Open Cavity Solutions to the rf in Magnetic Field Problem

TL;DR

This paper investigates how magnetic field orientation affects RF breakdown in cavities, proposing an open iris design with solenoid coils to improve performance in muon collider cooling systems.

Contribution

It introduces a novel cavity design concept that mitigates breakdown issues by adjusting magnetic and electric field angles, with a proposed lattice for 6D muon cooling.

Findings

Breakdown occurs at lower gradients with axial magnetic fields in pill-box cavities.

Open iris cavities show different breakdown behavior depending on magnetic field orientation.

A new lattice design for 6D cooling using this principle is proposed.

Abstract

It has been observed \cite{break} that breakdown in an 805 MHz pill-box cavi ty occurs at much lower gradients as an external axial magnetic field is inc reased. This effect was not observed with on open iris cavity. It is propose d that this effect depends on the relative angles of the magnetic and maximu m electric fields: parallel in the pill-box case; at an angle in the open ir is case. If so, using an open iris structure with solenoid coils in the iris es should perform even better. A lattice, using this principle, is presented, for use in 6D cooling for a Muon Collider. Experimental layouts to test th is principle are proposed.