S800 Documentation

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trigger [2013/12/11 16:25]
pereira [Begin sequence] 		trigger [2013/12/21 07:38]
pereira [Trigger schematic]
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 +====== Trigger ======
 +
 + 
 +   * [[Trigger#Trigger schematics|Trigger schematic]]
 +     * [[Trigger#Trigger box|Trigger box]]
 +     * [[Trigger#Gate generation|Gate generation]]
 +     * [[Trigger#Inspect channels|Inspect channels]]
 +     * [[Trigger#Busy Circuit|Busy Circuit]]
 +     * [[Trigger#Time Stamping Scheme|Time Stamping Scheme]]
 +   * [[Trigger#Trigger module|Trigger module]]
 +     * [[Trigger#CAMAC commands|CAMAC commands]]
 +     * [[Trigger#Inputs and outputs|Inputs and outputs]]
 +     * [[Trigger#FPGA firmware|FPGA firmware]]
 +   * [[Trigger#Time stamping|Time stamping]]
 +   * [[Trigger#Configuration for S800 in tandem with other detectors|Configuration for S800 in tandem with other detectors]]
 +   * [[Trigger#Begin sequence|Begin sequence]]
 +   * [[Trigger#Scalers and dead time|Scalers and dead time]]
 +
 +
 The main purpose of the trigger is to implement a coincidence between the S800 focal-plane fast timing scintillator [[Detectors#Plastic scintillators|E1]] and a secondary detector principally located at the target location. This coincidence is often a mandatory requirement when the trigger rate of the S800 alone (S800 singles) is too high for the data acquisition and the resulting dead time is prohibitive.  The main purpose of the trigger is to implement a coincidence between the S800 focal-plane fast timing scintillator [[Detectors#Plastic scintillators|E1]] and a secondary detector principally located at the target location. This coincidence is often a mandatory requirement when the trigger rate of the S800 alone (S800 singles) is too high for the data acquisition and the resulting dead time is prohibitive. 
  
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 The S800 trigger from the [[Detectors#Plastic scintillators|E1 scintillator]] provides also the reference time for the [[Detectors#Cathode Readout Drift Chambers (CRDC)|CRDCs]] as well as time-of-flight measurements. Note that because the FPGA uses a 40 MHz internal clock, the time reference of the signals in the trigger circuit set the phase of that clock, and therefore jitter by 25 ns with respect to the source signals. This jitter is measured with a TDC and can be subtracted to the time measurements to recover the timing relative to the source signals.  The S800 trigger from the [[Detectors#Plastic scintillators|E1 scintillator]] provides also the reference time for the [[Detectors#Cathode Readout Drift Chambers (CRDC)|CRDCs]] as well as time-of-flight measurements. Note that because the FPGA uses a 40 MHz internal clock, the time reference of the signals in the trigger circuit set the phase of that clock, and therefore jitter by 25 ns with respect to the source signals. This jitter is measured with a TDC and can be subtracted to the time measurements to recover the timing relative to the source signals. 
  
- +===== Trigger schematics =====
-===== Trigger schematic =====+
    
 The trigger schematic is shown on the Graphical User Interface (GUI) displayed in the figure below.  The trigger schematic is shown on the Graphical User Interface (GUI) displayed in the figure below. 
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 In addition, scalers are connected to the raw and live trigger signals. For the determination of the dead time, both a free running and vetoed 10 kHz pulser signal are also connected to scalers. This is the preferred method because the pulser is not subject to possible double triggering effects like the raw trigger.  In addition, scalers are connected to the raw and live trigger signals. For the determination of the dead time, both a free running and vetoed 10 kHz pulser signal are also connected to scalers. This is the preferred method because the pulser is not subject to possible double triggering effects like the raw trigger. 
  
 +The list below is a direct copy of the scaler description file for the s800. This file maps channel names to channel numbers, and in addition determines the layout.
 +
 +^ Channel name ^ Channel number ^ Channel name ^ Channel number |
 +| Live.Trigger  ^ 10 | Raw.Trigger    ^ 9 |
 +| Live.Clock    ^ 12 | Raw.Clock      ^ 11 |
 +| S800.Source   ^ 0 | S800.Trigger   ^ 4 |
 +| Second.Source ^ 1 | Second.Trigger ^ 8 |
 +| Ext1.Source   ^ 2 | Ext1.Trigger   ^ 6 |
 +| Ext2.Source   ^ 3 | Ext2.Trigger   ^ 7 | 
 +| Coinc.Trigger ^ 5 |                ^  |
 +| E1.Up         ^ 16 | E1.Down        ^ 17 |
 +| E2.Up         ^ 18 | E2.Down        ^ 19 |
 +| CRDC1.Anode   ^ 22 | CRDC2.Anode    ^ 23 |
 +| TPPAC1        ^ 27 | TPPAC2         ^ 28 |
 +| OBJ.Scint     ^ 24 | XFP.Scint      ^ 25 |
 +| TAR.Scint     ^ 26 | XFP.Scint      ^ 25 |
 +| S800.Source   ^ 0 | OBJ.Si         ^ 26 |
 +| S800.Source   ^ 0 | OBJ.Scint      ^ 24 |
 +| S800.Source   ^ 0 | XFP.Scint      ^ 25 |
 +| Hodo.OR       ^ 30 |                ^  | 
  
  
trigger.txt · Last modified: 2023/10/24 16:47 by swartzj

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