New compact TEM-type deflecting and crabbing rf structure

Self Cite

Recent applications in need of compact low-frequency deflecting and crabbing cavities have initiated the design and development of new superconducting structures operating at high gradients with low losses. Previously, TM 110 -type deflecting and crabbing cavities were developed and have also been operated successfully. However, these geometries are not favorable designs for low operating frequencies. The superconducting rf-dipole cavity is the first compact deflecting and crabbing geometry that has demonstrated high gradients and high shunt impedance. Since the fundamental operating mode is the lowest mode and is widely separated from the nearest higher order mode, the rf-dipole design is an attractive geometry for effective damping of the higher order modes in high current applications. A 400 MHz rf-dipole cavity was designed, fabricated, and tested as a proof-of-principle cavity. The cavity achieved high operating gradients, and the multipacting levels were easily processed and did not reoccur.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cryogenic test of a proof-of-principle superconducting rf-dipole deflecting and crabbing cavity

Silva

Delayen

2013

Self Cite

“…To restore this capability, several options including the extension of existing CEBAF normal conducting (NC) structures or a potential 499 MHz TEM-type superconducting (SC) design [1] are under investigation. The detailed electromagnetic characterizations of the TEM-type superconducting structure have been confirmed by the three-dimensional simulations [1,2]. Also, the rigorous analysis of the existing CEBAF normal conducting cavity from the rf design viewpoint has been reported in [3,4] and, more importantly, the device is presently operating.…”

Section: Introductionmentioning

confidence: 67%

“…2 and 4. The details of these cavities from the electromagnetic design viewpoints are well documented in [2][3][4], however, we will discuss briefly for the sake of completeness. The superconducting structure consists of a beam pipe, passing between the two perpendicular =2 parallel rods as shown in Fig.…”

Section: A Radio-frequency Structuresmentioning

confidence: 99%

Beam dynamics studies for transverse electromagnetic mode type rf deflectors

Ahmed

Krafft

Deitrick

et al. 2012

We have performed three-dimensional simulations of beam dynamics for transverse electromagnetic mode (TEM) type rf deflectors: normal and superconducting. The compact size of these cavities as compared to the conventional TM 110 type structures is more attractive particularly at low frequency. Highly concentrated electromagnetic fields between the parallel bars provide strong electrical stability to the beam for any mechanical disturbance. An array of six 2-cell normal conducting cavities or a single cell superconducting structure is enough to produce the required vertical displacement at the target point. Both the normal and superconducting structures show very small emittance dilution due to the vertical kick of the beam.

“…The possible luminosity upgrade of the LHC [12] has lately drawn attention to the design of compact crabbing cavity systems operating at low frequencies. Some of those designs are the SLAC half-wave spoke resonator crabbing cavity [13], the parallel-bar cavity [14], the Lancaster University-Cockroft Institute 4-rod cavity [15], the KEK Kota Cavity [16], and the BNL quarter wave cavity [17].…”

Section: Introductionmentioning

confidence: 99%

Design evolution and properties of superconducting parallel-bar rf-dipole deflecting and crabbing cavities

Silva

Delayen

2013

Self Cite

Deflecting/crabbing cavities serve a variety of purposes in different accelerator applications, primarily in separating a single beam into multiple beams and in rotating bunches for head-on collisions at the interaction point in particle colliders. Deflecting/crabbing cavities are also used for transverse and longitudinal emittance exchange in beams, x-ray pulse compression, and for beam diagnostics. Compact superconducting deflecting/crabbing cavities are under development due to strict dimensional constraints and requirements for higher field gradients with low surface losses. The TEM-like superconducting parallel-bar cavity supports low operating frequencies, thus making the design favorable for many of the deflecting/crabbing cavity applications. The design of the parallel-bar cavity based on cylindrical straight loading elements and rectangular outer conductors has evolved and been adapted to improve the design properties by modifying the design geometry. The improved design with trapezoidalshaped loading elements and cylindrical outer conductor has attractive properties such as low and wellbalanced peak surface fields and high transverse shunt impedance. Additionally, the wide separation of modes in the higher-order mode spectrum and the absence of lower-order mode are advantageous in high current applications. The evolution of the parallel-bar geometry into an rf-dipole geometry is presented with a detailed analysis of the properties for each design.