Fabrication Process of Rounded Damped Detuned Structure

TL;DR

This paper details the fabrication process of Rounded Damped Detuned Structures (RDDS) with curved cavities, emphasizing techniques to achieve high precision and minimal misalignment for linear collider applications.

Contribution

It introduces advanced fabrication techniques for RDDS disks with micron-level accuracy, building upon previous DDS methods for improved structure performance.

Findings

Achieved +-1 micron surface accuracy in RDDS1 disks.

Disks showed minimal misalignment within 1 micron.

Successfully corrected bowing and flares in assembled structures.

Abstract

Following the successful design and fabrication of Damped Detuned Structures (DDS), the JLC/NLC linear collider project advanced to Rounded Damped Detuned Structures (RDDS) with curved cross section of the cavity shape for increased shunt impedance. Various advanced techniques for fabricating RDDS1 disks comparing to those for DDS were established to satisfy the dimension accuracy of +-1 micron over the entire surface made by ultra-precision turning. These disks were assembled with almost the same stacking and bonding jigs and processes as those of DDS3 assembly. In consequence, the assembly showed little disk-to-disk misalignment within 1 micron before and after the process. Though, it had 200 micron smooth bowing, which was subsequently corrected as DDS3, and flares at both ends.