After pioneering gaseous detectors of single photon for RICH applications using CsI solid state photocathodes in MWPCs within the RD26 collaboration and by the constructions for the RICH detector of ...the COMPASS experiment at CERN SPS, in 2016 we have upgraded COMPASS RICH by novel gaseous photon detectors based on MPGD technology. Four novel photon detectors, covering a total active area of 1.5m2 have been installed in order to cope with the challenging efficiency and stability requirements of the COMPASS physics programme. They are the first application in an experiment of MPGD-based single photon detectors. All aspects of the upgrade are presented, including engineering, mass production, quality assessment and performance.
Perspectives for further developments in the field of gaseous single photon detectors are also presented.
Large-size Resistive Micromegas have been chosen for the upgrade of the forward muon spectrometer of the ATLAS experiment, the New Small Wheel project. These chambers, together with small-strip Thin ...Gap Chambers (sTGC), allow reconstruction of high-momentum muon tracks in a high-radiation environment and provide a robust low-threshold single-muon trigger. A collaboration of seven INFN units built 32 SM1 type chambers, corresponding to one fourth of the total number needed for this upgrade. Each SM1 chamber has a surface of approximately 2 m2 and four sensitive layers. The production was shared among five INFN construction sites and it was completed in fall 2020. The construction methods, as well as the results of the quality tests done on components of the detector and on the assembled chambers, are reported in the present paper.
Abstract
A prototype of a dual-readout calorimeter using brass
capillary tubes surrounding scintillating and clear plastic optical
fibres was tested using beams of particles with energies between 10
...and 100 GeV produced by the CERN SPS. The scope of the test was to
characterise the performance of the tube-based detector response to
positrons in terms of response linearity, energy resolution, and
lateral granularity. After calibrating the detector and processing
the output signal to correct for the energy dependency on the
particle impact point, the linearity of the measurement was found to
be better than 1%. The response to positron was compared to that
predicted by a Geant4-based simulation, finding good agreement both
in terms of energy resolution and shower profile. These results
confirm the validity of the tube-based mechanical option and SiPM
readout as a promising one for future developments.
The novel MPGD-based photon detectors of COMPASS RICH-1 consist of large-size hybrid MPGDs with multi-layer 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 misbehavior. 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.
Abstract
In this paper, we report on a novel cost-effective module structure for future Dual-Readout fiber Calorimetry. We have designed and constructed the system required for the fabrication of the ...first proof-of-concept prototype module. The instruments, the procedures and the quality control tools used in the assembly of the prototype, and its equipment, are described exhaustively. A mechanical precision of 50 μm required for the interlocking of the tower structures into a compact module has been achieved. A similar system will be used for the assembly of a full-scale prototype based on the Dual-Readout technique.
Experiments at the future Electron Ion Collider require excellent hadron identification in a broad momentum range, in harsh conditions. A RICH capable to fulfill the PID requirements of the EIC could ...use MPGD-based photon detectors with solid photocathodes for covering large surfaces at affordable cost, providing good effciency, high resolution and compatibility with magnetic field. Photon detectors realized by coupling THGEMs and Micromegas have been successfully operated at the RICH-1 detector of the COMPASS Experiment at CERN since 2016. A similar technology could be envisaged for an EIC RICH, provided a large improvement in the photon position resolution is achieved. An R&D effort in this direction is ongoing at INFN Trieste. Few prototypes with smaller pixel size (down to 3 mm x 3 mm) have been built and tested in the laboratory with X-Ray and UV LED light sources. A modular mini-pad detector prototype has also been tested at the CERN SPS H4 beamline. New data acquisition and analysis software called Raven DAQ and Raven Decoder have been developed and used with the APV-25 based Scalable Readout System (SRS), for the modular mini-pad prototype tests. The main characteristics of the new mini-pad hybrid MPGD-based detector of single photons are described and preliminary results of laboratory and beam tests are presented.
In 2016 we have upgraded the COMPASS RICH by novel gaseous photon detectors based on MPGD technology. Four new photon detectors, covering a total active area of 1.5
m
2
, have been installed in order ...to cope with the challenging efficiency and stability requirements of the COMPASS physics programme. The new detector architecture consists in a hybrid MPGD combination: two layers of THGEMs, the first of which also acts as a reflective photocathode thanks to CsI coating, are coupled to a bulk Micromegas on a pad-segmented anode. These detectors are the first application in an experiment of MPGD-based single photon detectors. Presently, we are further developing the MPGD-based PDs to make them adequate for a setup at the future EIC collider. All aspects of the COMPASS RICH-1 Photon Detectors upgrade are presented: R&D, engineering, mass production, QA and performance; the on-going development for collider application is also presented.
COMPASS is a fixed target experiment at CERN SPS aimed to study hadron structure and spectroscopy. Hadron identification in the momentum range between 3 and 55 GeV/c is provided by a large gaseous ...Ring Imaging Cherenkov Counter, RICH-1. To cope with the challenges imposed by the new physics program of COMPASS, RICH-1 has been upgraded by replacing four MWPC-based photon detectors with newly developed MPGD-based photon detectors. The architecture of the novel detectors is a hybrid combination of two layers of THGEMs and a Micromegas. The top of the first THGEM is coated with CsI acting as a reflective photo-cathode. The anode is segmented in pads capacitively coupled to the APV-25 based readout. The new hybrid detectors have been commissioned during the 2016 COMPASS data taking and stably operated during the 2017 run. In this paper design, construction, operation and performance aspects of the novel photon detectors for COMPASS RICH-1 are discussed.
After pioneering gaseous detectors of single photon for RICH applications using CsI solid state photocathodes in MWPCs within the RD26 collaboration and by the constructions for the RICH detector of ...the COMPASS experiment at CERN SPS, in 2016 we have upgraded COMPASS RICH by novel gaseous photon detectors based on MPGD technology. Four novel photon detectors, covering a total active area of 1.5 m2, have been installed in order to cope with the challenging effciency and stability requirements of the COMPASS physics programme. They are the first application in an experiment of MPGD-based single photon detectors. All aspects of the upgrade are presented, including engineering, mass production, quality assessment and performance. Perspectives for further developments in the field of gaseous single photon detectors are also indicated.
Identification of high momentum hadrons at the future EIC is crucial, gaseous RICH detectors are therefore viable option. Compact collider setups impose to construct RICHes with small radiator ...length, hence significantly limiting the number of detected photons. More photons can be detected in the far UV region, using a windowless RICH approach. QE of CsI degrades under strong irradiation and air contamination. Nanodiamond based photocathodes (PCs) are being developed as an alternative to CsI. Recent development of layers of hydrogenated nanodiamond powders as an alternative photosensitive material and their performance, when coupled to the THick Gaseous Electron Multipliers (THGEM)-based detectors, are the objects of an ongoing R&D. We report about the initial phase of our studies.
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