1 / 12

Optimal Positions of BPMs

Optimal Positions of BPMs. David Kelliher ASTEC/CCLRC/RAL 9 th February, 2007. MADX ‘Correct’ Module. The CORRECT statement makes a complete closed orbit or trajectory correction using the computed values at the monitors from the Twiss table.

ayanna
Download Presentation

Optimal Positions of BPMs

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Optimal Positions of BPMs David Kelliher ASTEC/CCLRC/RAL 9th February, 2007

  2. MADX ‘Correct’ Module • The CORRECT statement makes a complete closed orbit or trajectory correction using the computed values at the monitors from the Twiss table. • There are three corrections modes – MICADO, LSQ, SVD. MICADO is used in this study as it tries to minimise the number of correctors used. • The MICADO algorithm solves a system of linear equations • Where b is the vector of BPM measurements, q is the correction kick vector and A is the beam response matrix to a set of kicks. The algorithm iteratively minimises the norm of the residual vector r using least squares method. At each iteration it finds the corrector that most effectively lowers r.m.s BPM distortion.

  3. Error simulation • Errors in the magnet horizontal position (up to 50mm) simulated by allowing a shift in the magnet dipole field. • Random errors with a Gaussian distribution, cut-off point at 2s. • MADX was run with 100 instances of such randomly perturbed magnets at each BPM location.

  4. Error distribution – F magnet

  5. EMMA cell in MADX

  6. F D F D F D F D BPM configurations c1 c2 F D F D c3 c4 F D F D c6 c5

  7. Scan c5-c6 F D • Each point represents the average rms of 100 runs • The error tolerance in MICADO is 50mm • On average, five correctors were not used by MICADO.

  8. Error tolerance – 100 mm F magnet correctors used Error tolerance – 500 mm • Optimal BPM position on either side of F magnet in each case • Error tolerance of 100mm results in 58 correctors being used on average • Error tolerance of 500mm results in 4 correctors being used.

  9. F D Scan c1-c6 • The error tolerance in MICADO is 50mm • If BPM placed upstream of the F magnet, other BPM should be either side of the D magnet.

  10. F D F D Scan c3-c4 • The error tolerance in MICADO is 50mm

  11. Lattice functions

  12. Conclusions • If a BPM is placed downstream of the D magnet, then other BPM should be either side of the F magnet. • Conversely, if a BPM is placed upstream of the F magnet, then other BPM should be either side of the D magnet. • Due to the bellows just downstream of the D magnet in every second cell, the first option may be impractical • Therefore, the optimal configuration is to have a BPM upstream of the F magnet and a second in between the magnets but as close to the D magnet as possible

More Related