Jitter Monitor – Overview and Status Report Glenn Christian, Alexander Kalinin 30 May 2005

Contents Jitter Monitor Hardware Overview Measurement procedure March 2005 data taking Status of Analysis –Resolution studies Plan for current run

Jitter Monitor Schematic

Jitter Monitor Hardware

Measurement Procedure Synchronisation –Sum and Difference signals must be aligned to ~10 ps –Dedicated data run for each processor at each pick-up with large beam displacement to suppress common-mode –Each processor will have a general delay value due to difference in cable lengths and intrinsic delay on board

Measurement Procedure 2 Time align signals using synchronisation delay Calculate position as Calibrate position using correctors and known displacements

Overview of March 2005 data taking Four jitter monitor processors used at BPMs 8,10,13 in ExtLine, and BPMs 26,27 in DR. Data taken during three shifts : –Single-bunch mode: synchronisation data for 8,13,26,27 and calibration for 26,27 –Multi-bunch: synchronisation for bpm10, calibration for 8,10,13 and resolution –Single-bunch mode: 8,13 SB calibration. 26,27 to 8,13 correlation studies varying y, y’, E. –Data taken with all quads off after QD6X.

Resolution Assuming the BPM thermal noise to be small the resolution will be dominated by discretisation noise of scopes. 3 BPM method: –Use position measured in two BPMs to predict position in third BPM. –Assuming noise of all three BPMs to be the same, resolution is determined by std of residuals divided by geometric factor.

Position in Extraction Line

Resolution

Angle-angle correlation With all quads off between three BPMs the trajectory should form straight line!

Resolution studies (cont) General increase in resolution as function of bunch number along train + lack of angle-angle correlation suggest that residuals contain contribution from jitter. Can not be sure how the jitter propagates between BPMs. Therefore 3 BPM method can not be used for discretisation resolution.

Plan for parasitic work this run Plan to measure resolution by hooking up two processors in series on one set of pick-ups. Method eliminates bunch jitter from the calculation leaving only dicretisation noise. By making measurements at different scope scales can also measure the resolution dependence on number of discretes

Summary Jitter monitor analysis still in progress. Once present problems encountered with resolution are solved, there is still lots of interesting data to analyse from March. Plan to take data parasitically to measure the 2- BPM resolution in this visit.