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tuning_the_s800_xdt [2017/04/08 13:40] pereira [FP scintillator setup] |
tuning_the_s800_xdt [2017/06/17 15:03] pereira [Coincidences] |
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* Check CFD walk inspect signal in scope by triggering scope with CFD output | * Check CFD walk inspect signal in scope by triggering scope with CFD output | ||
* Ensure that CFD delay cable is ok: about 80% of raising time of the input signal | * Ensure that CFD delay cable is ok: about 80% of raising time of the input signal | ||
- | * Adjust CFD threshold looking at scalers. The ratio of OBJ to XFP scaler rates (channels OBJ.Scint and XFP.Scint) should reflect the transmission of the cocktail beam | + | * Adjust CFD threshold looking at scalers. |
+ | * With beam on/off, check amplitude of signals from OBJ. You should be able to clearly see the difference between noise signals and fragment-beam signals. | ||
+ | * Raise thresholds to get rid of noise signals. | ||
+ | * NOTE: Be aware that sometimes, after running for a while, the OBJ box is activated. This results in a non-negligible count rate in OBJ scalers with beam off, which comes from HIGH amplitude signals (not noise). DO NOT try to eliminate this " | ||
+ | * The ratio of OBJ to XFP scaler rates (channels OBJ.Scint and XFP.Scint) should reflect the transmission of the cocktail beam (between 60% to 90%, depending on quality of tunning) | ||
* Adjust MCFD threshold: | * Adjust MCFD threshold: | ||
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==== FP scintillator setup ==== | ==== FP scintillator setup ==== | ||
+ | |||
+ | * Make sure that S800 DAQ is in [[s800 daq tools# | ||
* Set trigger to “s800 trigger” | * Set trigger to “s800 trigger” | ||
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{{: | {{: | ||
+ | |||
+ | * Check **[[s800 SpecTcl|Spectcl]]** window **S800_CRDCS_EFF.win** (see figure below) to verify the efficiency of the detectors. | ||
+ | * Start a new run recording data on disk | ||
+ | * Make a gate in spectrum **ic.sum** (top right plot) to select the Z region of interest, and call it **ic** | ||
+ | * Make a summing region around the " | ||
+ | * Stop the run and rescan data from disk | ||
+ | * Compare the number of event inside the 2D summing regions with the number of events inside the **ic** gate. Typically the former are very close to the later (nearly 100% efficiency for medium/high Z) | ||
+ | |||
+ | {{: | ||
==== Timing setup ==== | ==== Timing setup ==== | ||
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* For each ToF, SpecTcl will search the hit number that fits in the selected region. The new MTDC ToF parameters are **s800.fp.vmetdc.mtdc_rf**, | * For each ToF, SpecTcl will search the hit number that fits in the selected region. The new MTDC ToF parameters are **s800.fp.vmetdc.mtdc_rf**, | ||
- | * If necessary, adjust delays: | + | * If necessary, adjust delays |
- | * Using the [[S800 DAQ tools# | + | * Using the [[S800 DAQ tools# |
- | * Select | + | * Connect |
- | * Adjust the TDC delays of OBJ and XFP using the delay boxes connected to the CANBERRA CFD 454 in data U6 | + | * Adjust the TDC delays of OBJ and/or XFP with respect to the TDC start using the delay boxes connected to the CANBERRA CFD 454 in data U6 (~200 ns delay is good) |
- | * Adjust | + | * Check the corresponding ToF spectra in SpecTcl to confirm that the timings are properly |
- | * In principle, | + | |
* Check the efficiencies of the Phillips TDC, TACs, and MTDC for the OBJ-FP and XFP-FP ToFs: | * Check the efficiencies of the Phillips TDC, TACs, and MTDC for the OBJ-FP and XFP-FP ToFs: | ||
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* Set trigger to “s800 trigger” | * Set trigger to “s800 trigger” | ||
- | * Ensure that the **[[s800 daq tools# | + | * Ensure that the **[[s800 daq tools# |
* Under trigger tab select **s800 trigger** (which is E1 up by definition) | * Under trigger tab select **s800 trigger** (which is E1 up by definition) | ||
* Deselect experiment trigger | * Deselect experiment trigger | ||
* SAVE TO FILE | * SAVE TO FILE | ||
- | * Stop and start **[[s800 daq tools#Run Control Window|RunControl]]** to assert new trigger condition | + | * Begin a new run on [[#Readout GUI|Readout GUI]] to assert new trigger condition |
* Select **[[s800 SpecTcl|Spectcl]]** window **S800_DISPMATCH.win** | * Select **[[s800 SpecTcl|Spectcl]]** window **S800_DISPMATCH.win** | ||
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* The auxiliary detector provides a secondary trigger that is fed into the S800 trigger system | * The auxiliary detector provides a secondary trigger that is fed into the S800 trigger system | ||
* A key part of setting up the S800 for such experiments is getting proper timing setup between the S800 and any auxiliary detectors | * A key part of setting up the S800 for such experiments is getting proper timing setup between the S800 and any auxiliary detectors | ||
- | * For cases where the Secondary detector has a slow response relative to the S800, the coincidence timing must be reset to the S800 timing by delaying the S800 trigger using the third gate and delay generator on the trigger GUI | + | * For cases where the Secondary detector has a slow response relative to the S800, the coincidence timing must be reset to the S800 timing by delaying the S800 trigger using the third gate and delay generator on the * [[S800 DAQ tools|trigger GUI]] |
* A typical S800 delay for SeGA is 450 ns | * A typical S800 delay for SeGA is 450 ns | ||
* Probably smaller typical S800 delay needed for HiRA | * Probably smaller typical S800 delay needed for HiRA |