LCLSII cryomodule alignment LCLSII cryomodule alignment Topics Alignment

LCLS-II cryomodule alignment

LCLS-II cryomodule alignment Topics • Alignment of Components inside the CM • Tunnel Network • Tolerances LCLS-II cryomodule alignment workshop Friday May 22 nd at FNAL https: //indico. fnal. gov/conference. Display. py? conf. Id=9994 Wednesday meeting, 6/17/2015 2

Mechanical design – images from the CAD model (from Yuriy Orlov) • 38” vacuum vessel with 8” vacuum releave valve. • 2 - cryomodule adjustment supports • Sliding interconnection Bellow. • 8 - coupler ports with power couplers and vacuum manifold. • Instrumentation ports & magnet CL Flange. Wednesday meeting, 6/17/2015 3

Mechanical design – images from the CAD model (from Yuriy Orlov) • Cryomodule length: ~12. 3 m • 3 supports for cold mass (1 -fix. and 2 -sld. ) • 300 mm –ID, 12 m long tube, as backbone for cavity string, piping system and thermal shielding. • 8 - 9 -cell dressed elliptical SRF cavities(with mag. Shielding) + 1 -BPM +1 - SC splitable quadrupole + 2 Gate valves. (one of the each end of Cavity string) • Piping system of Cryomodule. • 50 K aluminum shielding with 30 layers of MLI insulation around cold mass. Wednesday meeting, 6/17/2015 4

BPM & QUAD Wednesday meeting, 6/17/2015 5

Cavity alignment (from Virgil Bocean) The RF group will provide the mechanical to electrical center offsets for each cavity with respect to the cavity end flanges Offsets of 300µm between electrical and mechanical centers have been found. Tolerance of individual cell? Wednesday meeting, 6/17/2015 6

String Alignment in warm conditions Different offsets between Cavities (x=0. 24 mm; y=1. 97 mm) and Quad (x= 0. 00 mm; y=1. 97 mm) Tolerance: 150µm, wavelength 13 m Wednesday meeting, 6/17/2015 7

Cold vs. Warm repeatability Wednesday meeting, 6/17/2015 8

String Alignment: Cold vs. warm Z position changes of up to 17 mm depending on distance to main support. Offsets are based on DESY numbers. Tolerance: +/-0. 175 mm RMS, 3 m pattern (the support posts seem to be stable) Wednesday meeting, 6/17/2015 9

Cold mass vs. vacuum vessel Support posts are removed during installation, repeatability needs to be determined No possibility to check movements after insertion into vacuum Vessel. Wednesday meeting, 6/17/2015 10

Cold mass vs. vacuum vessel Fiducial on gate valve and support posts will be transferred to vacuum vessel fiducials Tolerance: <100µm (picture curtesy Tom Peterson) Wednesday meeting, 6/17/2015 11

QC at SLAC after transport Same measurements as cold mass vs. vacuum vessel, gate valve fiducials and support posts relative to vacuum vessel fiducials. DESY reported up to 300µm discrepancies. Acceptance tolerances have to be specified. Tolerance: 0. 3 mm RMS, 3 m pattern (I assume that the support posts don’t move) Wednesday meeting, 6/17/2015 12

Tunnel Alignment Local alignment of CM: 0. 05 mm RMS, every 15 m Alignment network: 0. 3 mm RMS at 100 m distance. Coordinate change [µm] Tunnel is narrow -> refraction will affect measurements. Position [m] Wednesday meeting, 6/17/2015 13

Summary of Alignment Tolerances Different aspects of error budget stack up: Relative alignment of cavities to string: +/-0. 075 mm RMS; every 1. 3 m Cold/warm uncertainty: +/-0. 175 mm RMS, 3 m pattern (the support posts seem to be stable) Transport shifts: 0. 3 mm RMS, 3 m pattern (I assume that the support posts don’t move) Single cavity to cavity assembly: 0. 3 mm RMS? , every ~0. 15 m Alignment of components in the tunnel: 0. 05 mm RMS, every 13 m Alignment network: 0. 3 mm RMS, ~100 m wavelength Wednesday meeting, 6/17/2015 14