CAL Energy Calibrations

Run 700000460 : CPT calu_collect_mu

Results Status: OK

Note: Whatever is highlighted above in red indicates the status of the data analysis results for this run.  Experts are expected to update this page and highlight the right status. 

Muon peaks seen by David Paneque indicate that the calibration is roughly correct, yet there is an overall 10% discrepancy from the expected values. The discrepancy in the individual layers could go up to 15-20%. See presentation in VRVS meeting

David stressed that the analysis is very rough, and that a more detailed analyis is required to evaluate precisely the calilbration
constants.

His selection cuts are very simple:

• TkrNumTracks == 1
• Tkr1Hits > 20
• TMath::Abs((acos(Tkr1ZDir)*(180./3.14159))-180.) < 20
• GltTower == 2 (3) ; This is used to select rougly events hiting the calorimeter of the 2 (3) tower.

Philippe Bruel argues that the muon peaks are not correct and uses the this root macro. 

His selection cuts are

• Tkr1Z0>0 && CalCsIRLn>0 and :
• for tower2 and 3, I require that the trajectory of the muon crosses the top plane and bottom plane of the calorimeter not more than 150mm from the center (in X and Y);

For calenergyraw.ps  he has 4 plots

• CalEnergyRaw corrected for path length (tower2 in black, tower 3 in red);
• Tkr1ZDir distribution
• profile CalEnergyRaw versus Tkr1ZDir (tower 2)
• profile CalEnergyRaw versus Tkr1ZDir (tower 3)

You can see the correlation between CalEnergyRaw and Tkr1ZDir. The CalEnergyRaw distributions for tower2 and 3 are similar.

For calelayer.ps : -Tkr1ZDir*CalELayer distributions (tower2 in black, tower 3 in red)

The distributions are no longer similar for tower 2 and 3, and there is a clear indication that the calibration is either wrong or not applied.

calelog_tower2.ps and calelog_tower3.ps:

For each layer, -Tkr1ZDir*CalELayer? versus the direction perpendicular to the log axis (so you have 12 bins for the 12 logs). Each column (i.e log) is scaled independently such that the max scale (red) corresponds to the bin that has the maximum of entries. So if the calibration is good, all the red bins should be around 11MeV, which is clearly not the case.

I'm not an expert of the calibration, so can someone comment on that ?

Runs 700000276 to 286, 700000490 to 500 : BT13

BT configuration: 4 range readout, no Zero suppression, muon Gain, CAL_LO 15MeV 

More muon peaks: 

David had another quick look to the runs proposed by Johan in an e-mail sent to the beamlist on July 18, 2006.

Those are runs  700000276 to 700000286 and runs 700000490 to 700000500. 

For simplicity (and to be quick) he used the same cuts he used before. That is: 

• TkrNumTracks == 1
• Tkr1Hits > 20
• TMath::Abs((acos(Tkr1ZDir)*(180./3.14159))-180.) < 20
• GltTower == 2 (3) ; This is used to select rougly events hiting the calorimeter of the 2 (3) tower.

Somehow, in ALL those runs the location of the muon peaks is wrong by more than a factor 2.

Below plots are provided for run 280 and 495. All runs are very similar. 

It seems that the calibration of the calorimeter was not properly performed for these runs. Any idea of what went wrong ?  

Run 280 

Energy (raw) deposited in "tower 2": ps file gif file

Energy (raw) deposited in "tower 3" : ps file ps file

Energy (raw) deposited in "single layers of tower 2" : ps file gif file

Energy (raw) deposited in "single layers of tower 3" : ps file gif file

Run 495 

Energy (raw) deposited in "tower 2": ps file gif file

Energy (raw) deposited in "tower 3" : ps file gif file

Energy (raw) deposited in "single layers of tower 2" : ps file gif file

Energy (raw) deposited in "single layers of tower 3" : ps file gif file