Development of an eccentric cam-based active pre-alignment system for the compact linear collider main beam quadrupole magnet

Abstract

Compact linear collider (CLIC) is a study for a future electron–positron collider that would allow physicists to explore a new energy region beyond the capabilities of today's particle accelerators. The demanding transverse and vertical beam sizes and emittance specifications are resulting in stringent alignment and a nanometre stability requirement. In the current feasibility study, the main beam quadrupole magnets have to be actively pre-aligned with a precision of 1 µm in five degrees of freedom before being mechanically stabilized to the nanometre scale above 1 Hz. This contribution describes the approach of performing this active pre-alignment based on an eccentric cam system. In order to limit the amplification of the vibration sources at resonant frequencies, a sufficiently high eigenfrequency is required. Therefore, the contact region between cam and support was optimized for adequate stiffness based on the Hertzian theory. Furthermore, practical tests performed on a single-degree-of-freedom mockup will show the limitation factors and further improvements required for successful integration in a full-scale quadrupole mockup presently under design.

Control strategies for the final focus of future linear particle collider

“…Apart from the increased robustness to the technical noise, the cables also allows to change the position of the cantilever tube, and can potentially replace the alignment stage currently foreseen inside the tube [32]. …”

Validation test of a cam mover based micrometric pre-alignment system for future accelerator components

“…One degree of freedom mock-up Fig.6 presents the 1 d.o.f. mock-up described in [5]. The cam mover (A) is installed under a cam follower plate (B).…”

Budgeting and control of the mechanical noise in the International Linear Collider final focus system

“…For the CLIC [5][6][7] beam structure intratrain feedback is less efficient and a combination of a careful design of the support structures with an active stabilization system is required [8][9][10], in combination with a repositioning system [11] and a preisolator [12]. The CLIC final doublet is required to be as stable as 0.15 nm above 4 Hz [5].…”