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Trigger data in 2000
--------------------

In 2000 we were reading out bit patterns, ADC, TDC, scalers, related to 
the trigger operation. You can use this information in your analysis. 
Below is the description of the channels. Ask me if you want to know more. 

D. Miskowiec, October 2001
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	Downscalers (bit patterns)
	--------------------------

The bit patterns can be used to figure out who triggered given event. 
Available in root tree as trig.pattern. Example: trig.pattern&4 is 1
if the trigger was cent. 

		byte0		byte1 
         --------------------------------
bit 0		beam		MT
bit 1		minb		SDD inj
bit 2		central		UV1
bit 3		-		UV2
bit 4		-		TPC laser
bit 5		-		-

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	Scalers
	-------

We read 3*16+1 scaler channels. The scalers were reset at the beginning 
of burst, i.e. every 20 s, except for the last channel, which was reset 
by a peak of 50 Hz, i.e. every 20 ms. Available in root tree as 
trig.scaler[49]. 

VME ECL scaler0
---------------
0.	BC1     
1.	BC2     
2.	BC3     
3.	MClow	
4.	MC	
5.	MD	
6.	VC  	
7.	VW>thr 	
8.	beam            = BC1*2          [*bbp] [*ibp] 
9.	minb            = BC1*2*^3       [*bbp] [*ibp] 
10.	central         = BC1*2*^3*MC*MD [*bbp] [*ibp] 
11.	                = BC1*2                        
12.	                = BC1*2*^3                     
13.	                = BC1*2*^3*MC*MD               
14.	beam            = BC1                          
15.	interaction     = BC1*MD                       

VME ECL scaler1
---------------
0.	burst     
1.	noburst   
2.	pulser    
3.	SDD_inj 	
4.	UV1     	
5.	UV2     	
6.	laser   	
7.
8.	MT              = pulser  [&burst] [&noburst]
9.	SDD_inj         = SDD_inj [&burst] [&noburst]
10.	UV1             = UV1     [&burst] [&noburst]
11.	UV2             = UV2     [&burst] [&noburst]
12.	laser           = laser   [&burst] [&noburst]
13.
14.
15.

VME NIM scaler2
---------------
 0.	FLT
 1.	central FLT (empty)
 2.	SDD abort attempt (empty)
 3.	beam after-protection abort attempt
 4.	inter. after-protection abort attempt
 5.	Abort
 6.	SLT
 7.	Reset
 8.     FEDC trigger
 9.	Clock 10 MHz
10.	Clock 50 Hz
11.     1.5LT
12.	SDD FADC stop
13.	
14.	
15.	

VME NIM scaler3 (reset by 50 Hz)
--------------------------------
 0.	10 MHz
 1-15.  -

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	Discriminators
	--------------

The centrality threshold on MC, 0-255 in units of 4 mV. In root tree available 
as trig.thr[4]. One of them, I think 0th, is the MC threshold used for the cent 
trigger. 

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	ADCs
	----

Three LeCroy 1182 8-channel charge ADC modules. The channels are

 0.	BC1
 1.	BC2
 2.	BC3
 3.	MC
 4.	MD

In root tree available as trig.adc[5]. In addition, a calibrated variable 
(adc-mean_adc)/sigma is provided for BC1 and BC2: trig.BC1Adc amd trig.BC2Adc. 
Cut on it to suppress beam pile-ups which has not been detected by the before/
after protection. (The before/after protection by principle will not work 
below certain separation.) 

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	TDCs
	----

Two LeCroy 1176 modules: 16 channels, common stop, multihit, 1 ns/count. 
In root tree trig.tdcn[32][2] and trig.tdc[32][2][16]. First index is channel, 
see the list below. Second is the edge: 0 - trailing, 1 - leading. Third is 
the hit number, going from 0 to tdcn[i][j]. 

trigger TDC
-----------
 0.	BC1
 1.	BC2
 2.	BC3
 3.	MC low
 4.	MC 
 5.	MD
 6.	VC
 7.	VW>thr
 8.	FLT 1 us
 9.	-
10.	TPC trigger sync (added during run)
11.	TPC trigger sync (bad, only 75 ns jitter)
12.	SDD sync TC1
13.	SDD sync TC14
14.	SDD sync TC15
15.	-

Jan's TDC
---------
 0.	FLT
 1.	-
 2.	SDD sync TC2
 3.	SDD sync TC3
 4.	SDD sync TC4
 5.	SDD sync TC5
 6.	SDD sync TC6
 7.	SDD sync TC7
 8.	SDD sync TC8
 9.	SDD sync TC9
10.	SDD sync TC10
11.	SDD sync TC11
12.	SDD sync TC12
13.	SDD sync TC13
14.	222 NIM (= FLT?)
15.	-

In addition, the calibrated variables trig.jitterForTPC and 
trig.jitterForSD[16] contain the trigger jitter correction in ns, 
centered at zero. This information is here only for checking; it 
has been already used to correct the TPC and SD data before their 
hits were made. 

In addition, the before/after protection cuts can be done using 
the calibrated variable trig.timeBC1[16] and the BC1 hit multiplicity 
trig.nBC1. Example: 

  hit = 0;
  for (i=0; i<trig.getNBC1(); i++) { // loop over BC1 hits
    if (trig.getTimeBC1(i)>-2000 && trig.getTimeBC1(i)<-1000) hit = 1; 
  }
  if (hit) {
    cout<<"This event had an additional beam particle between 1 ";
    cout<<"and 2 microseconds after the official beam particle. ";
  }


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