Target Boiling Tests, scheduled for May 3, 2004

1. Measure the dependence on the degree of sub-cooling. No interaction with the MCC is required. This could be done without the FPDs, SMS, etc., although in principle if we are doing it, we might as well record FPD data at the same time. Rather than take the time to set up the special NA scaler arrangement with Paul, we'll just rely on the lumis and the French scalers. Minimum requirements: stable beam conditions, target, lumis. This should not take more than 1 hour. Make sure the beam position, etc.  does not change during these measurements. To my knowledge we have not explored this parameter space before, this will be an interesting test.
   
• Take a 5 minute run at the canonical 19K setting. Record lumi widths. They should be below 300ppm to begin with, if not, something's wrong. Pick a couple representative lumi widths to record in your log entry at each temperature, and record them. Don't forget to clear the lumi widths in the realtime monitor each time you change the target temperature or whatever.
  
• Change liquid hydrogen temperature to 18.5K. Do this by changing the "Set Val" temperature in the middle of the "High Power Heater Control" GUI (accessed from the "Heater Control" button on the main GUI). Look at the temperature strip charts and wait for the temperature to stabilize. This should only take a minute or so.  It would be good if one of our target experts (Silviu, Greg, Lars) was there for this.
  
• Look at how much the HPH has moved. If it has dropped more than about half your usual overhead, then you'll have to compensate by opening the JT a little. Always keep more than about 50-75W of HPH overhead.
  
• We shouldn't run into ESR problems either, but if you see the coolant supply temperature start to rise more than a half degree, then back off.
  
• You may also run into the ceiling on the maximum heater power. If you need to raise this, do it from the same "High Power Heater Control" GUI (accessed from the "Heater Control" button on the main GUI). You have to change it in two places: in the "PID max heat limit" and "Maximum Target Power" fields in the upper right corner of the GUI. Check that it actually changed by clicking on the "PID setting" button, which brings up the PID parameter GUI. Do not raise this above 750 Watts. If you think you need to, then just stop, you're trying to run the target colder than you should.
• Take a 10 minute run at this new temperature. Record the lumi widths.
  
• Repeat all this at 18K (if you can), 20K, 21K, and finish at 19K. Take a new run at each temperature, record lumi widths in a log entry as you go. The target boils at 22.0 K (at 8.5 psig), but this depends on the pressure.
  
• Return target to original conditions. That includes the goal temperature (19K), JT, max power setting, etc.
2. Measure the dependence on intrinsic beam spot size. Interaction with the MCC is required. Our contact on this is Chao (6292). This could be done without the FPDs, SMS, etc., although in principle if we are doing it, we might as well record FPD data at the same time. Rather than take the time to set up the special NA scaler arrangement with Paul, we'll just rely on the lumis and the French scalers. Minimum requirements: stable beam conditions, target, lumis. This should not take more than 2 hours. Make sure the beam position, etc.  does not change during these measurements. A preliminary procedure/test plan for this was discussed with MCC optics people April 27. The MCC should be ready to change the spot size from nominally 100, to 200 and 300 microns using the Hall quads, leaving the rest of the beam properties intact. What we really want is a factor of 2 and a factor of 3 bigger intrinsic area than whatever we have as nominal. I think the last measurement was 50x170 microns ^2 at harp G0A  (Apr 20).
   

• How to establish the tunes/Hall C quad settings for each intrinsic beam size? We need raster off to do this, but we'd prefer to stay cw. Since it takes so long to move the target in/out of the beam, we agreed Tuesday that it would make sense to move the target out of the beam (once), go to 10 uA with the raster off, and establish the quad settings needed for all three tunes. This would involve using the harps G0 and G0A repeatedly. The hope is that these quad settings could be found within an hour's time,  since we have only allocated about 2 hours for this aspect of the boiling studies. Once the quad settings have been found, the raster can be restored, the target can be re-inserted, the current set to 40 ua again, and the three measurements performed in quick succession with each of the quad settings.
  
• As usual, with 40 uA CW beam we need to take a 10-15 minute run at each quad/intrinsic beam spot setting. Record the lumi widths as before. When finished, restore the original quad settings.
  

1. Measure the dependence on intrinsic pump speed. No interaction with the MCC is required. This could be done without the FPDs, SMS, etc., although in principle if we are doing it, we might as well record FPD data at the same time. Rather than take the time to set up the special NA scaler arrangement with Paul, we'll just rely on the lumis and the French scalers. Minimum requirements: stable beam conditions, target, lumis. This should not take more than 1 hour. Make sure the beam position, etc.  does not change during these measurements.

• This was sort of already done. But only as part of other studies. We haven't changed the pump speed in consecutive steps in which only the pump speed was changed. So we do that now, and try to get several pump speeds taken all in a row, with nothing else changing.
• Minimal data set: 20, 30, 40 Hz. All at 40 uA with 2x2 mm^2 raster. As usual, with 40 uA CW beam we need to take a 10-15 minute run at each pump speed. Record the lumi widths as before. When finished, restore the original pump setting (~30 Hz).