Micro-pattern gas detectors, such as the Gas Electron Multiplier (GEM) and the Micromegas need narrow high density anode readout elements to achieve good spatial resolution. A high-density anode readout would require an unmanageable number of electronics channels for certain potential micro-detector applications such as the Time Projection Chamber. We describe below a new technique to achieve good spatial resolution without increasing the electronics channel count in a modified micro-detector outfitted with a high surface resistivity anode readout structure. The concept and preliminary measurements of spatial resolution from charge dispersion in a modified GEM detector with a resistive anode are described below.
We report the application of the resistive anode readout method on a two dimensional imaging GEM detector. The resistive anode consists of $6\times6$ cells with the cell size $6~\mathrm{mm}\times6~\mathrm{mm}$. New electronics and DAQ system are used to process the signals from the 49 readout channels. The detector has been tested by using the X-ray tube (8~keV). The spatial resolution of the detector is about $103.46~\mathrm{μm}$ with the detector response part about $66.41~\mathrm{μm}$. The nonlinearity of the detector is less than $1.5\%$. A quite good two dimensional imaging capability is …
A two-dimensional position-sensitive microchannel plate detector, with a Ø100 mm sensitive area and equipped with four integrated amplifiers, is realized with a new anode scheme. The anode is constructed by two independent one-dimensional resistive anodes, each consisting of an array of parallel copper strips connected by resistors in series on a printed circuit board. The arrays are perpendicularly aligned to realize two-dimensional position resolution, with the intervals between the adjacent strips on the PCB nearer to the MCP cut out to allow electrons passing through. The detector is teste…
In this work we investigate three variants of single amplification-stage detector elements; they comprise THGEM electrodes closed at their bottom with metallic or resistive anodes to form WELL-type configurations. We present the results of a comparative study of the Thick-WELL (THWELL), Resistive-WELL (RWELL) and Segmented Resistive WELL (SRWELL), focusing on their performance in terms of spark-quenching capability, gain variation with position and counting rate, pulse shapes and signal propagation to neighboring readout pads; the study included both 30x30 and 100x100 mm$^2$ detectors. It was …
Digital signal processing techniques were employed to investigate the joint use of charge division and risetime analyses for the resistive anode (RA) coupled to a microchannel plate detector (MCP). In contrast to the typical approach of using the relative charge at each corner of the RA, this joint approach results in a significantly improved position resolution. A conventional charge division analysis utilizing analog signal processing provides a position measured resolution of 170 $μ$m (FWHM). By using the correlation between risetime and position we were able to obtain a measured resolution…
The spherical proportional counter is a gaseous detector used in a variety of applications, including direct dark matter and neutrino-less double beta decay searches. The ACHINOS multianode structure is a read-out technology that overcomes the limitations of single-anode read-out structures for large-size detectors and operation under high pressure. A resistive ACHINOS is presented, where the 3D printed central component is coated in a Diamond-Like Carbon (DLC) layer. The production and testing of the structure, in terms of stability and resolution, is described. Further applications in fundam…
The optimization of resistive anode for two dimensional imaging detectors which consists of a series of high resistive square pads surrounding by low resistive strips has been studied by both numerical simulations and experimental tests. It has been found that to obtain good detector performance, the resistance ratio of the pad to the strip should be larger than 5, the nonuniformity of the pad surface resistivity had better be less than $20\%$, a smaller pad width leads to a smaller spatial resolution and when the pad width is $6mm$, the spatial resolution ($σ$) can reach about $105μm$. Based …
We have studied the performance of two different types of front-end systems for our gamma camera based on Hamamatsu H8500 (flat-panel 64 channels multi-anode PSPMT) with a CsI(Tl) scintillator array. The array consists of 64 pixels of $6\times6\times20{\rm mm}^3$ which corresponds to the anode pixels of H8500. One of the system is based on commercial ASIC chips in order to readout every anode. The others are based on resistive charge divider network between anodes to reduce readout channels. In both systems, each pixel (6mm) was clearly resolved by flood field irradiation of $^{137}$Cs. We als…
With the tenfold luminosity increase envisaged at the HL-LHC, the background (photons, neutrons, ...) and the event pile-up probability are expected to increase in proportion in the different experiments, especially in the forward regions like, for instance, the muons chambers of the ATLAS detector. Detectors based on the Micromegas principle should be good alternatives for the detector upgrade in the HL-LHC framework because of a good spatial (<100 \mum) and time (few ns) resolutions, high-rate capability, radiation hardness, good robustness and the possibility to build large areas. The aim o…
The TPC for the International Linear Collider (ILC) will need to measure about 200 track points with a transverse resolution close to 100 microns. The resolution goal is beyond the capability of the conventional proportional wire/cathode pad TPC and Micro-Pattern Gas Detectors (MPGD) are being developed to meet the challenge. The standard MPGD readout techniques will, however, have difficulty in achieving the ILC-TPC resolution goal with the 2 mm x 6 mm pads as was initially envisioned. Proposals for smaller width pads will improve the resolution but will require a larger number of readout cha…
The Micro Pixel Chamber (mu-PIC) using resistive electrodes has been developed and tested. The surface cathodes are made from resistive material, by which the electrical field is reduced when large current is flowed. Two-dimensional readouts are achieved by anodes and pickup electrodes, on which signals are induced. High gas gain (> 60000) was measured using 55Fe (5.9 keV) source, and very intensive spark reduction was attained under fast neutron. The spark rate of resistive mu-PIC was only 10^-4 times less than that of conventional mu-PIC at the gain of 10^4. With these developments, a new MP…
We present the first results from tests of a MICROMEGAS detector manufactured using the so-called "bulk" technology and having a resistive cathode mesh instead of the conventional metallic one. This detector operates as usual MICROMEGAS, but in the case of sparks, which may appear at high gas gains, the resistive mesh reduces their current and makes the sparks harmless. This approach could be complementary to the ongoing efforts of various groups to develop spark-protected MICROMEGAS with resistive anode planes.
Piggyback Micromegas consists in a novel readout architecture where the anode element is made of a resistive layer on a ceramic substrate. The resistive layer is deposited on the thin ceramic substrate by an industrial process which provides large dynamic range of resistivity (10$^6$ to 10$^{10}$\,M$Ω$/square). The particularity of this new structure is that the active part is entirely dissociated from the read-out element. This gives a large flexibility on the design of the anode structure and the readout scheme. Without significant loss, signals are transmitted by capacitive coupling to the …
We describe here various detectors designs: GEM type, MICROMEGAStype, PPACtype as well as cascaded detectors made of a resistive mesh manufactured from a resistive Kapton foil, (20 microns thick, resistivity a few MOhm per square) by a laser drilling technique. As in any other micropattern detectors the maximum achievable gas gain of these detectors is restricted by the Raether limit, however, the resistive mesh makes them and the front end electronics fully spark protected. This approach could be an alternative or complimentary to the ongoing efforts in developing MICROMEGAS and GEMs with res…
Micromegas technology is a promising candidate to replace Atlas forward muon chambers -tracking and trigger- for future HL-LHC upgrade of the experiment. The increase on background and pile-up event probability requires detector performances which are currently under studies in intensive RD activities. We studied performances of four different resistive Micromegas detectors with different read-out strip pitches. These chambers were tested using \sim120 GeV momentum pions, at H6 CERN-SPS beam line in autumn 2010. For a strip pitch 500 micrometers we measure a resolution of \sim90 micrometers an…
A novel read-out architecture has been developed for the Micromegas detector. The anode element is made of a resistive layer on a ceramic substrate. The detector part is entirely separated from the read-out element. Without significant loss, signals are transmitted by capacitive coupling to the read-out pads. The detector provides high gas gain, good energy resolution and the resistive layer assures spark protection to the electronics. This assembly could be combined with modern pixel array electronic ASICs. This readout organization is free on how the pixels are designed, arranged and connect…
A study of the localization properties of a single-element Resistive Plate WELL (RPWELL) detector is presented. The detector comprises of a single-sided THick Gaseous Electron Multiplier (THGEM) coupled to a segmented readout anode through a doped silicate-glass plate of 10$^{10}$ $Ω\cdot$cm bulk resistivity. Operated in ambient Ne/(5$\%$CH$_4$) gas, the detector has been investigated with 150 GeV muons at CERN-SPS. Signals induced through the resistive plate on anode readout strips were recorded with APV25/SRS electronics. The experimental results are compared with that of Monte Carlo simulat…
T2K is a long baseline neutrino experiment that has been operating since 2009 providing some of the world-wide leading measurements for neutrino oscillation parameters. An upgrade for the Near Detector, ND280, of T2K has been proposed. It includes the installation of two new Time Projection Chambers (TPC) based on a new read-out technology: the resistive anode MicroMegas (RMM). This technology is expected to reduce the number of electronic channels while maintaining or improving the current ND280 TPCs' bulk MicroMegas perfomance. A series of tests have been performed and further studies are on…
Large-Area Picosecond Photo-Detectors (LAPPDs) show great potential for expanding the performance envelope of Micro-Channel Plates (MCPs) to areas of up to 20 x 20 cm and larger. Such scaling introduces new challenges, including how to meet the electronics readout burden of ever larger area MCPs. One solution is to replace the traditional grid anode used for readout with a microwave stripline anode, thus allowing the channel count to scale with MCP width rather than area. However, stripline anodes introduce new issues not commonly dealt with in grid-anodes, especially as their length increases…
We present the results of first studies of the Resistive Plate WELL (RPWELL): a single-faced THGEM coupled to a copper anode via a resistive layer of high bulk resistivity. We explored various materials of different bulk resistivity (10^9 - 10^12 Ohm cm) and thickness (0.4 - 4 mm). Our most successful prototype, with a 0.6 mm resistive plate of ~10^9 Ohm cm, achieved gains of up to 10^5 with 8 keV x-ray in Ne/5%CH4; a minor 30% gain drop occurred with a rate increase from 10 to 10^4 Hz/mm^2. The detector displayed a full "discharge-free" operation--even when exposed to high primary ionization …
We present the results of our recent studies on a Thick Gas Electron Multiplier (THGEM)-based imaging detector prototype. It consists of two 100x100 mm^2 THGEM electrodes in cascade, coupled to a resistive anode. The event location is recorded with a 2D double-sided readout electrode equipped with discrete delay-lines and dedicated electronics. The THGEM electrodes, produced by standard printed-circuit board and mechanical drilling techniques, a 0.4 mm thick with 0.5 mm diameter holes spaced by 1 mm. Localization resolutions of about 0.7 mm (FWHM) were measured with soft x-rays, in a detector …
We present for the first time, discharge-free operation at cryogenic conditions of a Resistive-Plate WELL (RPWELL) detector. It is a single-sided Thick Gaseous Electron Multiplier (THGEM) coupled to a readout anode via a plate of high bulk resistivity. The results of single- and double-stage RPWELL detectors operated in stable conditions in Ne/5$\%$CH$_{4}$ at 163 K are summarized. The RPWELL comprised a ferric-based (Fe$^{3+}$) ceramic composite ("Fe-ceramic") as the resistive plate, of volume resistivity $\sim$$10^{11}$ $Ω$$\cdot$cm at this temperature. Gains of $\sim$$10^{4}$ and $\sim$$10^…
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
We present the results of the first in-beam studies of a medium size (10$\times$10 cm$^2$) Resistive-Plate WELL (RPWELL): a single-sided THGEM coupled to a pad anode through a resistive layer of high bulk resistivity ($\sim$10$^9 Ω$cm). The 6.2~mm thick (excluding readout electronics) single-stage detector was studied with 150~GeV muons and pions. Signals were recorded from 1$\times$1 cm$^2$ square copper pads with APV25-SRS readout electronics. The single-element detector was operated in Ne\(5% $\mathrm{CH_{4}}$) at a gas gain of a few times 10$^4$, reaching 99$\%$ detection efficiency at ave…
The design of a detector based on MICROMEGAS (MICRO MEsh GAseous Structure) technology is presented. Our detector is characterized by a large active area of 398(\times)281 mm(^{2}), a pad read-out with 20(\times)22 mm(^{2}) segmentation, and an uniform amplification gap obtained by insulating spacers (100 (μ)m high and 200 (μ)m in diameter). The performances of several prototypes have been evaluated under irradiation with secondary beams of 2 GeV/c momentum charged pions and electrons. We consider such a detector as the basic element for a pre-shower detector to equip the PHOton Spectrometer (…
An upgrade of the Near Detector of the T2K long baseline neutrino oscillation experiment, ND280, has been proposed. This upgrade will include two new Time Projection Chambers, each equipped with 16 resistive MicroMegas modules for gas amplification. A first prototype of resistive MicroMegas has been designed, built, installed in the HARP field cage, and exposed to a beam of charged particles at CERN. The data have been used to characterize the performances of the resistive MicroMegas module. A spatial resolution of 300 $μm$ and a deposited energy resolution of 9% were observed for horizontal e…
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.
Discharge quenching mechanism and performance of RPWELL with tunable 3D printed resistive plates, charge evacuation in semiconductive glass RPWELL and discharge quenching for Cryogenic-RWELL over a wide range of resistivity
High-precision beam profile measurement with a microchannel-plate detector in the high magnetic field of the WISArD experiment
Université de Bordeaux, CNRS/IN2P3, LP2i Bordeaux UMR5797（波尔多大学）；Université de Caen Normandie, ENSICAEN, CNRS/IN2P3, LPC Caen UMR6534（卡昂诺曼底大学）；Belgian Nuclear Research Centre SCK-CEN（比利时核研究中心SCK-CEN）；Center for Exotic Nuclear Studies, Institute for Basic Science（基础科学研究院奇异核研究数据中心）；KU Leuven, Instituut voor Kern- en Stralingsfysica（荷语鲁汶大学）
We describe the most recent efforts made by various groups in implementing resistive electrodes in micropattern gaseous detectors with the aim to combine in the same design the best features of RPCs (for the example, their robustness and spark protection property) with the high granularity and thus the good position resolution offered by microelectronic technology. In the stream of this activity, we have recently developed two novel detectors with resistive electrodes: one was based on resistive micromeshes and the second one is a MSGC with resistive electrodes. We have demonstrated that the r…
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, resistive 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 detec…
The second phase of the T2K experiment is expected to start data taking in autumn 2022. An upgrade of the Near Detector (ND280) is under development and includes the construction of two new Time Projection Chambers called High-Angle TPC (HA-TPC). The two endplates of these TPCs will be paved with eight Micromegas type charge readout modules. The Micromegas detector charge amplification structure uses a resistive anode to spread the charges over several pads to improve the space point resolution. This innovative technique is combined with the bulk-Micromegas technology to compose the "Encapsula…
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 cm2 prototype detector with 1 cm2 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…
We present results from further tests of Microstrip Gas Counters (MSGCs) with resistive electrodes. The maim advantage of this detector is that it is spark-protected: in contrast to "classical" MSGCs with metallic electrodes, sparks in this new detector do not destroy its electrodes. As a consequence the MSGC with resistive electrodes is more reliable in operation which may open new avenues in applications. One of them which is under investigation now is the use of Resistive electrodes MSGC (R-MSGC) as photodetector in some particular designs of noble liquid dark matter detectors.
We have designed and tested a robust 20 $\times$ 20 cm$^2$ thin metal film internal anode capacitively coupled to an external array of signal pads or micro-strips for use in fast microchannel plate photodetectors. The internal anode, in this case a 10nm-thick NiCr film deposited on a 96% pure Al$_2$O$_3$ 3mm-thick ceramic plate and connected to HV ground, provides the return path for the electron cascade charge. The multi-channel pickup array consists of a printed-circuit card or glass plate with metal signal pickups on one side and the signal ground plane on the other. The pickup can be put i…
Micro-channel-plate-based photo-detectors are unique in being capable of covering areas of many square-meters while providing sub-millimeter space resolution, time resolutions of less than 10 picoseconds for charged particles, time resolutions of 30-50 psec for single photons. Incorporating a capacitively-coupled anode allows for the use of external pickup electrodes optimized for occupancy, rate, and time/space resolution. The signal pickup antenna can be implemented as a printed circuit card with a pattern chosen to match the specific application needs. The electrode elements are typically e…
The Thick Gaseous Electron Multiplier (THGEM) is a simple and robust electrode suitable for large area detectors. In this work the results of extensive comparative studies of the physical properties of different THGEM-based structures are reviewed. The focus is on newly suggested THGEM-like WELL configurations as well as on recently developed characterization methods. The WELL structures are single-sided THGEM electrodes directly coupled to different anode readout electrodes. The structures differ by the coupling concept of the bottom THGEM electrode to the metallic readout pads: a Thick WELL …
Timing information in current and future accelerator facilities is important for resolving objects (particle tracks, showers, etc.) in extreme large particles multiplicities on the detection systems. The PICOSEC Micromegas detector has demonstrated the ability to time 150\,GeV muons with a sub-25\,ps precision. Driven by detailed simulation studies and a phenomenological model which describes stochastically the dynamics of the signal formation, new PICOSEC designs were developed that significantly improve the timing performance of the detector. PICOSEC prototypes with reduced drift gap size ($…
We describe the first tests with a new proportional gas detector. Its geometry consists in slits opened in a copper metallized kapton foil with 30 micron anode strips suspended in these openings. In this way the multiplication process is similar to a standard MSGC. The fundamental difference is the absence of an insulating substrate around the anode. Also the material budget is significantly reduced, and the problems related to charging-up or polarization are removed. Ageing properties of this detector are under study.
In recent years, micropattern gaseous detectors, which comprise a two-dimensional readout structure within one PCB layer, received significant attention in the development of precision and cost-effective tracking detectors in medium and high energy physics experiments. In this article, we present for the first time a systematic performance study of the signal characteristics of a resistive strip micromegas detector with a two-dimensional readout, based on test-beam and X-ray measurements. In particular, comparisons of the response of the two independent readout-layers regarding their signal sh…
The paper summarizes our latest progress in the development of newly introduced micro pattern gaseous detectors with resistive electrodes. These resistive electrodes protect the detector and the front-end electronics in case of occasional discharges and thus make the detectors very robust and reliable in operation. As an example, we describe in greater detail a new recently developed GEM-like detector, fully spark-protected with electrodes made of resistive kapton. We discovered that all resistive layers used in these studies (including kapton), that are coated with photosensitive layers, such…
We developed a tool for the simulation of charge transport on a conducting plate of finite dimensions. This tool is named Chani. Main motivation of developing Chani was to provide a tool for the optimization of the dimensions and resistivity of the anode electrodes in spark-protected Micropattern Gaseous Detectors (MPGD). In this thesis, we start with the general description of the LHC and the ATLAS Experiment. Then, we review the gaseous ionization detector technologies and in particular, the micromegas technology. We then present the working principles of Chani along with the example calcula…
In the Kaos spectrometer at the Mainz Microtron a high-resolution coordinate detector for high-energy particles is operated. It consists of scintillating fibres with diameters of < 1mm and is read out by > 4000 multi-anode photomultiplier channels. It is one of the most modern focal-plane detectors for magnetic spectrometers world-wide. To correct variations in the detection efficiency, caused by the different gains and the different optical transmittances, a fully automated off-line calibration procedure has been developed. The process includes the positioning of a radioisotope source alongsi…
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 paper 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, improveme…
We have developed microstrip gas counters manufactured on standard printed circuit board and having the following features: resistive cathode strips, thin (10 micron) metallic anode strips and electrodes protected against surface discharges by a Coverlay layer at their edges. These features allow the detector to operate at gas gains as high as can be achieve with the best microstrip gas counters manufactured on glass substrates. We believe that after further developments this type of detectors can compete in some applications with other micropattern detectors, for example MICROMEGAS.
Resistive-anode Micromegas detectors are in development since several years, in an effort to solve the problem of sparks when working in high flux and high radiations environment like in the HL-LHC (ten times the luminosity of the LHC). They have been chosen as one of the technologies that will be part of the ATLAS New Small Wheel project (forward muon system). An ageing study is mandatory to assess their capabilities to handle the HL-LHC environment on a long-term period. A prototype has been exposed to several types of irradiations (X-rays, cold neutrons, 60 Co gammas) up to an equivalent HL…
The $μ$-RWELL is a single-amplification stage resistive Micro-Pattern Gaseous Detector (MPGD). The detector amplification element is realized with a single copper-clad polyimide foil micro-patterned with a blind hole (well) matrix and embedded in the readout PCB through a thin Diamond-Like-Carbon (DLC) sputtered resistive film. The introduction of the resistive layer, suppressing the transition from streamer to spark, allows to achieve large gains ($\geq$10$^4$) with a single amplification stage, while partially reducing the capability to stand high particle fluxes. The simplest resistive layo…
In this report we discuss static and time dependent electric fields in detector geometries with an arbitrary number of parallel layers of a given permittivity and weak conductivity. We derive the Green's functions i.e. the field of a point charge, as well as the weighting fields for readout pads and readout strips in these geometries. The effect of 'bulk' resistivity on electric fields and signals is investigated. The spreading of charge on thin resistive layers is also discussed in detail, and the conditions for allowing the effect to be described by the diffusion equation is discussed. We ap…
Beam studies of thin single- and double-stage THGEM-based detectors are presented. Several 10 x 10 cm^2 configurations with a total thickness of 5-6 mm (excluding readout electronics), with 1 x 1 cm^2 pads inductively coupled through a resistive layer to APV-SRS readout electronics, were investigated with muons and pions. Detection efficiencies in the 98% range were recorded with an average pad-multiplicity of ~1.1. The resistive anode resulted in efficient discharge damping, with few-volt potential drops; discharge probabilities were ~10^{-7} for muons and 10^{-6} for pions in the double-stag…
Resistive-anode micromegas detectors are in development since several years, in an effort to solve the problem of sparks when working at high flux and high ionizing radiation like in the HL-LHC (up to ten times the luminosity of the LHC). They have been chosen as one of the technologies that will be part of the ATLAS New Small Wheel project (forward muon system). An ageing study is mandatory to assess their capabilities to handle the HL-LHC environment on a long-term period. A prototype has been exposed to several types of irradiation (X-rays, cold neutrons, $^{60}$Co gammas and alphas) above …
