1. October 21, 2005 Internal LCLS Undulator Alignment and Motion Review Georg Gassner, SLAC / MET gassner@slac.stanford.edu 1 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

2. October 21, 2005 Internal LCLS Undulator Alignment and Motion Review Georg Gassner, SLAC / MET gassner@slac.stanford.edu 2 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

3. October 21, 2005 Internal LCLS Undulator Alignment and Motion Review Georg Gassner, SLAC / MET gassner@slac.stanford.edu 3 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 moon Are up to 30  m for a 123 m long Undulator Can be modeled Ocean tide loading and atmospheric loading Can 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 moon Are up to 30  m for a 123 m long Undulator Can be modeled Ocean tide loading and atmospheric loading Can reach up to 30  m Can not be modeled

4. October 21, 2005 Internal LCLS Undulator Alignment and Motion Review Georg Gassner, SLAC / MET gassner@slac.stanford.edu 4 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

5. October 21, 2005 Internal LCLS Undulator Alignment and Motion Review Georg Gassner, SLAC / MET gassner@slac.stanford.edu 5 HLS Configuration There are two principle configurations: Full filled pipe system Faster damping time <2 min Easier installation Half filled pipe system Temperature differences do not affect the measurements Damping time ~10 min There are two principle configurations: Full filled pipe system Faster damping time <2 min Easier installation Half filled pipe system Temperature differences do not affect the measurements Damping time ~10 min

6. October 21, 2005 Internal LCLS Undulator Alignment and Motion Review Georg Gassner, SLAC / MET gassner@slac.stanford.edu 6 Types of Sensors - Capacitive Sensor Principle Measures the Capacity C of the System Attributes Proven 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 Attributes Proven 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

7. October 21, 2005 Internal LCLS Undulator Alignment and Motion Review Georg Gassner, SLAC / MET gassner@slac.stanford.edu 7 Types of Sensors - Ultrasound Sensor Principle Measures the runtime of an ultrasound pulse Attributes No 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 Attributes No drift (self calibrating) Precision < 0.1  m Accuracy (10 mm range) < 3  m Absolute Measurements More expensive No long-term experience (10 years)

8. October 21, 2005 Internal LCLS Undulator Alignment and Motion Review Georg Gassner, SLAC / MET gassner@slac.stanford.edu 8 HLS measurements related to the Girder Any three HLS sensors provide independent monitoring of Height 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 of Height of the girder Roll of the girder Pitch of the girder The fourth sensor provides a controlled measurement

9. October 21, 2005 Internal LCLS Undulator Alignment and Motion Review Georg Gassner, SLAC / MET gassner@slac.stanford.edu 9 Integration of HLS with the Undulator Three capacitive sensors per girder reliable determination of height, roll and pitch One ultrasonic sensor per girder Absolute 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 girder reliable determination of height, roll and pitch One ultrasonic sensor per girder Absolute 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

10. October 21, 2005 Internal LCLS Undulator Alignment and Motion Review Georg Gassner, SLAC / MET gassner@slac.stanford.edu 10 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

11. October 21, 2005 Internal LCLS Undulator Alignment and Motion Review Georg Gassner, SLAC / MET gassner@slac.stanford.edu 11 End of Presentation