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tuning_the_s800_xdt [2017/05/26 16:08] pereira [Timing setup] |
tuning_the_s800_xdt [2017/06/17 14:44] pereira [Object scintillator setup] |
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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 ==== | ||
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+ | * 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) | ||
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+ | {{: | ||
==== Timing setup ==== | ==== Timing setup ==== | ||
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* If necessary, adjust delays of Phillips TDC (in principle, the TACs delays don't need to be adjusted): | * If necessary, adjust delays of Phillips TDC (in principle, the TACs delays don't need to be adjusted): | ||
- | * Using the [[S800 DAQ tools# | + | * Using the [[S800 DAQ tools# |
* Connect the XFP and/or OBJ signals going to the Phillips TDC (via cables plugged to patch #66 and #67, respectively) to the scope | * Connect the XFP and/or OBJ signals going to the Phillips TDC (via cables plugged to patch #66 and #67, respectively) to the scope | ||
- | * 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 | + | * 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) |
- | * Be aware that the after adjusting OBJ and XFP delays in the scope, the signal will be further delayed by ~200 ns due to the length of the cable between dataU6 patch panel and the Phillips TDC in the S3 vault. | + | |
* Check the corresponding ToF spectra in SpecTcl to confirm that the timings are properly adjusted. | * Check the corresponding ToF spectra in SpecTcl to confirm that the timings are properly adjusted. | ||