Transcript Bench Requirements.ppt

Undulator Bench
Requirements
Zack Wolf
SLAC
October 14, 2004
Undulator Bench Requirements
Zack Wolf
[email protected]
Introduction
 We require a measurement bench to move
probes through the undulators.
 To purchase the bench, we must determine
specifications for it:
 Physical characteristics such as the length
must be determined.
 The quality of the bench performance must
be specified.
October 14, 2004
Undulator Bench Requirements
Zack Wolf
[email protected]
Measurement System Overview
October 14, 2004
Undulator Bench Requirements
Zack Wolf
[email protected]
Example Of A Bench
Stages, Probes
ANL Bench
Carriage
Bench
Air Bearing
(Vacuum Load)
Drive
Vertical Reference
Surface
Horizontal Reference
Surface
Photo courtesy of R. Ruland
October 14, 2004
Undulator Bench Requirements
Zack Wolf
[email protected]
Tasks and Measurement Equipment
Requirements




Straighten trajectory (Hall probe, coil)
K vs x (Hall probe)
Phase shimming (Hall probe)
First and second field integrals (Hall probe, coil,
wire system)
 Phase matching (Hall probe, two undulators on
bench)
 Fiducialization (Add “pointed” magnets, bench flat)
Account for all equipment space requirements when specify length.
October 14, 2004
Undulator Bench Requirements
Zack Wolf
[email protected]
Bench Dimensions
 Length, important
 Transverse dimensions, leave up to
manufacturer to meet probe motion
tolerances, handling requirements, etc.
 Shape, need carriage constrained so air
bearing can not come free
Need to specify length and shape
October 14, 2004
Undulator Bench Requirements
Zack Wolf
[email protected]
Bench Length
Wire
System
Phase
Matching
Specify: 8 m bench
October 14, 2004
Undulator Bench Requirements
Zack Wolf
[email protected]
Bench Shape
Roll Stage,
Goniometer
Hall Probe
X Y Stage
Carriage
Linear Motor
Granite Table
DESY Bench
Carriage is captured.
October 14, 2004
Undulator Bench Requirements
Zack Wolf
[email protected]
Quality of Bench Construction
 Probe position affects the measurement
results.
 Bench errors affect the probe position.
We must specify the bench errors so the
measurements are within tolerance.
October 14, 2004
Undulator Bench Requirements
Zack Wolf
[email protected]
Plan to Specify Bench Error Limits
Bench Error
Probe Motion Error
Measurement Error
Calculated Undulator Parameter Error
Undulator Error After Tuning
October 14, 2004
Undulator Bench Requirements
Zack Wolf
[email protected]
Undulator Requirements*
Parameter
Value Units
Max trajectory walkoff per 10 m 5
mm
Max first field integral
Max second field integral
Electron phase deviation
RMS magnet error DB/B
40
50
10
0.015
mTm
mTm2
degrees
%
*From the LCLS parameters database on the web.
October 14, 2004
Undulator Bench Requirements
Zack Wolf
[email protected]
Measurement Result Error Limits
Parameter
Value
Units
mm
Calc trajectory walkoff in undulator 2
Calc trajectory slope at exit
8.80x10-7
Calc trajectory offset at exit
1.10x10-6
m
Calc phase deviation
10
deg
Field measurement accuracy
0.015
%
October 14, 2004
Undulator Bench Requirements
Zack Wolf
[email protected]
Probe Motion Errors
Probe motion errors cause
measurement errors which cause
errors in calculated undulator parameters
Actual path
Ideal path
Need limits on dx, dy, dz, and dp
October 14, 2004
Undulator Bench Requirements
Zack Wolf
[email protected]
Vertical Probe Motion
By
By(y, z) = B0 cosh(2py/lu) sin(2pz/lu)
Vertical probe motion error limit
set by field measurement accuracy
(LCLS-TN-04-8):
By
DB
Dy
y
For DB/B0 < 0.015 %,
Dy < 83 mm
Take Dymax = 20 mm
(Agrees with fiducialization requirement of 20 μm.)
October 14, 2004
Undulator Bench Requirements
Zack Wolf
[email protected]
Horizontal Probe Motion
DB/B0 = -(0.77 1/m) Dx
Horizontal probe motion error limit
set by field measurement accuracy
(LCLS-TN-04-8):
By
DB
Dx
x
For DB/B0 < 0.015 %,
Dx < 195 mm
Take Dxmax = 40 mm
(Agrees with fiducialization requirement of 40 μm.)
October 14, 2004
Undulator Bench Requirements
Zack Wolf
[email protected]
Axial Probe Motion
Calculated trajectory offset error places limit Dzmax = 5.9 mm
Take Dzmax = 3 mm
(LCLS-TN-04-8)
October 14, 2004
Undulator Bench Requirements
(Don’t use entire error budget on one error.)
Zack Wolf
[email protected]
Summary of Probe Motion Requirements
Parameter
Value
Units
Maximum vertical deviation Dy
20
mm
Maximum horizontal deviation Dx
40
mm
Maximum axial deviation Dz
3
mm
Maximum probe angle error
8
mrad
(see LCLS-TN-04-8 for details)
October 14, 2004
Undulator Bench Requirements
Zack Wolf
[email protected]
Bench Errors Cause Probe Motion
X Deviation (Δx)
Y Deviation (Δy)
Pitch Deviation (Δy, Δz)
October 14, 2004
Undulator Bench Requirements
Roll Deviation (Δy)
Yaw Deviation (Δz)
Zack Wolf
[email protected]
Summary of Bench Construction Requirements
Parameter
Probe
Motion
Carriage x deviation
Dx
Carriage y deviation
Dy
Carriage roll deviation
Dy
Carriage pitch deviation Dy, Dz
Carriage yaw deviation Dz
October 14, 2004
Undulator Bench Requirements
Quad
Limit
40
14
14
4.2
4.2
Zack Wolf
[email protected]
Units
mm
mm
mrad
mrad
mrad
Conclusion
We request from the vendor
1) An 8 meter long bench, 7 meters of travel
2) Carriage motion with the following specifications
Parameter
Max
Units
Carriage x deviation
40
mm
Carriage y deviation
14
mm
Carriage roll deviation
14
mrad
Carriage pitch deviation
4.2
mrad
Carriage yaw deviation
4.2
mrad
3) Limit switches, brakes, bench non-magnetic, …
(see LCLS-TN-04-8 for complete list)
October 14, 2004
Undulator Bench Requirements
Zack Wolf
[email protected]