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

Map Approach Process Results Future

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

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.” The Problem

SPEAR painted white Reflects more radiation and lowers daily temperature variation of the ring Summer 2008 Reduce diurnal heating and cooling of the ring Cover half of asphalt with highly reflective Mylar Cut temperature variation in asphalt, thereby reduce expansion Installed June 30 Prevent asphalt from expanding and contracting Since Mylar worked well on reducing asphalt temp, use on ring walls and roof Further reduce diurnal variation Installed last Wednesday Reduce ring temperature variation further ?

The Tools

The Method Search and Replace Filter Planar Extraction

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

Spectral Analysis 24 hr 12 hr

Project (Ratio) HLS VariationOutdoor B116Roof G13R1C2 Ring Ambient WHITEWASH (May 2009/ May 2008) MYLAR on ASPHALT (6/13-6/30/09 / 6/30-7/16/09) RF: MYLAR – Roof/Walls (6/30-7/05/09 / 7/29-8/03/09) (BL 11 Only – No plane fit) Upstream: Downstream: (Interior Wall TC Girder 13)

Integrated Displacement Difference across 24-hr Frequency Domain Roof Painting

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

BL7 Anomaly

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

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?

SPEAR painted white Reflects more radiation and lowers daily temperature variation of the ring Summer 2008 Reduce diurnal heating and cooling Cover half of asphalt with highly reflective Mylar Cut temperature variation in asphalt, thereby reduce expansion Installed June 30 Prevent asphalt from expanding and contracting Since Mylar worked well on reducing asphalt temp, use on ring walls and roof Further reduce diurnal variation Installed last Wednesday Reduce ring temperature variation further If our theory is correct, a large portion of the variation is caused by walls that extend into the floor and cause stress on the ring foundation Test this theory by selectively insulating cast walls and observing the effects of the sensors nearby Insulate or modify cast walls to lower HLS variation

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.

Tidal Approximation How well does the planar fit approximate tidal motion? RatioAmplitude 12-hr 24-hr Tidal Slope X Best-fit Slope X (Phase Difference) (4.326 hrs) ( hrs) Tidal Slope Z Best-fit Slope Z (Phase Difference) (3.163 hrs) ( hrs)

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

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.