ATF2 Q-BPM Magnet Movers & 1 st Pulse Calibration Progress from May 7-11

1. ATF2 Q-BPM Magnet Movers&1st Pulse CalibrationProgress from May 7-11 • J. May, D. McCormick, T.Smith (SLAC) • S. Boogert (RH)

2. Magnet mover progress • Installed electronics for the Magnet mover test bed and Honda-san’s BPMs. • Established control of motors • Reading out cam angle potentiometers and LVDT .

3. 1st Pulse Calibration Progress • Installed electronics on reference, prototype and test bed RF cavities. • Adjusted phases of all cables as described in step 1 • Measured distance between prototype and test bed bpm. Distance = 2824mm +-2mm. • At 6426 MHz the phase difference between the cavities is ~26 deg. • Because this phase difference is less than 180deg, the waveforms for the prototype and the test bed bpms will have the same phase when the beam is in the same quadrant.

4. 1st Pulse Calibration Method

7. ATF bpms 11 &12 both positive Y position. Prototype bpm is between bpms 11&12 and is also positive Y position • From phase matching cables and phase information from the distance between bpms, the test bed bpm should also be positive Y.

8. Test bed quad and BPM • If beam is positive Y in the BPM , moving the bpm up will place the beam at a negative Y position. As beam moves across center line of bpm the phase of the waveform will flip.

9. Moving the bpm up flips the phase of the signal. • This indicates that the phase information from the cable matching and the bpm distance measurements correctly determines the sign for the positive Y position.

10. Confirm that bpm separation determines the phase for a positive Y signal. • Unable to move bpm in Z. • Adjust test bed LO phase by 180 degrees with short section of cable. • This cable effectively moves the test bed bpm 180degrees or ~23mm closer to the prototype bpm. • Repeat the previous experiment and move the bpm up.

11. After phase shifting the test bed LO, the beam was steered until wave form has the same phase as the prototype wave form.

12. Test bed bpm is moved up. Although it looks like a there may be a phase shift…….

13. Overlaying test bed waveforms before and after bpm move shows no phase shift.

14. Goals for this week • Develop magnet mover software for bpm calibration • Develop software for 1st pulse calibration amplitude scaling. • Compare results of 1st pulse calibration to normal magnet mover calibration.

15. X lvdt counts for y move • Pure y move would ideally read zero change in counts from x lvdt • Smooth surfaces important for lvdt bearing surfaces 30 counts ~= 5.3 micrometers

16. Goals for 1st pulse calibration method • Measure distance between prototype and test bed bpms • Phase match cables from bpms to digitizer for prototype and test bed cavities • Verify 1st pulse calibration scheme using prototype and test bed cavity. • Develop software for scaling raw bpm waveforms to beam positions. • Calibrate test bed bpm using magnet mover. Compare position of calibrated bpm with scaling of raw waveforms.

17. Goals for Magnet movers • Finish read back of camshaft ADC and LVDT module. • Integrate mover “C” code to run with Matlab calibration routines. • Create stand alone C software for control of magnet movers. • Work on Epics interface for magnet movers……