LCLS prototype undulator report.

Abstract

The Linac Coherent Light Source (LCLS) undulator line will consist of 33 undulator segments separated by breaks of two different lengths. The undulator segments are 3.4-m-long permanent-magnet planar hybrid devices with a period length of 30 mm and a magnetic gap of approximately 6 mm. Focusing quadrupoles, in a FODO lattice, and electron-beam diagnostics will be located in the breaks between undulator segments. Every third break will be longer in order to also accommodate x-ray diagnostics. Thus, taking the alternating focusing and defocusing quadrupoles into account, the ''super-period'' length before the undulator line repeats itself is six undulator segments. For additional details on the LCLS project and the undulator line, please refer to the conceptual design report (CDR). A full-length prototype undulator segment has been designed, manufactured and tested, and this document provides a comprehensive report of our experience with the prototype. It contains sections on the overall design philosophy and presents many important measurements including magnetic measurements of the magnet blocks, as well as of the assembled device, and mechanical and thermal measurements. It also contains a summary section (section 5) and one section that summarizes some remaining issues being investigated (section 6).