1. HCAL DPG News Sunanda Banerjee – SINP Olga Kodolova – SINP MSU
June 7, 2012
June, 7 HCAL General
S. Banerjee, O. Kodolova

2. HBHE drift from 2011 to 2012
HCAL General Meeting
June, 7

3. PMT gain loss in 2012 We prepared chain for per week
LED corrections but, seems,
drift start to be slower
PMT gain drop ~3% per 1/fb
For the first 2012 week
Multianode PMT are stable.
HCAL General Meeting
June, 7

4. Radiation damages
HCAL General Meeting
June, 7

5. Phi-symmetry HF calibration (2012)
Without 29, 41
With 29, 41
Calibration group
- HF rings are phi-symmetric within 2%
- results of intercalibration doesn't allow to improve something
- indications that precision of Iterative method in 2012 is worse w.r.t. 2011
HCAL General Meeting
June, 7

6. Z->ee correction
Need to account for possible radiation damage losses in HF
LHC providing lots of data (20 fb this year ?) calibration passes?
2012 trigger improvement
- L1 seeding using ECAL only
- ECAL+HF selection in HLT
Clear evidence of Z->ee peak
With first data
(up to 20th of May
HCAL General Meeting
June, 7

7. Isolated tracks Re-examine the PU contamination in 2012 data
Make adjustment to the
trigger to ensure it can
collect useful data in the 2012 environment and beyond
HCAL General Meeting
June, 7

8. HBHE timing
PFG studies
HCAL General Meeting
June, 7

9. HO issues
HO response correction file is generated and will be included after ICHEP
PFG studies
HCAL General Meeting
June, 7

10. HF simulation Currently there are 3 options for HF simulation:
Using shower library (cannot simulate PMT hits)
Full Geant4 simulation (too time consuming)
Hybrid parameterization (Geant4+Gflash/showerlibrary)
Now introduce identical fiducial volume cut (gaps between the wedges and some non-existing fibre locations) for all three options
Also introduce some aperture cut in the parameterized approach for photons from the non-EM component.
Some differences in
long. shower profile
Investigation
continues
1 TeV π־
1 TeV e־
HCAL General Meeting
June, 7
z (mm)
z (mm)

11. Back-up
HCAL General Meeting
June, 7

12. Radiation damages in HF: fibers
2011
Only HFM
2012
Latest results confirm raddam observation
In 2011
A.Volkov, D.Elumahov
HCAL General Meeting
June, 7

13. Consequences of HF losses
PMT gain loss starts to be the issue and high voltage may need to be lowering – need to verify the effect of S/N change to jet/met reconstruction
Request for MC samples with the 3 times gain change was ordered to estimate the effect on the jet/met reconstruction
Radiation damages of fibers need to be corrected. As rough estimation the sqrt of raddam measurement may be taken as the correction factor.
HCAL General Meeting
June, 7

14. Calibration procedure from 2011 to 2012
HPD and PMT gain drift
HPD gain drift correction once per month (as in 2011)
PMT gain drift correction once per week (roughly each ~1/fb) due to much
higher degradation rate of gains in PMT (change w.r.t. 2011)
HF Fibers degradation
Radiation damage correction in HF based on the radiation damage
measurements once per month (depends on the measurement)
(change w.r.t. 2011)
We consider HF is correctly calibrated with Z->ee corrections for the 2012 startup
The above corrections as HcalGain condition IOV will be uploaded by creation to _express, _prompt and _offline tags and (by agreement) to _hlt tag
HCAL General Meeting
June, 7

15. Calibration procedure (continuation)
phi-symmetry corrections with iterative and NZS method (as in 2011) during technical stops while the needed statistics is available
Isolated track calibration (as in 2011) during technical technical stops
while the needed statistics is available
Absolute scale in HF with Z->ee corrections (Long fibers). Short fibers will be calibrated using Long fibers calibration and MC correction for ratio between Long and short taking into account RadDam estimation for Short fibers
The above corrections as HcalRespCorrs condition IOV will be uploaded by approval to_express, _prompt, _offline and _hlt tags
HCAL General Meeting
June, 7

16. Sercan Sen, Lev Kheyn, Rahmat Rahmat
HF simulation
Sercan Sen, Lev Kheyn, Rahmat Rahmat
Looks like better
Performed Shower
library then Gflash
But dead zones in
HF are not included
More difference in
Short fibers then in
Long fibers
Difference in eta
Dependence between
Data and MC seen
In energy flow
Overall problem: we do
not have process that
can calibrate Short fibers
HCAL General Meeting
June, 7

17. HBHE filter performance
Alex Mott
1. HCAL Noise filters were deployed on MET paths last year (vetoing RBX noise flagged events with little other energy except RBX noise candidate)
These filters started to be ineffective with increasing PU.
: the new approach: try to remove the HCAL noise and evaluate the underlying event
(underlying MET, for now)
The behavior of filter with the first data is as expected: reduction of MET rates by 50-70%..
Need the provement that it is safe for physics.
HCAL General Meeting
June, 7

18. HO: ring0 + ring1
Including Ring0 and Ring1 improve slightly jet and MET resolution (talks from Gobinda and Caroline at the last HCAL DPG, 27th of April)
Need to introduce HO both in PF and Calo
Data certification for Ring0 and Ring1 started
ChannelQuality status was updated yesterday/today to be included in 600pre4 for MC simulation with 530
HCAL General Meeting
June, 7

19. LUT regeneration Recalibration was done with iterative and NZS methods
Combined tag with coefficients was added as IOV to the Resp Corrections tag for LUT regeneration
Pablo did LUT generation/Validation
New LUTs were reported at L1 DPG and uploaded to DB before VdM scan (before 16th of April)
HCAL General Meeting
June, 7