1. Alignment of Main Linac Cryomodule (MLC)
Yun HE
MLC Internal Review
9/5/2012
Yun HE, MLC Internal Review

2. Yun HE, MLC Internal Review
Outline
Beamline support and alignment
Alignment of beamline at room temperature
Monitoring beamline position at cold
Differential thermal contractions during cool-down
9/5/2012
Yun HE, MLC Internal Review

3. Beamline support and alignment
HGRP determines longitudinal position
Precision machined surfaces with central pin holes
guarantee vertical/horizontal alignment
Alignment pins provides horizontal alignment
Alignment keys allow for differential thermal displacement of beamline components relative to HGRP
Flexible support allows for differential thermal displacement of helium vessel relative to HGRP during cool-down/warm-up
9/5/2012
Yun HE, MLC Internal Review

4. Alignment of beamline at room temperature
Level of posts can be adjusted via 4 rods
Adjust post position using references on vacuum vessel end flange
All interfaces are precision machined surfaces
w/ tolerances <±0.001”
Flat reference surfaces spaced 90° apart
on vacuum vessel end flanges
Two alignment pins
9/5/2012
Yun HE, MLC Internal Review

5. Monitoring beamline position at cold
For prototype module only
Mounted on end cap flanges (room temperature), thus the wire position is not influenced by cool-down
Two sensors for 1st, 3rd, 5th cavities
One sensor for each of the rest three cavities
Sensors attached to end flange of cavity LHe vessel
Heat treated CuBe wire (ɸ0.5 mm) is stretched parallel to the beam axis providing a position reference
A WPM sensor consists of four striplines spaced 90° apart
9/5/2012
Yun HE, MLC Internal Review

6. Differential contraction between shield and HGRP during cool-down
Sliding post
Fixed post
Sliding post
Left/right posts can move relative to shield in Z axis during cool-down
At room temperature, side post was
offset to vac vessel port center
Concentric to shield opening
At cold, side post moved due to HGRP contraction, became
concentric to vac vessel port center
Slightly offset to shield opening center
9/5/2012
Yun HE, MLC Internal Review