The first successful attempts to optimize the electric field in Resistive Microstrip Gas Chamber and resistive microdot detectors using additional field shaping strips located inside the detector substrate are described
The first successful attempts to optimize the electric field in Resistive Microstrip Gas Chamber (RMSGC) using additional field shaping strips located inside the detector substrate are described.
We have developed a cost effective technology for manufacturing various layouts of micropattern gaseous detectors for a wide range of applications. Such devices feature resistive electrodes interfaced to a network of thin readout strips/electrodes. T
he following three examples of such innovative designs and their applications will be presented: a prototype of a novel double-phase LAr detector with a CsI photocathode immersed inside the LAr, a CsI-RICH detector prototype for ALICE upgrade and GEM-like sensors for environmental safety/security applications.
Nowadays RPCs are in a booming phase: they are successfully used in many experiments, including LHC; there are ambitious plans to use them in several upgrade detectors and in some new experiments as well as in various applications. The aim of this pa
per is to highlight the main challenges which the RPC community may face in the next few years and which were addressed in talks presented at this conference. Examples could be: new and difficult requirements from experiments (and their upgrades) and applications, optimization and improvements of the existing traditional detector designs, improvement of their characteristics (timing /rate performance, aging, dark current and so on), implementation of new more sensitive electronics, investigation of new materials, development of large- area detectors. We will also review the fast and very promising developments of another type of resistive electrode gaseous detector -micropattern detectors having at least one of their electrodes made of resistive materials. These innovative detectors combine in one design the best features of RPC (spark protection) and micropattern detectors (high granularity-high position resolution).
In the last few years our group have focused on developing various designs of spark-protected micropattern gaseous detectors featuring resistive electrodes instead of the traditional metallic ones: resistive microstrip counters, resistive GEM, resist
ive MICROMEGAS. These detectors combine in one design the best features of RPCs (spark-protection) and micropattern detectors (a high position resolution). In this paper we report the progress so far made in developing other types of resistive micropattern detectors: a microdot-microhole detector and a microgap-microstrip detector. The former detector is an optimal electron amplifier for some special designs of dual phase noble liquid TPCs, for example with a CsI photocathode immersed inside the noble liquid. Preliminary tests of such a detector, for the first time built and investigated, are reported in this paper. The latter detector is mainly orientated towards medical imaging applications such as X-ray scanners. However, we believe that after a proper gas optimization, these detectors could also achieve a high time resolution and could thus be used in applications as TOF-PET, detection of charged particles with simultaneous high time and position resolution etc.
A new family of spark-protected micropattern gaseous detectors is introduced: a 2-D sensitive restive microstrip counter and hybrid detectors, which combine in one design a resistive GEM with a microstrip detector. These novel detectors have several
important advantages over other conventional micropattern detectors and are unique for applications like the readout detectors for dual phase noble liquid TPCs and RICHs.
We have built a RICH detector prototype consisting of a liquid C6F14 radiator and six triple Thick Gaseous Electron Multipliers (TGEMs), each of them having an active area of 10x10 cm2. One triple TGEM has been placed behind the liquid radiator in or
der to detect the beam particles, whereas the other five have been positioned around the central one at a distance to collect the Cherenkov photons. The upstream electrode of each of the TGEM stacks has been coated with a 0.4 micron thick CsI layer. In this paper, we will present the results from a series of laboratory tests with this prototype carried out using UV light, 6 keV photons from 55Fe and electrons from 90Sr as well as recent results of tests with a beam of charged pions where for the first time Cherenkov Ring images have been successfully recorded with TGEM photodetectors. The achieved results prove the feasibility of building a large area Cherenkov detector consisting of a matrix of TGEMs.
The very high momentum particle identification detector proposed for the ALICE upgrade is a focusing RICH using a C4F10 gaseous radiator. For the detection of Cherenkov photons, one of the options currently under investigation is to use a CsI coated
Triple-Thick-GEM (CsI-TTGEM) with metallic or resistive electrodes. We will present results from the laboratory studies as well as preliminary results of beam tests of a RICH detector prototype consisting of a CaF2 radiator coupled to a 10x10 cm2 CsI-TTGEM equipped with a pad readout and GASSIPLEX-based front-end electronics. With such a prototype the detection of Cherenkov photons simultaneously with minimum ionizing particles has been achieved for the first time in a stable operation mode.
We have developed and tested several new designs of GEM detectors with micropattern electrodes manufactured by microelectronic technology. In one design, the inner layer of the detector electrode consists of thin metallic strips and the outer layer i
s made of a resistive grid manufactured by a screen printing technology. In other designs, the electrodes were made of metallic strips fed by HV via micro-resistors manufactured by a screen printing technology. Due to these features, the new detectors have several important advantages over conventional GEMs or ordinary thick GEMs. For example, the resistive grid (in the first design) and the screen printed resistors (in other designs) limited the current in case of discharges, making these detectors intrinsically spark-protected. We will here describe our tests with the photosensiti
An innovative photosensitive gaseous detector, consisting of a GEM like amplification structure with double layered electrodes (instead of commonly used metallic ones) coated with a CsI reflective photocathode, is described. In one of our latest desi
gns, the inner electrode consists of a metallic grid and the outer one is made of resistive strips; the latter are manufactured by a screen printing technology on the top of the metallic strips grid The inner metallic grid is used for 2D position measurements whereas the resistive layer provides an efficient spark protected operation at high gains - close to the breakdown limit. Detectors with active areas of 10cm x10cm and 10cm x20cm were tested under various conditions including the operation in photosensitive gas mixtures containing ethylferrocene or TMAE vapors. The new technique could have many applications requiring robust and reliable large area detectors for UV visualization, as for example, in Cherenkov imaging devices.
