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RPC project Update on the trigger

RPC project Update on the trigger Two members of the RPC group are active in the trigger simulation to review and cross check all the figures Production of gaps The production of CMS gaps has started. Tests in Summer/Autumn 2001 Irradiation with gammas and neutrons

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RPC project Update on the trigger

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  1. RPC project • Update on the trigger • Two members of the RPC group are active in the trigger simulation to • review and cross check all the figures • Production of gaps • The production of CMS gaps has started. • Tests in Summer/Autumn 2001 • Irradiation with gammas and neutrons • DT-RPC test • RPC-LinkBoard test

  2. 50 Hz/cm2 Neutron factor 3

  3. 1/02 1/06 1/04 1/0 5 1/03 100% end +2 +1,0 2/04 readiness wheel +2 8/03 Trial wheel 0 7/04 Install. Milestones(V.31) 70% 120 RB1, 120 RB2, 120 RB3, 40 RB4 80 RB4 # of chambers needed for install. in SX 820 gap Febbraio 03 Readiness wheel -2 8/04 500 gap Maggio 02 End of UX installation 6/05 End of SX installation 12/04 Begin mass production 9/ 01 10% < installation of wheels +2, -1, -2> < install. of wheels 0 ,+1 > 01 03 06 02 04 05

  4. Gap production at GT • So far 40 gaps (RB3 type) have been produced). The goal is to have 100 gaps ready for the end of the year. • Quality control: • pressure test up to 20 mbar • HV test up to 8000 in pure C2H2F4 ( I < 3 mA) • Quality of the oil coating ( by opening 1/10 of chambers) • Plan for next year: • J F M A M J J A S O N D • 40 140 240 330 450 500 550 600 650 650 650 650 • Bakelite procurement: 300 foils arriving at GT in January • 300 in production in January

  5. Assembly at GT Double gap assembly foreseen at GT. Tools in preparation. Assembly should start very soon, but space, resources and schedule at GT still to de defined. The option to use additional INFN manpower for the assembly has been very preliminary discussed in the INFN RPC committee Chamber assembly at GT: Idem Chamber assembly in Sofia : ready Chamber assembly in Pavia: site in preparation Chamber assembly in Bari: ready

  6. Combined DT-RPC test DT + RPC under tested at ISR DT + RPC at GIF

  7. Efficiency No SF6; data with SF6 being analysed

  8. Rate from cluster counting Efficiency 99% No SF6; data with SF6 being analysed Strip # is fired if it the median of the considered cluster

  9. Cluster size Hit counting No SF6; data with SF6 being analysed

  10. Spatial resolution Distributions of residuals between reconstructed impact point from DT and the median strip in the RPC cluster events

  11. Gamma irradiation @ GIF • “Oiled” chamber at GIF from October 2000 to May 2001: • Monitor rate and current • Study the efficiency to cosmic Before irradiation Two month after irradiation

  12. Efficiency

  13. Rate

  14. Monitor the chamber at different source conditions (ABS) NABS = number of hit expected at a given ABS,as computed by the simulation

  15. If R is the total resistance of the system, the quantity Hvgas should be invariant: HV HVgas The system resistance remains constant during irradiation

  16. Neutron irradiation Legnaro (Padova INFN) 17 mCi 252Cf: a-3%spontaneous fission; b-97%a decay 1 gap oiled 1 gap not oiled 3.8 n/fission Eav= 2.14 MeV Measure the sensitivity to low energy neutrons

  17. Neutron irradiation Lovain Centre de Recherches du Cyclotron (Louvain la Neuve, Belgium) Reaction: 9Be (d,n) Neutron Flux at 90 cm: 8.15 107 n/cm2 s mA 3 double gap RPCs 90 cm from the target

  18. Neutron sensityity Single gap sensitivity at low energy: (2.5-3.5) 10-4 Single gap sensitivity at high energy: (2-3) 10-3 Same chamber used for both measurements No difference between the oiled and the no oiled gaps Double gap sensitivity is twice the single gap value

  19. n ageing @Louvain 1 gap with oil coating (Resistivity:  1.4 1010 W cm) 1 gap without oil coating (Resistivity:  3.2 109 W cm) Gas mixture: 96.5% C2H2F4 3.5% i-C4H10 The Neutron Flux can be adjusted by tuning the current of the beam: at 90 cmf = 8.15 107 n/cm2 s mA High neutron fluxes (2-3 107 n/s cm2) Irradiation schedule

  20. non oiled GAP Chamber noise monitoring BEAM ON BEAM OFF At constant neutron flux the contribution of the neutron activation must be added. The chamber noise is decreasing following the decay law

  21. Efficiency and noise: before after irradiation The chamber efficiency was measured using cosmic muon triggers

  22. Conclusion • Satisfactory results on the performance of the RPC system • Barrel production has started • The schedule at GT needs some refining • Man power required (art. 2222) • Specification for the gas system defined (tender ready to go) • Pavia site in preparation

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