Recent Cavity Monitor Tests Credit John Musson Anna

Recent Cavity Monitor Tests Credit: John Musson, Anna Boehle, Vince Sulkosky • Good position & current for 10 n. A to 100 u. A • At 10 n. A : • Need absolute position to 0. 2 mm • Need resolution of ~ 0. 5 mm (1 -shot at 200 nsec) • HRS rates ~ 200 k. Hz good for Q 2 Goals ~achieved, but need to repeat with a current & position scan with constant gain. PREX Mtg, July 2008 R. Michaels, JLab

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

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

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

Low - Current Steering Coils ( 50 n. A ) Cavity X, Y, Q Tests Target deflected beam Bigbite 8. 8 k. Hz u. A Stripline X, Y PREX Mtg, July 2008 R. Michaels, JLab

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

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

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

At 9. 5 u. A PREX Mtg, July 2008 (oops ! Gain adjusted) R. Michaels, JLab

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

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

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 ! PREX Mtg, July 2008 R. Michaels, JLab

Summary -- Cavity Monitors • Working well, we have the G 0 version of electronics • Good signals at 10 n. A Can measure Q • Plan to repeat scan ( I beam , X, Y ) 2 with constant gains PREX Mtg, July 2008 R. Michaels, JLab