692 research outputs found
CLAM, a continuous line alignment and monitoring method for RICH mirrors
A method is proposed for the angular alignment of RICH mirrors and for its monitoring, in particular for the COMPASS RICH-1 mirror system. Observing (by means of four cameras) apparent discontinuities in the images of continuous linear objects reflected by the mirrors surface, a relative misalignment of adjacent mirrors can be deduced and then corrected. The method can attain a sensitivity of at least 0.1 mrad, and can also be applied on-line to keep under control the stability of the mirrors during data taking
RHIP, a Radio-controlled High-Voltage Insulated Picoammeter and its usage in studying ion backflow in MPGD-based photon detectors
A picoammeter system has been developed and engineering. It consists in a
current-voltage converter, based on an operational amplifier with very low
input current, a high precision ADC, a radio controlled data acquisition unit
and the computer-based control, visualization and storage. The precision is of
the order of a tenth of picoampers and it can measure currents between
electrodes at potentials up to 8 kV. The system is battery powered and a number
of strategies have been implemented to limit the power consumption. The system
is designed for multichannel applications, up to 256 parallel channels. The
overall implementation is cost-effective to make the availability of
multichannel setups easily affordable. The design, implementation and
performance of the picoammeter system are described in detail as well as a an
application: the measurement of ion backflow in MPGD-based photon detectors.Comment: 5th International Conference on Micro-Pattern Gas Detectors
(MPGD2017), presentation by Silvia Dalla Torr
Development of large area resistive electrodes for ATLAS NSW Micromegas
Micromegas with resistive anodes will be used for the NSW upgrades of the ATLAS experiment at LHC. Resistive electrodes are used in MPGD devices to prevent sparks in high-rate operation. Large-area resistive electrodes for Micromegas have been developed using two different technologies: screen printing and carbon sputtering. The maximum resistive foil size is 45 Ă— 220 cm with a printed pattern of 425-ÎĽm pitch strips. These technologies are also suitable for mass production. Prototypes of a production model series have been successfully produced. In this paper, we report the development, the production status, and the test results of resistive Micromegas
Simulation studies related to the particle identification by the forward and backward RICH detectors at Electron Ion Collider
The Electron-Ion collider (EIC) will be the ultimate facility to study the
dynamics played by the colored quarks and gluons to the emergence of the global
phenomenology of the nucleons and nuclei as described by Quantum
Chromodynamics. The physics programs will greatly rely on efficient particle
identification (PID) in both the forward and the backward regions. The forward
and the backward RICHes of the EIC have to be able to cover wide acceptance and
momentum ranges; in the forward region a dual radiator RICH (dRICH) is foreseen
and in the backward region a proximity-focusing RICH can be foreseen to be
employed. The geometry and the performance studies of the dRICH have been
performed as prescribed in the EIC Yellow Report using the ATHENA software
framework. This part of our work reports the effort following the call for EIC
detector proposal the studies related to the forward and the backward RICHes
performance. In the forward region, dRICH performance showed a pion-kaon
separation from around 1 GeV/c to 50 GeV/c at a three sigma level; the
proximity focusing RICH (pfRICH) foreseen for the backward region can reach
three sigma separation up to 3 GeV/c for e/ and up to 10 GeV/c for /K
mass hypothesis.Comment: 4 pages, 8 figure
Characterization of the water diffusion in GEM foil material
Systematic studies on the GEM foil material are performed to measure the moisture diffusion rate and saturation level.These studies are important because the presence of this compound inside the detector’s foil can possibly change its mechanical and electrical properties,and in such a way,the detector performance can be affected.To understand this phenomenon,a model is developed with COMSOL Multiphysicsv.4.3 which described the adsorption and diffusion within the geometry of GEM foil,the concentration profiles and the time required to saturate the foil.The COMSOL model is verified by experimental observations on a GEM foil sample.This note will describe the model and its experimental verification results
Nanodiamond photocathodes for MPGD-based single photon detectors at future EIC
The design of a Ring Imaging CHerenkov (RICH) detector for the identification
of high momentum particles at the future Electron Ion Collider (EIC) is
extremely challenging by using current technology. Compact collider setups
impose to construct RICH with short radiator length, hence limiting the number
of generated photons. The number of detected photons can be increased by
selecting the far UV region. As standard fused-silica windows is opaque below
165 nm, a windowless RICH can be a possible approach. CsI is widely used
photocathode (PC) for photon detection in the far UV range. Due to its
hygroscopic nature it is very delicate to handle. In addition, its Quantum
Efficiency (QE) degrades in high intensity ion fluxes. These are the key
reasons to quest for novel PC with sensitivity in the far UV region. Recent
development of layers of hydrogenated nanodiamond powders as an alternative PC
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 here some preliminary results on the initial phase of these studies.Comment: 6 pages, 5 figures, MPGD-2019 La Rochelle, Proceedin
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