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MOPA03 |
Beam Diagnostics for PAL-XFEL | |
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| Pohang Accelerator Laboratory started its XFEL program from 2011. The XFEL project in Pohang Accelerator Laboratory (PAL) requires low beam-emittance, ultra-short bunch length, high peak current, high stability of beam energy. Therefore, beam diagnostics for SASE XFEL should be, focused on attaining femto-second precision in the measurement of temporal beam parameters, and sub-micrometer precision in beam position measurement. Charge measurement and energy measurement and their feedback are important as well. In this work, technical concepts regarding the diagnostic monitors will be summarized and present status of them will be described. | ||
MOPB66 |
Optimization of the Interferometry Beam Size Monitor in PLS-II | |
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| Pohang Light Source-II (PLS-II) is recently upgraded to 3 GeV and the circumference, beam current, emittance of PLS-II storage ring are 281.82 m, 100 mA and 5.7 nm-rad, respectively. The storage ring includes an interferometry beam size monitor system in 2B beam line. It consists of the quadrature slit, lens, 650 nm wave-length filter and CCD camera. We will present the measurement results and the issues to optimize the beam size monitor system in the beam line. | ||
| TUPA34 | Inverse Response Matrix Computation for the Storage Ring Slow Orbit Feedback Control: Synthesized Topological Inversion Computation | 1 |
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Using the derivative response matrix between BPM-data and MPS-setting, we described the inverse computation methodology for the storage ring orbit feedback control. Practically useful for SOFB with assistance of FOFB, the inverse of SVD manipulation is less efficient because a type of consecutive instability noise irreversibly accumulates in the beam trajectory deviation. In contrast, a novel numerical recipe based on topological math can lead to a self-consistent solution, dramatically suppressing ill-posed instability problems. This approach, known as a singularity regularization method, makes it feasible to compute a system-matched de-noising filter. The response matrix in H/V dimensions reflects a global beam dynamics along the storage ring lattices. Matrix refinement manipulatcan can be made to filter out the uncertainty of measurement errors escaping from beam dynamics constraints. Then we believe that algorithm filter can be effective as a software part of FOFB control. Our math STIC (Synthesized Topological Inversion Computation*) appears to be the most reliable inverse computation methodology. Our PLS-2 response matrix will be presented to explain our ORBIT-STIC test.
* Jay Min Lee et al, presented at the 15th International Conference on X-ray Absorption Fine Structure, Beijing, July 22-28, 2012. |
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