1. R. Michaels, JLab PREX Mtg, July 2008 Recent Cavity Monitor Tests Credit: John Musson, Anna Boehle, Vince Sulkosky Good position & current for 10 nA to 100 uA At 10 nA : Need absolute position to 0.2 mm Need resolution of ~ 0.5 mm (1-shot at 200 nsec) HRS rates ~ 200 kHz  good for Q Goals ~achieved, but need to repeat with a current & position scan with constant gain. 2

2. R. Michaels, JLab PREX Mtg, July 2008 Cavity BPM EPICS Interface (beam off)

3. R. Michaels, JLab PREX Mtg, July 2008 Cavity BPMs correlated to Striplines Spectrometer DAQ High current tests (Jan 2008) Good Saturated gain (oops) Good

4. R. Michaels, JLab PREX Mtg, July 2008 Beam Current correlated to Standard BCMs

5. R. Michaels, JLab PREX Mtg, July 2008 Low - Current ( 50 nA ) Tests Bigbite 8.8 kHz uA deflected beam Target Cavity X,Y,Q Stripline X,Y Steering Coils

6. R. Michaels, JLab PREX Mtg, July 2008 Cavities are calibrated here (1 uA)

7. R. Michaels, JLab PREX Mtg, July 2008 100 nA : Striplines disappear, Cavity positions ~ same

8. R. Michaels, JLab PREX Mtg, July 2008 50 nA: Calibration Changed ! (oops ! Gain adjusted)

9. R. Michaels, JLab PREX Mtg, July 2008 (oops ! Gain adjusted) At 9.5 uA

10. R. Michaels, JLab PREX Mtg, July 2008 Resolution Analysis Method 1: Use 1 BPM as a measure of beam motion on the other. Subtract it off, residual is the resolution (approx).

11. R. Michaels, JLab PREX Mtg, July 2008 50 nA Resolution ~ 400 um 1-shot at 200 nsec. It will be better with averaging

12. R. Michaels, JLab PREX Mtg, July 2008 Resolution Analysis Method 2: Using a line built from other monitors, look at residual to the line. Results comparable to method 1. Position is known much better than the beam pipe diameter !

13. R. Michaels, JLab PREX Mtg, July 2008 Summary -- Cavity Monitors Working well, we have the G0 version of electronics Good signals at 10 nA  Can measure Q Plan to repeat scan ( I beam, X, Y ) with constant gains 2 2