tuning_the_s800_xdt
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tuning_the_s800_xdt [2015/10/21 13:57] pereira |
tuning_the_s800_xdt [2015/10/25 16:27] pereira |
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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 " | ||
| Line 14: | Line 15: | ||
| * 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 Barney | + | * Verify that the beam blocker (labeled I255 Slits) in the S3 page of Barney |
| - | * Expected " | + | * 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) | ||
| Line 54: | Line 55: | ||
| * 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** | ||
| Line 111: | Line 114: | ||
| * 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) | ||
| Line 122: | Line 126: | ||
| * 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) | ||
| Line 129: | Line 133: | ||
| * 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) | ||
| Line 145: | Line 149: | ||
| | | ||
| * 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. |
| {{: | {{: | ||
| Line 155: | Line 159: | ||
| === Timing setup === | === Timing setup === | ||
| + | |||
| + | Overview: | ||
| + | |||
| + | * 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:// | ||
tuning_the_s800_xdt.txt · Last modified: 2023/09/22 15:15 by swartzj
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