Identifying Sources of Vertical Motion in the SSRL Storage Ring using Spectral Analysis

1. Identifying Sources of Vertical Motion in the SSRL Storage Ring using Spectral Analysis Nikita Sunilkumar Mentor: James Safranek 8/6/09

2. Map Approach Process Results Future

3. SPEAR BL10 East Pit BL12 BL7 Asphalt Cast Wall Block Wall BL6 North Arc South Arc Z Floor joint X HLS Sensor BL4 West Pit

4. The Problem Users at SSRL complained that they are having trouble keeping the photon beam fixed on their samples despite precision optics and other forms of beam control. One user wrote: “One of our constant battles in trying to have a stable beam is that the building itself has a large movement due to the diurnal effect of the building heating up and cooling down.”

6. The Tools

7. The Method Planar Extraction

8. Planar Extraction refers to a code that was written to • calculate the plane formed by the 22 sensors at each point in time • use this plane equation to calculate the theoretical position for each sensor at each time • subtract this theoretical value from the actual value • return the slope of the plane at each time Microradians Microradians

9. Spectral Analysis 24 hr 12 hr

11. Integrated Displacement Difference across 24-hr Frequency Domain Roof Painting

12. Integrated Displacement Difference across 24-hr Frequency Domain Roof Painting BL 12 Alcove ? WP North Arc EP South Arc

13. BL7 Anomaly

14. SPEAR BL10 East Pit BL12 BL7 Asphalt Cast Wall Block Wall BL6 North Arc South Arc Z Floor joint X HLS Sensor BL4 West Pit

15. Hypothesis: The sections of the ring with cast inner walls respond more to diurnal temperature fluctuations because these walls have not been entirely decoupled from the floor. How can we test this hypothesis?

17. A Tangent… What is the planar extraction actually removing from the data? Nothing important, hopefully For the area covered by the 22 sensors, the extraction is supposed to remove uniform movement, which is not particularly relevant to our analysis. However, for areas not monitored by sensors, like certain quadrants of the storage ring and many of the tangent beamlines, the extraction may be removing more than just uniform movement.

18. Tidal Approximation How well does the planar fit approximate tidal motion?

19. Future • Design more experiments to qualitatively and quantitatively determine how temperature variation is ‘transmitted’ to the building • Install more sensors • Along the rest of the North Arc • In the beamline alcoves • Across significant features of the structure (major joints, cracks, etc.) • Install more thermocouples • Feedback HLS data to magnets • Determine ideal planar/tidal extraction

20. Acknowledgements This effort would not have been possible without funding from the Department of Energy Office of Science and the SULI program at SLAC National Laboratory. Special thanks to my mentor, James Safranek, for his unfailing guidance and support. Thanks also to Steve Gierman, Ben Scott, Ann Trautwein, Georg Gassner, Tom Rabedeau, Ray Ortiz, Harvey Rarback, Jim Sebek and the rest of the SSRL Accelerator Systems Division for their very helpful contributions.