Wide energy bandwidth superconducting accelerating cavities

Abstract

a b s t r a c tSuperconducting cavities have been widely used in high intensity proton accelerators. In this paper, we discuss parameters that affect energy bandwidth of the accelerating cavity and propose a new energy averaged transit time factor to help choose transition energy between different sections and cavity geometry parameters in the linac design. These wide energy bandwidth superconducting cavities can potentially be used to accelerate a proton beam multiple times. A time-pass condition is defined to attain fixed RF phases during multiple passes of the beam. Such a superconducting recirculating proton linac could significantly reduce the number of RF cavities in the accelerator and lower construction and operational costs of the facility.

Beam dynamics simulation of a double pass proton linear accelerator

“…A multi-GeV recirculating proton LINAC was proposed in Ref. [8]. There, an initial 150 MeV proton beam is accelerated in three sections of recirculating LINAC to attain a final 8 GeV energy.…”

“…However, despite the success for an electron beam, the recirculating concept for a proton beam is not yet well studied. Especially, the subtlety of rf phase synchronization for a recirculated proton beam must be studied [8].…”

“…When the beam passes LINAC only twice, the phase synchronization can be achieved with proper choice of the separation length between the cavities [8]. It can be understood by the following condition:…”

Overtaking collision effects in a cw double-pass proton linac

“…The concept of a recirculating proton linac was recently proposed in Ref. [8] and is shown in Fig. 1.…”

“…A synchronous condition proposed in Ref. [8] has to be satisfied in order to accelerate the proton beam multiple times using the same fixed rf phase inside a cavity.…”