Taking MAIN detector Counting Run
From PREX Wiki
- Move to Ca-48 target (if you are not already there)
- Call MCC and ask for 0.3uA cw beam, ask them to set IPM1C12 to normal mode
- Monitor HALLA:dpp and BPM target locks stripchart, wait until the BPM locks and dpp get stablize
- HALLA:dpp should be stable ~-1e-4
- Make sure the raster size is 2x2 mm^2 and beam is collimator centered
- Turn ON Scintillators (Follow the instructions in HVgui
- Monitor the scaler GUI, the T1 rate on both arms should be ~200k
- Be careful, consider the safety of VDCs --> Look into white board for VDC safe zone
- Turn ON VDCs (NOTE: Again, make sure the scintillator rate is below 500k before turning VDC ON)
- Set the HV for DN-Quartz (MAIN) detectors in both arms to -1900V (as explained in HVgui)
- L1.1 channel in S1 (Slot1) in each arm HV GUI (See Image 1)
- Enable the HV channels
- Important Note: Once you are done with counting Run Turn this channel OFF and set the value to 0.0
- Make sure that the IPM1C12.XPOS and HALLA:dpp stripcharts are working
- Click on the HALLA:dpp stripchart to mark the time and value of dpp (Again, it should be stable ~-1e-4)
- Take counting runs on both arms (LHRS and RHRS) at least 200k events
- To analyze the runs:
- ssh -Y a-onl@aonl1
- goprex
- analyzer -l
- .x setup2.C(runNumber,200000)
- The rootfiles are stored in /chafs1/work1/prex_counting/
- To produce plots:
- In a-onl@aonl1 machine:
- cd devi/crex/alignment
- analyzer prex_counting/prexLHRS_runNumber_200000.root for LHRS
- analyzer prex_counting/prexRHRS_runNumber_200000.root for RHRS
- .x alignDS.C
- Note: please don't modify the macro, if you want you can copy it to your directory and modify there
- Look into the elastic peak and read the edge of quartz (the intersection of red and blue histograms in "Projected x on detector plane" plot)
- Zoom in to see the precise edge
- If everything is OK, and the HALLA:dpp during the run is ~-1e-4 the elastic peak and edge position should be the following:
- LHRS --> Elastic Peak: -0.009 m, Edge: ~-0.028 m giving the difference ~19 mm
- RHRS --> Elastic Peak: -0.043 m, Edge: ~-0.0615 m giving the difference ~18.5 mm
- Note:: If the fit is not working properly, carefully look into the peak
- If these numbers are different by more than 1 mm, monitor how HALLA:dpp is doing, also monitor the Dipole set values and readback values
- If both arms are showing the shift, if any, in the same direction, it is more likely the energy is changing
- If only one arm is showing the shift, if any, it is more likely due to the magnet settings in the arm
- If you have any doubt, or can't resolve the issue, call expert
- For every runs, halog the plots. Also halog the HALLA:dpp stripchart (showing the marked value)
- When you are done with taking counting data turn OFF the DN-Quartz (MAIN) detectors, VDCs and Scintillators HVs
- NOTE: never turn ON DN-Quartz and VDCs HVs during high current production running keeping them at higher HV (they will die)
- For safety, set their HV to 0.0V at the end
- NOTE: Remember to turn ON UP-Quartz and AT detectors before going to production
