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TMB Upgrade Considerations

TMB Upgrade Considerations. Jason Gilmore Vadim Khotilovich Alexei Safonov Indara Suarez. Muon Electronics Upgrade Workshop The Ohio State University April 23-24, 2010. Outline. Improvements to the CSC local trigger performance Motivation for early TMB Upgrade

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TMB Upgrade Considerations

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  1. TMB Upgrade Considerations Jason Gilmore Vadim Khotilovich Alexei Safonov Indara Suarez Muon Electronics Upgrade Workshop The Ohio State University April 23-24, 2010

  2. Outline • Improvements to the CSC local trigger performance • Motivation for early TMB Upgrade • Limitations of the current TMB • Efficiencies and rates • Performance at the very high luminosity regime (Phase II) • Efficiencies and rates • Conclusion

  3. Motivation for TMB Upgrade • Maximizing physics output at 14 TeV is a high priority: • Lack of m triggering in 2.1<h<2.4 would havemajor impact on physics • Turning on ME1/a with current TMB will not work for long (more later) • Constraints in upgrade situation: • Machine schedule changes (shutdowns 2012 and 2015) • DCFEBs most likely not ready by 2012 • Have to deal with ganged ME1/a strips longer • Possible strain due to limited spares to equip ME4/2 • TMB (+CSCTF) upgrade is still a good solution PU100: large neutron and beam BG not in simulation yet Old CFEBs: ganged ME1/a ME1/3 ME1/2 ME1/1b ME1/1a

  4. Limitations of Current TMB • Estimates for Phase Iluminosities • x2 PU factor (missing BGsin simulation & safety margin) • Turn ME1/a completely off: • No triggering in2.1<h<2.5 • Eff. ~93% in ME1/b • Include ME1a: • 85% efficiency across the whole ME1/1 • No proof that current CSC TF can handle it • Might expect significant additional TF inefficiency in ME1/a • Larger ME1/a LCT rates might be a problem for TF at higher luminosities • Both scenarios are not acceptable! PU100: large neutron and beam BG not in simulation yet Old CFEBs: ganged ME1/a Similar for PU50 and PU25: in backup

  5. Proposed Solution: Upgraded TMB 95% • Large improvement in performance even before DCFEB installation • Robust ME1/a triggering • Two-chamber solution resolves current TMB’s ME1/a problem • Higher efficiency • Main contribution comes from reduced TMB dead time • Improved geometrical and time matching for ALCT&CLCT • More details in backup… • Upgraded TMB is designed to operate at luminosities up to and including Phase II • Do all TMB hardware modifications in 2012 • Eventual DCFEB installation needs only firmware changes in TMB 97% PU100: large neutron and beam BG not in simulation yet Old CFEBs: ganged ME1/a Similar for PU50 and PU25: in backup

  6. ME1 60o Sector Rates • Rates on TF input • No cut at MPC • If additional rate control at high L needed:restrict CLCT bend to, e.g., only two straightest patterns • Little effect on efficiency of pT>5 muons • Even slightly higher efficiency for pT>10 • However, needs for low pT triggers have to be taken into account PU100: large neutron and beam BG not in simulation yet Old CFEBs: ganged ME1/a

  7. ME1 60o Sector Rates • Rate plot from the previous page in log scale to see the tails better • This is minbias only • Signal muons would be present on top of that PU100: large neutron and beam BG not in simulation yet Old CFEBs: ganged ME1/a

  8. MPC Sector Rates • Rates on input toMPC • All except the black line • No bend restriction • When considering a cut on max MPC one needs to keep in mind: • There are physics processes with two close muons • E.g., dark matter lepton jets or NMSSM higgs searches • Probabilities of #LCTs per ME1 30o subsector per BX: • ≥0 : 6.2%, ≥1 : 0.7%, ≥2 : 0.06%, ≥3 : 0.02% PU100: large neutron and beam BG not in simulation yet Old CFEBs: ganged ME1/a

  9. Ultimate SLHC Luminosities • New DCFEBs are necessary to handle high rates from strips • Much higher occupancy at TMB level • Pulls the efficiency down • Rates might become much more of a concern • Unganged strips in ME1/a: • Good for LCT efficiency • Good for TF • Phase II estimates use PU400 simulations: • Hopefully a reasonable approximation for PU~200 as simulation does not include neutron or beam backgrounds + important margin of safety!

  10. Efficiency at PU400 • For PU400 we can reach : • ME1/b: 96% • ME1/a: 93% • Note ~5% improvement from unganging • TF efficiency and resolution should also greatly benefit from unganging • TF needs further studies

  11. Rates for #LCT per sector • Important numbers for estimation of input to • MPC • TF (assuming no cut on max #LCTs at MPC) • Rates for various numbers of LCT per sector • Instantaneous rates between beam gaps • After all algorithm improvements • With bend restriction • Reminder: • signal muons would be present on top of that • Probabilities of #LCTs from MinBias per ME1 30o subsector per BX: • ≥0 : 15%, ≥1 : 2.9%, ≥2 : 0.25%, ≥3 : 0.03%

  12. Conclusions Strong benefits from building a new TMB early Can provide significant improvements even before the DCFEBs are installed Robust and reliable triggering in the forward region without efficiency loss in 1.6<h<2.1 Relieves the stress with spares (old ME1/1 TMBs will go to ME4/2) and can be installed without a long shutdown Is in line with the concept of introducing Phase I upgrades in adiabatic fashion Forward/backward compatibility with old and new CFEBs Only one upgrade, prototype is being built, studies in progress LTP simulation for upgrades is rather mature and provides valuable estimates: Important to-do: add neutron and beam backgrounds Will port the new CSC TF emulation when available

  13. Backup

  14. Efficiency at PU50 Efficiency at PU50 96-97% with new TMB 90-92% with old TMB if ME1/a is in PU50: large neutron and beam BG not in simulation yet Old CFEBs: ganged ME1/a • Nominal LHC luminosity has PU25at 2808 BX orbit fill • We should design for at least PU50 • Safety factor • Some backgrounds in sumulation are not accounted for

  15. Efficiency at PU25 Efficiency at PU25 Over 97% with new TMB 93-95% with old TMB if ME1/a is in PU25: large neutron and beam BG not in simulation yet Old CFEBs: ganged ME1/a • Noticeable improvementeven for such lowluminosity case

  16. Improving LCT Efficiency for SLHC Improved emulator algorithm: Add un-ganged ME1/1a into trigger as separate chamber CLCT: localized deadtime, restricting pattern bend, median timing resolution ALCT: narrow pattern in R=1, median timing, other minor adjustments LCT: match all possible A&CLTC combinations in |DBX|≤1 #LCT ≤ 2 in whole ME1/1(a+b) Minor effect on efficiency Allows to avoid many problems restores efficiencies in ME1/1 to at least 95% level in PU400 • ME1 is the most important for TF and ME1/1 is the most affected by high PU ME1/3 ME1/2 ME1/1b ME1/1a • PU400 is used for safety • as a number of factor is not accounted for, e.g., neutron or halo BG 16

  17. ME1/a on/off: matching inefficiency • Current TMB with ME1/a: • Current TMB with ME1/a off: • Conclusion: inefficiency of LCT matching is ~5% higher with ME1/a

  18. ALCT & CLCT rates: 2002 vs. 2010 • Current predictions are ~2 times lower, especially for CLCTs • A numbers of factors may contribute: differences in algorithms, minbias generation, simulation… • Is it worth investigating? • Probably not. Rates look sensible enough. • To compare rates per chamber type to the old results: • Use no algorithm improvements except addition if ME1/a into trigger • Linearly scale rates Old results from 2002/007:

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