ICFA Mini Workshop on Higher Order Modes in Superconducting Cavities (HOMSC2018)

Session

Design of SRF Cavities and HOM Damping Schemes

Oct 2, 2018, 11:00 AM

401 (Physical Science building (PSB))

Conveners

Design of SRF Cavities and HOM Damping Schemes

• Matthias Liepe (Cornell U.)

Design of SRF Cavities and HOM Damping Schemes

• Georg Hoffstaetter (Cornell University)

Design of SRF Cavities and HOM Damping Schemes

• Jacek Sekutowicz (DESY)

Design of SRF Cavities and HOM Damping Schemes

• James Maniscalco

16. SRF cavity design and HOM damping for eRHIC e- storage ring

Dr Wencan Xu (bnl)

10/2/18, 11:00 AM

Oral presentation

The RF system of eRHIC e- storage ring has to satisfy wide range of scenarios of eRHIC operation. This presentation will present the considerations and design of the fundamental and high harmonic SRF cavities for the storage ring. And the HOM damping scheme for these cavities will be discussed as well.

20. HL-LHC DWQ HOM coupler design and SPS measurements

Mr James Mitchell (CERN)

10/2/18, 11:30 AM

Oral presentation

The Double Quarter Wave (DQW) crab cavity will be installed as part of the High-Luminosity LHC (HL-LHC) upgrade. Proof-of-principle tests are currently on-going in CERN’s Super Proton Synchrotron (SPS). For the tests, the DQW has three on-cell coaxial HOM couplers per cavity. Currently, due to SPS space constraints, the HOM coupler is not optimal and a re-design is necessary for HL-LHC. ...

19. Design of the BESSY VSR waveguide damped cavities and ancillary components for the cold string

Dr Andranik Tsakanian (Helmholtz-Zentrum Berlin)

10/2/18, 1:00 PM

Oral presentation

The BESSY Variable pulse length Storage Ring (VSR) project is a future upgrade of the 3rd generation BESSY II light source. The key feature of the project is the simultaneous storage of long (ca. 15 ps) and short (ca. 1.7 ps) electron bunches under “standard” user optics. This challenging goal requires installation of SRF higher harmonic cavities of the fundamental 500 MHz at two different...

27. BESSY VSR and bERLinpro HOM loads development

Jiquan Guo (JLAB)

10/2/18, 1:45 PM

Oral presentation

Two accelerator projects at Helmholtz-Zentrum Berlin (HZB), bERLinPro and BESSY-VSR (Variable pulse length Storage Ring) upgrade, need to design three variants of SRF cavities, 1.3GHz cavities for bERLinPro and 1.5GHz/1.75GHz cavities for BESSY-VSR. These cavities have adopted waveguide HOM dampers in their design, with a few tens of watts HOM power in each load for bERLinPro cavities and a...

29. SRF above 1.3 GHz: Motivation and Implications for Higher Order Modes

James Maniscalco

10/2/18, 2:15 PM

Oral presentation

Recent research into impurity-doped niobium and Nb3Sn have pushed towards unprecedentedly high quality factors and low cryogenic power consumption for SRF accelerators. These open the way to high frequency cavities (above the 1.3 GHz standard in contemporary SRF projects such as EXFEL and LCLS-II) which could significantly decrease costs for new accelerator facilities. In this talk we provide...

18. HOM damping schemes for the FCC-ee cavities

Mr Shahnam Gorgi Zadeh (Universität Rostock)

10/3/18, 9:30 AM

Oral presentation

An $e^{+}{e}^{-}$ collider is foreseen in the design of future circular collider (FCC-ee) to make precise measurements of the properties of the Z, W, H bosons and the top quark ($\text{t}\overline{\text{t}}$). The two limiting cases from the SRF point of view are the Z operation which is characterized by low voltage and high beam current (1.39 A) and the $\text{t}\overline{\text{t}}$ operation which requires...

28. JLEIC HOM damping study

Jiquan Guo (JLAB)

10/3/18, 10:00 AM

Oral presentation

The JLab Electron-Ion Collider (JLEIC) proposed by Jefferson Lab is a high luminosity collider consists of a few high current sub-complexes, including a 3-12 GeV electron collider ring with up to 3 A beam current, a 20-100 GeV ion collider ring of up to 1 A, and a 20-55 MeV circulation bunched electron cooler ring with up to 1.5 A. Beam induced HOM problems are prevalent in the RF systems of...

9. HOM Damping in Accelerating Cavities with Large Number of Cells: Application to 44-Cell TWCs of CERN SPS

Dr Nasrin Nasresfahani (Beams Department, RF Group, Beams and RF Studies Section)

10/3/18, 11:00 AM

Oral presentation

Extensive beam dynamic studies conducted in the framework of LIU (LHC Injectors Upgrade) project revealed a serious intensity limitation due to HOMs of the 200 MHz travelling wave cavities (TWCS) of SPS in the frequency range of 629-630 MHz. However, finding appropriate distributed damping scheme in cavities with large number of cells (like TWCs of SPS) usually accompanied with the...

1. Higher Order Mode and Cavity Studies at the University of Rostock since HOMSC16

Prof. Ursula van Rienen (University of Rostock)

10/3/18, 11:30 AM

Oral presentation

The characterization of higher order modes in chains of superconducting cavities with couplers is a challenging task that is typically accomplished using high-performance computers in combination with dedicated software packages. During the last years, an alternative approach has been developed at the University of Rostock. It is referred to as State-Space Concatenations (SSC) and allows for...