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EE at SLHC

EE at SLHC. What do we expect at SLHC? EE Layout VPT vulnerability to radiation - Faceplate darkening - Photocathode ageing HV Filter card Active electronics Other EE components Induced activity Summary. What do we expect at SLHC?. LHC. SLHC. ∫ L ~ 440 fb -1.

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EE at SLHC

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  1. EE at SLHC • What do we expect at SLHC? • EE Layout • VPT vulnerability to radiation • - Faceplate darkening • - Photocathode ageing • HV Filter card • Active electronics • Other EE components • Induced activity • Summary EE at SLHC CERN 15/04/08 R M Brown - RAL 1

  2. What do we expect at SLHC? LHC SLHC ∫L~ 440 fb-1 ∫L~ 3040 fb-1 Total ∫ L~ 3500 fb-1(107 s/year, 50% efficiency) (cf ECAL TDR: ∫L~ 500 fb-1)  ~ x7 Koutchouk IoP Liverpool Jun 2007 Instantaneous luminosity (cm-2s-1) Year EE at SLHC CERN 15/04/08 R M Brown - RAL 2

  3. Dose versus  in EE (LHC) EE at SLHC CERN 15/04/08 R M Brown - RAL 3

  4. Neutron fluence (>100keV) in EE EE at SLHC CERN 15/04/08 R M Brown - RAL 4

  5. 500 fb-1 Immediately behind crystals 500 fb-1  Fluence and Dose for 500 fb-1 500 fb-1 Neutron + charged hadron fluence (cm-2) for E>100 keV 500 fb-1 Absorbed dose (Gy) EE at SLHC CERN 15/04/08 R M Brown - RAL 5

  6. Layout of EE elements EE at SLHC CERN 15/04/08 R M Brown - RAL 6

  7. Faceplate exposures to n and g Neutron fluence is 7x1014n/cm2 (Reactor) Accompanying g-dose ~100 kGy Relative loss at 425 nm = 25% For comparison, expected exposures at LHC (500 pb-1) at  = 3 are: 7x1014 n/cm2 and 50 kGy Induced absorption vs wavelength for 1mm thick sample of US-49C exposed to 20kGy g (60Co) ( = 2.6 at LHC) Light loss (PWO) ~ 9% Induced absorption l (nm) EE at SLHC CERN 15/04/08 R M Brown - RAL 7

  8. Extrapolation to SLHC exposures Transmission loss for PWO light under 60Co irradiation • A faceplate of US-49A glass has been irradiated up to 1250 kGy • The damage tends to saturate and the ratio:(DT/T0)450 (350 kGy)  1.7 x (DT/T0)450 (50 kGy) •  For US-49C: loss of PWO light < 20% for 350 kGy( = 3.0 at SLHC) ●US-49A ■ US-49C X VPT anode response A US-49A faceplate was exposed to 1016 n/cm2 with an accompanying g dose of 1600  250 kGy Unfolding the neutron damage using extrapolated 60Co data (and ignoring gs from induced activity in the glass): DT/T0 (neutron) < 15% for  < 3.0 at SLHC ( DT/T0 (neutron) < 30% for US-49C at SLHC????) EE at SLHC CERN 15/04/08 R M Brown - RAL 8

  9. Photocathode lifetime IK(0) = 200 nA Photocathode current for L =1034 cm-2s-1 30 days at IK(0) = 200 nA  ~ 650 fb-1 at h = 2.9  ~ 2000 fb-1 at h = 2.5 IK(0) = 200 nA EE at SLHC CERN 15/04/08 R M Brown - RAL 9

  10. 1.6 1.6 1.2 1.2 Capacitance (pF) Capacitance (pF) 0.8 0.8 0.4 0.4 0.0 0.0 103 105 107 103 105 107 101 101 Frequency (Hz) Frequency (Hz) HV Filter Card components (g) Before irradiation After 135 kGy • HV Filter card components irradiated to 135 kGy (60Co) (~ SLHC at h = 2.6) • Small change in capacitor values (slight improvement in leakage current) • Negligible change in resistor values EE at SLHC CERN 15/04/08 R M Brown - RAL 10

  11. HV Filter Card components (n) Resistors • HV Filter card components irradiated to 1015 n/cm2 (spallation spectrum at ISIS) • (h > 3.0 at LHC, h ~ 2.0 at SLHC ) • (While biased at 1 kV) • (Components similar but not identical to final selection) • - Small change in capacitor values (slight improvement in leakage current) • Negligible change in resistor values • No breakdown up to 2 kV Capacitors EE at SLHC CERN 15/04/08 R M Brown - RAL 11

  12. h 3.0 2.6 2.0 1.6 400 Absorbed dose for 3500 fb-1 kGy 300 Inner limit of active electronics 200 100 200 600 1000 1400 5.0 Radial distance from beam (mm) 1015/cm2 4.0 Neutron fluence for 3500 fb-1 3.0 Active electronics behind polyethylene moderator 2.0 Hadron fluence at ADCs z = 3520 mm 1.0 Active electronics • MGPA tested to 50 kGy (~1/3 worst SLHC)(10 keV X-rays at ~10 kGy/h) •  3% reduction in gain (pulse shape unchanged) • APV25 exposed to 2x1014p/cm2 (300/MeV/c) 15% reduction in gain • Optical link components (Tracker version) tested to 1.5 MGy (60Co) and ~5x1015 n/cm2 (18 MeV)(~10x SLHC for EE)  g – loss in fibres small • – TX (LLD ASIC + laser diodes) OK • – Optical cables OK • – Optical connectors appear OK • – QR codes OK • – PCB and connector embrittlement •  n – Lasers die at 2-3 1015 n/cm2 • BarrelTriggerTower irradiated with p (63MeV)to 1.5x1013 p/cm2 (20 kGy at 1.7 Gy/s)(Dose ~worst LHC,Hadron fluence ~1/3 worst LHC) • Tower still working at end of exposure Will LV Regulators survive 5x1014 n/cm2 ? EE at SLHC CERN 15/04/08 R M Brown - RAL 12

  13. Radiation tests of other components EE at SLHC CERN 15/04/08 R M Brown - RAL 13

  14. 24 54 Estimated dose rate in mSv/h after 60d at L = 5x1033cm-2s-1 and 1d cooling. (CMS closed) After 4 months cooiling the dose rates are ~2.5x lower 150 150 r(cm) 100 50 0 0 100 200 300 400 z(cm) EE Activation LHC (ECAL TDR) Occupational dose limits: - 1 mSv/wk - 15 mSv/yr Assume induced activity levels at SLHC ~10xLHC  Time to Annual limit at h = 3 is ~10 h EE at SLHC CERN 15/04/08 R M Brown - RAL 14

  15. Summary Passive components: – including HV filter card – OK Active electronics: - Optical links - OK - MGPA gain -15% at h = 2.6? - Trigger towers not tested to full EE fluence at LHC!! VPTs: - Faceplate darkening -30% - Photocathode ageing -40%  Combined loss 60%? Crystals: - Ask Francesca! EE at SLHC CERN 15/04/08 R M Brown - RAL 15

  16. Endcap upgrade for SLHC? At VPTs: Dose(h=2.2)/Dose(h =3.0) ~1/10 (neutron fluence ~1/3) ~25% (18/71) Supercrystals are at h>2.2 Replace for SLHC? Unfortunately, complete rows of supercrystals must be dismounted to replace inner units – remote handling! VPTs with Ce-glass windows – very rad-hard But photocathode ageing depends on integrated charge - NB LYSO has a high light yield and would accelerate this effect. h EE at SLHC CERN 15/04/08 R M Brown - RAL 16

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