Evolution of EE response

Reminders of past work

VPT steps wrt LHC fills, Henry Aldrich
VPT-quantum-efficiency-vs-laser.pdf

Current laser powers, April 2021
Blue, 473 nm, 1 mJ
Green, 527 nm, 200 microJ

Laser signals in Run3

18 April 2021
Current run 1 + run 2 + run 3 integrated luminosity expectations, Luca Malgeri, Slide 16, CMS week, Feb 2021
End 2022 240 fb-1
End 2023 306 fb-1
End 2024 384 fb-1

Lost crystals, eta > 2.05, by 450 fb-1, if laser barrack moved to surface

16 April 2021
R/R0 losses, ring 21 = eta 2.1 etc:
Sasha: R/R0 evolution with respect to luminosity:


Table of losses:

19 March 2021
First-pass-Dejardin-data.pdf:
Email to Marc Dejardin - impact of removed cuts, data below 6 ADC counts now present in LaserFarm data.
Slide 1 of the attached shows the new amplitude distribution that now goes all the way down to ~0 adc counts - great news.
So the missing data are back. However, there are also a handful of -ve amplitudes.
26 Feb 2020 DPG
Laser-scan-laserfarm-vs-dqm-data-informal-with-MD-comment
Slide 16, proposal for a new, more powerful of-the-shelf green laser
Longevity_during_Run3_and_laser_scan_results
Data driven estimates of future EE response losses
23 May 2019 ECAL DAYS Zurich
Laser-power-scans, implications for Run 3
Absence of LaserFarm data below 6 ADC counts.
Presence of DCC data below 6 ADC counts in the DQM data files.
Evidence of SYSTEMATIC errors on laser pulse height reconstruction below 3 ADC counts.
EEM lower quadrant - pn gain stuck always on 16 - an issue for higher power laser runs.
Studies of pn signal (non)linearity with gain 16 and gain 1.

14 March 2018 Laser power scans

Reference plots

• Ageing_contribution-to-resolution.png:
  
  

From CMS DP-2013/026, for 14 TeV running. ageing_resolution.pdf

• Sasha-channel-response-evolution.png:
  
  

From page 74, Figure 3.3, "TECHNICAL PROPOSAL FOR THE PHASE-II UPGRADE OF THE COMPACT MUON SOLENOID".

New WG3 working group twiki

References:

• Pushpa's dose/fluence calculator
• Sasha - predictions EM+Had damage, ECAL Upgrade Meeting, 18.10.2011
• CMS IN-2010/026, 'Estimates for the changes in light yield from the CMS ECAL during LHC operation'
• EE xtal-dose-profiles, Fig 8
• EE-long-term-Sat-4-9-2010-0928.pdf: EE long term, Sat 4 Sep 2010, 0928

• RCA-Photomultiplier_Handbook.pdf, see pages 41 onwards and figures 54, 55
• PM-tube-Nuggets.pdf, from the RCA handbook
• p49 - Cesium, for example, is very volatile and may be redistributed within the tube causing loss of secondary emission gain or loss of cathode sensitivity.
• VPT ageing discussion, ion bombardment, Cs desorption, Bob-FNAL-Nov2008.pdf

Talks

28 Oct 2016 D. Cockerill, BTCP-SIC-laser-corrections-study.pdf
14 June 2012 D.Cockerill, VPT loss estimates

Plots

Proton damage
Quote from Lecomte et al., NIM A 587 (2008) 266-271, "Comparison between high-energy proton and charged pion induced damage in PbWO4 calorimeter crystals":
"...at eta = 2.2 and for an integrated luminosity of 5.10**5 pb-1, the expected induced absorption coefficient corresponds to the one observed for a proton fluence of 10**13 p/cm2 (Fig. 15 in Ref. [3])."

Note from F Nessi, 3 Apr 2014, "...the star densities for CMS, that are used to scale the damage observed in proton and pion irradiations, come from a full FLUKA propagation of minimum bias events in CMS. Thus, high-energy neutrons are included already. Just the low energy ones that fall below the FLUKA thresholds, are not."

Ref [3], Huhtinen et al., NIM A 545 (2005) 63-87, "High-energy proton induced damage in PbWO4 calorimeter crystals"

• NIM545-2005-63-Fig-15.png:
  

Proton-damage-resolution/proton-lyloss.C

• lyloss-versus-eta.png
• from Proton-damage-resolution/lyloss-versus-eta.C:
  

• resolution-cropped.png
• from Proton-damage-resolution/resolution-formula.C:
  

• resolution:
• from Resolution/resolution.C
  

• dosepr-crop.pdf: xtal-dose-profiles

-- DavidCockerill - 30-Jan-2012

• Bob-FNAL-Nov2008.pdf: Bob-FNAL-Nov2008.pdf

• PM-tube-Nuggets.pdf: PM-tube-Nuggets.pdf

• RCA-Photomultiplier_Handbook.pdf: RCA-Photomultiplier_Handbook.pdf

• proton-lyloss.png:
  

• proton-lyloss.C: proton-lyloss.C

• proton-lyloss.png:
  

• proton-lyloss.C: proton-lyloss.C

• NIM545-2005-63-Fig-15.png:
  

• NIM545-2005-63-Fig-15.png:
  

• proton-lyloss.png:
  

• proton-lyloss.C: proton-lyloss.C

• proton-lyloss.png:
  

• proton-lyloss.C: proton-lyloss.C

• Sasha-channel-response-evolution.png:
  

• BTCP-SIC-laser-corrections-study.pdf: BTCP-SIC-laser-corrections-study.pdf

• Ageing_contribution-to-resolution.png:
  

• ageing_resolution.pdf: ageing_resolution.pdf

• First-pass-Dejardin-data.pdf: New LaserFarm data

• R/R0 losses:
  

• Laser-power-scans-14March2019:
  

• Sasha-R-over-R0-predictions:
  

• Lost crystals:
  

• VPT-quantum-efficiency-vs-laser.pdf: VPT quantum efficiency vs wavelength

• VPT-quantum-efficiency-vs-laser.pdf: VPT-quantum-efficiency-vs-laser.pdf