Post on 15-Dec-2015
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 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
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
rcSouth 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, 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?
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.