Design of Liquid Nitrogen Cooled 80 K Thermal Shield and Flexibility Analysis of Internal Piping for Cryogenic Distribution Box of Horizontal Test Stand

Horizontal Test Stand (HTS) cryostat at RRCAT is capable of housing two high beta 650 MHz dressed Superconducting Radio Frequency (SCRF) cavities at nominal 2 K in a single cool down and can absorb the 50 W dissipative power by cavity. Test stand plays an important role for developing and testing superconducting pulsed proton accelerator project at RRCAT. Achieving and maintaining a stable cryogenic temperature at 2 K in HTS on regular and reliable basis is a challenging task and requires broad range of cryogenic expertise, large scale system level understanding and many in-house technological and process developments. Detailed design of distribution box for efficient distribution of cryogen is very important for reliable operation of HTS. Liquid nitrogen cooled 80 K shield is one of the important components of distribution box to arrest the ambient heat in leak and reduce the heat load. Present paper describes the flexibility analysis, design of 80 K nitrogen shielding, cool-down study, different tube tracing arrangements for efficient cooling of the shield and effect of thermal parameters.