4) demonstration of absolute calib algo on single particle M-C


 Goal: determine absolute calibration of BSMDE,P planes

Method: identify isolated EM shower and match BSMD cluster energy to tower energy

INPUT events: single particle per event, fixed ET=6 GeV, flat eta [-0.1,1.1], flat  |phi| <5 deg, 5k eve per sample, Geant geometry y2006

Cluster finder algo (seed is sliding fixed window), tuned on pi0 events

  • work with 150 Eta-strips per module or 900 Phi-strips at fixed eta
  • all strips are marked as 'unused'
  • use only module 13, covering ~1/3 of probed phase space
  1. sum geant dE in fixed window of 3 unused strips, snap at location which maximizes the energy
  2. if sum below 5 keV STOP searching for clusters in this module
  3. add energy from one strip on each side, mark all 1+3+1 strips as 'used'
  4. compute energy weighted  cluster position and RMS
  5. goto 1

This cluster finder process full Barrel West, more details about clustering is in one cluster topology , definition of 'barrel cell' 

Isolated EM shower has been selected as follows, tuned on gamma events,

  • select isolated eta-cluster in every segment of 15 eta strips.
  • require cluster center is at least 3 strips away from edges  of this segment (defined by eta values of 0.0, 0.1, 0.2,....0.9, 1.0)
  • require there is only one phi-cluster in the same 0.1x0.1 eta.phi cell
  • require phi-cluster center is at least 3 strips from the edges
  • find tower matching to the cross of eta & phi cluster
  • require this tower has ADC>100

Example of EM cluster passing all those criteria is below:

smdE: ene/keV= 40.6   inTw 451.or.471
 cell(15,12),   jStr=7 in xCell=15
id=1731  ene/keV=4.9  *
id=1732  ene/keV=34.3  X *
id=1733  ene/keV=1.5  *
---- end of SMDE dump

smdP: ene/keV= 28.5  inTw 471.or.472
  cell(15,12),   jStr=7 in xCell=15
id=1746  ene/keV=2.7  *
id=1756  ene/keV=22.0  X *
id=1766  ene/keV=3.7  *
---- end of SMDE dump

muDst BTOW
  id=451, m=12 rawADC=12.0 
* id=471, m=12 rawADC=643.0
  id=472, m=12 rawADC=90.0 
  id=473, m=12 rawADC=10.0 

 Results for gamma events

will be show with more details. The following PDF files contain full set of plots for all other particles.



# of eve  plots
gamma 25K  PDF
e- 50K  PDF
pi0 50K  PDF
eta 50K  PDF
pi- 50K  PDF



Fig 1, Any  Eta-cluster, single gamma,  25K events

TOP: a) Cluster (Geant) energy; b) Cluster RMS, c) # of cluster per event, 

BOTTOM: X-axis is eta location, 20 bins span eta [-1,+1]. d) cluster ene vs. eta, e) cluster RMS vs. eta, f) cluster yield vs. eta & phi.

Fig 2, Any  Phi-cluster, single gamma,  25K events

see Fig 1 for details


Fig 3, Isolated EM shower, single gamma,  90K events

TOP: a) cluster loss on subsequent cuts, b) # of accepted EM cluster vs. eta location, c) ADC distribution of hit tower (some wired gains are in default M-C), tower ADC is in ET

BOTTOM: X-axis is eta location, 20 bins span eta [-1,+1]. d) Eta-cluster , e) phi-cluster energy, f) hit tower ADC .


Fig 4, Calibration plots, single gamma,  90K events.

TOP: BSMD Eta vs. Phi  as function of pseudorapidity.
BOTTOM: BSMD vs. BTOW as function of pseudorapidity.

3  eta location of 0.1, 0.5, 0.9 of reco EM cluster  are shown in 3 panels (2x2)

1D plots are ratios of the respective 2D plots.

The  mean values of 1D fits are  relative gains of BSMDP/BSMDP and  BSMD/BTOW , determine for 10 slice in pseudorapidity. Game is over :).


Fig 5, Same as above, eta=0.1, single pi0, 50K events.


Fig 6, Same as above, eta=0.1, single pi minus, 50K events.


Below are PDF plots for all particles:

Correction - label on the X-axis for 1D plots is not correct. I did not apply log10() - a regular ratio is shown, sorry.