Status of the spallation neutron source superconducting RF facilities

The spallation neutron source (SNS) project was completed with only limited superconducting RF (SRF) facilities installed as part of the project. A concerted effort has been initiated to install the infrastructure and equipment necessary to maintain and repair the superconducting Linac, and to support power upgrade research and development (R&D). Installation of a Class 10/100/10,000 cleanroom and outfitting of the test cave with RF, vacuum, controls, personnel protection and cryogenics systems is underway. A horizontal cryostat, which can house a helium vessel/cavity and fundamental power coupler for full power, pulsed testing, is being procured. Equipment for cryomodule assembly and disassembly is being procured. This effort, while derived from the experience of the SRF community, will provide a unique high power test capability as well as long term maintenance capabilities. This paper presents the current status and the future plans for the SNS SRF facilities.

INTRODUCTION

The SNS project was completed in June 2006 with only limited SRF facilities installed as part of the project, namely a 5 MW, 805 MHz RF test stand, a fundamental power coupler processing system, a concrete test cave shell, and temporary cleaning/assembly facilities. Approximately 800 of the nominal 1000 MeV of H-acceleration is provided by 23 superconducting RF cryomodules, 11 of which are 3 cavity, structures, and 12 are 4 cavity, structures. Recent operational experience has resulted in the turning off of several cavities due to excessive fundamental power coupling through higher order mode (HOM) antennas, while other cavities performance is limited by field emission [1]. Thus a concerted effort has been initiated to install the infrastructure and equipment necessary to maintain and improve the superconducting Linac.