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Due to the importance of these developments an RD 51collaboration was formed a CERN

Development of a new generation of micropattern gaseous detectors for high energy physics, astrophysics and medical applications. A.Di Mauro, 1 P. Fonte 2 , P. Martinengo 1 , E.,Nappi 3 , R. Oliveira 1 , V. Peskov 1 , P. Pietropaolo 4 , P. Picchi 5 1 CERN, Geneva, Switzerland

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Due to the importance of these developments an RD 51collaboration was formed a CERN

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  1. 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, Switzerland 2 LIP/ISEK Coimbra, Portugal 3INFN Bari, Italy 4INFN Padova, Italy 5INFN Frascati, Italy

  2. 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

  3. There are four main designs of micropattern gaseous detectors: 1) Strip type Example: Microstrip gas counters (MSGCs) A. Oed, NIM A263, 1988, 351 Glass substrate 3) Parallel-plate type Example: Micromesh gas chamber (MICROMEGAS) Y. Giomataris et al., NIM A376, 1996, 29 2) Microdot ~100μm S.Biagi et al., NIMA392, 1997, 131 4) Hole type Examples: CAT/WELL, Gas Electron multiplier (GEM) A.Del Guerra et al., NIM A257, 1987,609 M. Lemonnier et al., Patent FR 2727525 , 1994 F. Sauli, NIM,A386,1997,531 CAT/WELL GEM Anodes

  4. 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

  5. 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 caseof traditional detectors: wire and parallel-plate type)

  6. See, for example G. Charles et al., NIM A648, 2011, 174 .. and sparks, unfortunately, in experiments are practically unavoidable

  7. 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 use resistive electrodes.

  8. The first micropattern detector with resistive electrodes was GEM, and later this approach was also applied to otherdetectors: MICROMEGAS and CAT (all had unsegmented electrodes) Res. mesh R.Oliveira etal., IEEE Nucl. Sci 57,2010, 3744 Res. MICROMEGAS R.Oliveira etal., IEEE Nucl. Sci 57,2010, 3744 • Res. GEM • Oliveir at al., NIM A576, 2007, 362 • Res. CAT • Di Mauro et al., IEEE Nucl. Sci Conf Rec, • 6, 2006,3852

  9. They were hybrids layout between GEM and RPC -V Resistive electrodes The principle of operation of RPC: discharge energy is quenched because of the resistivity of electrodes

  10. 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:

  11. See for example: a photo of RETGEMfrom: R. Akimoto et al,presentation at 1st MPGDs conference in Crete,2009or Spark protected RETGEMs and Res. CAT: Several groups (mostly Japanese) are now successfully developing various designs of RETGEMs Res. CAT developed by Breskin group L. Arazi et al., JINST 7 C05011, 2012

  12. Today we would like to present a new approach: resistive electrodes segmented on strips with a network of metallic readout strips located under the resistive grid 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 1) 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) 2) 3)

  13. 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

  14. 1. Resistive microstrip detector

  15. PCB with 5μm thick Cu layer on the top and two layers of readout strips (oriented perpendicularly) on the bottom a) 0.5mm 0.1mm 0.2mm 0.6mm b) Milled grooved 100 μm deep and 0.6 μm wide, pitch 1mm. 0.5-1mm 1mm Cathode res. strips c) The grooves were then filled with resistive paste (ELECTRA Polymers) 20μm Anode strips By a photolithographic technology Cu 20 μm wide strips were created between the grooves d) e) Finally the entire detector was glued on a supporting FR-4 plate

  16. Cathode resistive strips Connections to X pick up strips Anode strips Connections to Y pick up strips

  17. Gas gains Pos. resol. measurements Rate characteristics ~200μm

  18. 2. Resistive microdot-microhole detector

  19. Manufacturing steps: Multilayer PCB with Cu layers on the top and bottom and with the inner layer with readout strips 0.1mm a) v v v Upper Cu layer etching v v b) The remaining grooves were then filled with resistive paste (ELECTRA Polymers) v c) 1mm 0.1mm d) Removal of the Cu Resistive cathode strips Resistive anode dots Filling with Coverlay with “dot” opening e) Readout strips Holes

  20. 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) Magnified photograph

  21. 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). 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. In all gases tested the maximum gains achieved with the R-Microdot detectors were 3-10 time higher than with R-MSGCs Interesting feature: at high gains operates in self-quenched streamer mode

  22. 3. Resistive microgap-microstrip detector

  23. M-M- RPC manufacturing steps: Multilayer PCB with a Cu layer on the top and one layer of readout strips on the bottom, 0.5 pitch a) b) v v Upper Cu layer etching 0.035mm The grooves were then filled with resistive paste (ELECTRA Polymers) c) 0.5 mm 0.2mm d) Removal of the Cu Resistive strips If necessary, filling with Coverlay (an option) e) 0.1mm Readout strips

  24. Top view: Contact pad A Surface resistivity 100kΩ/□(can be adjusted to exper. needs) Total resistivity of the zone B 500MΩ (adjustable) Resistivity of zones A and C 500MΩ (adjustable) B C Contact pad Resistive strips

  25. 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

  26. Artistic view of the M-M RPC PCB sheet Inner signal strips Orthogonal resistive strips From these plates RPC were assembled with gaps ether 0.5 or 0.18mm

  27. An option with pillars (similar to MICROMEGAS) Res. strips Pillars

  28. A fundamental difference between “classical “ RPC and M-M- RPC “Signal” electrodes Usual RPC Current 500MΩ M-M-RPC Film resistor Current Orthogonal resistive strips Inner signal strips 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

  29. Gain estimation in an RPC geometry: 0.5mm x Photoelectron tracks X-rays Fe anode A=expαx 0.1-0.2mm UV CsI layer (Due to the time constrains the CsI coating was done by a spray technique)

  30. M-M-RPC with spacers in corners The highest gains were obtained with resistive micropattern detectors (combined current and pulsed measurements) Typical rate response

  31. Now shortly about the applications in which our team is involved

  32. 1. RICH (recent results)

  33. 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)

  34. The suggested detector will consist of a gaseous radiator (for example, CF4 orC4F10 ) and a planar gaseous photodetector The key element of the VHMPID is 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

  35. Our previous prototype (very successful!) RE Triple res. GEM with metallic strips P. Martinengo, V. Peskov, et al., NIM, 639,2011,126 V. Peskov et all., arXiv:1107.4314 (2011) 1-7 HMPID readout electronics Cherenkov ring Cherenkov light was detected MIP (For more details see A.Di Mauro talk)

  36. Pilot studies: (while LoI was written and circulated) Main advantages: Two times less elements, Less voltages, Very high gain (an important safety factor) Concerns: Aging (to be studied) New prototype (recently tested) RETGEM coated with CsI R-MSGC or R-MICRODOT R-MSGC+Cs-IRETGEM R-MSGC 100 10 FWHM (%) 1

  37. Tests with EF vapors Ist day 2d day Preliminary Inject EF and sealed when the signal was close to maximum QE enhancement (after correction) is about 50%; work is still going on)

  38. 2.A new double-phase detector(work in progress)

  39. The concept of usual double phase noble liquid dark matter detectors Two parallel meshes where the secondary scintillation light is produced From the ratio of primary/secondary lights one can conclude about the nature of the interaction Primary scintillation light

  40. 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 ..) One large low cost “PM” Large amount of PMs in the case of the large-volume detector significantly increase its cost In E. Aprile XENON: a 1-ton Liquid Xenon Experiment for Dark Matter http://xenon.astro.columbia.edu/presentations.html It was suggested to use CsI photocathode immersed inside the noble liquid (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).

  41. This suggestion was based on our early studies which we made together with Aprile’s team

  42. However, this concept was never materialized in any detector…To verify feasibility of this approach we made some preliminary tests

  43. PM grids 10 cm CsI photocathode Experimental setup (ICARUS cryostat combined with a purification system) Ar gas Ar gas, room temper., 1 atm Alpha source LAr 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 LAr+ gas phase

  44. The possible way to suppress the feedback Photodetectors?? (if microdot gain is insufficient) R-Microdot Anodes Multiplication region Resistive cathodes Shielding RETGEMs (with HV gating capability) Charge Event LXe hv hv CsI photocathode 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

  45. Measurements in Ar at room and cryogenic temperatures (preliminary) “streamer” mode Results obtained with alphas and 55Fe No feedback pulses were observed 105-115K 300K Stability with time

  46. 3. Micrpstrip-microgap for imaging applications (Work just started)

  47. Scanners: • X-ray • (edge on) Pos. resol. 50μm in digital form, rate 105Hz/strip T. Francke et al., NIM A471, 2001, 85 T. Francke et al., NIM A508, 2003, 83 Tantalum convertor b) Gamma ray 30% efficiency for 400 keV at shallow angle Contacts with industry are established; they already evaluate our prototypes I. Dorion et al., IEEE Nucl, Sci., 34. 1987,442

  48. Another goal was/is to combine high 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). Bidimentional position resolution 70μm in with combination 80 ps timing Besides the particle detections another application is TOF- PET on which Fonte group is actively working

  49. 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:

  50. 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 detector Sensitivity 100 higher any commercial detector Prototype of Rn detector Sensitivity is equal to commercial Rn detectors Operating in on line mode, but ~50 times cheaper

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