Experimental And Analytical Investigation Of Steady-State Thermal Profile Of Forced-Flow Ln₂-Cooled Thermal Radiation Shield For Superconducting Linear Accelerator Cryomodule

Abstract

Acceleration of heavy ions through the superconducting linear accelerator is achieved by superconducting resonators housed in the cryomodules operating at 4.2 K. In the cryomodule, radiation heat flow from the ambient to the 600 kg of cold mass at 4.2 K is thermally screened by the intermediate thermal shield made of copper. The six surfaces of 17 m² total surface area of the box-shaped thermal shield are cooled in series by the forced flow of liquid nitrogen at 3.2 bar absolute pressure. The boiling temperature of liquid nitrogen at 3.2 bar is 90 K. The steady-state temperatures of the different surfaces of the thermal shield are in the range of 96–115 K at 21.25 L/h flow rate. The steady-state thermal profile of the different surfaces of the thermal shield has also been estimated for different flow rates using a simple analytical technique. The analytical thermal profile of the thermal shield has been correlated with the experimental measurement.