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during_experiments [2015/10/27 16:06]
pereira [Replacing OBJ scintillator] 		during_experiments [2023/07/20 10:43] (current)
swartzj
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 ====== During experiment ====== ====== During experiment ======
 +This section describes support tasks that are typically requested during the course of an experiment. Some of them, like Mask calibration, need to be coordinated with the experimenters. 
 +
 +  * [[#Mask calibration]]
 +  * [[#Particle identification corrections]]
 +  * [[#Efficiency of OBJ Scintillator]]
  
  
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   * Set the trigger to S800 singles and downscale factor 1    * Set the trigger to S800 singles and downscale factor 1 
  
-  * On PanelMate, open page 4 in S800DRIV +  <del>* On PanelMate, open page 4 in S800DRIV</del> 
  
-  * Click on "upstream mask" and hit the "insert" button. This puts the mask in front of CRDC1+  * On Diag_Main.opi, open Device Drives tab. The mask drive controls are at the bottom of this page in the Focal Plane section, namely RBT_BTS34:MSK_D2692 (Mask #1) and RBT_BTS34:MSK_D2703 (Mask #2).  
 + 
 +  * Click on Mask #1 (the upstream mask) and hit the "insert" button. This puts the mask in front of CRDC1
    
   * Start a run without taking to disk and look in the S800 SpecTcl at the 2D  xy position spectrum of (s800.fp.crdc1.x,s800.fp.crdc1.tac). If it starts to look like the spectrum shown below (the screenshot corresponds to mask 2, mask 1 looks inverted, in the sense of the triangle of dots pointing downwards), start taking data to disk until it has about the quality of the screenshot shown. If only a small fraction of the S800 focal plane is illuminated (dispersion-matched optics), consult with the S800 group to sweep the beam across the focal plane by changing the Brho of segment 8. The figure below shows the SpecTcl spectrum of the mask "shadow" measured in CRDC2 during a reaction setting.   * Start a run without taking to disk and look in the S800 SpecTcl at the 2D  xy position spectrum of (s800.fp.crdc1.x,s800.fp.crdc1.tac). If it starts to look like the spectrum shown below (the screenshot corresponds to mask 2, mask 1 looks inverted, in the sense of the triangle of dots pointing downwards), start taking data to disk until it has about the quality of the screenshot shown. If only a small fraction of the S800 focal plane is illuminated (dispersion-matched optics), consult with the S800 group to sweep the beam across the focal plane by changing the Brho of segment 8. The figure below shows the SpecTcl spectrum of the mask "shadow" measured in CRDC2 during a reaction setting.
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 {{:wiki:crdc2_56ti.jpg?550|Mask pattern measure in CRDC2 during a reaction setting.}} {{:wiki:crdc2_56ti.jpg?550|Mask pattern measure in CRDC2 during a reaction setting.}}
  
-  * Remove the "upstream mask" with PanelMate+  * Remove Mask #1 by pressing "Out". 
  
-  * Repeat the procedure with CRDC2 by inserting the "downstream mask" on the same PanelMate page. +  * Repeat the procedure with CRDC2 by inserting Mask #2 (the downstream mask) on the same diagnostics page. 
  
   * {{:wiki:mask.pdf|Mask pattern}}    * {{:wiki:mask.pdf|Mask pattern}} 
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 {{:wiki:pid.tac.obj_ic.sum_e15040-r226.jpg?650|"Uncorrected" PID spectrum.}} {{:wiki:pid.tac.obj_ic.sum_e15040-r226.jpg?650|"Uncorrected" PID spectrum.}}
  
-The following process describes how to improve the PID resolution. This correction is supposed to be done "offline", i.e. using a data file recorded in the stagearea:+The following process describes how to improve the resolution of the PID. This correction is supposed to be done "offline", i.e. using a data file recorded in the stagearea:
  
-  * The SpecTcl parameter **s800.tof.obje2** corresponds to the "raw" parameter **s800.tof.tac_obj**, corrected from the dependences described above+The SpecTcl parameters **s800.tof.objcorr1**, **s800.tof.objcorr2**, and **s800.tof.objcorr3** correspond to the "raw" parameters **s800.tof.obj**, **s800.tof.tac_obj**, and **s800.tof.mtdc_obj** corrected from the dependences described above 
  
-  * Open the **Variables** page in SpecTcl and make sure that the variables **s800.tof.obje1Correction** and **s800.tof.obje2Correction** are zero. (The figure below shows the Variables page with the final values of the correction variables)+The SpecTcl parameters **s800.tof.xfpcorr1**, **s800.tof.xfpcorr2**, and **s800.tof.xfpcorr3** correspond to the "raw" parameters **s800.tof.xfp**, **s800.tof.tac_xfp**, and **s800.tof.mtdc_xfp** corrected from the dependences described above 
 + 
 +The process described below describes to improve the resolution of the PID based on the **OBJ-FP** ToF from the ORTEC TAC. The correction process for the PID spectra based on other ToFs is similar 
 + 
 +  * Open the **Variables** page in SpecTcl and make sure that the variables **s800.tof.obj2Correction1** and **s800.tof.obj2Correction2** are zero. (The figure below shows the Variables page with the final values of the correction variables)
  
 {{:wiki:spectclgui-variables.jpg?750|Variable page in SpecTcl.}} {{:wiki:spectclgui-variables.jpg?750|Variable page in SpecTcl.}}
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   * 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   * 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
  
-  * Looking at the spectrum **PID:TAC.OBJ2_TRACK.AFP** (figure below, left), change the value of the variable **s800.tof.obje1Correction** +  * Looking at the spectrum **PID:OBJCORR2_TRACK.AFP** (figure below, top), change the value of the variable **s800.tof.obj2Correction1** 
          * Enter a new value (typically in the range 500-1000)          * Enter a new value (typically in the range 500-1000)
          * Click **Set**          * Click **Set**
          * Re-scan the data file          * Re-scan the data file
-         * Keep trying different values, until the dependence is eliminated. The figure below (right) shows the corrected spectrum (for this particular case, **s800.tof.obje1Correction** = 450)+         * Keep trying different values, until the dependence is eliminated. The figure below (bottom) shows the corrected spectrum (for this particular case, **s800.tof.obj2Correction1** = 450)
  
-{{:wiki:pid.tac.obj2_track.afp-uncorrected.jpg?500|s800.tof.obje2 vs. dispersive angle before correction}} +{{:wiki:pid.tac.obj2_track.afp-uncorrected.jpg?500|s800.tof.objcorr2 vs. dispersive angle before correction}} 
-{{:wiki:pid.tac.obj2_track.afp-corrected.jpg?500|s800.tof.obje2 vs. dispersive angle after correction}}+{{:wiki:pid.tac.obj2_track.afp-corrected.jpg?500|s800.tof.objcorr2 vs. dispersive angle after correction}}
  
  
-  * Repeat the process looking now at the spectrum **PID:TAC.OBJ2_CRDC1.X** (figure below, left)  +  * Repeat the process looking now at the spectrum **PID:OBJCORR2_CRDC1.X** (figure below, top)  
-         * Enter a new value for the variable **s800.tof.obje2Correction** (typically in the range 0.01-0.1)+         * Enter a new value for the variable **s800.tof.obj2Correction2** (typically in the range 0.01-0.1)
          * Click **Set**          * Click **Set**
          * Re-scan the data file          * Re-scan the data file
-         * Keep trying different values, until the dependence is eliminated. The figure below (right) shows the corrected spectrum (for this particular case, **s800.tof.obje2Correction** = 0.05)+         * Keep trying different values, until the dependence is eliminated. The figure below (bottom) shows the corrected spectrum (for this particular case, **s800.tof.obj2Correction2** = 0.05) 
 + 
 + 
 +{{:wiki:pid.tac.obj2_crdc1.x-uncorrected.jpg?500|s800.tof.objcorr2 vs. CRDC1.x before correction}} 
 +{{:wiki:pid.tac.obj2_crdc1.x-corrected.jpg?500|s800.tof.objcorr2 vs. CRDC1.x after correction}} 
 + 
 +  * The figure below shows the spectrum **PID:OBJCORR2_IC_SUM** after the right corrections were included in SpecTcl 
 + 
 +{{:wiki:pid.tac.obj2_ic.sum.jpg?650|"Corrected" PID spectrum.}}
  
 +  * The correction process described above can be used for other ToF. SpecTcl includes a set of corrected ToF parameters and variables for the OBJ-FP and XFP-FP ToFs taken from the Phillips TDC, TACs, and MTDC:
 +         * **s800.tof.objcorr1**, **s800.tof.obj1Correction1**, **s800.tof.obj1Correction2**: Corrected parameter and correction variables for the OBJ-FP ToF taken from the Phillips TDC
 +         * **s800.tof.objcorr2**, **s800.tof.obj2Correction1**, **s800.tof.obj2Correction2**: Corrected parameter and correction variables for the OBJ-FP ToF taken from the ORTEC TAC   
 +         * **s800.tof.objcorr3**, **s800.tof.obj3Correction1**, **s800.tof.obj3Correction2**: Corrected parameter and correction variables for the OBJ-FP ToF taken from the MTDC
 +         * **s800.tof.xfpcorr1**, **s800.tof.xfp1Correction1**, **s800.tof.xfp1Correction2**: Corrected parameter and correction variables for the XFP-FP ToF taken from the Phillips TDC
 +         * **s800.tof.xfpcorr2**, **s800.tof.xfp2Correction1**, **s800.tof.xfp2Correction2**: Corrected parameter and correction variables for the XFP-FP ToF taken from the ORTEC TAC   
 +         * **s800.tof.xfpcorr3**, **s800.tof.xfp3Correction1**, **s800.tof.xfp3Correction2**: Corrected parameter and correction variables for the XFP-FP ToF taken from the MTDC
  
-{{:wiki:pid.tac.obj2_crdc1.x-uncorrected.jpg?500|s800.tof.obje2 vs. CRDC1.x before correction}} 
-{{:wiki:pid.tac.obj2_crdc1.x-corrected.jpg?500|s800.tof.obje2 vs. CRDC1.x after correction}} 
  
-  * The figure below shows the spectrum **PID:TAC.OBJ2_IC_SUM** after the right corrections were included in SpecTcl 
  
-{{:wiki:pid.tac.obj2_ic.sum_e15040-r226.jpg?650|"Corrected" PID spectrum.}}+===== Efficiency of OBJ Scintillator ===== 
 +At relatively high rates (~0.5 MHz), the OBJ scintillator will be gradually damaged. Experimenters should check the efficiency of this detector continuously during the course of the experiment. Whenever the rates drop below ~90%, they may request the Device/Beam Physicist to shim the detector. 
  
-  * The correction process described above can be used for other ToF. SpecTcl includes a set of corrected ToF parameters: 
-         *s800.tof.obje2: Corrected ToF calculated from the OBJ-FP TAC    
-         *s800.tof.xfpe2: Corrected ToF calculated from the XFP-FP TAC    
-         *s800.tof.obje1: Corrected ToF calculated from the OBJ-FP Phillips TDC    
-         *s800.tof.xfpe1: Corrected ToF calculated from the XFP-FP Phillips TDC  
-  * Note that although the SpecTcl correction variables are shared between the ToFs from the TACs and Phillips TDC, they won't work simultaneously, i.e. the variables that work to "clean" the TAC-based PID spectrum won't work for the TDC-based PID spectrum  
  
  
 +Before shimming, make sure that the thresholds are set properly (not too high) (refer to section "Object Scintillator Setup during [[Tuning the S800 (XDT)#Object scintillator setup|XDT]]" 
  
-===== Handling detectors ===== 
  
 ==== Shimming OBJ scintillator ==== ==== Shimming OBJ scintillator ====
during_experiments.1445976415.txt.gz · Last modified: 2015/10/27 16:06 by pereira

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