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tuning_the_s800_xdt [2015/10/21 13:50] pereira |
tuning_the_s800_xdt [2015/10/26 13:21] 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 | * 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) | ||
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- | === Object scintillator setup === | + | ==== Object scintillator setup ==== |
* Bias detector. Typical bias: **1200-1800 V** (up to 2200 V) | * Bias detector. Typical bias: **1200-1800 V** (up to 2200 V) | ||
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* Adjust MCFD threshold: | * Adjust MCFD threshold: | ||
+ | * Open configuration file **MCFD16.tcl** in **/ | ||
* The OBJ signal feeding this module is not patched out to data U6 | * 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 (channel OBJ.MCFD.Scint) | * The OBJ signal from MCFD-16 module goes to the Mesytec MTDC32 module and scaler (channel OBJ.MCFD.Scint) | ||
- | * Adjust | + | |
+ | | ||
+ | * 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 " | |
- | * See [[http://groups.nscl.msu.edu/ | + | |
- | + | ||
- | * The TDC delays | + | |
- | * The “S800” trigger is from E1 up signal | ||
- | * Trigger | + | * Select SpecTcl window **S800_TOF.win** |
- | * There are 4 trigger inspect channels patched | + | * The three columns correspond to the **RF-FP** ToF (left), **OBJ-FP** (center), and **XFP-FP** (right) |
+ | * The first (top) row corresponds to the Phillips TDC | ||
+ | * The second row corresponds to the MTDC with all the hits included | ||
+ | * The third row corresponds | ||
+ | * The fourth row corresponds to the ORTEC TACs. Note that there is not **RF-FP TAC** | ||
+ | * The two spectra in the fifth row corresponds | ||
+ | * An empty ToF spectrum means that either the delays are not right (and need to be adjusted) or the spectrum range is too narrow | ||
+ | * The MTDC spectra should never be empty because | ||
- | * 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 | + | |
- | * Information | + | * If necessary, adjust delays: |
- | * The signal delays controlled by the GUI (and not by cable delays) are not “pipelined” -– i.e., any new signals that arrive during | + | * Using ULM GUI assign TDC-start to one of the Inspect Trigger channels |
- | * All of the trigger signals are not pipelined and are thus subject | + | * Select the timing signals (Delay inspect channels) E1 up, OBJ and XFP with the Delay GUI and look at them in the scope |
+ | * Adjust the TDC delays of OBJ and XFP using the delay boxes connected | ||
+ | * Adjust the TDC delays | ||
+ | * In principle, the TACs delays don't need to be adjusted | ||
- | === 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 === |