03 tagging desynchronized capID


BPRS Polygraph detecting corrupted capIDs.

Goal: tag events with desynchronized CAP id, find correct cap ID


  1. build ped(capID, softID)
  2. pick one BPRS crate (19W)
  3. compute chi2/dof for  series capID+/-2
  4. pick 'best'  capID with smallest chi2/dof
  5. use pedestals for best capID for this crate for this event
  6. if best capID differs from nominal capID call this event 'desynchronized & fixed'

Input: 23K st_physics events from run 9067013.

For technical reason limited range of nominal capID=[122,126] was used, what reduces data sample to 4% ( 5/128=0.04).


Fig 1. ADC-ped(capID,softID) vs. softID for crate 1 (i.e. PSD19W) as is'. No capID corruption detection


Fig 2. ADC-ped(capID,softID) with capID detection & correction enabled. The same events.


Note, all bands are gone - the capID fix works.

Right: ADC-ped spectra: Black: 594 uncorrupted  events, red: 30 corrupted & fixed events.


The integral for ADC[10,70] are 2914 and 141 for good and fixed events, respectively.

141/2914=0.048;  30/594=0.051 - close enough to call it the same (within stats).





Fig 3. Auxiliary plots. 


TOP left: chi/dof for all events. About 1100 channels is used out of 1200 in served by crate 1. Rejected are bad & outliers.

TOP right: change of chi2/dof for events with corrupted & fixed capID. 

BOTTOM: frequency of capID for good & fixed events, respectively.




  • BPRS-Polygraph algo efficiently identifies and corrects BPRS for corrupted capID, could be adopted to used offline .
  • there is no evidence ADC integration widow changes for BPRS data with corrupted capID.   



Table 1.

shows capIDs for the 4 BPRS crates for subsequent events. Looks like for the same event cap IDs are strongly correlated, but different.
Conclusion: if we discard say capID=125, we will make hole of 1/4 of barrel , different in every event. This holds for BPRS & BSMD.

capID= 83:89:87:90: eve=134 
capID= 1:4:11:3: eve=135 
capID= 74:74:81:72: eve=136 
capID= 108:110:116:110: eve=137 
capID= 68:72:73:75: eve=138 
capID= 58:55:65:64: eve=139 
capID= 104:110:106:101: eve=140 
capID= 9:6:8:15: eve=141 
capID= 43:37:47:46: eve=142 
capID= 120:126:118:122: eve=143 
capID= 34:41:41:40: eve=144 
capID= 3:0:126:2: eve=145 
capID= 28:33:28:30: eve=146 
capID= 72:64:70:62: eve=147 
capID= 2:6:7:5: eve=148 
capID= 22:32:33:24: eve=149 
capID= 8:4:5:124: eve=150 
capID= 23:17:17:19: eve=151 
capID= 62:57:63:61: eve=152 
capID= 54:53:45:47: eve=153 
capID= 68:75:70:67: eve=154 
capID= 73:79:73:72: eve=155 
capID= 104:98:103:103: eve=156 
capID= 12:5:13:10: eve=157 
capID= 5:10:10:2: eve=158 
capID= 32:33:27:22: eve=159 
capID= 96:102:106:97: eve=160 
capID= 79:77:72:77: eve=161