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HCAL issues • replace dead PM/CW’s (3), PM/CW’s with high leakage (3); • check with LEDs (need DAQ to be operational) • Cs scan: right before the physics (does not require opening the detector) • replace passive radiation monitors (present on both front and rear planes of HCAL)
ECAL issues • replace dead PM/CW’s (~10); check with LEDs (need DAQ to be operational) • modification of integrators • studies of the LED system
ECAL integrators • New version: • uses ~90% of the anode current • sensitivity ~ 100 DCU counts/μA • DC gain ~2.2 no stability problems with TL072 (rad hard) • NB requires also slight modification of CW bases: install 100 nF in series with 25 Ω. This does not affect the signal. • Old version: • uses ~1.25% of the anode current • sensitivity ~ 30 DCU counts/μA • DC gain ~3300 stability problems TLE2022 used (less rad hard) instead of TL072 Replacement TLE2022 -> TL072 can be mechanically difficult in existing integrator boards new boards are in preparation (A. Zhokhov). If ready in time, the old boards will be replaced. Otherwise we can only replace passive components on the old boards (still an improvement), the installation of old boards postponed to the next shutdown. The corresponding CW bases will be modified in any case.
ECAL LED system studies • 11 kHz LED test showed a several % instability of the LED flash magnitude, need to study in more details: • measure the frequency dependence • try to understand the reason of instability (e.g. sensitivity to +15V power supply voltage) • if understood – decide whether we can fix it at the hardware level • Does not require opening the detector
Tentative planning, HCAL Replacement of PM/CWs (MUON tower should be closed; nacelle) C: Dec 09-14, 1 day A: Jan 14-19, 1 day Replacement of the radiation monitors A&C: Dec 09, during the detector movements. Nacelle! Source scans: right before the end of access (~Jan 18), and optionally right after the start of the access
Tentative planning, ECAL Replacement of PM/CWs, work on integrators (HCAL should be closed; nacelle) C: Dec 14-17 A: Jan 10-14 If new integrator boards will be ready only in January, we will ask for ~1 day opening of ECAL C Studies of the LED system:during the whole shutdown (does not depend on the detector opening)