M23 I nner R egions U pgrade with Triple-GEM detectors

1. M23 Inner RegionsUpgrade with Triple-GEM detectors The EVLGG (Davide, Gianni & Ale) INFN Cagliari LNF Frascati INFN Roma

2. Introduction • LHCb upgrade: the current scenario (from FTDR) • The weak points of the current system • The triple-GEM proposal • Preliminary Cost estimate • 2013 R&D activity • Conclusions the EVLGG (Davide, Gianni & Ale)

3. LHCb Upgrade: The Scenario • 40 MHz readout + flexible software-based trigger • This will allow annual rates x5 (muon ch.) – x10 (hadronicch.), • LHCb will also become a general-purpose forward detector • Running conditions: • Luminosity of 1e33 in LoI; but now in FTDR we plan for 2e33… and what about a safety factor? The central regions of M2 and M3 are hot and could be much hotter than expected (no M1, no PS, no lead, no SPD anymore, splashes inside calorimeter hole, …) • Beam structure: 25 ns spacing, mu=2-4 • 5 fb-1/year for a 10 years operation • Muon system needs to remain efficient and to operate for ~10 years the EVLGG (Davide, Gianni & Ale)

4. The Current Muon System • As reported by Giovanni on March 27th at the Muon General Meeting, “as far as rates are concerned we are already marginal at 1x1033 but we are definitely out at 2x1033” • We strongly believe that we cannot go for a marginal detector which seems “just fine” for 2x1033 – we have to use our experience and include a reasonable safety margin… and upgrade the muon detector to be efficient up to ~5x1033 • The muon system was designed to operate at a maximum of 1MHz/cm2/FE-channel  we need to push this limit at least by x5, better x10 in central regions • In fact, the higher rates will create large dead-time with the current electronics and layout  muon system inefficiency • In addition, these higher particle fluxes will: • Possibly create (position dependent) chamber inefficiencies due to local space-charge effects • Age detectors (much) faster • Thisisparticularlytrue for the centralregions of M2 and M3 • Weneed to carefullyaddressall the aboveissues the EVLGG (Davide, Gianni & Ale)

5. M23R12 Triple-GEM Proposal • For the upgrade of most irradiated parts of the muon system, regions M2R12 and M3R1, we propose Triple-GEM detectors as a possible rad-hard technology • Our proposal is to use 4-gaps Triple-GEM detectors • These detectors: • Innovative construction technique, both for GEM foils and Detector • Use MWPC gas • Simplified HV supply (using resistive dividers) • Anode pad (size of current logical pad) readout the EVLGG (Davide, Gianni & Ale)

6. A Working Solution • Triple-GEM detectors with pad readout have already been selected to be used in M1R1 and have operated according to expectations • Future M2R1/M3R1 rates will be similar (or even higher) than the current M1R1 rates  it seems natural to consider this technology for these inner regions • In the last 10 years, since the M1R1 triple-GEM proposal, these detectors have increased in popularity and have been used successfully in many experiments: they are now cheaper and more reliable thanks to the improvement in GEM fabrication technology • In addition, the experience we accumulated for M1R1 allows us to be much more confident in proposing this type of detector and in operating it  We strongly believe that this detector type is the RIGHT solution for this environment the EVLGG (Davide, Gianni & Ale)

7. Triple-GEM detectors performance • Can stand up to 50 MHz/cm2 [1] • Aging has been demonstrated [2] up to 2.2 C/cm2; after the aging test the detectors show the expected efficiency and time resolution with only a 15V increase in supply • Current integrated charge estimate is 40 mC/cm2/recorded fb-1 in the most irradiated detector of M1R1 (horizontal plane)  since M1R1 and M2R1_upgraded have similar particle rates, ready to integrate 50 fb-1 at these rates, which are similar to what we will have in M2R1 in LHCb upgraded • This technology seems to be already certified for the M23 inner regions operation at the LHCb upgrade! • Weplan to use MWPC gas mixture: Ar/CO2/CF4 40/55/5 to simplify the integration of this detector technology in M23 • The use of a higher-gain gas mixturewillminimizesthe required GEM operatingvoltage, and by consequence the sparkprobability, improving detector reliability [1] http://www.infn.it/thesis/PDF/244-Poli%20Lener-laurea.pdf [2] M. Alfonsi et al., IEEE TRANS. NUCL. SCIENCE, vol. 52 (2005) the EVLGG (Davide, Gianni & Ale)

8. Assembly Scheme Summary The new design of GEMs detector offers many advantages: • No gluing, no soldering during the assembly procedure • No special tooling required • The detector does not need spacers in the active area • Assembly is very fast and easy (~ 1/day with 2 people crew) • If needed, the detector can be re-opened for modifications, repairs, or to replace a GEM foil the EVLGG (Davide, Gianni & Ale)

9. Production Cost Estimate M2R1 (48 detectors) (or M3R1) GEM foil  10.8 m2 x 2000 CHF/1.2 18.000 €/48 det.s = 375 € /det. PCBs (cath.+anode)  200 +576+350+1104 = 2230 €/48 det.s = 50 € /det. Honeycomb+ backplane  80x96 = 7680 €/48 det.s = 160 € /det. Detector mechanics  300 € /det. ___________ total 885 € /det. TOTAL COST ESTIMATE FOR M2R1 or M3R1  885 x 48 = 42.480 € M2R2 (96 detectors) GEM foil  43.2 m2 x 2000 CHF/1.2  72.000 €/96 det.s= 750 € /det. PCBs (cath.+anode)  220+2304+350+4320 = 7194€/96 det.s = 75 € /det. Honeycomb+ backplane  100x192 = 19200€/96 det.s = 200 € /det. Detector mechanics  500 € /det. ____________ total 1525 € /det. TOTAL COST ESTIMATE FOR M2R2  1525 x 96 = 146.400 € In green : budgetary offer In yellow : estimate (in excess) from our personal experiences the EVLGG (Davide, Gianni & Ale)

10. Tentative Planning • 2012 • Prototype assembly and test • Start to study triple-GEM detector performance with MWPC gas mixture • 2013 • Start detector design • Production of 2 real-size detectors • Test with CARIOCAGEM • 2014 • Final design • Build a full detector • Test with new electronics the EVLGG (Davide, Gianni & Ale)

11. R&D Activity in 2013 • The following are the activities that we would like to perform in 2013 and for which we will ask funding to INFN: • Built 2 detectors with the size of M3R1 chambers using the new assembly technique (embedded stretcher) to assess the assembly technique and possibly improve it, and also to have some real-size prototypes that we could use on beam test • Also built a few 10x10 cm2 detectors for laboratory testing • Test detector performance with the MWPC gas mixture: time resolution (cosmic rays), gain (55Fe source), spark (alpha source) • Perform a test with ~10 MeV neutrons (likely at ENEA-Frascati) to evaluate the impact of Heavy Ionizing Particles on detector performances • In conjunction with our electronic team, start developing the new detector electronics (FEE + post-processing) • We are currently not planning a test beam for 2013 – all measurements we have in mind could be done in an alternate way the EVLGG (Davide, Gianni & Ale)

12. Conclusions • The inner regions of M2 and M3 of the current muon detector cannot be operated with the required performances at 2x1033 • MWPC technology does not seem to guarantee a sufficient operational safety margin if used in M2/M3 inner regions  replace them with Triple-GEM Detectors • We need to test the performance of a 4-gap Triple-GEM detector using the current MWPC gas mixture • GEM foil new fabrication technique is cheap and reliable; together with the proposed detector assembly scheme we can built fast and easily the required chambers • The total cost of the detectors for M2R12 and M3R1 is ≈250k€ • Triple-GEM detector seems the right choice to equip M2 and M3 inner regions • A R&D activity is planned for 2013 to give clear answers to all pending issues the EVLGG (Davide, Gianni & Ale)