Cryogenic Controls for Fermilab's SRF Cavities and Test Facility.

摘要

A new superconducting radio frequency (SRF) cavities test facility is now operational at Fermilab's Meson Detector Building (MDB). The facility is supplied cryogens from the Cryogenic Test Facility (CTF) located in a separate building 500-m away. The design incorporates ambient temperature pumping for super-fluid helium production, as well as three 0.6-kW at 4.5-K refrigerators, five screw compressors, a helium purifier, helium and nitrogen inventory, cryogenic distribution system, and a variety of test cryostats. To control and monitor the vastly distributed cryogenic system, a flexible scheme has been developed. Both commercial and experimental physics tools are used. APACS+, a process automation control system from Siemens-Moore, is at the heart of the design. APACS+ allows engineers to configure an ever evolving test facility while maintaining control over the plant and distribution system. APACS+ nodes at CTF and MDB are coupled by a fiber optic network. DirectLogic205 PLCs by KOYO are used as the field level interface to most I/O. The top layer of this system uses EPICS (Experimental Physics and Industrial Control System) as a SCADA/HMI. Utilities for graphical display, control loop setting, real time/historical plotting and alarming have been implemented by using the world-wide library of applications for EPICS. OPC client/server technology is used to bridge across each different platform. This paper presents this design and its successful implementation.