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

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

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

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

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

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