Due to the importance of these developments an RD 51collaboration was formed a CERN
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Transcript of Due to the importance of these developments an RD 51collaboration was formed a CERN
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Development of a new generation of micropattern gaseous detectors for
high energy physics, astrophysics and medical applications
A.Di Mauro,1 P. Fonte2, P. Martinengo1, E.,Nappi3, R. Oliveira1, V. Peskov1, P. Pietropaolo4, P. Picchi5
1CERN, Geneva, Switzerland2 LIP/ISEK Coimbra, Portugal
3INFN Bari, Italy4INFN Padova, Italy5INFN Frascati, Italy
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In the last two decades very fast developments happened in the filed of gaseous detectors of photons and particles. Traditional gases detectors: wire–type and parallel plate-type (RPCs) -which are widely used in high
energy and astrophysics experiments have now serious competitors: Micropattern Gaseous Detectors
(MPGDs)
Due to the importance of these developments an RD 51collaboration was formed a CERN
The aim of this collaboration is to coordinate affords from various groups working on MPGDs
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1) Strip typeExample: Microstrip gas counters (MSGCs)A. Oed, NIM A263, 1988, 351
Examples:CAT/WELL, Gas Electron multiplier (GEM)A.Del Guerra et al., NIM A257, 1987,609M. Lemonnier et al., Patent FR 2727525 , 1994F. Sauli, NIM,A386,1997,531
3) Parallel-plate typeExample: Micromesh gas chamber (MICROMEGAS)Y. Giomataris et al., NIM A376, 1996, 29
4) Hole type
Glass substrate
There are four main designs of micropattern gaseous detectors:
CAT/WELLGEM
Anodes
~100μm2) MicrodotS.Biagi et al., NIMA392, 1997, 131
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The main advantage of MPGDs is that they are manufactured by means of microelectronics
technology, which offers high granularity and consequently an excellent position resolution.
Due to their advantages the MPGDs cangue more and more applications. In high energy physics they were already successfully used in:Hera-B, COMPASS TOTEM, LHC B etc.
Their use in CMS, ATLAS ALICE and in some other experiments under consideration
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However, the fine structure of their electrodes and the small gap between them make MPGDs electrically “weak.” In fact, their maximum achievable gain is
usually not very high, compared to traditional detectors, and without special precautions they can be easily destroyed by sparks, which may occur during their
operation
(which is not the case of traditional detectors: wire and parallel-plate type)
6See, for example G. Charles et al., NIM A648, 2011, 174
.. and sparks, unfortunately, in experiments are practically unavoidable
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There are several methods of protecting micropattern detectors and FEE from destruction: segmentation of electrodes on smaller parts, protective diodes…These methods were successfully implemented in the case of GEM and in some MICROMEGAS designs
Alternative approach, which becomes more and more frequent inside the
RD51collaboration, is the useresistive electrodes.
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The first micropattern detector with resistive electrodes was GEM, and later this approach was also applied to other
detectors: MICROMEGAS and CAT (all had unsegmented electrodes)
Res. GEMOliveir at al., NIM A576, 2007, 362
Res. CATA.Di Mauro et al., IEEE Nucl. Sci Conf Rec, 6, 2006,3852
Res. meshR.Oliveira etal., IEEE Nucl. Sci57,2010, 3744
Res. MICROMEGASR.Oliveira etal., IEEE Nucl. Sci57,2010, 3744
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They were hybrids layout between GEM and RPC
The principle of operation of RPC: discharge energy is quenched because of the resistivity of electrodes
-V
Resistiveelectrodes
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This study triggered a sequence of similar developments, which are nowadays pursued not only by our group, but by several other groups in the frame
work of CERN RD51 collaboration
See recent reports at the 2nd Intern. Conf. on Micro Pattern Gaseous Detectors, August 2011, Kobe, Japan (to be published in JINST)(http://ppwww.phys.sci.kobeu.ac.jp/%7Eupic/mpgd2011/abstracts.pdf)
A couple of examples of main developments will be given below:
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See for example: a photo of RETGEM
from: R. Akimoto et al,presentation at 1st
MPGDs conference in Crete,2009
or
Several groups (mostlyJapanese) are now successfullydeveloping various designs ofRETGEMs
Spark protected RETGEMs and Res. CAT:
Res. CAT developed by Breskin groupL. Arazi et al., JINST 7 C05011, 2012
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Advantages: 1. More suitable for large-area detectors2. Better fit requirements for position measurements 3.Flexible in design implementation4. In some designs offer better rate characteristics
Tested configurations:
1) Resistive strips without intermediate layer between the strips and the metal readout strip(see for example V. Peskov et al., NIM, A610 2009 169)
2) Res. electrode strips with a thin FR-4 glue intermediate layer(R. Oliveura et al., NIM,A576,2007,362)
3) Resistive strips with a thick FR-intermediate layer (T. Alexopoulos et al NIM A 640, 2011, 110)
Today we would like to presenta new approach:resistive electrodes segmented on stripswith a network of metallic readout strips located under the resistive grid
1)
2)
3)
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As was shown in the previous slide, first we applied this new technology to resistive GEMs (~2009).
In the last couple of years (2010-2012) we extended this approach to all other main micropattern designs.
Below are examples of only three of such detectors.We choose them because they are oriented towards applications in which some members of our team are currently involved:
1.RICH,2.Dual-phase noble liquid TPCs, 3. X/gamma ray imaging deices
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1. Resistive microstrip detector
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PCB with 5μm thick Cu layer on thetop and two layers of readout strips (oriented perpendicularly) on the bottom
Milled grooved 100 μm deep and0.6 μm wide, pitch 1mm.
The grooves were then filled with resistive paste (ELECTRA Polymers)
By a photolithographic technology Cu 20 μm wide strips were created between the grooves
0.6mm
1mm
20μm
a)
b)
c)
d)
0.5mm
e)Finally the entire detector was glued on a supporting FR-4 plate
0.2mm 0.1mm
0.5-1mm
Cathode res. strips
Anode strips
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Connections toX pick up strips
Connections toY pick up strips
Anode strips
Cathode resistivestrips
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Gas gains
Pos. resol. measurements Rate characteristics
Runs #12-17
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~200μm
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2. Resistive microdot-microhole detector
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a)
Multilayer PCB with Cu layers on the top and bottom and with the inner layer with readout strips
Upper Cu layer etching
The remaining grooves were then filled with resistive paste (ELECTRA Polymers)
Removal of the Cu
v
v
v
v
Filling withCoverlay with“dot” opening
b)
c)
d)
e)
v
v
Resistive anode dotsResistive cathode strips
Readout strips
1mm 0.1mm
Holes
0.1mm
Manufacturing steps:
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Magnified photograph
Schematic drawing and a principle of operation of res. microdot detector(resembling MHC, see:J. Maia et al., IEEE Trans. Nucl. Sci 49, 2002, 875)
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Gas gain vs. the voltage of R-Microdot measured in Ne and Ne+1.5%CH4 with alpha particles (filled triangles and squares) and with 55Fe (empty triangles and squares).
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Gain (triangles) dependence on voltage applied to R-Microdotmeasured in Ar (blue symbols) and Ar+1.6%CH4 (red symbols)and in Ar+9%CO2. Filled triangles and squares –measurements performed with alpha particles, open symbols - 55Fe.
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Interesting feature: at high gains operates in self-quenched streamer mode
In all gases tested the maximum gains achieved with the R-Microdot detectors were 3-10 time higher than with R-MSGCs
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3. Resistive microgap-microstrip detector
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a)
Multilayer PCB with a Cu layer on the top and one layer of readout strips on the bottom, 0.5 pitch
Upper Cu layer etching
The grooves were then filled with resistive paste (ELECTRA Polymers)
Removal of the Cu
v
If necessary, filling withCoverlay (an option)
b)
c)
d)
e)
M-M- RPC manufacturing steps:
Resistive strips
Readout strips
0.5 mm 0.2mm
v
0.035mm
0.1mm
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A
B
C
Contact pad
Contactpad
Resistive strips
Total resistivity ofthe zone B 500MΩ(adjustable) Resistivity of zones A and C500MΩ (adjustable)
Surface resistivity100kΩ/□ (can beadjusted to exper.needs)
Top view:
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This plate is in fact a reproduction of the resistive MICROMEGAS anode board
(see the following talks)
The idea is to assemble from these plates a parallel- plate detector (M-M-
RPC), so that the cathode metallic mesh is not used
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Orthogonalresistive strips
Inner signal strips
Artistic view of the M-M RPC
PCB sheet
From these plates RPC were assembled with gaps ether 0.5 or 0.18mm
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An option with pillars (similar to MICROMEGAS)
PillarsRes. strips
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A fundamental difference between “classical “ RPC and M-M- RPC
Film resistor
M-M-RPC offers high2D position resolutions (with orthogonal strip or various stereo strip arrangements to avoid ambiguity) and have potential for good timing properties
Usual RPC
M-M-RPC
“Signal”electrodesCurrent
Orthogonalresistive strips
Current
500MΩ
Inner signal strips
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Gain estimation in an RPC geometry:
CsI layerUV
X-raysFe anode
0.5mm
0.1-0.2mm
Photoelectron tracks
(Due to the time constrains the CsI coating was done by a spray technique)
A=expαx
x
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M-M-RPC with spacers in corners
The highest gains were obtained with resistive micropattern detectors
Estimated gain, preiminary
1.00E-01
1.00E+00
1.00E+01
1.00E+02
1.00E+03
1.00E+04
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1.00E+06
1.00E+07
0 500 1000 1500 2000
Voltage (V)
Gain
Ar+10%ethnan0.5 mme,
X-rays and UV
Ar+25%CO2UV, 0.18mm
Ar+25%CO2X-rays
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Counting rate (Hz/mm 2)
Mea
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Typical rate response
(combined current and pulsed measurements)
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Now shortly about the applications in which our team
is involved
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1. RICH(recent results)
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The VHMPID should be able to identify, on a track-by- track basis, protons enabling to study the leading particles composition in jets (correlated with the π0 and /or γ
energies deposited in the electromagnetic calorimeter).
There is a proposal (LoI) to upgrade ALICE RICH detector in order to extend the particle identification for hadrons up to 30GeV/c. It is called VHMPID.
(HMPID)
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The suggested detector will consist of a gaseous radiator (for
example, CF4 orC4F10 ) and a planar gaseous photodetector
The key element of the VHMPIDis a planar photodetector
C4F10
For details see a talk at this conference: DI MAURO, Antonello (CERN) R&D for the high momentum particle identification upgrade detector for ALICE at LHC
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Our previous prototype (very successful!)
Triple res. GEM with metallic strips
P. Martinengo, V. Peskov, et al., NIM, 639,2011,126V. Peskov et all.,arXiv:1107.4314 (2011) 1-7
RE
HMPID readout electronics
Cherenkov light was detected
(For more details see A.Di Mauro talk)
MIP
Cherenkov ring
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RETGEMcoated with CsI
R-MSGCor R-MICRODOT
Main advantages:Two times less elements,Less voltages,Very high gain (an important safety factor)
Concerns:Aging (to be studied)
New prototype (recently tested)
1.E-011.E+001.E+011.E+021.E+031.E+041.E+051.E+06
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Voltage (V)
Gai
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FW
HM
(%
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R-MSGC
R-MSGC+Cs-IRETGEM
Pilot studies:(while LoI was written and circulated)
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Inject EF and sealed when the signal was close to maximum
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Tests with EF vapors
Ist day 2d day
QE enhancement (after correction) is about 50%; work is still going on)
Preliminary
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2.A new double-phase detector(work in progress)
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The concept of usual double phase noble liquid dark matter detectors
Two parallel mesheswhere the secondary scintillation light is produced
Primary scintillation light
From the ratio ofprimary/secondarylights one canconclude about thenature of the interaction
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Several groups are trying to develop designs with reduced number of PMs(there was work from Novosibirsk group, we made sealed gaseous PMs, Breskin group is working on sealed gaseous PMs ..)
In E. Aprile XENON: a 1-ton Liquid Xenon Experiment for Dark Matterhttp://xenon.astro.columbia.edu/presentations.htmlIt was suggested to use CsI photocathode immersed inside the noble liquid
Large amount of PMs in thecase of the large-volume detectorsignificantly increase its cost
(Another option for the LXe TPC, which is currently under the study in our group, is to use LXe doped with low ionization potential substances (TMPD and cetera).
One large lowcost “PM”
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This suggestion was based on ourearly studies which we made togetherwith Aprile’s team
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However, this concept was never materialized in any
detector…
To verify feasibility of this approach we made some preliminary tests
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CsI photocathode
grids
PM
10 cmAlpha source
Ar gas
LAr
Experimental setup(ICARUS cryostat combinedwith a purification system)
Ar gas, room temper., 1 atm
LAr+ gas phase
V. Peskov, P. Pietropaolo, P. Pchhi, H. Schindler
ICARUS group
Performance of dual phase XeTPC with CsI photocathode and PMTs readout for the scintillation lightAprile, E.; Giboni, K.L.; Kamat, S.; Majewski, P.; Ni, K.; Singh, B.KetalDielectric Liquids, 2005. ICDL 2005. 2005 IEEE International Conference Publication Year: 2005 , 345 - 348
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EventCharge
hvhv
R-Microdot
CsI photocathode
Shielding RETGEMs(with HV gatingcapability)
LXe
Photodetectors?? (if microdot gain is insufficient)
Anodes Resistive cathodesMultiplication region
The possible way to suppress the feedback
In hybrid R-MSGC, the amplification region will be geometrically shielded from the CsI photocathode (or from the doped LXe) and accordingly the feedback will be reduced
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Results obtainedwith alphas and 55Fe
Measurements in Ar at room and cryogenic temperatures (preliminary)
“streamer”mode
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Stability with time
No feedback pulses were observed
105-115K
300K
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3. Micrpstrip-microgap for imaging applications
(Work just started)
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Scanners:
30% efficiency for 400 keVat shallow angle
b) Gamma ray
a) X-ray (edge on)
T. Francke et al.,NIM A508, 2003, 83
T. Francke et al.,NIM A471, 2001, 85
I. Dorion et al., IEEE Nucl, Sci., 34. 1987,442Contacts with industry are established;they already evaluate our prototypes
Pos. resol.50μm in digitalform, rate 105Hz/strip
Tantalumconvertor
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Another goal was/is to combinehigh pos. resolution with high time resolution.
First step in this direction was already successfully done by Fonte et al(see Proc. of Science, RPC 2012, 081).
Besides the particle detections another application is TOF- PET on which Fonte group is actively working
Bidimentional position resolution 70μmin with combination 80 ps timing
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Above only three examples of applications in which members of our
team are currently working were given
In reality much more work is going on
restive strip micropattern detectors.
A few more examples:
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1) Res. TGEM with metallic strips for environmental and safety applications(CERN-KTT project)
(this project is in a final stage, ready for commercialization)
Prototype of a flame detectorSensitivity 100 higher any commercial detector
Prototype of Rn detectorSensitivity is equal to commercial Rn detectorsOperating in on line mode, but ~50 times cheaper
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2) A.Ochi et al., Resistive strips microdot detector
Presented 10th RD51 collaboration meeting, October 2012
3) D. Attie et al., A piggyback resistive Micromegas
Presented at the RD51 meeting, December 2012
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Resistive MICROMEGASis planned to be also used insome other applications, for example environmental (muon tomography of undergroundwater reservoir),
4) However, the most remarkable example is MICROMEGAS for ATLAS upgrade
P. Salin, Presenation at the RD51 meeting, december2012
…see also today presentations
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Conclusions:1) A new generation of micropattern gaseous detectors with
resistive-strip electrodes combined with metallic 2D readout strips was developed. They offer excellent position resolution and are spark protected
2) We try to implement these detectors in several applications:RICH,
Noble liquid TPC, Scanner/medical,
environmental/security
3) A similar approach was in parallel developed by MAMMA collaboration and resistive strip MICROMEGAS will be employed in the ATLAS small wheel. More developments are in progress
4) Of course, these detectors have limited rate capabilities and this can be an issue in high rate environment, however some improvements in their rate characteristics still are possible
In progress
In a final stage
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Back up slides
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Optimization of the RPC electrodes resistivity for high rate applications
P. Fonte et al., NIM A413,1999,154
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ATLAS R-MICROMEGAS characteristics
T. Alexopoulos et al., NIM A640, 2011,110
103Hz/mm2
(2-3)104
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The concept of this detector is resembling the so called MHCP detector , however the important differences were that it was
manufactured from a printed circuit plate 0.4 mm and had resistive cathode strips making it spark-protective.
J.M. Maia et al., NIM A504,2003, 364
Anode stripsCathode strips
Holes
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Images with strip RETGEM
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00.20.40.60.8
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Counting rate (Hz/mm 2)
Me
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Rate response (MSGC):
The gas gain variations with counting rate. Measurements were performed in Ne+10%CO2 at gas gain of 5103
(signal drop at counting rate >103Hz/mm2 is due to the PCB board surface charging up, but not due to the voltage drop on resistive strips)
103
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Physics behind this phenomena
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Results of measurements induced signals profile from the readout strip oriented along(green curve with crosses) and perpendicular to the anode strips of R-MSGCs (rhombuses, triangles and squares). Rhombus- the collimator is aligned along the strip #0. Triangles -the collimator was moved on 200μm towards the strip#1. Squares- the collimator was aligned between the strip#0 and # 1. Measurements were
performed in Ar+10%CO2 at a gas gain of 5x103.
Preliminary results of measuremenst the induced signals on the strips:
More precisely the positionresolution will be determinedduring the oncoming beam test
Runs #3-6
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Profiles of signals induced on pick up strips(0.3mm wide collimator)
Correlation between the measured and actual position of the collimator
Expected
Measured
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Gas gains
Pos. resol. measurements Rate characteristicsRuns #12-17
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The main detectors on which RD-51 is focused
All of them can be done resistive, hence spark protected
Micromegas GEM TGEM
Micrpixel MHSC Ingrid