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tuning_the_s800_xdt [2015/10/20 14:54] pereira [Reaction Setting] |
tuning_the_s800_xdt [2015/10/26 12:00] pereira [Timing setup] |
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====== Focus Mode ====== | ====== Focus Mode ====== | ||
For most of the experiments in the S800, the analysis line is run in focus mode. In this optics, the analysis line is achromatic, i.e. the dispersive position of the beam focused in the target area (pivot point) does not depend on the momentum. Thus, this mode provides the biggest momentum acceptance (4%). On the other hand, since the spectrograph focal plane is chromatic, the resolution is limited to about 1 part in 1000 in energy. | For most of the experiments in the S800, the analysis line is run in focus mode. In this optics, the analysis line is achromatic, i.e. the dispersive position of the beam focused in the target area (pivot point) does not depend on the momentum. Thus, this mode provides the biggest momentum acceptance (4%). On the other hand, since the spectrograph focal plane is chromatic, the resolution is limited to about 1 part in 1000 in energy. | ||
+ | |||
===== Unreacted beam ===== | ===== Unreacted beam ===== | ||
In the first part of the XDT, the rigidity of the S800 is typically set to match the value of the fragment beam (selected in the A1900) after passing through the S800 target. This is where the term " | In the first part of the XDT, the rigidity of the S800 is typically set to match the value of the fragment beam (selected in the A1900) after passing through the S800 target. This is where the term " | ||
- | === 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 | + | |
- | === Object scintillator setup === | ||
- | * Use **[[electronics overview|scope]]** to look at signal patched out to data-U6 | + | ==== Object scintillator setup ==== |
- | * This signal is a copy of what goes to the CFD in the vault | + | * Bias detector. Typical bias: **1200-1800 V** (up to 2200 V) |
- | * Good signal | + | * Use **[[electronics overview|scope]]** to look at signal |
+ | | ||
+ | | ||
+ | * Check raising time and amplitude. Good signal: ~10 ns raising time; 400-500 mV amplitude | ||
+ | |||
+ | | ||
+ | * 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 | ||
+ | | ||
- | * Typical bias: **1200-1800 V** (up to 2200 V) | + | * Adjust MCFD threshold: |
+ | | ||
+ | * The OBJ signal feeding this module is not patched out to data U6 | ||
+ | * The OBJ signal from MCFD-16 module goes to the Mesytec MTDC32 module and scaler | ||
+ | * 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 | ||
+ | * 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 | ||
+ | * Save new threshold in configuration file **MCFD16.tcl** | ||
+ | |||
* 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 | ||
- | === 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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- | === Ionization Chamber setup === | + | ==== Ionization Chamber setup ==== |
* Gas should be [[Gas handling system# | * Gas should be [[Gas handling system# | ||
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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 |
- | === CRDCs setup === | + | ==== CRDCs setup ==== |
* **[[hv bias#hv remote control|Bias]]** CRDCs | * **[[hv bias#hv remote control|Bias]]** CRDCs | ||
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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) | ||
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* Count rate is a little higher than on scintillator due to noise or thresholds | * Count rate is a little higher than on scintillator due to noise or thresholds | ||
- | * Check **[[s800 SpecTcl|Spectcl]]** window **S800_CRDCS.win** to verify the good performance of the detectors. (The spectra for each CRDC can be checked separatelly in windows **s800_CRDC1.win** and **S800_CRDC2.win**) | + | * Check **[[s800 SpecTcl|Spectcl]]** window **S800_CRDCS.win** |
* Spectra **crdc1.raws** and **crdc2.raws** (top and middle spectra in the leftmost (first) column) | * Spectra **crdc1.raws** and **crdc2.raws** (top and middle spectra in the leftmost (first) column) | ||
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* Width of beam peak is proportional to A1900 p-acceptance in focus optics | * Width of beam peak is proportional to A1900 p-acceptance in focus optics | ||
* Width is narrower in match optics | * Width is narrower in match optics | ||
- | * Adjust anode HV to bring fuzzy maximum to around 600-700 channels (the ADC for each pad saturates | + | * Adjust anode HV to bring fuzzy maximum to around 600-700 channels (saturation of each pad at ~ 1000 ch) |
* Spectra **crdc1.anode_crdc1.tac** and **crdc2.anode_crdc2.tac** (top and middle spectra in the second column) | * Spectra **crdc1.anode_crdc1.tac** and **crdc2.anode_crdc2.tac** (top and middle spectra in the second column) | ||
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| | ||
* Spectra **crdc1.xg** and **crdc2.xg** (bottom spectra in first and second columns) | * Spectra **crdc1.xg** and **crdc2.xg** (bottom spectra in first and second columns) | ||
- | * It shows the position of the beam in the dispersive direction, evaluated by calculating the " | + | * It shows the position of the beam in the dispersive direction, evaluated by calculating the " |
* Spectra **crdc1.tac** and **crdc2.tac** (bottom spectra in third and fourth columns) | * Spectra **crdc1.tac** and **crdc2.tac** (bottom spectra in third and fourth columns) | ||
- | * They correspond to the non-dispersive position of the beam in the CRDCs. | + | * They correspond to the non-dispersive position of the beam in the CRDCs. |
{{: | {{: | ||
- | === Timing setup === | + | ==== Timing setup ==== |
+ | At present, there are three electronic " | ||
+ | |||
+ | * Although the ToF reference (" | ||
+ | * Before going to the ToF modules, the OBJ and XFP signals are sent to a CANBERRA CFD 454 CFD in data U6 from the data-U6 patch panel (OBJ: patch panel #54, XFP: patch panel #1). (The exception is the OBJ signal into the MTDC) | ||
+ | * MTDC: | ||
+ | * Before getting into the MTDC, the OBJ, XFP, and E1 up signals in the MTDC go through a Mesytec MCFD | ||
+ | * The OBJ signal into the MCFD comes directly from the detector via S3 patch panel #94 (i.e., there is no signal to check in data U6) | ||
+ | * The XFP signal into the MCFD module comes from data-U6 patch panel #70, connected to the CANBERRA 454 CFD XFP output | ||
+ | * SpecTcl calculates the OBJ-to-Focal-Plane and XFP-to-Focal-Plane ToFs by substracting the E1 up time (MTDC channel 15) to the OBJ time (MTDC channel 3) and the XFP time (MTDC channel 2) | ||
+ | * The MTDC timing signals do not require external delay adjustments because the matching window is sufficiently wide | ||
+ | * Tennelec TACs: | ||
+ | * The OBJ **stop** signal to the " | ||
+ | * The XFP **stop** signal to the " | ||
+ | |||
+ | * Phillips TDC: | ||
+ | * The OBJ output signal from the CANBERRA 454 CFD is delayed with the low-noise delay boxes in data-U6, and sent to the TDC via patch panel #67 | ||
+ | * The XFP output signal from the CANBERRA 454 CFD is delayed with the low-noise delay boxes in data-U6, and sent to the TDC via patch panel #66 | ||
+ | * SpecTcl calculates the OBJ-to-Focal-Plane and XFP-to-Focal-Plane ToFs by substracting the E1 up time (channel 8) to the OBJ time (channel 14) and the XFP time (channel 15) | ||
+ | |||
+ | * The TDC start is sent from the ULM trigger module. Since the delay of the S800 trigger may be adjusted during XDT, the stop signals (e.g. from OBJ or XFP) will need to be re-adjusted. | ||
+ | |||
+ | * Examine the timing of each of the selectable listed signals with respect to the “Live Trigger” signal | ||
+ | * There are 4 TDC inspect channels patched to data-U6 that can be assigned using the trigger GUI | ||
+ | * The full range of the TDC is 400 ns | ||
+ | * Set each timing to 200 ns | ||
+ | * TDCs of last 4 listed signals (including XF and object scintillators) are bypassed with cable delays inside the vault and thus their delays cannot be controlled with the GUI | ||
+ | * They can be inspected, however using the GUI | ||
+ | |||
+ | |||
+ | * The TDC delays can only be changed when the run control is stopped; must SAVE settings before starting run control not to overwrite adjustments being made | ||
+ | |||
+ | * Trigger the scope with the “Live Trigger” signal patched to data-U6 | ||
+ | * There are 4 trigger inspect channels patched to data-U6 that can be assigned using the trigger GUI | ||
+ | |||
+ | * Examine the timing of each of the selectable listed signals with respect to the “Live Trigger” signal | ||
+ | * There are 4 TDC inspect channels patched to data-U6 that can be assigned using the trigger GUI | ||
+ | * The full range of the TDC is 400 ns | ||
+ | * Set each timing to 200 ns | ||
+ | * TDCs of last 4 listed signals (including XF and object scintillators) are bypassed with cable delays inside the vault and thus their delays cannot be controlled with the GUI | ||
+ | * They can be inspected, however using the GUI | ||
* See [[http:// | * See [[http:// | ||
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* All of the trigger signals are not pipelined and are thus subject to deadtime | * All of the trigger signals are not pipelined and are thus subject to deadtime | ||
- | === Checking Particle ID and rate at S800 FP === | + | ==== Checking Particle ID and rate at S800 FP ==== |
* Establish PID | * Establish PID | ||
* Refer to information on setting from A1900 FP | * Refer to information on setting from A1900 FP | ||
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- | === Analysis line classic PPAC setup (Focus optics only) === | + | ==== Analysis line classic PPAC setup (Focus optics only) ==== |
* " | * " | ||
* Classic PPACs have rate limitations from pileups | * Classic PPACs have rate limitations from pileups | ||
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- | === Setup beamline === | + | ==== Setup beamline |
* Object and XF scintillators and intermediate image PPACs inserted if they will be used | * Object and XF scintillators and intermediate image PPACs inserted if they will be used | ||
* If Object scintillator will not be used, there is no reason to look at beam on it unless to debug a problem with the transmission | * If Object scintillator will not be used, there is no reason to look at beam on it unless to debug a problem with the transmission | ||
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* Set spectrograph Brho for unreacted fragment | * Set spectrograph Brho for unreacted fragment | ||
- | === Start scalers === | + | ==== Start scalers |
* Use s800 account | * Use s800 account | ||
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* scalers (gives error if no bridge) | * scalers (gives error if no bridge) | ||
- | === Setting Optimization === | + | ==== Setting Optimization |
=== Focused optics === | === Focused optics === |