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--- tuning_the_s800_xdt [2023/08/18 17:53]
pereira [Object scintillator setup]
+++ tuning_the_s800_xdt [2023/08/18 17:59]
pereira [Object scintillator setup]
@@ Line 54: / Line 54: @@
       * Adjust threshold to minimize noise
       * Check if MCFD output displays signals triggered by reflections (~300 ns following main peak). If that is the case, increase thresholds or signal width (this is valid only for low-rate experiments)
+      * Measure OBJ in scalers and compare it with DB5. Does it make sense?
+      * Stop beam and verify background (it should be minimum)
-      * The OBJ signal from MCFD module goes to the Mesytec MTDC module and scaler (channel OBJ.MCFD.Scint)
+  * Using the scope, check settings of DU4 CFD (used for TAC):
-      * Make sure that the threshold of the XFP MCFD channel is reasonable. Rates in scaler channels XFP.Scint and XFP.MCFD.Scint should be comparable
+      * Check CFD walk: inspect signal in scope by triggering scope with CFD output
-      * Adjust MCFD OBJ threshold looking at scalers. The ratio of OBJ to XFP scaler rates (channels OBJ.MCFD.Scint and XFP.MCFD.Scint) should reflect the transmission of the cocktail beam
+      * Ensure that CFD delay cable is ok: about 80% of raising time of the input signal
-      * Save new threshold in configuration file **MCFD16.tcl**
+      * Trigger oscilloscope with CFD output, and check analog signals
+      * Adjust threshold to minimize noise
+      * Check if CFD output displays signals triggered by reflections (~300 ns following main peak). If that is the case, increase thresholds or signal width (this is valid only for low-rate experiments)
+      * Measure OBJ in scalers and compare it with DB5. Does it make sense?
+      * Stop beam and verify background (it should be minimum)
-  * Using the scope, check the CFD setting:
+  * NOTE:
-      * Check CFD walk inspect signal in scope by triggering scope with CFD output
+      * 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 "activation" counts by raising the thresholds because that would reduce the efficiency of the detector. Instead, evaluate this activation background rate.
-      * Ensure that CFD delay cable is ok: about 80% of raising time of the input signal
+      * The ratio of OBJ to ARIS (DB5) 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 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 "activation" counts by raising the thresholds because that would reduce the efficiency of the detector.
-          * 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)
-  * Watch for no rate change on scaler display with a bias adjustment up or down of about 50-100 V
 ==== FP scintillator setup ====

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