Thermal Engineering of the Cryogenic Beam Position Monitors for the EIC Hadron Storage Ring

Abstract The Electron Ion Collider (EIC) Hadron Storage Ring (HSR) will reuse most of the existing superconducting magnets from the RHIC storage ring. However, the existing stripline beam position monitors (BPM) used for RHIC will not be compatible with the planned EIC hadron beam parameters that include higher intensity, shorter bunches, and some operational scenarios with large radial offsets of the beam in the vacuum chamber. To address these challenges, the existing RHIC stripline BPMs will be decommissioned, and a new BPM design using button pick-ups integrated in a new vacuum interconnect/bellows assembly will be installed adjacent to the decommissioned BPMs. A dedicated analysis of the new BPM housing and button pick-up design has been conducted to assess the thermal effects caused by heat conduction, beam induced resistive wall heating and the RF heating from the BPM signal propagation through the cryogenic cables. This paper reports on the thermal design and analysis results to quantify the heat transfer and temperature distribution that can be expected on the new HSR cryogenic BPM.