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tuning_the_s800_xdt [2015/10/20 14:54] pereira [Unreacted beam] |
tuning_the_s800_xdt [2015/10/21 14:03] pereira |
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=== Send beam to FP === | === Send beam to FP === | ||
+ | * Ensure that the S800 spectrograph magnets are tuned to the right rigidity | ||
+ | |||
+ | * Verify that the beam blocker (labeled I255 Slits) in the S3 page of Barney is open: | ||
+ | * Expected " | ||
* Ensure that CRAD04 (typically connected to object scintillator) is enabled with a rate limit of **20 kHz** (CRAD04 looks at E1 up FP scintillator) | * Ensure that CRAD04 (typically connected to object scintillator) is enabled with a rate limit of **20 kHz** (CRAD04 looks at E1 up FP scintillator) | ||
- | * FP rate limit: **6 kHz** | + | * Remember: S800 FP rate limit is **6 kHz** |
* **[[hv bias|Bias]]** S800 FP scintillator photomultipliers | * **[[hv bias|Bias]]** S800 FP scintillator photomultipliers | ||
* Set bias to best guess based on previous experience for the fragment Z being used (bias will be adjusted later during tuning) | * Set bias to best guess based on previous experience for the fragment Z being used (bias will be adjusted later during tuning) | ||
- | * Typical values: | + | * Typical values |
* For He-3 @ ~130 MeV/u: UP (1790 V); DOWN (1760 V) | * For He-3 @ ~130 MeV/u: UP (1790 V); DOWN (1760 V) | ||
* For Be-12 @ ~30 MeV/u: UP (1770 V); DOWN (1700 V) | * For Be-12 @ ~30 MeV/u: UP (1770 V); DOWN (1700 V) | ||
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* Remove stops to look for beam at S800 FP with **[[s800 daq tools# | * Remove stops to look for beam at S800 FP with **[[s800 daq tools# | ||
- | * Look at FP scintillator scalers (E1 up, E1 down): | + | * Look at FP scintillator scalers (E1 up, E1 down) |
- | * There are typically a few scaler counts without beam | + | * There are typically a few scaler counts without beam |
- | * Ion chamber does not have scalers | + | |
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=== Object scintillator setup === | === Object scintillator setup === | ||
- | * Use **[[electronics overview|scope]]** to look at signal patched out to data U6 (channel #54 in data U6 patch panel) | + | * Bias detector. Typical bias: **1200-1800 V** (up to 2200 V) |
- | * This signal is a copy of what goes to the CFD in the vault | + | |
+ | | ||
+ | * One of the output from this CFD is sent (via patch panel #62) to the TAC and scaler (channel OBJ.Scint) in S3. The other output | ||
+ | * Check raising time and amplitude. Good signal: ~10 ns raising time; 400-500 mV amplitude | ||
+ | |||
+ | * Using the scope, check the CFD setting: | ||
+ | * Check CFD walk inspect 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 | ||
- | * Good signal height: **400-500 mV** | + | * Adjust MCFD threshold: |
+ | | ||
+ | | ||
+ | | ||
- | * Typical bias: **1200-1800 V** (up to 2200 V) | + | |
* Watch for no rate change on scaler display with a bias adjustment up or down of about 50-100 V | * Watch for no rate change on scaler display with a bias adjustment up or down of about 50-100 V | ||
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=== FP scintillator setup === | === FP scintillator setup === | ||
- | * 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 | + | * End and Begin **[[s800 daq tools#Run Control Window|ReadoutGUI]]** to assert new trigger condition |
* Select **[[s800 SpecTcl|Spectcl]]** window **S800_SCINT.win** | * Select **[[s800 SpecTcl|Spectcl]]** window **S800_SCINT.win** | ||
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{{: | {{: | ||
- | * Gains are controlled in **s800shpini.tcl** file in directory | + | * Gains are controlled in **s800shpini.tcl** file in directory |
* First shaper is for ion chamber | * First shaper is for ion chamber | ||
* Typically, only coarse gains are used | * Typically, only coarse gains are used | ||
- | * Stop and start **[[s800 daq tools#Run Control Window|RunControl]]** to assert new gain values | + | * End and Begin **[[s800 daq tools#Run Control Window|ReadoutGUI]]** to assert new gain values |
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* Patched to data-U6 on labeled connector | * Patched to data-U6 on labeled connector | ||
* **200 – 500 mV** signals are good | * **200 – 500 mV** signals are good | ||
+ | * CRDC1 anode is noisier (digital noise) than CRDC2 | ||
* Bias CRDC1 and CRDC2. Typical starting values: | * Bias CRDC1 and CRDC2. Typical starting values: | ||
* For He-3 @ ~130 MeV/u: CRDC1 (Anode=1120 V, Drift=1000 V); CRDC2 (Anode=1120 V; Drift=1000 V) | * For He-3 @ ~130 MeV/u: CRDC1 (Anode=1120 V, Drift=1000 V); CRDC2 (Anode=1120 V; Drift=1000 V) |