• Y. Ivanyushenkov, K.D. Boerste, T.W. Buffington, C.L. Doose, Q.B. Hasse, M.S. Jaski, M. Kasa, S.H. Kim, R. Kustom, E.R. Moog, D.L. Peters, E. Trakhtenberg, I. Vasserman
  ANL, Argonne
• A.V. Makarov
  Fermilab, Batavia

Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.

An extensive R&D program is underway at the Advanced Photon Source (APS) with the aim of developing a technology capable of building a 2.4-m-long superconducting planar undulator for APS users. The initial phase of the project concentrates on using a NbTi superconductor and includes magnetic modeling, development of manufacturing techniques for the undulator magnet, and design and test of short prototypes. The current status of the R&D phase of the project is described in this paper.

• S.H. Kim, C.L. Doose, Y. Ivanyushenkov
  ANL, Argonne

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.

The baseline configuration of the proposed International Linear Collider includes superconducting helical undulators as a scheme to produce positrons. This paper presents a conceptual design of the magnetic field measurement system for helical undulators with the undulator axis in a horizontal direction at liquid helium temperature. The system consists of a cryomodule and a linear stage unit with a travel length of approximately 3.5 m. The linear stage unit provides the motion control for the Hall probe housing, which is connected to a small-diameter carbon fiber rod inside bellows-flange connections. Stainless steel bellows are at the same vacuum pressure as the cold mass in the cryomodule. A linear encoder is used for motion control of the stage, but precise position measurement of the Hall probe relies on the laser interferometer system.