Dan Potratz M.S. Student Mechanical Engineering Email: dcpotratz@wisc.edu 1335 ERB Hometown: Oshkosh, WI Thesis: Experimental Investigation and Confirmation of a Helium Thermosiphon 1

Experimental Investigation and Confirmation of the Predicted Performance of a Helium Thermosiphon Background: The Advanced Photon Source at Argonne National Lab is developing a superconducting undulator insertion device to supply higher intensity x-rays for its users. The design is predicated on a closed cryogenic platform to enable continuous operation with a minimal footprint. To operate as a superconductor, the NbTi wire used to produce the magnetic fields is cooled with liquid helium. The magnet structures are to be cooled with a helium thermosiphon passing through the cores. A large portion of the thermosiphon loop and the heat load occurs horizontally. The heat load available to induce the flow must be kept below 1.5 [W], which is the capacity of the cryocooler available for recondensing. 2

Experimental Set-Up 3

Key Areas of Interest Determine the heat load effect on mass flow rate Previous studies have focused on forced flow systems Establish the conditions at which vapor lock can occur Demonstrate the principles used in the cooling system design as capable for the desired performance Proposed Superconducting Undulator Insertion Device Design Y. Ivanyushenkov, SCU0 Conceptual Design Review, February 5, 2010 4