Thermal Transition Design and Beam Heat-load Estimation for the COLDDIAG Refurbishment

The COLDDIAG (cold vacuum chamber for beam heat load diagnostics)
developed at Karlsruhe Institute of Technology has been modified for more
studies at cryogenic temperatures different from the previous operations at 4
K in a cold bore and at 50 K in a thermal shield. The key components in this
campaign are two thermal transitions connecting both ends of the bore at 50
K with the shield at the same or higher temperature. In this paper, we
present design efforts for the compact transitions, allowed heat intakes to the
cooling power margin and mechanical robustness in the cryogenic
environment. A manufacture scheme for the transition and its peripheral is
also given. In addition, the beam heat loads in the refurbished COLDDIAG are
estimated in terms of the accelerator beam parameters.