Emittance compensation in a superconducting rf gun with a magnetic mode

K. Flöttmann; D. Janssen; V. Volkov

doi:10.1103/PhysRevSTAB.7.090702

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Emittance compensation in a superconducting rf gun with a magnetic mode

K. Flöttmann, D. Janssen, V. Volkov

DOI 10.1103/PhysRevSTAB.7.090702 · Physical Review Special Topics - Accelerators and Beams

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Abstract

External fields are necessary for emittance compensation and beam focusing in rf photoelectron guns. For rf guns with superconducting cavities two fields have been discussed up to now. The first field is a specially designed radial component of the rf field immediately after the cathode and the second is a static magnetic field downstream of the superconducting cavity. In this paper we discuss a third possibility. Inside the cavity the magnetic rf field of a TE mode focuses the electron beam and prevents the increase of the transverse emittance. The results depend only weakly on the phase of the TE mode. For a bunch charge of 1 nC, an emittance of 0.7 mm mrad has been obtained with a surface field strength of the magnetic field below the quench limit.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
Nb Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown