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tuning_the_s800_xdt [2015/10/26 13:25]
pereira [Timing setup]
tuning_the_s800_xdt [2015/10/26 14:07]
pereira [Setting up Reaction Settings]
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       * Adjust the TDC delays of E1 up, down using the Delay GUI       * Adjust the TDC delays of E1 up, down using the Delay GUI
       * In principle, the TACs delays don't need to be adjusted       * 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 + 
-      * Refer to information on setting from A1900 FP +  * Select SpecTcl window **S800_PID.win** in directory **/user/s800/operations/spectcl/Windows**  
-      * dE-TOF +      * The three columns correspond to the PID determined with the **RF-FP** ToF (left), **OBJ-FP** (center), and **XFP-FP** (right) 
-           dE signal from Ion Chamber +      * The first (top) row corresponds to the Phillips TDC 
-           TOF from XF or Object scintillator to S800 FP +      The second row corresponds to the MTDC with just the first hit included 
-           Not necessary to implement dEor TOF-based corrections +      The third row corresponds to the ORTEC TACs. Note that there is not **RF-FP TAC** 
-      Document rate of fragment of interest with run to disk +      You might need to adjust the limits of the spectra to get a good resolution 
-          * Measure beam current with appropriate Faraday cups + 
-          Timed run+{{:wiki:SpecTcl-e14019-PID-r103.jpg?850|S800_PID.win page}} 
 + 
 + 
 +  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 **/user/s800/stagearea/experiment/runxxxx**, where xxxx stands for the run number 
 +      * Check the run time and live time from the corresponding scaler file in directory **/user/s800/converged_daq/scalers** 
 +      * 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) ==== ==== Analysis line classic PPAC setup (Focus optics only) ====
 +
   * "Classic" PPACs are the default detector, not TPPACs or CRDCs   * "Classic" PPACs are the default detector, not TPPACs or CRDCs
       * Classic PPACs have rate limitations from pileups       * Classic PPACs have rate limitations from pileups
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           * Confirm correlations between dispersive angle at intermediate image and p in FP (e.g., crdc1x). This correlation will be somewhat washed out by straggling in the target; in principle, this should be checked without the target, but the benefit vs. cost in time to remove the target is not worth it.           * Confirm correlations between dispersive angle at intermediate image and p in FP (e.g., crdc1x). This correlation will be somewhat washed out by straggling in the target; in principle, this should be checked without the target, but the benefit vs. cost in time to remove the target is not worth it.
  
- 
- 
-==== Setup beamline ==== 
-  * 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 
- 
-  * Set spectrograph Brho for unreacted fragment 
- 
-==== Start scalers ==== 
-  * Use s800 account 
- 
-  * Make sure experiment daq is: 
-      * Stopped 
-      * Gone 
-          * Open terminal window (from bottom of mac) 
-          * ssh to spdaq20 
-          * ps auw | grep Readout 
-      * Does not get restarted 
- 
-  * Under operations folder on mac 
-      * scalers (gives error if no bridge) 
  
 ==== Setting Optimization ==== ==== Setting Optimization ====
  
 === Focused optics === === Focused optics ===
 +
   * Expectations for A1900 FP to S800 FP transmission   * Expectations for A1900 FP to S800 FP transmission
       * 80% or better for mid-Z fragments       * 80% or better for mid-Z fragments
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   * Document optimized transmission with another run to disk to measure rate of fragment of interest at S800 FP   * Document optimized transmission with another run to disk to measure rate of fragment of interest at S800 FP
  
- 
- 
-=== Matched optics === 
-  * Typically much more time is invested for optimizing optics for matched optics than for focused optics 
- 
-  * One input is optimizing for transmission 
- 
-  * For tritons a scintillator is required at the pivot position since fragments at 5 Tm will not reach S800 FP 
- 
-  * The last two analysis line triplets are used to tweak for the desired optical properties 
- 
-  * Document optimized transmission with another run to disk to measure rate of fragment of interest at S800 FP 
  
  
 ===== Reaction Setting ===== ===== Reaction Setting =====
  
-==== Setting up Reaction Settings ==== 
-  * Calculating reaction setting 
-      * Center unreacted beam at S800 FP 
-          * Adjust spectrograph Brho to center beam at S800 FP 
-          * Requirements for a beam to be “Centered” 
-              * Spectrograph dipoles matched 
-              * Beam position within about 1 cm of center as judges by 0 point on crdc1x spectrum or on track.xfp spectrum 
-          * Record run to disk to document centered unreacted beam setting 
-      * Calculate reaction setting using “effective” beam energy and the nominal target thickness 
-          * Ideally, experimenters should be the ones making this calculation 
-          * This approach assumes that the target thickness is known 
  
 +==== Coincidences ====
  
-  * Reaction setting to FP  
-      * Start with Attenuator setting of unreacted beam and step up in intensity 
-      * Set up beam blocker, if necessary 
-          * Expect to see unreacted beam if reaction setting is within +/- 3% of unreacted beam setting 
-          * Should have to move only one of the two blockers unless charge states are present 
-          * A graphic tool is available to help (not yet calibrated) 
-          * Try to cut only as much as necessary; depends on 
-              * What rate limits allow 
-              * What experimenters want (e.g., if they want singles, the cut has to be more restrictive to limit acquisition deadtime) 
-          * Move blocker, decrease attenuator, repeat 
- 
-==== Coincidences ==== 
   * Overview   * Overview
       * Most experiments at the S800 involve setting up an auxiliary detector system (e.g. SeGA, HiRA, etc) to be used in coincidence with the standard detectors of the S800.       * Most experiments at the S800 involve setting up an auxiliary detector system (e.g. SeGA, HiRA, etc) to be used in coincidence with the standard detectors of the S800.
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 ====== Dispersion Matching tuning ====== ====== Dispersion Matching tuning ======
 +
 In the dispersion-matching optics, the S800 focal point is achromatic, i.e. the position of the beam in the dispersive direction does not depend on the momentum. As a consequence, the beam is momentum-dispersed on the target area (pivot point) with a dispersion of about 10 cm/%. The main goal of the tuning is to ensure that the position and angle dispersion are cancelled at the focal plane, thus maximizing the resolution at that point. We also want a good image in the object position, which will also contribute to increase the resolution at the focal plane.  In the dispersion-matching optics, the S800 focal point is achromatic, i.e. the position of the beam in the dispersive direction does not depend on the momentum. As a consequence, the beam is momentum-dispersed on the target area (pivot point) with a dispersion of about 10 cm/%. The main goal of the tuning is to ensure that the position and angle dispersion are cancelled at the focal plane, thus maximizing the resolution at that point. We also want a good image in the object position, which will also contribute to increase the resolution at the focal plane. 
  
tuning_the_s800_xdt.txt · Last modified: 2023/09/22 15:15 by swartzj