High Level Physics Applications for LCLS Commissioning

1. High Level Physics Applications for LCLS Commissioning Henrik Loos

2. Outline • LCLS • Physics Application Overview • Application Examples • E-Beam Data Acquisition • Summary

3. beam parked here Nov 2008… Commission Jan-Aug 2008 Commission Mar-Aug 2007 LCLS Accelerator Layout 250 MeV z  0.19 mm   1.6 % 4.30 GeV z  0.022 mm   0.71 % 13.6 GeV z  0.022 mm   0.01 % 6 MeV z  0.83 mm   0.05 % 135 MeV z  0.83 mm   0.10 % Linac-X L =0.6 m rf= -160 Linac-0 L =6 m rf gun L0-a,b Linac-3 L 550 m rf  0° Linac-1 L 9 m rf  -25° Linac-2 L 330 m rf  -41° 25-1a 30-8c 21-3b 24-6d ...existing linac 21-1 b,c,d undulator L =130 m X BC1 L 6 m R56 -39 mm BC2 L 22 m R56 -25 mm undulator DL1 L 12 m R56 0 DL2 L =275 m R56  0 SLAC linac tunnel research yard X-rays in spring 2009

4. Physics Applications Overview • Matlab framework for development • ~45 applications developed by physicists • All with graphical user interfaces (GUIs) • Created and grown within last two years • Development driven by commissioning needs • Quick adoption of new features

5. Diagnostics Profile Monitors Wire Scanners Emittance/Tomography Bunch Length Correlation Plot Cathode QE Laser Pulse Length Orbit Response Status Displays Operating Point Orbit RF Status Beam Jitter Beam Images Machine Control & Tuning Beam Line Switching Bunch Compressor Control Twiss Matching Fast Energy Change Simulation LiTrack 1D FEL Code Undulator/FEL Undulator Girder/Quad Motion Undulator Beam Based Alignment Undulator K-Measurement FEL Gain Measurement Application Types

6. Physics HLA Launch Screen

7. Operating Point • Primary definition for main machine parameters • Used as defaults for other applications • Electronic checklist • Compares actual values with set points • No machine control H.-D. Nuhn

8. Linac Beam Jitter • Measures transverse beam jitter in injector and near end of linac • Display of jitter in terms of normalized phase space • Display of energy jitter throughout machine D. Ratner

9. RF Phase Scans • Beam based measurement of all RF phases • Integrates Epics and SCP controls • Amplitude calibration and phase re-golding • Stores results in PVs for archiving P. Emma

10. Dispersion Measurement P. Emma • Orbit measurement after chicanes with varying beam energy • Calculates resulting emittance growth and corrector quad strengths • Applies correction

11. Bunch Compressor Control • Set R56 of chicane • Controls • Dipole strengths • Chicane motion • Matching quads • Upstream RF phases P. Emma

12. BFW Quad RF BPM Undulator In/Out Beam Scan Girder Undulator Girder Position GUI to plot positions of all 33 girders, absolute or w.r.t. reference GUI to move girder at quad location or BFW location Low level Matlab adjusts BPM offset to keep beam orbit constant J. Welch H.-D. Nuhn

13. Beam Diagnostics Application Hierarchy Correlation Plot Twiss Matching Bunch Length Emittance Profile Analysis Profile Monitor Wire Scan

14. Application Structure • Common user interface • Start/Abort acq. • Save/Load data • Save/Load application configuration • Automatic/Manual data acq., retake data • Archiving • Logbook feature/Autosave • Data saved as .MAT files in Year/Month/Day/Filename folder structure • Control system interface • EPICS via lcaGet/lcaPut • Oracle database & SLC via Aida data provider

15. Common User Interface Features Files Configs Measure Export Data Point Data Sliders Profile Analysis Method

16. Image Acquisition • Live image display • Pixels or calibrated display • Line outs • Intensity histogram • Fit results • Interactive screen calibration

17. Image/Profile Processing • Automatic background image acquisition & subtraction • Background estimation from distribution mode • For wire scan data, use most probable PMT count value • Image slicing for time resolved measurements (Emittance) • Multiple Fit methods implemented • Gaussian • Asymmetric Gaussian • Super-Gaussian • Raw RMS • RMS peak cut • RMS area cut • Generate fit profiles & statistics for each method • Sum, centroid, sigma, skewness, kurtosism, x/y correlation

18. Wire Scans • Beam synchronous acquisition of wire position, PMT signals, charge, and beam position • Automatic set of scan range from BPM reading • Optional jitter correction and charge normalization • Applies set of fit algorithms to profiles • Normal wire scanners and undulator beam finder wires supported Raw Data Processed Scan Profile Statistics

19. Bunch Length Measurement • Measures bunch length at various profile monitors using TCAV0 and 3 • Scans TCAV phase for calibration. • Plot of measured images, profiles, and beam size fit.

20. Emittance Overview Slice Plot Phase Space Summary Plot

21. Emittance GUI Features • Measures emittance at various profile monitors and wire scanners. • Uses quadrupole scan or acquisition at multiple locations (multi screen). • Projected emittance or slice emittance • Sets PVs for archiving and matching • Plot of measured profiles, beam size fit, and phase space view. • Add emittance measurement using undulator beam finder wires.

22. Phase Space Tomography Uses beam profiles for tomographic phase space reconstruction Maximum entropy & algebraic reconstruction implemented Profiles Phase Space

23. Twiss Parameter Matching • Retrieves Twiss parameters from previous emittance measurement • Wire scanner or profile monitor • Applies solution to magnet settings • Includes undulator energy matching

24. Correlation Plot Overview

25. Correlation Plot Features • Scans any epics process variable (PV) • Measures multiple samples of any number of PVs • Non-synchronous and synchronous acquisition • Scan of 2 PVs for 2-D plots • Scan of SLC magnets • Time scan • Measurement of emittance, bunch length, profile monitors, wire scanners • Selection of different fit functions • Plot of selected results

26. Undulator Beam Based Alignment Measurement of undulator orbit at 3+ energies Fit of BPM & quad offsets and orbit Changes BPM offsets Moves quads with undulator girders Launches beam into undulator Integrates simulation Orbit Measurement of deliberate x & y bump Simulation Measurement Offsets

27. Summary and Outlook • Physics applications motivated by needs for fast online diagnostics and for automating many commissioning tasks • Complicated machine tuning tasks and multi step measurement procedures with one button click • Plan to migrate applications from physicists (Matlab) to software group (Java) • Matlab applications were developed in interaction with control room needs • Existing Matlab applications are used to define software requirements • Gradual replacement from lower level apps (e.g. wire scan) to highest level (e.g. correlation plots)

28. R. Akre K. Bertsche A. Brachmann F.J. Decker Y. Ding D. Dowell P. Emma A. Fischer J. Frisch S. Gilevich G.R. Hays Ph. Hering Z. Huang R. Iverson C. Limborg-Deprey H. Loos A. Miahnahri A. Novokhatski H.-D. Nuhn D. Ratner J. Turner J. Welch W. White J. Wu D. Xiang LCLS Commissioning Team