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1October 21, 2005Internal LCLS Undulator Alignment and Motion Review
Georg Gassner, SLAC / [email protected]@slac.stanford.edu
HLS Monitoring System Georg Gassner, SLAC / MET
October 21, 2005
HLS Monitoring System Georg Gassner, SLAC / MET
October 21, 2005
HLS Introduction HLS Principle Types of Sensors Integration of HLS with the Undulator
HLS Introduction HLS Principle Types of Sensors Integration of HLS with the Undulator
2October 21, 2005Internal LCLS Undulator Alignment and Motion Review
Georg Gassner, SLAC / [email protected]@slac.stanford.edu
Hydrostatic Leveling System Introduction
The free surfaces of bodies of water have been used for several thousand years as a vertical reference.
The proposed Hydrostatic Level Systems (HLS) has several significant advantages over optical methods in determining height differences between two points. Some of these advantages are:
No direct line of sight needs to exist
Not affected by optical refraction
Higher accuracy
Fully automated
Self calibrating
Equipotential surface is the reference
The free surfaces of bodies of water have been used for several thousand years as a vertical reference.
The proposed Hydrostatic Level Systems (HLS) has several significant advantages over optical methods in determining height differences between two points. Some of these advantages are:
No direct line of sight needs to exist
Not affected by optical refraction
Higher accuracy
Fully automated
Self calibrating
Equipotential surface is the reference
3October 21, 2005Internal LCLS Undulator Alignment and Motion Review
Georg Gassner, SLAC / [email protected]@slac.stanford.edu
Motion of Earth Surface
The disadvantage of using the equipotential surface as a reference is that the earth surface itself is not stable but in constant motion.
Earth tides due to sun
and moonAre up to 30m
for a 123 m long
Undulator
Can be modeled
Ocean tide loading
and atmospheric loadingCan reach up to 30 m
Can not be modeled
The disadvantage of using the equipotential surface as a reference is that the earth surface itself is not stable but in constant motion.
Earth tides due to sun
and moonAre up to 30m
for a 123 m long
Undulator
Can be modeled
Ocean tide loading
and atmospheric loadingCan reach up to 30 m
Can not be modeled
4October 21, 2005Internal LCLS Undulator Alignment and Motion Review
Georg Gassner, SLAC / [email protected]@slac.stanford.edu
HLS Principle
Hydrostatic Leveling Systems are based on the principle of communicating vessels or more precisely on the equilibrium of the pressure of the fluid in the communicating vessels. This is mathematically described by the Bernoulli equation.
p + g Z = const.
p = 0.10 hPa => Z = 1.02 mm
Temp = 1°C; Z = 100 mm => Z = 67 m
Hydrostatic Leveling Systems are based on the principle of communicating vessels or more precisely on the equilibrium of the pressure of the fluid in the communicating vessels. This is mathematically described by the Bernoulli equation.
p + g Z = const.
p = 0.10 hPa => Z = 1.02 mm
Temp = 1°C; Z = 100 mm => Z = 67 m
5October 21, 2005Internal LCLS Undulator Alignment and Motion Review
Georg Gassner, SLAC / [email protected]@slac.stanford.edu
HLS Configuration
There are two principle configurations:
Full filled pipe systemFaster damping time <2 min
Easier installation
Half filled pipe systemTemperature differences
do not affect the measurements
Damping time ~10 min
There are two principle configurations:
Full filled pipe systemFaster damping time <2 min
Easier installation
Half filled pipe systemTemperature differences
do not affect the measurements
Damping time ~10 min
Air Circuit
Water Circuit
HLS Sensor
Pipe half-filled with Water
HLS Sensor
6October 21, 2005Internal LCLS Undulator Alignment and Motion Review
Georg Gassner, SLAC / [email protected]@slac.stanford.edu
Types of Sensors - Capacitive Sensor
Principle
Measures the Capacity C of the System
AttributesProven to work for many years
Inexpensive
Precision < 1 m
Accuracy (10 mm range) < 5 m
Possibly affected by drift
Absolute height measurements are only indirectly achievable
Principle
Measures the Capacity C of the System
AttributesProven to work for many years
Inexpensive
Precision < 1 m
Accuracy (10 mm range) < 5 m
Possibly affected by drift
Absolute height measurements are only indirectly achievable
WaterAir CCC
111
D
AC
Ceramic
plate
ElectronicSensing Electrode
Air
Water DWater
DAir
7October 21, 2005Internal LCLS Undulator Alignment and Motion Review
Georg Gassner, SLAC / [email protected]@slac.stanford.edu
Types of Sensors - Ultrasound Sensor
Principle
Measures the runtime of an
ultrasound pulse
AttributesNo drift (self calibrating)
Precision < 0.1 m
Accuracy (10 mm range) < 3 m
Absolute Measurements
More expensive
No long-term experience (10 years)
Principle
Measures the runtime of an
ultrasound pulse
AttributesNo drift (self calibrating)
Precision < 0.1 m
Accuracy (10 mm range) < 3 m
Absolute Measurements
More expensive
No long-term experience (10 years)UltrasoundProbe
Fiducial
Reference surfaces
8October 21, 2005Internal LCLS Undulator Alignment and Motion Review
Georg Gassner, SLAC / [email protected]@slac.stanford.edu
HLS measurements related to the Girder
Any three HLS sensors provide independent monitoring ofHeight of the girder
Roll of the girder
Pitch of the girder
The fourth sensor provides a controlled measurement
Any three HLS sensors provide independent monitoring ofHeight of the girder
Roll of the girder
Pitch of the girder
The fourth sensor provides a controlled measurement
HLS 1 HLS 2
HLS 4 HLS 3Beam
pitch
rollheight
9October 21, 2005Internal LCLS Undulator Alignment and Motion Review
Georg Gassner, SLAC / [email protected]@slac.stanford.edu
Integration of HLS with the Undulator
Three capacitive sensors per girderreliable determination of height, roll and pitch
One ultrasonic sensor per girderAbsolute measurements
Calibration of the system
Controlled measurements
2 inch stainless steel pipes to connect the pots for optimal
damping and maintenance
All sensors are connected with TCP/IP (IEEE 802.3af)Following a standard (off the shelf products)
Power supply included
Each sensor communicates independently from all others
Three capacitive sensors per girderreliable determination of height, roll and pitch
One ultrasonic sensor per girderAbsolute measurements
Calibration of the system
Controlled measurements
2 inch stainless steel pipes to connect the pots for optimal
damping and maintenance
All sensors are connected with TCP/IP (IEEE 802.3af)Following a standard (off the shelf products)
Power supply included
Each sensor communicates independently from all others
10October 21, 2005Internal LCLS Undulator Alignment and Motion Review
Georg Gassner, SLAC / [email protected]@slac.stanford.edu
Conclusion
Reliable and controlled method for monitoring heights of the girders (1 m level small range)
pitches of the girders (0.5 rad)
rolls of the girders (2 rad)
Damping within 10 min
Supplies Wire Positioning System with information to determine the sag
Reliable and controlled method for monitoring heights of the girders (1 m level small range)
pitches of the girders (0.5 rad)
rolls of the girders (2 rad)
Damping within 10 min
Supplies Wire Positioning System with information to determine the sag
11October 21, 2005Internal LCLS Undulator Alignment and Motion Review
Georg Gassner, SLAC / [email protected]@slac.stanford.edu
End of Presentation