National Superconducting
Cyclotron Laboratory

Rao Ganni
Rao Ganni
Professor, Director for MSU Cryogenics Inititative
Accelerator Physics
M.S. Mechanical Engineering, Thermal Sciences, University of Wisconsin at Madison, 1976 Ph.D., Mechanical Engineering, Thermal Sciences, Oklahoma State University at Stillwater, 1979
Joined NSCL in 2016
Office 5320

Rao Ganni

The superconducting accelerators require helium cryogenic systems. The MSU-FRIB and many present day accelerators utilize Superconducting Radio Frequency (SRF) technologies and require 2 K cryogenic systems that are complex and extremely energy intensive. Many of the components for the cryogenic systems are adopted with limited research from commercial refrigeration systems, presenting a considerable opportunity for advancements in efficiency and reliability. The selection of the operating temperature is a multi-disciplinary and iterative optimization that has not yet been fully integrated in to these systems designs. Sub-system R&D and integrated multi-disciplinary design optimization is pivotal for efficient operation that provides high availability, reliability, maintainability and upgradability for the future accelerators and user facilities.

My research activities have been focused on advancement of thermodynamic principles and theories applied to cryogenic cycles, cryogenic systems and the related component development. Most of the research topics have been in the applied sciences related to cryogenic systems and they include thermodynamic exergy studies, heat exchangers, turbo machinery, screw compressors, sub-atmospheric pumping systems, control theories and instrumentation for these systems.

Many of the recent cryogenic systems installed or under construction have adopted practical advancements resulting from these theories, including the Ganni Cycle - Floating Pressure Technology. These complex cryogenic systems benefit immensely from these and other advancements in regards to the system efficiency, reliability and reducing both the initial and operating costs. These include, the cryogenic systems for the superconducting accelerators at Jefferson Lab (JLab) in Newport News, the SNS at Oak Ridge, RHIC at BNL, MSU-FRIB in East Lansing, LCLS-II at Stanford, and the James Webb Telescope Ground Testing facility at NASA in Houston.

Many years of working in industry and accelerator laboratories, as well as, building, commissioning and operation of these helium refrigeration systems for many of the particle accelerators, increased my curiosity for a deeper understanding of the thermodynamic principles in order to improve the efficiency, reliability and operational flexibility.

Development of practical and new cryogenic systems and components needed for the efficient and reliable operation of superconducting accelerators is my primary interest. My activities at FRIB presently concern sub-system components required for small scale 2-K helium refrigeration systems, small scale 2-K helium refrigeration system development, freeze-out purifiers for helium gas purification, and a controlled cool-down and warmup system for the FRIB fragment separator area magnets.

Selected Publications

V. Ganni, P. Knudsen, “Optimal Design and Operation of Helium Refrigeration Systems Using the Ganni Cycle,” Advances in Cryogenic Engineering 55, American Institute of Physics, New York (2010), 1057-1071.

V. Ganni, et al, “Compressor System for the 12 GeV Upgrade at Thomas Jefferson National Accelerator Facility”, Proceedings of the 23rd International Cryogenic Engineering Conference, Wroclaw, Poland, July 19-23, 2010, 859-863.

V. Ganni, et al, “Application of JLab 12 GeV Helium Refrigeration System for the FRIB Accelerator at MSU,” Advances in Cryogenic Engineering 59, American Institute of Physics, New York (2014).

V. Ganni, et al, “Helium Refrigeration Considerations for Cryomodule Design,” Advances in Cryogenic Engineering 59, American Institute of Physics, New York (2014).