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trigger [2013/12/11 16:24]
pereira [Begin sequence]
trigger [2013/12/11 16:38]
pereira
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 +====== Trigger ======
 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 data acquisition begin sequence of the trigger module is the following: The data acquisition begin sequence of the trigger module is the following:
-reset time stamp counter to 0 +  - reset time stamp counter to 0 
-reset trigger register to 0 +  reset trigger register to 0 
-after all modules in all crates have been initialized, send CAMAC command to set "Go" state to true +  after all modules in all crates have been initialized, send CAMAC command to set "Go" state to true 
-after a preset delay of 200 to 300 microseconds, the "Go" level is set to true +  after a preset delay of 200 to 300 microseconds, the "Go" level is set to true 
- +  
-The last step of the begin sequence allows enough time for the CCUSB crate controller to switch from its interactive mode to data acquisition mode. The end sequence script executed at the end of a run sets the "Go" state of the module back to false.+The last step of the begin sequence allows enough time for the CC-USB crate controller to switch from its interactive mode to data acquisition mode. The end sequence script executed at the end of a run sets the "Go" state of the module back to false.
  
 ====== Scalers and dead time ====== ====== Scalers and dead time ======
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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