suffered fewer cathode-excitation induced effects as compared to CsI-MWPC and had better stability at high counting rates. KEYWORDS: Micropattern gaseous detectors; Photon detectors for UV, visible and IR photons;Avalanche-induced secondary effects; Cherenkov detectors. 1. High gains (> 10 5 ) are reachable with single-or cascaded-THGEM electrodes in selected gases; mixtures of choice could be Ne with a small addition of quenchers (CH 4 , CF 4 ) [3,4]. Due to the exponential nature of single-photoelectron pulse-height distributions, and taking into account signal-over-threshold considerations, a high detector gain is an important factor in improving single-photon detection efficiency. 2. A THGEM can operate in poorly quenched gas mixtures as well as in gases emitting UV light (e.g. noble gases [5], CF 4 [6,4]). This permits conceiving windowless detectors (same detector and radiator gas, e.g. like in [7]), with simpler layout and larger Cherenkov-photon detection yields. 3. In intense-background environment, THGEMs can operate in the so-called "Hadron-Blind mode" with zero or reversed electric field above the photocathode [8]; this significantly reduces particle-induced ionization signals [7]. CsI-THGEMs are currently considered for the upgrade of the RICH systems at the 10]. The reasons to replace the CsI-MWPCs [11] in these experiments are numerous: The CsI-MWPCs operate at relatively low gas gains (~10 4 ), limited by avalanche photon-feedback. Furthermore, there is evidence that at high counting rates the MWPCs suffer from feedback-related discharges, followed by difficulties to restore the operating voltage, up to 1-day periods [12]. This could have resulted from a cathode excitation process [13], in which the surface is modified under discharge-induced ion bombardment, with

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Section: Summary and Discussionmentioning

confidence: 99%

Further evaluation of a THGEM UV-photon detector for RICH – comparison with MWPC

et al. 2010

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“…Gain variations with time have been reported and are common in detectors containing dielectric materials in contact with the gas medium where multiplication occurs; the effects have been noticed particularly in detectors based on hole-type MPGDs with insulating surfaces in contact with active gases, e.g. Gas Electron Multipliers (GEMs) [1][2][3] and Thick-GEMs (THGEMs) [4][5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Simulation of gain stability of THGEM gas-avalanche particle detectors

et al. 2018

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Charging-up processes affecting gain stability in Thick Gas Electron Multipliers (THGEM) were studied with a dedicated simulation toolkit. Integrated with Garfield++, it provides an effective platform for systematic phenomenological studies of charging-up processes in MPGD detectors. We describe the simulation tool and the fine-tuning of the step-size required for the algorithm convergence, in relation to physical parameters. Simulation results of gain stability over time in THGEM detectors are presented, exploring the role of electrode-thickness and applied voltage on its evolution. The results show that the total amount of irradiated charge through electrode's hole needed for reaching gain stabilization is in the range of tens to hundreds of pC, depending on the detector geometry and operational voltage. These results are in agreement with experimental observations presented previously.

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“…The stability of the detector's gain over time is vital for reaching a stable performance of gasavalanche detectors, manifested in detector efficiency and energy resolution. Changes in the detector gain over the first hours of operation have been observed in gaseous detectors incorporating insulating electrode substrates; examples are in Gas Electron Multipliers (GEM) [1][2][3], Large Electron Multiplier (LEM) [4,5] and Thick Gaseous Electron Multiplier (THGEM) -based detectors [6][7][8][9][10][11]. The gain variation has been commonly attributed to charging-up of the detector's insulating surfaces that modifies the electric field in the charge-multiplication region.…”

Section: Introductionmentioning

confidence: 99%

Measurements of charging-up processes in THGEM-based particle detectors

et al. 2018

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A: The time-dependent gain variation of detectors incorporating Thick Gas Electron Multipliers (THGEM) electrodes was studied in the context of charging-up processes of the electrode's insulating surfaces. An experimental study was performed to examine model-simulation results of the aforementioned phenomena, under various experimental conditions. The results indicate that in a stable detector's environment, the gain stabilization process is mainly affected by the charging-up of the detector's insulating surfaces caused by the avalanche charges. The charging-up is a transient effect, occurring during the detector's initial operation period; it does not affect its long-term operation. The experimental results are consistent with the outcome of model-simulations.

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Development of THGEM-based photon detectors for Cherenkov Imaging Counters

Cited by 64 publications

References 21 publications

Further evaluation of a THGEM UV-photon detector for RICH – comparison with MWPC

Further evaluation of a THGEM UV-photon detector for RICH – comparison with MWPC

Simulation of gain stability of THGEM gas-avalanche particle detectors

Measurements of charging-up processes in THGEM-based particle detectors

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