Talk #3: Novel Detector technologies and R&D M. Abbrescia, P. - PowerPoint PPT Presentation

Talk #3: Novel Detector technologies and R&D M. Abbrescia, P. Iengo (ATLAS), D. Pinci (LHCb)

Preliminary caveat  One of the main goals of the HL-LHC ECFA workshop is to find synergies between different LHC experiments, and possible follow-ups in terms of common R&D, etc. Therefore the approach of this talk will not be  “ experiment-oriented ”: novel detectors in CMS novel detectors in ATLAS …. then ALICE, then LHCb  but “ detector-oriented ”: GEMs in CMS (ATLAS), ALICE and LHCb iRPC in CMS, ATLAS MicroMegas and Thin-Gap in ATLAS (others?) other possible detectors  Here just the (preliminary) material coming from CMS is reported Note: a dedicated GMM is foreseen on the 23 to look at the full talks

Another caveat Has cost to be discussed?  It was specifically requested in the guidelines  There was some discussion during last meeting with the workshop Steering Committee  They requested to include it in the final document (post ECFA workshop)  The general feeling is that: “ it is difficult to discuss of this topic in the restricted framework (and time) of the workshop” “ there are too many variables (and options) to be taken into consideration ”  During last GMM it was stated that “ cost will not be discussed during the workshop” Decision?

Slides…

Why we need “ new ” detectors during Phase II?  All detectors foreseen for post-LS3 with the aim of restore redundancy or increase coverage should stand a rate capability higher then the present  Because installed in high- η regions  From 1 kHz/cm 2  5-10 kHz/cm 2 RPC rate capability  In addition we could be willing to improve also:  Time resolution – from o(1 ns)  o(100 ps)  Spatial resolution – from o(1 cm)  o(1-0.1 mm) Given requirement on rate capability choice of the technology will be driven by the physics case:  plus robustness, cost, easiness of construction, etc.

Detectors proposed

Gas Electron Multipliers (GEMs)

Principles of operation GEMs are made of a copper-kapton-copper sandwich, with holes etched into it Electron microscope photograph of a GEM foil Triple-GEM Developed by F. Sauli in 1997 Main characteristics:  Excellent rate capability: up to 10 5 /cm 2  Gas mixture: Ar/CO 2 /CF 4 – not flammable  Large areas ~1 m x 2m with industrial processes  Long term operation in COMPASS, TOTEM and LHCb 8

GEMs for CMS: performance Timing studies σ t =4 ns

GEMs for CMS: performance Position resolution (full size prototypes)

GEMs for CMS: performance Efficiency vs. gain Gain = 10 4 Triple GEM detectors, as proposed for the CMS experiment, with different gas mixtures and different gap sizes, in dedicated test-beams – comparison between double and single mask tecniques

Common: single side etching tecnique

Common: the New Stretching Technique

The GEM project for CMS: GE1/1 The GEM project: GE1/1 After LHC LS1 the | η |< 1.6 endcap region will be covered with 4 layers of CSCs and RPCs; the | η |>1.6 region (most critical) will have CSCs only!  Restore redundancy in muon system for robust tracking and triggering  Improve L1 and HLT muon momentum resolution to reduce or maintain global muon trigger rate  Ensure ~ 100% trigger efficiency in high PU environment

GEMs for the ALICE TPC Material provided by the ALICE collaboration

ALICE TPC Upgrade with GEMs Replace wire chambers With quadruple-GEM chambers Exploded view of a GEM IROC 16

TPC upgrade – Why? ROC ion feedback ( l int and l readout dependent) GG open GG closed inter. L1a (drift time) (ion coll. time in ROCs) Int. + 100 m s Int. + 280 m s t0+7.7 m s t0 Space charge (no ion feedback from triggering interaction)  GG open [t0, t0+100us], t0  interaction that triggers TPC • GG closed [t0+100us, t0+280us] • Effective dead time ~ 280us  max readout rate ~3.5 kHz • Maximum distortions for l int =50kHz and L1=3.5kHz: D r ~1.2mm • (STAR TPC distorsions ~1cm) MWPC not compatible with Space charge for continuous readout (GG always open)  50 kHZ operation gain ~6x10 3 • 20% ion feedback if GG always open  ion feedback ~10 3 x ions generated in • drift volume Max distortions for 50kHz ~100cm • 17

TPC upgrade − GEM -IROC prototype at test-beam CERN PS TESTBEAM GEM-IROC only tracks fib dE/dx: ~10% ⇠ µ same as in current TPC fixe field firs fi ⇥ dE/dx spectrum of 1GeV/c electrons and pions Relative dE/dx measurements for different HV settings for e and p With momentum from 1 to 3 Gev/c. 46 pad rows used for this analysis 18

GEMs for LHCb Material to be given by the LHCb collaboration (1-2 slides)

A perfect example of cross- fertilization: RD51 collaboration RD51 MPGD Collaboration Motivation and Objectives ~450 Authors from 75 Institutes World-wide coordination of the research in the field to advance technological development of Micropattern Gas Detectors. from 25 Countries  Foster collaboration between different R&D groups; optimize communication and sharing of knowledge/experience/results concerning MPGD technology within and beyond the particle physics community  Investigate world-wide needs of different scientific communities in the MPGD technology  Optimize finances by creation of common projects (e.g. technology and electronics development) and common infrastructure (e.g. test beam and radiation hardness facilities, detectors and electronics production facilities)  The RD51 collaboration will steer ongoing R&D activities but will not direct the effort and direction of individual R&D projects  Applications area will benefit from the technological developments developed by the collaborative effort; however the responsibility for the completion of the application projects lies with the institutes themselves. http://rd51-public.web.cern.ch/rd51-public/Welcome.html MicroPIC Ingrid MicroMegas GEM THGEM MHSP

Micro Megas for ATLAS Another detector studied in the framework of the RD51 collaboration… (Material to be added)

New Thin Gap Chambers for ATLAS (Material to be added)

improved Resistive Plate Chambers (iRPC)

Possible options Rate capability in RPCs can be improved in many ways:  Reducing the electrode resistivity (to be < 10 10 Ω cm)  reduces the electrode recovery time constant τ ≈ ρε – needs important R&D on electrodes materials  Changing the operating conditions  reduces the charge/avalanche, i.e. transfers part of the needed amplification from gas to FE electronics (already done in 1990s!) – needs an improved detector shielding against electronic noise  Changing detector configuration  Improves the ratio (induced signal)/(charge in the gap) Just some of these possibilities are being explored in present R&D

The role of resistivity CMS/RPCs are characterized by a resistivity around 10 10 Ω cm  Proposed glass-RPC have a resistivity of the same order of magnitude  At a first approximation, the improvement observed is not due to the resistivity (confirmed by a few hints)  Previous studies and a (semi) theoretical consideration limit the lowest resistivity usable at 10 7 Ω cm  At this point the detector practically looses its self-quenching capabilities (behaves like having metallic plates)  In principle a lot of room (3 orders of magnitude) to exploit:  Need studies on (new?) materials  Detector less stable

New Glass Resistive Plate Chambers And beyond… R&D on glass RPC New “low” resisitivity (10 10 Ω cm) glass used for high rate RPC  RPC rate capability depends linearly on electrode resistivity  Smoother electrode surfaces  reduces the intrinsic noise  Improved electronics characterized by lower thresholds and higher amplification  Single and multi-gap configurations under study Readout pads Mylar layer (50 μ ) PCB interconnect (1cm x 1cm) PCB (1.2mm)+ASICs(1.7 mm) Readout ASIC PCB support (polycarbonate) (Hardroc2, 1.6mm) Gas gap(1.2mm) Cathode glass (1.1mm) Mylar (175 μ ) Ceramic ball spacer + resistive coating Multigap option Glass fiber frame (≈1.2mm) Single gap option

GRPCs for CMS Effect of reduced resistivity on rate capability Comparison between standard low resistivity (10 10 Ω cm) and float glass RPC  Caveat: localized irradiation different from an uniform irradiation At the moment low resistivity GRPCs at GIF for a series of high rate and aging tests

GRPCs for CMS: performance Performance at “low” rate Multigap performance Excellent performance at localized beam tests even at high rate  Rate capability ~ 30 kHz/cm 2 (multi-gap)  Time resolution 20-30 ps

iRPC for ATLAS

R&D@GIF++  Essential is to testing these detectors in (harsh) conditions as close as possible to the ones there will be at LHC phase II  High rate, high flux of neutron and photons  For a long time! (not all effects are just related to the integrated dose… ) Prodution of chemical potentially capable of material damage to be monitored The environment needed is similar for all detectors A common facility GIF++ is being developed at CERN as…