Engineering topics
Publications and source records attributed to Brennan, J.M..
The Electron-Ion Collider (EIC) is being designed for construction at Brookhaven National Laboratory. Activities have been focused on beam-beam simulations, polarization studies, and beam dynamics, as well as on maturing the layout and lattice design of the constituent accelerators and the interaction region. The latest design advances will be presented.
The Electron Ion Collider (EIC) Hadron Storage Ring (HSR) will use the existing Relativistic Heavy Ion Collider storage rings, including the superconducting magnet arcs [1]. The vacuum chambers in the superconducting magnets and the cold mass interconnects were not designed for EIC beams and so must be updated to reduce resistive-wall heating and to suppress e-clouds. To do so without compromising the EIC luminosity goal, a stainless steel beam screen with colaminated copper and a thin layer of amorphous carbon will be installed. This paper describes the main requirements that our solution for the hadron ring vacuum chamber needs to satisfy, including impedance, aperture limitations, vacuum, thermal and structural stability, mechanical design, installation and operation. The conceptual design of the beam screen currently under development is introduced.
The EIC will make use of the existing RHIC storage rings with their superconducting (SC) magnet arcs. A stain-less-steel beam screen with co-laminated copper and a thin amorphous carbon (aC) film on the inner surface will be installed in the beam pipe of the SC magnets. The copper will reduce the beam-induced resistive-wall (RW) heating from operation with the higher intensity EIC beams, that if not addressed would make the magnets quench. Limiting the RW heating is also important to achieve an adequately low vacuum level. The aC coating will reduce secondary electron yield which could also cause heating and limit in-tensity. Among all the RHIC SC magnets, the arc dipoles present the biggest challenge to the design and installation of beam screens. The arc dipoles, which make up for 78% (2.5 km) length of all SC magnets in RHIC, expect the larg-est RW heating due to their smallest aperture. These mag-nets are also the longest (9.45 m each), thus experiencing the largest temperature rise over their length, and have a large sagitta (48.5 mm) that increases the difficulty to in-stall the beam screen in place. This paper presents a de-tailed thermal analysis of the magnet-screen system.
A folded coaxial tuner without spring fingers was de-signed for the Low Energy Relativistic Heavy Ion Collider (RHIC) electron Cooler (LEReC) 2.1 GHz warm cavity. During RHIC run 2019, this tuner was found to cause cavity trips via different failure modes. After analyzing these failure modes, a new straight coaxial tuner without spring fingers was proposed and was installed. We show the operational experience of the new tuner in this paper.
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