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during_experiments [2015/10/29 14:12] pereira [Particle identification corrections] |
during_experiments [2017/06/17 14:52] 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, | This section describes support tasks that are typically requested during the course of an experiment. Some of them, like Mask calibration, | ||
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+ | * [[#Mask calibration]] | ||
+ | * [[#Particle identification corrections]] | ||
+ | * [[# | ||
+ | |||
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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: | + | * Looking at the spectrum **PID: |
* 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.obj2Correction1** = 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) |
{{: | {{: | ||
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- | * Repeat the process looking now at the spectrum **PID: | + | * Repeat the process looking now at the spectrum **PID: |
* Enter a new value for the variable **s800.tof.obj2Correction2** (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.obj2Correction2** = 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) |
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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.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.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.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.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.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.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. | ||
+ | Before shimming, make sure that the thresholds are set properly (not too high) (refer to section " | ||
- | ===== Handling detectors ===== | ||
==== Shimming OBJ scintillator ==== | ==== Shimming OBJ scintillator ==== |