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

Nikita Sunilkumar Mentor: James Safranek

8/6/09

MapApproach

ProcessResults

Future

Asphalt

BL7

BL10

BL12

BL6

BL4

East Pit

West Pit

Z

X

Cast Wall

Block Wall

Floor joint

HLS Sensor

Nor

th A

rcSouth 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

Reduce diurnal heating and

cooling of the ring

• SPEAR painted white • Reflects more radiation and lowers daily

temperature variation of the ring• Summer 2008

Prevent asphalt from expanding and contracting

• Cover half of asphalt with highly reflective Mylar

• Cut temperature variation in asphalt, thereby reduce expansion

• Installed June 30

Reduce ring temperature

variation further

• Since Mylar worked well on reducing asphalt temp, use on ring walls and roof

• Further reduce diurnal variation• Installed last Wednesday

?

The Tools

The MethodSearch 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

Mic

rora

dian

s

Mic

rora

dian

s

Spectral Analysis24 hr 12 hr

Project(Ratio) HLS Variation Outdoor B116 Roof G13R1C2

Ring Ambient

WHITEWASH(May 2009/May 2008) 0.846 0.999 0.5308 0.8494

MYLAR on ASPHALT(6/13-6/30/09 /6/30-7/16/09)

1.077RF: 1.67 1.087 1.087 0.8185

MYLAR – Roof/Walls(6/30-7/05/09 /7/29-8/03/09)

(BL 11 Only – No plane fit) Upstream: 1.314Downstream: 0.9182

0.9473 0.8054

(Interior Wall TC Girder 13)0.4338

Integrated Displacement Difference across 24-hr Frequency DomainRoof Painting

Integrated Displacement Difference across 24-hr Frequency DomainRoof Painting

BL 12 Alcove

South Arc

North ArcWP

EP

?

BL7 Anomaly

Asphalt

BL7

BL10

BL12

BL6

BL4

East Pit

West Pit

Z

X

Cast Wall

Block Wall

Floor joint

HLS Sensor

Nor

th A

rc 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?

Reduce diurnal heating and

cooling

• SPEAR painted white • Reflects more radiation and lowers daily

temperature variation of the ring• Summer 2008

Prevent asphalt from expanding and contracting

• Cover half of asphalt with highly reflective Mylar

• Cut temperature variation in asphalt, thereby reduce expansion

• Installed June 30

Reduce ring temperature

variation further

• Since Mylar worked well on reducing asphalt temp, use on ring walls and roof

• Further reduce diurnal variation• Installed last Wednesday

Insulate or modify cast walls to lower

HLS variation

• 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

A Tangent…What is the planar extraction actually

removing from the data? Nothing important, hopefullyFor 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?

Ratio Amplitude 12-hr 24-hr

Tidal Slope XBest-fit Slope X

(Phase Difference)0.8623(4.326 hrs)

0.3194(10.055 hrs)

Tidal Slope ZBest-fit Slope Z

(Phase Difference)0.6806(3.163 hrs)

0.2283(12.285 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

AcknowledgementsThis 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.