HCal MIP Calibration
MIP calibration constants have units [ADUp/Mip], where ADUp are ADC unit in physics mode and a Mip is defined by the most probable value of the spectrum recorded from the passage of a minimum ionizing particle at normal incidence. The constants are made available in the database in folder
/cd_calice/Hcal/mip_constants
These calibration parameters are temperature dependent. The slopes dMip/dT for each channel are stored in the database folder
/cd_calice/Hcal/mip_slopes
Every entry gets tagged to allow permanent reference. Users are encouraged to use tags rather than the HEAD, i.e. make sure they know which assumptions are valid on the constants they use.
Tag description: mip_constants
Tag 
Time / HV Period 
Description 
ahc_mip_constants_001 
2006  2009 
Mip values at 0 degress centigrade extracted from linear fit to CERN 2007 measurements. Mip coefficients for linear fit extracted by Andrea. 
ahc_mip_constants_002 
C06 
same as ahc_mip_constants_001 
C07 
mip values extracted by Andrea from runs 330254, 330255, 330256, 330257, 330258. 

F081 
Values from period F082 (valid for different voltage settings). Only commissioning data in this period. 

F082 
mip values extracted by Andrea from runs 500105, 500106, 500107 

F083 
mip values extracted by Andrea from runs 500278, 500279, 500285, 500286, 500293, 500300, 500305, 500306. Only one muon per event is used for calibration, additional muons are rejected. 

F084 
mip values extracted by Andrea from runs 530741, 530742, 530744, 530745, 530746, 530747, 530762, 530763, 530764, 530765, 530766, 530767, 530768, 530770. Value for hot cell (signal too high in online monitor; module 4, chip 2, channel 15) removed manually. 

ahc_mip_constants_003 
C06 
same as ahc_mip_constants_001 
C07 
average of mip values extracted by Boris for runs 330254, 330255, 330256, 330257, 330258. 

F081 
Empty. Only commissioning data in this period. 

F082 
same as ahc_mip_constants_002 

F083 
same as ahc_mip_constants_002 

F084 
same as ahc_mip_constants_002 

ahc_mip_constants_004 
2006  2009 
Copy of ahc_mip_constants_001, added default mip value to collection parameters (default = 100000) 
ahc_mip_constants_005 
2006  2009 
Copy of ahc_mip_constants_002, added default mip value to collection parameters (default = 100000) 
ahc_mip_constants_006 
2006  2009 
Copy of ahc_mip_constants_003, added default mip value to collection parameters (default = 100000) 
ahc_mip_constants_007 
C06 
same as ahc_mip_constants_001 
C07 
mip values extracted by Boris with likelihood fit to merged histograms from runs 330254, 330255, 330256, 330257, 330258. 

F081 
empty 

F082 
mip values extracted by Boris with likelihood fit to merged histograms from runs 500105, 500106, 500107 (WARNING: low statisitcs, large errors!) 

F083 
mip values extracted by Boris with likelihood fit to merged histograms from runs 500278, 500279, 500285, 500286, 500293, 500300, 500305, 500306. Only one muon per event is used for calibration, additional muons are rejected. 

F084 
mip values extracted by Boris with likelihood fit to merged histograms from runs 530741, 530742, 530744, 530745, 530746, 530747, 530762, 530763, 530764, 530765, 530766, 530767, 530768, 530770 

ahc_mip_constants_008 
C06 
same as ahc_mip_constants_001 
C07 
same as ahc_mip_constants_007 

F081 
Values from period F083 (valid for different voltage settings). Only commissioning data in this period. 

F082 
same as ahc_mip_constants_007 

F083 
same as ahc_mip_constants_007 

F084 
same as ahc_mip_constants_007 

C10 
Values from period C07 (same voltage settings) 

ahc_mip_constants_009 
C06 
same as ahc_mip_constants_001 
C07 
same as ahc_mip_constants_007 

F081 
same as ahc_mip_constants_008 

F082 
same as ahc_mip_constants_007 

F083 
same as ahc_mip_constants_007 

F084 
same as ahc_mip_constants_007 

F09 
same as ahc_mip_constants_008 

C10 
mip values extracted by Andrea, Angela ... 

C11 
mip values from C07 

ahc_mip_constants_010 
C06 
same as ahc_mip_constants_001 
C07 
same as ahc_mip_constants_007 

F081 
same as ahc_mip_constants_008 

F082 
same as ahc_mip_constants_007 

F083 
same as ahc_mip_constants_007 

F084 
same as ahc_mip_constants_007 

F09 
same as ahc_mip_constants_008 

C10 
same as ahc_mip_constants_009 

C11 
mip values updated with the testbeam muon runs by CERN group 

ahc_mip_constants_011 
C06 
same as ahc_mip_constants_001 
C07 
mip constants value same as ahc_mip_constants_007, and reference temperature correction with median filter by Sergey, and AhcMedianFilterTempProvider will be used for the data to provide the corrected temperature at the same time 

F081 
same as ahc_mip_constants_008 

F082 
same as ahc_mip_constants_007 

F083 
same as ahc_mip_constants_007 

F084 
same as ahc_mip_constants_007 

F09 
same as ahc_mip_constants_008 

C10 
same as ahc_mip_constants_009 

C11 
mip values updated with the testbeam muon runs by CERN group 
Tag description: mip_slopes
Tag 
Time / HV Period 
Description 
ahc_mip_slopes_001 
2006  2009 
Absolute slopes extracted from linear fit to CERN 2007 measurements. mip coefficients for linear fit extracted by Andrea. 
ahc_mip_slopes_002 
C06 
same as ahc_mip_slopes_001 
C07 
For each channel: slope = 3.8%/K (average relative dependence) * mip constant (from ahc_mip_constants_002) 

F081 

F082 

F083 

F084 

ahc_mip_slopes_003 
2006  2009 
Copy of ahc_mip_slopes_001, added default slope to collection parameters (default = 0) 
ahc_mip_slopes_004 
2006  2009 
Copy of ahc_mip_slopes_002, added default slope to collection parameters (default = 0) 
ahc_mip_slopes_005 
C06 
same as ahc_mip_slopes_001 
C07 
For each channel: slope = 3.7%/K (average relative dependence) * mip constant (from ahc_mip_constants_007) 

F081 
 empty  

F082 
For each channel: slope = 2.4%/K (average relative dependence) * mip constant (from ahc_mip_constants_007) 

F083 
For each channel: slope = 2.4%/K (average relative dependence) * mip constant (from ahc_mip_constants_007) 

F084 
For each channel: slope = 2.4%/K (average relative dependence) * mip constant (from ahc_mip_constants_007) 

ahc_mip_slopes_006 
C06 
same as ahc_mip_slopes_001 
C07 
For each channel: slope = 3.7%/K (average relative dependence) * mip constant (from ahc_mip_constants_008) 

F081 
Values from period F083 (valid for different voltage settings). Only commissioning data in this period. 

F082 
For each channel: slope = 3.1%/K (average relative dependence) * mip constant (from ahc_mip_constants_008) 

F083 
For each channel: slope = 3.1%/K (average relative dependence) * mip constant (from ahc_mip_constants_008) 

F084 
For each channel: slope = 2.3%/K (average relative dependence) * mip constant (from ahc_mip_constants_008) 

C10 
Values from period C07 (same voltage settings) 

ahc_mip_slopes_007 
C06 
same as ahc_mip_slopes_001 
C07 
same as ahc_mip_slopes_006 

F081 
same as ahc_mip_slopes_006 

F082 
same as ahc_mip_slopes_006 

F083 
same as ahc_mip_slopes_006 

F084 
For each channel: slope = 3.4%/K (average relative dependence) * mip constant (from ahc_mip_constants_009) 

F09 
For each channel: slope = 3.4%/K (average relative dependence) * mip constant (from ahc_mip_constants_009) 

C10 
For each channel: slope = 3.7%/K (average relative dependence) * mip constant (from ahc_mip_constants_009) 

C11 
value from C07 

ahc_mip_slopes_008 
C06 
same as ahc_mip_slopes_001 
C07 
same as ahc_mip_slopes_006 

F081 
same as ahc_mip_slopes_006 

F082 
same as ahc_mip_slopes_006 

F083 
same as ahc_mip_slopes_006 

F084 
same as ahc_mip_slopes_007 

F09 
same as ahc_mip_slopes_007 

C10 
same as ahc_mip_slopes_007 

C11 
TODO: get the information from the provider? 
outdated MIP calibration folders
The tags of some outdated MIP calibration folders are still listed here.
How to obtain a MIP calibration
Individual MIP calibration constants for each SiPM, can be obtained using muon runs taken at the test beam area. Two Marlin processors and a fitting procedure are needed to obtain the MIP values.
A summary of the muon runs collected in CERN 2007, FNAL 2008 and FNAL 2009 can be found here HCAL MuonRuns.
Reconstruction of the muon track
TrackFinder is a Marlin processor which identifies miplike tracks using muon runs. It finds all muon tracks in the event if a tower of at least N entries is found. N is a steering parameter. The discrimination of signal hits to noise hits uses a 0.5 MIP cut. Therefore, initial MIP values like initialMips.txt have to be provided.
This processor returns a collection of calorimeter tracks. Each calorimeter track is build by hits where information on "module, chip, channel" and "amplitude" in units of [ADC] is stored.
A steering example for processing 2007 and 2008 muon data, you can find here muonTrack2007.txt, muonTrack2008.txt.
Creation of Histograms
Histograms are created with the CellAnalysisProcessor, it takes as input the calorimeter track collection defined by the TrackFinderProcessor. The binning and the intervals required to define the histograms are steering parameters. A root file containing 7608 histograms is produced. A steering example can be found here cellAnalysis.txt
Fitting Procedure
The last step involves the fitting of the histograms. A convolution of Gaussian and Landau distribution is used to fit the MIP spectra.