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tuning_the_s800_xdt [2015/10/22 16:43] pereira |
tuning_the_s800_xdt [2015/10/26 13:59] 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 " | ||
- | === 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 | ||
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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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* 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” | ||
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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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- | === CRDCs setup === | + | ==== CRDCs setup ==== |
* **[[hv bias#hv remote control|Bias]]** CRDCs | * **[[hv bias#hv remote control|Bias]]** CRDCs | ||
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- | === Timing setup === | + | ==== Timing setup ==== |
+ | At present, there are three electronic " | ||
- | Overview: | ||
- | * There are three electronic " | + | * Select SpecTcl window **S800_TOF.win** |
- | * Although | + | * The three columns correspond to the **RF-FP** |
- | * The OBJ, XFP, and E1 up signals in the MTDC come from the Mesytec MCFD | + | * The first (top) row corresponds |
- | | + | * The second row corresponds |
- | * MTDC: | + | * The third row corresponds to the MTDC with only the first hit |
- | * The OBJ signal into the MCFD comes directly from the detector via S3 patch panel #94 (going to the target area) | + | * The fourth row corresponds to the ORTEC TACs. Note that there is not **RF-FP TAC** |
- | * The XFP signal into the MCFD module comes from data-U6 patch panel #70, connected | + | |
- | * SpecTcl calculates the ToF by substracting | + | * 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 timing signals do not require external delay adjustments because | + | * The MTDC spectra should never be empty because |
- | | + | |
- | | + | |
- | * The XFP **stop** signal | + | |
- | * Phillips TDC: | + | {{:wiki: |
- | * 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 | + | |
- | * 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. | + | |
- | | + | |
- | * 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 | + | * 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 |
+ | ==== Checking Particle ID and rate at S800 FP ==== | ||
- | | + | * Select SpecTcl window **S800_PID.win** in directory **/ |
+ | | ||
+ | * The first (top) row corresponds to the Phillips | ||
+ | * The second row corresponds to the MTDC with just the first hit included | ||
+ | * The third row corresponds to the ORTEC TACs. Note that there is not **RF-FP TAC** | ||
+ | * You might need to adjust the limits of the spectra | ||
- | * 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 | ||
+ | * 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 | ||
- | * See [[http:// | ||
- | * 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 is from E1 up signal | ||
- | * 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 | ||
- | * Information | ||
- | * 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 === | ||
- | * Establish PID | ||
- | * Refer to information on setting from A1900 FP | ||
- | * dE-TOF | ||
- | * dE signal from Ion Chamber | ||
- | * TOF from XF or Object scintillator to S800 FP | ||
- | * Not necessary to implement dE- or TOF-based corrections | ||
- | * Document rate of fragment of interest with run to disk | ||
- | * Measure beam current with appropriate Faraday cups | ||
- | * Timed run | ||
- | === 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 === |