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trigger [2013/12/26 13:26] pereira [Trigger box] |
trigger [2014/03/11 11:18] pereira [Scalers and dead time] |
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==== Inspect channels ==== | ==== Inspect channels ==== | ||
- | A set of four inspect channels are patched out to the Data-U6 panels. Each channel can be assigned to any connection drawn on the GUI, thereby providing a convenient way to diagnose and adjust the timings at each step of the trigger circuit. | + | A set of four inspect channels are patched out to the data-U6 panels. Each channel can be assigned to any connection drawn on the GUI, thereby providing a convenient way to diagnose and adjust the timings at each step of the trigger circuit. |
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===== Trigger module ===== | ===== Trigger module ===== | ||
- | The S800 trigger logic is built in a LeCroy ULM2367 | + | The S800 trigger logic is built in a FPGA {{: |
==== CAMAC commands ==== | ==== CAMAC commands ==== | ||
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====== Time stamping ====== | ====== Time stamping ====== | ||
- | The S800 trigger provides a vetoed 10 MHz clock signal (derived from the 40 MHz FPGA clock) used for time stamping. An external clock can also be used, after selecting the appropriate check box in the [[Trigger# | + | The S800 trigger provides a vetoed 10 MHz clock signal (derived from the 40 MHz FPGA clock) used for time stamping. An external clock can also be used, after selecting the appropriate check box in the [[Trigger# |
The time stamping clock is available as an output that can be distributed to other time stamp modules, such as the one located in the S800 VME crate, or in other data acquisition systems coupled to the S800. | The time stamping clock is available as an output that can be distributed to other time stamp modules, such as the one located in the S800 VME crate, or in other data acquisition systems coupled to the S800. | ||
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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. | + | The remining 16 scaler input channels (pins 17 to 32 in module) are connected to a 16-channel CFD CAEN C808, which sends the signals from the S800 detectors (E1 up, E1 down, CRDC1, CRDC2, OBJ_SCI, A1900 SCI, and OR Hodoscopes). |
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+ | 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 | | ^ Channel name ^ Channel number ^ Channel name ^ Channel number | | ||
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| S800.Source | | S800.Source | ||
| Hodo.OR | | Hodo.OR | ||
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+ | In principle, it is possible to include other signals into the scaler channels that are not used. This requires some manipulation of tcl scripts, according to the following steps: | ||
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+ | * Modify the scaler display script to include the new signals: Go to / | ||
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+ | * Connect the new logic signals into the free input channels of the 1**6-ch CFD CAEN C808.** Follow the output ribbon cable to know the corresponding scaler channel where the new signals from the CFD are sent. | ||
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+ | * Enable the new CFD CAEN C808 channels (if they are not yet enabled): Go to / | ||
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+ | * Start the scalers display script. You should see the new channels in the display counting. If they are zero, the CFD thresholds may be too high. If that is the case, you should lower them in file **s800cfdini.tcl** (directory / | ||
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