Transcript nuhn_alignment_diagnostics_20_apr_2006_r11.ppt

Undulator Alignment Strategy
Heinz-Dieter Nuhn, SLAC / LCLS
April 20, 2006
Alignment Overview
Alignment Tolerances
Alignment Monitoring
Correction Zones
Undulator Alignment Strategy – April 20, 2006
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Heinz-Dieter Nuhn, SLAC / LCLS
[email protected]
Undulator Alignment Overview
The focus of the undulator alignment is on
Quadrupoles and Beam Position Monitors (BPMs)
Beam Finder Wires (BFW)
Undulator Strongbacks (Segments)
The alignment procedures include
Girder Component Alignment [checked on CMM]
Conventional Tunnel Alignment
Beam Based Alignment (BBA) [Energy Scan followed by BFW]
Continuous Monitoring and Correcting of Component Positions
Auxiliary alignment procedures include
Segment Fiducialization [SUSA wrt. Segment fiducials]
Quadrupole Fiducialization [Magnetic center wrt. Quad fiducials]
BFW Fiducialization [Wire location wrt. BFW fiducials]
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Heinz-Dieter Nuhn, SLAC / LCLS
[email protected]
Main Alignment Concepts
Pre-alignment (baselining) uses the manual adjustments on top of the
support structures.
Relative alignment of Girder components is achieved and maintained
through common-girder mounting checked by CMM
Girder-to-Girder alignment is (remotely) controlled based on cam-shaft
technology
During initial alignment [with focus on quadrupole and BFW positions]
For quadrupole position control, i.e. beam steering during BBA
For compensation of ground motion effects etc.
Beam-Based-Alignment uses quadrupole magnets in two ways:
1) via off-center dipole fields. [Change is done through cam-based girder
motion, which will align all girder components to the beam. Minimum
motion range covers area of circle with 700 µm radius ]
2) via dipole trim-windings on Quadrupole Magnets (used for fine
adjustments.) [Range equivalent to ±100 µm of Quad motion]
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Heinz-Dieter Nuhn, SLAC / LCLS
[email protected]
Girder Components Summary
Main girder components include
Beam Finder Wire (BFW)
Undulator strongback arrangement mounted on horizontal slides
Vacuum chamber support
BPM
Quadrupole
Mounts for the Wire Position Monitor (WPM) system
Sensors of the Hydrostatic Leveling System (HLS)
Diagnostics components
The undulator strongback arrangement (Segment) is mountable on and
removable from the girder with the vacuum chamber in place and
without compromising the alignment of the vacuum chamber
Segments will be taken off the girder for magnetic measurements
Segments will be interchangeable without the need for the CMM
The complete girder assembly will be aligned on the Coordinate
Measurement Machine (CMM).
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Heinz-Dieter Nuhn, SLAC / LCLS
[email protected]
Beam Finder Wire (BFW)
BFW
A misaligned undulator will not steer the beam. It
will just radiate at the wrong wavelength.
The BFW allows the misalignment to be detected.
(also allows beam size measurements)
Vacuum Chamber
BFW
Wake Mitigation
Undulator
Quad
Wires
Beam Direction
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Heinz-Dieter Nuhn, SLAC / LCLS
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Undulator–to–Quad Fiducialization
Tolerance Budget
Vertical
[µm]
Horizontal
[µm]
10
20
10
25
10
20
10
25
20
20
20
15
20
20
40
20
30
30
20
50
Undulator Segment Roll-Away Repeatability
10
10
Alignment Quadrupole to Undulator
60
125
Grand Total [Beam-to-Undulator]
80
140
Quadrupole Fiducials
Pulsed Wire Center Definition
Wire to Wire Finder (WF) Fiducial
WF Fiducial to Quadrupole Fiducial
Quadrupole BBA Offset
Undulator Fiducials
Hall Probe Resolution/Positioning
Needle Hall Probe Resolution
Needle Center to Fiducial
Fixture Fiducial to Undulator Fiducial
Individual contributions are added in quadrature
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Heinz-Dieter Nuhn, SLAC / LCLS
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Undulator–to–BFW Fiducialization
Tolerance Budget
Vertical
[µm]
Horizontal
[µm]
20
10
20
30
20
10
20
30
20
15
20
20
40
20
30
30
20
50
X-Wire Positioning Repeatability
-
80
Y-Wire Positioning Repeatability
30
-
CAM Positioning Repeatability
4
4
Undulator Segment Roll-Away Repeatability
10
10
Alignment BFW to Undulator
55
100
Grand Total [Beam-to-Undulator]
80
140
BFW Fiducials
BFW Wire to Reference Stop
Reference Stop Definition
Reference Stop Fiducial
Undulator Fiducials
Hall Probe Resolution/Positioning
Needle Hall Probe Resolution
Needle Center to Fiducial
Fixture Fiducial to Undulator Fiducial
Individual contributions are added in quadrature
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Heinz-Dieter Nuhn, SLAC / LCLS
[email protected]
Alignment Tolerance Summary
Tolerances for Component Alignment on Girder
Value
Horizontal alignment of quadrupole and BPM to Segment (rms)
Vertical alignment of quadrupole and BPM to Segment (rms)
Horizontal alignment of BFW to Segment (rms)
Vertical alignment of BFW to Segment (rms)
Tolerances for Girder Alignment in Tunnel
Unit
125
µm
60
µm
100
µm
55
µm
Value
Unit
Initial rms uncorrelated x/y quadrupole alignment tolerance wrt straight line
100
µm
Initial rms correlated x/y quadrupole alignment tolerance wrt straight line
300
µm
Longitudinal Girder alignment tolerance
±1
mm
Undulator Segment yaw tolerance (rms)
240
µrad
Undulator Segment pitch tolerance (rms)
80
µrad
1000
µrad
Value
Unit
Undulator Segment roll tolerance (rms)
Component Monitoring and Control Tolerance
Horizontal / Vertical Quadrupole and BPM Positions (Depending on Zone)
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 ±2
µm
Heinz-Dieter Nuhn, SLAC / LCLS
[email protected]
Survey Monuments
Extract from ESD 1.4-113
Undulator Tunnel Survey
Monument Positions B. Fuss
1‘ stay-clear
wall monuments
(with removable spherical target)
6’
floor monument
(with removable spherical target)
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[email protected]
Undulator Hall Network
BTH
1600
UH Tunnel West
Side Thermal Barrier
STA 2237.33 ft
681.939 m
UH Tunnel Start
STA 1672.09 ft
509.653 m
1650
1700
1750
1800
1850
1900
1950
2000
2050
Undulator Hall Tunnel
Monuments
2100
2150
2200
24” Vertical Penetration
(approx. position)
2250
Beam
Dump
Tracker Positions
Quadruples
Inputs:
Results:
sD = 30 μm sh = 30 μm / D sv =50 μm /D
Tracker
Level
sdh = 50 μm
sz = 22 μm sx = 47 μm sy =46 μm
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[email protected]
Undulator Alignment Controls
Manual Adjustability:
Rough CAM position adjustability relative to fixed support.
ranges: x (12 mm); y (25 mm); z (12 mm)
Quadrupole, BFW, BPM, Vacuum Chamber, and Segment
adjustability to Girder.
ranges: x (>1 mm); y (>1 mm); z (>1 mm)
Remote Adjustability:
Girder: x, y, pitch, yaw, roll [1.5 mm x and y]
Enables alignment of all beamline components to the beam axis.
Roll motion capability is to be used to keep roll constant
Undulator: x [ 80 mm range]
Provides control of undulator field on beam axis.
Horizontal slide stages move undulator strongback independent of
Girder and vacuum chamber.
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Heinz-Dieter Nuhn, SLAC / LCLS
[email protected]
Undulator Segment Supports
Segment
Horizontal Slides
Manual Adjustments
Vacuum
Chamber
Support
Girder
Cam Movers
Manual
Adjustments
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Fixed Supports
Heinz-Dieter Nuhn, SLAC / LCLS
[email protected]
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Heinz-Dieter Nuhn, SLAC / LCLS
[email protected]
Undulator Alignment Monitoring Elements
Hydrostatic Leveling System (HLS)
Monitored Degrees of Freedom are: y, pitch, and roll
Wire Position Monitoring System (WPM)
Monitored Degrees of Freedom are: x, (y), (pitch), yaw, and roll
Temperature Sensors
In support of HLS/WPM readout corrections, undulator K corrections, and
component motion interpretation.
Beam Position Monitors*
Monitored quantities are: x and y position of electron beam
Quadrupoles*
Monitored quantities are: electron beam x and y offset from quad center
*Transverse
Locations Tracked by HLS and WPM
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Component Position Monitoring Systems
(Alignment Diagnostics System – ADS)
Wire Position Monitor system (WPM)
610 mm
Resolution
Instrument Drift
Moving Range
Accuracy
Availability
< 100 nm in X & Y direction
< 100 nm per day
±1.5 mm in X & Y direction
0.1 % of full Scale
Permanent, no interrupts
Position
Monitor
Wire1
240
•
•
•
•
•
280
Wire2
X and Y, can be measured
Roll, Jaw & Pitch can be calculated.
Hydrostatic Leveling System (HLS)
Sensing
Electrode
Electronic
Ceramic
plate
eAir
DAir
eWater
DWater
Capacitive Sensor
• Precision
< 1 mm
• Instrument Drift ~1-2 mm / month
• Accuracy < 0.1 % of full Scale
Y
height
Fiducial
Reference
surfaces
Ultrasound Sensor
• Precision
< 0.1 mm
• Instrument Drift potentially no drift
• Accuracy
< 0.1 % of full Scale
Ultrasound
Probe
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Beam
HLS 4
HLS 3
HLS 1
HLS 2
roll
Roll
pitch
Pitch
Y, can be measured
Roll & Pitch can be calculated.
Heinz-Dieter Nuhn, SLAC / LCLS
[email protected]
ADS…Common Sensor Support
265
50
Strongback
WPM supports
245
115
200
375
Quadrupole X & YPosition will be
measured relative to
the references.
550
470
WPM stay clear area
along entire Undulator
Quadrupole
200
55
90
260
25
Beam
245
245
155
80
M6
93
M6
H2O Level
60
130
M10
Roll, Pitch, Yaw and
Torsion of the Girder
can be calculated.
360
60
Girder
50
Girder
170
562
Girder
84
HLS pots
102
Distance to floor 1400 mm
2" Pipe
Yellow parts = Interface of
WPM & HLS to grider
SLAC / LCLS
720
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Engineering:
F. Peters
G. Gassner
Version:
Revision:
03/23/06
005
16
Dimensions in Millimeter
Wire Position Monitor &
Hydro Level System Interface
Heinz-Dieter Nuhn, SLAC / LCLS
[email protected]
Strategies for Controlling Component Motion
Girder motion will be caused by
Ground Motion
Temperature Changes
CAM Rotation
Girder motion will be monitored in 2 ways.
1. Directly, through the Alignment Diagnostics System
2. Indirectly, through impact on electron beam trajectory
(as detected by BPMs)
Girder Positions will be frequently corrected using the CAM
movers.
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Heinz-Dieter Nuhn, SLAC / LCLS
[email protected]
Correction Zones
Zone 1 (non-invasive correction)
• 120-Hz traj-feedback (LTU BPM’s)
• 0.1-Hz traj-feedback (und. BPM’s)
Zone 2 (Dt > 1 hr, P/P0 > 90%, non-invasive)
• Maintain component alignment based on ADS
mo
Zone 3 (Dt > 24 hr, P/P0 > 90%, non-invasive)
• Maintain component alignment based on ADS
• Possible x-ray pointing correction
Zone 4 (Dt > 1 mo, P/P0 > 75%, machine time)
• One iteration of BBA (<1 hr)
Zone 5 (Dt > 6 mo, shut-down)
• Reset movers set to zero and manual realignment (1 wk)
• Full 3 iterations of BBA (~3 hrs)
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Heinz-Dieter Nuhn, SLAC / LCLS
[email protected]
Alignment Function Diagram
MMF
USE OF DIAGNOSTICS COMPONENTS
Undulator Hall
Segment Tuning and Fiducialization
Supports Alignment
Quadrupole Fiducialization
Environmental Field Measurement
BFW Fiducialization
Girder Pre- Alignment
Component Alignment on Girder
ADS Installation
Undulator Segment Installation
Girder Alignment using ADS
Electron Beam-Based Alignment
Segment Tuning
ADS
Loose End-Alignment
(HLS/WPM)
BFWs
BPMs
Quads
Continuous Position Correction
Every 2 – 4 weeks: Invasive Correction
Once per month: Swap 3 Segments
Once every 6 month: Re-baselining
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Heinz-Dieter Nuhn, SLAC / LCLS
[email protected]
Conclusions
The X-ray-FEL puts very tight tolerances on magnetic field quality,
electron beam straightness, and Segment alignment.
These tolerances can be achieved through Beam Based Alignment
(BBA) procedures based on BPMs and Quadrupoles (with energy scan)
as well as BFWs.
Relative component alignment to required tolerances will be achieved
through common girder mounting.
Main tasks of the conventional alignment and motion systems are
Component fiducialization and alignment on girder
Conventional alignment of girders in Undulator Hall as prerequisite for BBA
The Alignment Diagnostic System measures and enables the correction
of girder movement due to ground motion, temperature changes, and
CAM mover changes.
A strategy is in place for using the monitor systems and controls to
establish and maintain a straight trajectory.
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Heinz-Dieter Nuhn, SLAC / LCLS
[email protected]
End of Presentation
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Heinz-Dieter Nuhn, SLAC / LCLS
[email protected]