Support System and Alignment. Sushil Sharma ME Group Leader ASAC Review of NSLS-II July 17-18, 2008. Support System and Alignment Team.
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ME Group Leader
ASAC Review of NSLS-II
July 17-18, 2008
R. Alforque, M. Anerella, C. Channing, L. Doom, G. Ganetis, P. He, A. Jain, P. Joshi,P. Kovach, F. Lincoln, S. Plate, V. Ravindranath, J. Skaritka
Alexander Temnykh(Cornell University, Ithaca, NY)
Storage Ring Cell
The low-emittance lattice has stringent alignment and stability requirements that have been met by innovative and cost-effective solutions.
For acceptable dynamic aperture the SR support system must meet the following alignment requirements:
* 30 µm is the goal; acceptable limit is 50 µm. An analysis of tolerance stack-up shows that 30-50 µm alignment is not possible with conventional support designs and alignment techniques.
Weight - 3200 kg
Length - 4.83 m
Width - 0.86 m
Height - 0.55 m
Wire Vibration detectors
(LED phototransistors, ~ 13 mV/micron)
Granite table for supporting magnets during R&D phase
Magnet movers(1 micron resolution)
Magnet Torque Test
X Center is given by intersection with 0A line
The magnet center can be located to within 4 μm.
Horizontal center, defined as the point of zero slope in B_y Vs. X, can be located to within 5 μm.
X-Y positioning fixture
Integral air jack
Differential screws provide .002mm per degree of hand wheel rotation
Girder with positioning fixtures installed
Torque wrench with 13:1
Hydraulic torque wrench
with split head design
Stability Requirements (Vibration and Thermal)
RMS Displacements at CFN (N. Simos)
( 0.5 - 4) Hz : 145 nm
(4 - 30) Hz : 14 nm
(30 - 100) Hz : 1 nm
Support System Design Approach: First resonant frequency > 30 Hz the rms motion that will be amplified by the magnets-girder assembly is only 1 nm.
Girder with Dummy Weights
Vibration tests were performed on:
Rocking Mode, 42 Hz
Bending Mode, 58 Hz
Twisting Mode, 112 Hz
Young’s modulus of the 2” bolt reduced by a factor of 10
MODE 1 ~40 Hz
Maximum vertical misalignment between the magnets: ~0.014 μm (tolerance = 0.025 μm )
Maximum vertical deflection of the vacuum chamber at the BPM locations (near Invar supports) : ~ 0.14 μm (tolerance = 0.20 μm)
DVRT (Displacement Variable Reluctance Transducer)
Composite Support Stand
Mechanical stability requirement: ±0.1 μm (rms, 4-50 Hz)
Stability – L-H Hua, S. Kramer, S. Krinsky, I. Pinayev, O. Singh, F. Willeke
Design – T. Dilgen, B. Mullany, D. Sullivan, W. Wilds