There are two sources for the ML requirements:
1. 300 μm / 200 m. (We assume this is quad to quad) and 2 mm / km global. Source: (Chris Adolphson)
2. Following are the tolerances for the alignment of quadrupoles
and cavities in the Main Linac Area.
This information was obtained from Kiyoshi Kubo who is the
group leader of the Accelerator Physics tech. group. They did
some simulation on emittance growth as a function of alignment
BPM Offset w.r.t. Cryomodule = 300 micron
Quad Offset w.r.t. Cryomodule = 300 micron
Quad Rotation = 300 μrad
Cavity Offset w.r.t. Cryomodule = 300 micron
Cryomodule Offset = 200 micron
Cavity Pitch w.r.t. Cryomodule = 300 μrad
Cryomodule Pitch = 20 μrad
Here, w.r.t. stands for “with respect to”, and these tolerances should
be applied to the distance about 200m which corresponds to half of the
betatron wave length.
Kiyoshi said there is no documentation yet on these tolerances but
these values are common understanding among the people of Accelerator
Physics tech. group.
- Ryuhei Sugahara, KEK