tuning_the_s800_xdt
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tuning_the_s800_xdt [2015/10/21 14:05] pereira |
tuning_the_s800_xdt [2015/10/26 13:57] pereira [Checking Particle ID and rate at S800 FP] |
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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 | ||
| Line 39: | Line 40: | ||
| - | === 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) | ||
| 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** | ||
| * 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” | ||
| Line 83: | Line 86: | ||
| - | === Ionization Chamber setup === | + | ==== Ionization Chamber setup ==== |
| * Gas should be [[Gas handling system# | * Gas should be [[Gas handling system# | ||
| Line 105: | Line 108: | ||
| - | === CRDCs setup === | + | ==== CRDCs setup ==== |
| * **[[hv bias#hv remote control|Bias]]** CRDCs | * **[[hv bias#hv remote control|Bias]]** CRDCs | ||
| Line 130: | 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 146: | 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. |
| {{: | {{: | ||
| - | === Timing setup === | + | ==== Timing setup ==== |
| - | + | At present, there are three electronic " | |
| - | * See [[http://groups.nscl.msu.edu/ | + | |
| - | * 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 | ||
| - | * The “S800” trigger | + | |
| + | | ||
| + | * 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 to the MTDC with only the first hit | ||
| + | * The fourth row corresponds to the ORTEC TACs. Note that there is not **RF-FP TAC** | ||
| + | * The two spectra in the fifth row corresponds to the MTDC summary spectra of OBJ-FP and XFP-FP ToFs (zoomed in). The spectra show the ToF (vertical axis) vs. hit number (horizontal axis). In an unreacted setting, one expects to see the most of the " | ||
| + | * 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 the matching window | ||
| - | * 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 | + | * If necessary, adjust delays: |
| - | * There are 4 TDC inspect channels | + | * Using the [[S800 DAQ tools# |
| - | * The full range of the TDC is 400 ns | + | * Select the timing signals (Delay |
| - | * Set each timing to 200 ns | + | * Adjust |
| - | * TDCs of last 4 listed signals (including XF and object scintillators) are bypassed with cable delays inside | + | * Adjust |
| - | * They can be inspected, however using the GUI | + | * In principle, the TACs delays don't need to be adjusted |
| - | * Information | + | ==== Checking Particle ID and rate at S800 FP ==== |
| - | * The signal delays controlled by the GUI (and not by cable delays) are not “pipelined” -– i.e., any new signals that arrive during the delay time of a previous signal are lost and thus deadtime is introduced into the system. | + | |
| - | * All of the trigger signals are not pipelined and are thus subject to deadtime | + | |
| - | === Checking Particle ID and rate at S800 FP === | + | * Select SpecTcl window **S800_PID.win** in directory **/ |
| - | | + | * The three columns correspond |
| - | * Refer to information on setting from A1900 FP | + | * The first (top) row corresponds |
| - | | + | * The second row corresponds to the MTDC with just the first hit included |
| - | * dE signal from Ion Chamber | + | * The third row corresponds to the ORTEC TACs. Note that there is not **RF-FP TAC** |
| - | * TOF from XF or Object scintillator to S800 FP | + | * You might need to adjust the limits of the spectra to get a good resolution |
| - | | + | |
| - | * Document rate of fragment of interest | + | |
| - | * Measure beam current with appropriate Faraday cups | + | |
| - | * Timed run | + | |
| + | {{: | ||
| - | === Analysis line classic PPAC setup (Focus optics only) === | + | * Establish PID and measure rate |
| + | * Determine the blob that corresponds to the unreacted beam (refer to information on setting from A1900 FP) | ||
| + | * Take gates around the fragment of interest | ||
| + | * Measure the beam intensity the appropriate faraday cup | ||
| + | * Take a run on disk | ||
| + | * Measure the beam intensity again and calculate the average value | ||
| + | * In **[[s800 SpecTcl|SpecTcl GUI]], click **Attach to File** and select data file **run-xxxx-xx.evt** in directory **/ | ||
| + | * Check the run time and live time from the corresponding scaler file in directory **/ | ||
| + | * Calculate the rate and purity and compare with the value in the A1900 FP to determine the transmission | ||
| + | ==== Analysis line classic PPAC setup (Focus optics only) ==== | ||
| * " | * " | ||
| * Classic PPACs have rate limitations from pileups | * Classic PPACs have rate limitations from pileups | ||
| Line 213: | Line 225: | ||
| - | === 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 | ||
| Line 219: | Line 231: | ||
| * Set spectrograph Brho for unreacted fragment | * Set spectrograph Brho for unreacted fragment | ||
| - | === Start scalers === | + | ==== Start scalers |
| * Use s800 account | * Use s800 account | ||
| Line 233: | Line 245: | ||
| * scalers (gives error if no bridge) | * scalers (gives error if no bridge) | ||
| - | === Setting Optimization === | + | ==== Setting Optimization |
| === Focused optics === | === Focused optics === | ||
tuning_the_s800_xdt.txt · Last modified: 2023/09/22 15:15 by swartzj
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