SRF2013 - List of Keywords (quadrupole)

Paper	Title	Other Keywords	Page
MOP021	Conceptual Design of SC Linac for RIBF-Upgrade Plan	linac, cryomodule, cavity, ion	137
	K. Yamada, O. Kamigaito, N. Sakamoto, K. Suda RIKEN Nishina Center, Wako, Japan
	For the intensity upgrade of very-heavy ions such as 238U and 124Xe at the RIKEN RI-Beam Factory (RIBF), a design study of new SC linac injector has started on. In the RIBF, the very-heavy ions are accelerated in a cascade of the injector linac (RILAC2), the RIKEN ring cyclotron (RRC), the fixed-frequency ring cyclotron (fRC), the intermediate-stage ring cyclotron (IRC), and the world's first superconducting ring cyclotron (SRC). We plan to substitute the SC linac for the RRC with respect to the very heavy ions, and to boost up the energy of ions with mass-to-charge ratio of 7 from 1.4 MeV/u to 11 MeV/u in the cw mode. The SC cavity is assumed to be a two gap QWR with an rf frequency of 73 MHz, that is twice the rf frequency of IRC and SRC. The cell parameters and number of cavity are determined by calculating the energy gain of synchronous ion by taking the rf phase at the center of gap into account. The transverse motion is calculated by the transfer matrix method and several types of lattice are studied. This contribution reports the progress of design study for the SC linac.

MOP047	Set up of Production Line for EXFEL Beam Position Monitor and Quadrupol Units for Cavity String Assembly at CEA	vacuum, alignment, controls, status	224
	M. Schalwat, M. Koepke, A. Matheisen, H. Weitkämper DESY, Hamburg, Germany
	The super conducting (s.c.) accelerator models of the EXFEL consist of eight s.c. resonators, one s.c. quadrupol magnet and one beam position monitor. These components are connected inside ISO 4 cleanroom at CEA Saclay to a so called cavity string under the guidance of the XFEL WP 09 activities. The eight s.c. cavities are handed from DESY to CEA for string assembly after successful RF test. The beam- position monitor and Quadrupol units (BQU) are assembled and cleaned in the DESY cleanroom at DESY Hamburg to the same standard’s of cleanliness as requested for s.c. Cavities. The completed BQU units are handed over to CEA IRFU / WP 9 in “ready for installation to cavity string“ status. The setup of infrastructure, the qualification of processes and transport as well as the ramp up to a delivery rate of 1 BQU per week will be presented.

TUP074	Development of an Optimized Quadrupole Resonator at HZB	cavity, niobium, resonance, focusing	614
	R. Kleindienst, J. Knobloch, O. Kugeler HZB, Berlin, Germany
	Funding: EuCARD II Current superconducting cavities are generally made of solid niobium. A possibility to reduce cost as well as increase accelerating fields and, essential for CW applications, the quality factor is to use thin-film coated cavities. Measuring and understanding the RF-properties of superconducting thin films, specifically the surface resistance at the operating field and frequency, is needed to drive forward this development. Presently, only few facilities exist capable of measuring the surface resistance of thin films samples with a resolution in the nano-ohm range at L-Band. We describe here a dedicated test stand consisting of a quadrupole resonator that was constructed at the Helmholtz Zentrum Berlin. Starting with 400-MHz quadrupole resonator developed at CERN, the design was adapted and optimized for resolution and reduced peak electric field to 433 MHz (making available the higher harmonic mode at 1,3GHz) using simulation data obtained with CST Microwave Studio as well as ANSYS. The relevant figures of merit have been improved, giving the possibility to perform measurements with high resolution at high field levels.

WEIOC01	High Resolution Surface Resistance Studies	niobium, cavity, shielding, superconductivity	785
	S. Aull, S. Döbert, T. Junginger CERN, Geneva, Switzerland S. Aull, J. Knobloch University of Siegen, Siegen, Germany J. Knobloch HZB, Berlin, Germany
	Funding: Work supported by the German Doctoral Students program of the Federal Ministry of Education and Research (BMBF). The attempt to reach quality factors beyond 10¹¹ and pushing the accelerating gradients of SRF cavities to the theoretical limit, the treatment depending loss mechanisms in niobium need better understanding. CERNs Quadrupole Resonator enables sub-nΩ-resolution measurements of the surface resistance. The available parameters cover resonant modes at 400, 800 and 1200 MHz, any temperature up to 15 K and rf fields up to 60 mT. Recently the setup has been extended with a coil creating a dc magnetic field for trapped flux studies. Overall, much more information about the rf performance is accessible compared to regular cavity measurements. Since the samples are flat disks of 75 mm diameter geometric fabrication issues are simplified which makes the Quadrupole Resonator also the perfect tool to study alternative materials or new coating techniques. In this contribution in depth studies of a heat treated bulk niobium sample exploiting the complete parameter range of the setup are presented.
	Slides WEIOC01 [2.724 MB]

THP048	The Influence of Tuners and Temperature on the Higher Order Mode Spectrum for 1.3 GHz SCRF Cavities	cavity, HOM, dipole, higher-order-mode	1016
	R. Ainsworth Royal Holloway, University of London, Surrey, United Kingdom N. Baboi, M.K. Grecki, T. Wamsat DESY, Hamburg, Germany N. Eddy Fermilab, Batavia, USA S. Molloy ESS, Lund, Sweden P. Zhang CERN, Geneva, Switzerland
	Higher Order Modes are of concern for superconducting cavities as they can drive instabilities and so are usually damped and monitored. With special dedicated electronics, HOMs can provide information on the position on the beam. It has been proposed that piezo tuners used to keep the cavities operating at 1.3 GHz could alter the HOM spectrum altering the calibration constants used to read out the beam position affecting long term stability of the system. Also, of interest is how the cavity reacts to the slow tuner. Detuning and the retuning the cavity may alter the HOM spectrum. This is of particular interest for future machines not planning to use dedicated HOM damping as the tuning procedure may shift the frequency of HOMs onto dangerous resonances. The effect of temperature on the HOM spectrum is also investigated. An investigation of these effects has been performed at FLASH and the results are presented including numerical simulations used to predict the resulting cavity distortion.

Paper

Title

Other Keywords

Page

MOP021

Conceptual Design of SC Linac for RIBF-Upgrade Plan

linac, cryomodule, cavity, ion

137

K. Yamada, O. Kamigaito, N. Sakamoto, K. Suda
RIKEN Nishina Center, Wako, Japan

For the intensity upgrade of very-heavy ions such as 238U and 124Xe at the RIKEN RI-Beam Factory (RIBF), a design study of new SC linac injector has started on. In the RIBF, the very-heavy ions are accelerated in a cascade of the injector linac (RILAC2), the RIKEN ring cyclotron (RRC), the fixed-frequency ring cyclotron (fRC), the intermediate-stage ring cyclotron (IRC), and the world's first superconducting ring cyclotron (SRC). We plan to substitute the SC linac for the RRC with respect to the very heavy ions, and to boost up the energy of ions with mass-to-charge ratio of 7 from 1.4 MeV/u to 11 MeV/u in the cw mode. The SC cavity is assumed to be a two gap QWR with an rf frequency of 73 MHz, that is twice the rf frequency of IRC and SRC. The cell parameters and number of cavity are determined by calculating the energy gain of synchronous ion by taking the rf phase at the center of gap into account. The transverse motion is calculated by the transfer matrix method and several types of lattice are studied. This contribution reports the progress of design study for the SC linac.

MOP047

Set up of Production Line for EXFEL Beam Position Monitor and Quadrupol Units for Cavity String Assembly at CEA

vacuum, alignment, controls, status

224

M. Schalwat, M. Koepke, A. Matheisen, H. Weitkämper
DESY, Hamburg, Germany

The super conducting (s.c.) accelerator models of the EXFEL consist of eight s.c. resonators, one s.c. quadrupol magnet and one beam position monitor. These components are connected inside ISO 4 cleanroom at CEA Saclay to a so called cavity string under the guidance of the XFEL WP 09 activities. The eight s.c. cavities are handed from DESY to CEA for string assembly after successful RF test. The beam- position monitor and Quadrupol units (BQU) are assembled and cleaned in the DESY cleanroom at DESY Hamburg to the same standard’s of cleanliness as requested for s.c. Cavities. The completed BQU units are handed over to CEA IRFU / WP 9 in “ready for installation to cavity string“ status. The setup of infrastructure, the qualification of processes and transport as well as the ramp up to a delivery rate of 1 BQU per week will be presented.

TUP074

Development of an Optimized Quadrupole Resonator at HZB

cavity, niobium, resonance, focusing

614

R. Kleindienst, J. Knobloch, O. Kugeler
HZB, Berlin, Germany

Funding: EuCARD II
Current superconducting cavities are generally made of solid niobium. A possibility to reduce cost as well as increase accelerating fields and, essential for CW applications, the quality factor is to use thin-film coated cavities. Measuring and understanding the RF-properties of superconducting thin films, specifically the surface resistance at the operating field and frequency, is needed to drive forward this development. Presently, only few facilities exist capable of measuring the surface resistance of thin films samples with a resolution in the nano-ohm range at L-Band. We describe here a dedicated test stand consisting of a quadrupole resonator that was constructed at the Helmholtz Zentrum Berlin. Starting with 400-MHz quadrupole resonator developed at CERN, the design was adapted and optimized for resolution and reduced peak electric field to 433 MHz (making available the higher harmonic mode at 1,3GHz) using simulation data obtained with CST Microwave Studio as well as ANSYS. The relevant figures of merit have been improved, giving the possibility to perform measurements with high resolution at high field levels.

WEIOC01

High Resolution Surface Resistance Studies

niobium, cavity, shielding, superconductivity

785

S. Aull, S. Döbert, T. Junginger
CERN, Geneva, Switzerland
S. Aull, J. Knobloch
University of Siegen, Siegen, Germany
J. Knobloch
HZB, Berlin, Germany

Funding: Work supported by the German Doctoral Students program of the Federal Ministry of Education and Research (BMBF).
The attempt to reach quality factors beyond 10¹¹ and pushing the accelerating gradients of SRF cavities to the theoretical limit, the treatment depending loss mechanisms in niobium need better understanding. CERNs Quadrupole Resonator enables sub-nΩ-resolution measurements of the surface resistance. The available parameters cover resonant modes at 400, 800 and 1200 MHz, any temperature up to 15 K and rf fields up to 60 mT. Recently the setup has been extended with a coil creating a dc magnetic field for trapped flux studies. Overall, much more information about the rf performance is accessible compared to regular cavity measurements. Since the samples are flat disks of 75 mm diameter geometric fabrication issues are simplified which makes the Quadrupole Resonator also the perfect tool to study alternative materials or new coating techniques. In this contribution in depth studies of a heat treated bulk niobium sample exploiting the complete parameter range of the setup are presented.

Slides WEIOC01 [2.724 MB]

THP048

The Influence of Tuners and Temperature on the Higher Order Mode Spectrum for 1.3 GHz SCRF Cavities

cavity, HOM, dipole, higher-order-mode

1016

R. Ainsworth
Royal Holloway, University of London, Surrey, United Kingdom
N. Baboi, M.K. Grecki, T. Wamsat
DESY, Hamburg, Germany
N. Eddy
Fermilab, Batavia, USA
S. Molloy
ESS, Lund, Sweden
P. Zhang
CERN, Geneva, Switzerland

Higher Order Modes are of concern for superconducting cavities as they can drive instabilities and so are usually damped and monitored. With special dedicated electronics, HOMs can provide information on the position on the beam. It has been proposed that piezo tuners used to keep the cavities operating at 1.3 GHz could alter the HOM spectrum altering the calibration constants used to read out the beam position affecting long term stability of the system. Also, of interest is how the cavity reacts to the slow tuner. Detuning and the retuning the cavity may alter the HOM spectrum. This is of particular interest for future machines not planning to use dedicated HOM damping as the tuning procedure may shift the frequency of HOMs onto dangerous resonances. The effect of temperature on the HOM spectrum is also investigated. An investigation of these effects has been performed at FLASH and the results are presented including numerical simulations used to predict the resulting cavity distortion.