First Tests of MICROMEGAS and GEM-Like Detectors Made of a Resistive Mesh

Oliveira, Rui de; Peskov, V.; Pietropaolo, F.; Picchi, P.

doi:10.1109/tns.2010.2073483

Cited by 11 publications

(10 citation statements)

References 33 publications

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“…The underlying motivation for using a resistive film as an intermediate layer between the THGEM and readout pads [20,21] is twofold: (1) decoupling of the sensitive readout electronics from direct currents during occasional energetic discharges, and (2) the ability of the resistive layers to effectively reduce the spark energy, as demonstrated in previous works [22,23]. In this article, we briefly describe the methodology and main results, referring the reader to a more complete work [24].…”

Section: Laboratory Randd On Resistive-anode Structuresmentioning

confidence: 99%

THGEM-based detectors for sampling elements in DHCAL: laboratory and beam evaluation

Arazi¹,

Luz²,

Freytag³

et al. 2012

J. Inst.

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We report on the results of an extensive R&D program aimed at the evaluation of Thick-Gas Electron Multipliers (THGEM) as potential active elements for Digital Hadron Calorimetry (DHCAL). Results are presented on efficiency, pad multiplicity and discharge probability of a 10x10 cm 2 prototype detector with 1 cm 2 readout pads. The detector is comprised of single-or double-THGEM multipliers coupled to the pad electrode either directly or via a resistive anode. Investigations employing standard discrete electronics and the KPiX readout system have been carried out both under laboratory conditions and with muons and pions at the CERN RD51 test beam. For detectors having a charge-induction gap, it has been shown that even a ~6 mm thick single-THGEM detector reached detection efficiencies above 95%, with pad-hit multiplicity of 1.1-1.2 per event; discharge probabilities were of the order of 10 -6 -10 -5 sparks/trigger, depending on the detector structure and gain. Preliminary beam tests with a WELL hole-structure, closed by a resistive anode, yielded discharge probabilities of <2x10 -6 for an efficiency of ~95%. Methods are presented to reduce charge-spread and pad multiplicity with resistive anodes. The new method showed good prospects for further evaluation of very thin THGEM-based detectors as potential active elements for DHCAL, with competitive performances, simplicity and robustness. Further developments are in course.

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Section: Laboratory Randd On Resistive-anode Structuresmentioning

confidence: 99%

THGEM-based detectors for sampling elements in DHCAL: laboratory and beam evaluation

Arazi¹,

Luz²,

Freytag³

et al. 2012

J. Inst.

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“…Since 2009 we also studied several schemes of resistive Micromegas detectors, but none of them showed performance adapted to our needs, in particular in term of reliability or of spatial resolution, excepted one scheme. This late scheme (figure 1) was proposed beginning of 2010 by Rui de Oliveira [10]. According to this scheme, the anode strips are covered by resistive pads connected to the strips by intermediate resistors placed horizontally.…”

Section: Discharge Impact Reductionmentioning

confidence: 99%

New pixelized Micromegas detector with low discharge rate for the COMPASS experiment

et al. 2012

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New Micromegas (Micro-mesh gaseous detectors) are being developed in view of the future physics projects planned by the COMPASS collaboration at CERN. Several major upgrades compared to present detectors are being studied: detectors standing five times higher luminosity with hadron beams, detection of beam particles (flux up to a few hundred of kHz/mm², 10 times larger than for the present Micromegas detectors) with pixelized read-out in the central part, light and integrated electronics, and improved robustness. Two solutions for a reduction of the impact of discharges have been studied, with Micromegas detectors using resistive layers and using an additional GEM foil. The performance of such detectors has been measured during beam test periods. A large size prototype with nominal active area and pixelized read-out has been produced and installed in the COMPASS spectrometer in 2010. In 2011 prototypes featuring an additional GEM foil, as well as a resistive prototype, were tested in similar conditions and preliminary results from those detectors are very promising. We present here the project and report on its status, in particular the performance of large size prototypes with an additional GEM foil.

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“…Advantages of this approach include large dynamic range, high rate capability, good time resolution, and fine segmentation. A manufacturing process to produce Micromegas chambers in bulk at relatively low cost has matured [17], and refinements to the basic design continue to develop [18]. In this work, we present a novel adaptation of the Micromegas technology for the proton therapy environment, where the device is operated at low gain and is operated in current mode rather than pulse mode.…”

Section: Introductionmentioning

confidence: 99%

A New Technology for Fast Two-Dimensional Detection of Proton Therapy Beams

Hollebeek

Newcomer

Mayers

et al. 2012

Physics Research International

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The Micromesh Gaseous Structure, or Micromegas, is a technology developed for high count-rate applications in high-energy physics experiments. Tests using a Micromegas chamber and specially designed amplifiers and readout electronics adapted to the requirements of the proton therapy environment and providing both excellent time and high spatial resolution are presented here. The device was irradiated at the Roberts Proton Therapy Center at the University of Pennsylvania. The system was operated with ionization gains between 10 and 200 and in low and intermediate dose-rate beams, and the digitized signal is found to be reproducible to 0.8%. Spatial resolution is determined to be 1.1 mm (1σ) with a 1 ms time resolution. We resolve the range modulator wheel rotational frequency and the thicknesses of its segments and show that this information can be quickly measured owing to the high time resolution of the system. Systems of this type will be extremely useful in future treatment methods involving beams that change rapidly in time and spatial position. The Micromegas design resolves the high dose rate within a proton Bragg peak, and measurements agree with Geant4 simulations to within 5%.

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First Tests of MICROMEGAS and GEM-Like Detectors Made of a Resistive Mesh

Cited by 11 publications

References 33 publications

THGEM-based detectors for sampling elements in DHCAL: laboratory and beam evaluation

THGEM-based detectors for sampling elements in DHCAL: laboratory and beam evaluation

New pixelized Micromegas detector with low discharge rate for the COMPASS experiment

A New Technology for Fast Two-Dimensional Detection of Proton Therapy Beams

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