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during_experiments [2015/10/27 16:06] pereira [Replacing OBJ scintillator] |
during_experiments [2017/06/17 14:50] pereira [Efficiency of OBJ Scintillator] |
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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, | ||
+ | |||
+ | * [[#Mask calibration]] | ||
+ | * [[#Particle identification corrections]] | ||
+ | * [[# | ||
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{{: | {{: | ||
- | The following process describes how to improve the PID resolution. This correction is supposed to be done " | + | The following process describes how to improve the resolution |
- | * The SpecTcl | + | The SpecTcl |
- | | + | The SpecTcl parameters **s800.tof.xfpcorr1**, |
+ | |||
+ | 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 | ||
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+ | | ||
{{: | {{: | ||
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* In [[s800 SpecTcl|SpecTcl GUI]], click **Attach to File** and select data file **run-xxxx-xx.evt** in directory **/ | * In [[s800 SpecTcl|SpecTcl GUI]], click **Attach to File** and select data file **run-xxxx-xx.evt** in directory **/ | ||
- | * Looking at the spectrum **PID:TAC.OBJ2_TRACK.AFP** (figure below, | + | * Looking at the spectrum **PID:OBJCORR2_TRACK.AFP** (figure below, |
* 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) |
- | {{: | + | {{: |
- | {{: | + | {{: |
- | * Repeat the process looking now at the spectrum **PID:TAC.OBJ2_CRDC1.X** (figure below, | + | * Repeat the process looking now at the spectrum **PID:OBJCORR2_CRDC1.X** (figure below, |
- | * 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) |
+ | |||
+ | |||
+ | {{: | ||
+ | {{: | ||
+ | * The figure below shows the spectrum **PID: | ||
- | {{: | + | {{: |
- | {{: | + | |
- | * The figure below shows the 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.objcorr2**, | ||
+ | * **s800.tof.objcorr3**, **s800.tof.obj3Correction1**, | ||
+ | * **s800.tof.xfpcorr1**, | ||
+ | * **s800.tof.xfpcorr2**, | ||
+ | * **s800.tof.xfpcorr3**, | ||
- | {{: | ||
- | * The correction process described above can be used for other ToF. SpecTcl includes a set of corrected ToF parameters: | ||
- | | ||
- | | ||
- | | ||
- | | ||
- | * Note that although the SpecTcl correction variables are shared between the ToFs from the TACs and Phillips TDC, they won't work simultaneously, | ||
+ | ===== 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. | ||
+ | Before shimming, make sure that the thresholds are set properly (not too high). | ||
- | ===== Handling detectors ===== | ||
==== Shimming OBJ scintillator ==== | ==== Shimming OBJ scintillator ==== |