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during_experiments [2015/10/29 14:15] pereira [Particle identification corrections] |
during_experiments [2023/07/20 10:43] swartzj |
====== 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. | 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. |
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| * [[#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 |
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* On PanelMate, open page 4 in S800DRIV | <del>* On PanelMate, open page 4 in S800DRIV</del> |
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* 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). |
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| * Click on Mask #1 (the upstream mask) and hit the "insert" button. This puts the mask in front of CRDC1 |
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* 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. |
{{: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.}} |
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* Remove the "upstream mask" with PanelMate | * Remove Mask #1 by pressing "Out". |
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* 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. |
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* {{:wiki:mask.pdf|Mask pattern}} | * {{:wiki:mask.pdf|Mask pattern}} |
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* 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: | * 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.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.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.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.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.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 | * **s800.tof.xfpcorr3**, **s800.tof.xfp3Correction1**, **s800.tof.xfp3Correction2**: Corrected parameter and correction variables for the XFP-FP ToF taken from the MTDC |
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| ===== 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. |
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| 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]]" |
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===== Handling detectors ===== | |
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==== Shimming OBJ scintillator ==== | ==== Shimming OBJ scintillator ==== |