LINAC2022 - List of Keywords (dipole)

Paper	Title	Other Keywords	Page
MOPOPA12	Preserving Bright Electron Beams: Distorted CSR Kicks	emittance, electron, radiation, synchrotron-radiation	91
	A. Dixon, T.K. Charles The University of Liverpool, Liverpool, United Kingdom T.K. Charles, P.H. Williams Cockcroft Institute, Warrington, Cheshire, United Kingdom S. Thorin MAX IV Laboratory, Lund University, Lund, Sweden P.H. Williams STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Short pulse, low emittance electron beams are necessary to drive bright FEL X-rays, for this reason it is important to preserve and limit emittance growth. The strong bunch compression required to achieve the short bunches, can lead to coherent synchrotron radiation (CSR)-induced emittance growth, and while there are some methods of CSR cancel- lation, these methods may be less effective when the CSR kicks are distorted. In an attempt to understand why CSR kicks become distorted, we compare the CSR kicks calcu- lated using the whole beam parameters to the CSR kicks calculated using the longitudinally sliced beam parameters, when propagated to the end of the bunch compressor. We find that CSR kicks can become distorted when calculated with non-uniform slice beam parameters. While slice beam parameters that are uniform along the centre of the bunch, do not result in distorted CSR kicks.
	Poster MOPOPA12 [1.553 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOPA12
About •	Received ※ 24 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 27 August 2022 — Issue date ※ 31 August 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOGE04	Cell Geometry Optimization for Dipole Kick Correction in a High-Frequency IH Structure	cavity, linac, DTL, impedance	146
	R. López López, P. Calvo, D. Gavela, J. Giner Navarro, G. Moreno, C. Oliver, J.M. Pérez Morales CIEMAT, Madrid, Spain M.C. Battaglia, J.M. Carmona AVS, Elgoibar, Spain A.M. Lombardi CERN, Meyrin, Switzerland
	Funding: CIEMAT Given the asymmetry in the stem configuration of an IH-DTL structure, an electric dipole component is always present between drift tubes, and it is especially significant for reduced dimensions in high-frequency regimes. Here we study the effect of different modifications of the drift tubes geometry of a 750 MHz IH-DTL to eliminate the impact of the dipole component in the transverse beam dynamics. Tracking simulations through a single cell are also performed to assess the outcomes in particle’s trajectory offset and angle.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE04
About •	Received ※ 24 August 2022 — Revised ※ 27 August 2022 — Accepted ※ 31 August 2022 — Issue date ※ 04 September 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPORI15	Update of Adjustable PMQ Lens	quadrupole, permanent-magnet, focusing, site	262
	Y. Iwashita Kyoto University, Research Reactor Institute, Osaka, Japan Y. Fuwa JAEA/J-PARC, Tokai-mura, Japan T. Hosokai ISIR, Osaka, Japan D. Oumbarek Espinos Osaka University, Graduate School of Engineering, Osaka, Japan
	Gluckstern’s adjustable permanent magnet quadrupole (PMQ) lens based on five rings is revisited to achieve a compact focusing system for laser-accelerated beams. The first prototype was fabricated for bore diameter of 50 mm. The integrated gradient was up to 6.8 T. A new PMQ with a bore diameter of 25 mm is under fabrication based on the same geometry. While the first prototype unit was developed for the final focus magnet of the ILC, the sec-ond unit is the first doublet element for laser-accelerated electron beam focusing to be combined with this first unit. The current status of the development is reported.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI15
About •	Received ※ 01 September 2022 — Revised ※ 03 September 2022 — Accepted ※ 05 September 2022 — Issue date ※ 15 September 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOGE20	Observation of Current-Driven Features of 2.5 Mev Ion Bunch With Complete and Efficient 5D Measurements at the SNS Beam Test Facility	rfq, quadrupole, space-charge, simulation	541
	K.J. Ruisard, A.V. Aleksandrov, S.M. Cousineau, A.M. Hoover, A.P. Zhukov ORNL, Oak Ridge, Tennessee, USA
	Funding: Work supported by U.S. Department of Energy, Office of Science, High Energy Physics. Authored by UT- Battelle, LLC under DOE Contract No. DE-AC05-00OR22725. The SNS Beam Test Facility research program is focused detailed studies of beam distributions for medium-energy ion beams, with the goal of reconstructing realistic 6D bunch distributions to enable halo prediction. For complete characterization of the initial distribution, scan time scales exponentially with scan dimension. Currently, a full 6D measurement with ~10 points across most dimensions requires 30 hours. However, measurement of the 5D distribution f(x, x’,y,y’,w) can be done very rapidly using a hybrid slit/screen method. This approach requires ~4 hours to obtain at least 32 points/dimension, with very high resolution (0.5 keV) in the energy distribution. This presentation reports on the approach and results for 5D characterization of the initial RFQ-formed bunch. This includes higher-resolution views of previously reported transverse-longitudinal dependence and additional interplane dependencies that were not previously reported.
	Slides TUPOGE20 [1.230 MB]
	Poster TUPOGE20 [1.406 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE20
About •	Received ※ 25 August 2022 — Revised ※ 30 August 2022 — Accepted ※ 04 September 2022 — Issue date ※ 16 September 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPORI25	Finding Beam Loss Locations at PIP2IT Accelerator With Oscillating Dipole Correctors	MEBT, cryomodule, linac, betatron	605
	A.V. Shemyakin Fermilab, Batavia, Illinois, USA
	Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics The PIP2IT accelerator was assembled in multiple stages in 2014 - 2021 to test concepts and components of the future PIP-II linac that is being constructed at Fermilab. In its final configuration, PIP2IT accelerated a 0.55 ms x 20 Hz x 2 mA H⁻ beam to 16 MeV. To determine location of the beam loss in the accelerator’s low-energy part, where radiation monitors are ineffective, a method using oscillating trajectories was implemented. If the beam is scraped at an aperture limitation, moving its centroid with two dipole correctors located upstream and oscillating in sync, produces a line at the corresponding frequency in spectra of BPM sum signals downstream of the loss point. Comparison of these responses along the beam line allows to find the loss location. The paper describes the method and results of its implementation at PIP2IT.
	Slides TUPORI25 [0.447 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPORI25
About •	Received ※ 24 August 2022 — Revised ※ 31 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 15 September 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOJO02	Commissioning of a Movable Bunch Compressor for Sub-fs Electron Bunches	electron, linac, MMI, diagnostics	695
	W. Kuropka, R.W. Aßmann, F. Burkart, H. Dinter, S. Jaster-Merz, F. Lemery, F. Mayet, B. Stacey, T. Vinatier DESY, Hamburg, Germany R.W. Aßmann LNF-INFN, Frascati, Italy S. Jaster-Merz University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
	Funding: DESY is a research center within the Helmholtz association HGF. We present the first commissioning results of the movable bunch compressor (BC) designed for the ARES linac at DESY. The development and simulated performance has been reported earlier and predicts sub-fs electron bunches with high charge densities. Commissioning results of the injector part of the ARES linac delivered promising beam quality results to achieve these numbers. The bunch compressor system is foreseen to be used to bench mark numerical models for coherent synchrotron radiation (CSR) and space charge (SC) for ultra-short electron bunches. Here we will present first measurements of the dispersion as well as calculations for the longitudinal dispersion. In the future the PolariX transverse deflecting structure (TDS) will be commissioned to fully characterize the ARES electron beam.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOJO02
About •	Received ※ 25 August 2022 — Revised ※ 23 August 2022 — Accepted ※ 31 August 2022 — Issue date ※ 15 September 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOJO21	Higher Order Modes Investigation in the PERLE Superconducting RF Cavity	HOM, cavity, damping, impedance	731
	C. Barbagallo, P. Duchesne, W. Kaabi, G. Olry, Z.F. Zomer Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France R.A. Rimmer, H. Wang JLab, Newport News, Virginia, USA
	The regenerative Beam Break Up (BBU) excited by the dipole Higher Order Modes (HOMs) in superconducting RF (SRF) cavities is a crucial issue for continuous-wave high-current energy recovery linacs. Beam-induced monopole HOMs can increase the cryogenic losses of the linac also. One of the ways to limit these effects is to use HOM couplers on the beam tubes of cavities to absorb and untrap cavity eigenmodes. These couplers feature antennas designed to damp dangerous HOMs and adequately reject the fundamental mode. This study illustrates an investigation of the HOMs of a 5-cell 801.58 MHz elliptical SRF cavity designed for PERLE (Powerful Energy Recovery Linac for Experiments), a multi-turn energy recovery linac (ERL) currently under study and later to be hosted at IJCLab in Orsay. Time-domain wakefield and frequency-domain eigenmode simulations have been used to calculate the cavity broadband HOM impedance spectra and identify the dangerous BBU HOMs. The transmission characteristics of several coaxial HOM couplers have been studied. The efficiencies of several HOM-damping schemes have been compared to propose a HOM endgroup to be fabricated and added to the existing bare SRF cavity.
	Poster THPOJO21 [2.090 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOJO21
About •	Received ※ 24 August 2022 — Revised ※ 27 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 23 September 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOJO26	Conceptual Design of the PERLE Injector	emittance, linac, space-charge, quadrupole	743
	B. Hounsell, M. Klein, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom B. Hounsell, B.L. Militsyn, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom B. Hounsell, W. Kaabi Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France B.L. Militsyn STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Energy Recovery Linacs such as PERLE require high average current high brightness beams. This sets particular requirements on the kind of injectors that they can use as the injectors must be capable of producing bunches at MHz repetition rates, compressing the bunches to the specified value and transporting those bunches while they are still in the space charge dominated regime into the main ERL all while keeping the emittance low. In particular, PERLE will require a 20 mA beam consisting of 500 pC bunches with a repetition rate of 40 MHz. These bunches will be required to have rms lengths of 3mm, a total beam energy of 7 MeV, appropriate Twiss parameters to match them to the main loop and transverse emittances of < 6 mm mrad. In this paper, a DC gun based injector capable of meeting this specification will be presented with beam dynamics simulation showing the behaviour of the beam from the photocathode to the exit of the first main linac pass. The beam dynamics challenges will be discussed in terms of both the transverse emittance growth and the sources of non-linearity in the longitudinal phase space.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOJO26
About •	Received ※ 20 August 2022 — Revised ※ 24 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 15 September 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOGE18	Design of a 1.3 GHz RF-Dipole Crabbing Cavity for International Linear Collider	cavity, HOM, electron, collider	832
	S.U. De Silva, J.R. Delayen ODU, Norfolk, Virginia, USA R.A. Rimmer JLab, Newport News, Virginia, USA
	The International Liner Collider (ILC) requires crabbing systems to increase the luminosity of the colliding electron and positron bunches. There are several frequency options for the crabbing cavity. We have designed a 1.3 GHz compact 1-cell and 2-cell rf-dipole crabbing cavity to compensate for luminosity degradation due to large crossing angle. This paper presents the 1-cell and 2-cell cavities designed to meet the current specifications including the fundamental power coupler and higher order mode couplers.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOGE18
About •	Received ※ 11 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 16 September 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

MOPOPA12

Preserving Bright Electron Beams: Distorted CSR Kicks

emittance, electron, radiation, synchrotron-radiation

91

A. Dixon, T.K. Charles
The University of Liverpool, Liverpool, United Kingdom
T.K. Charles, P.H. Williams
Cockcroft Institute, Warrington, Cheshire, United Kingdom
S. Thorin
MAX IV Laboratory, Lund University, Lund, Sweden
P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Short pulse, low emittance electron beams are necessary to drive bright FEL X-rays, for this reason it is important to preserve and limit emittance growth. The strong bunch compression required to achieve the short bunches, can lead to coherent synchrotron radiation (CSR)-induced emittance growth, and while there are some methods of CSR cancel- lation, these methods may be less effective when the CSR kicks are distorted. In an attempt to understand why CSR kicks become distorted, we compare the CSR kicks calcu- lated using the whole beam parameters to the CSR kicks calculated using the longitudinally sliced beam parameters, when propagated to the end of the bunch compressor. We find that CSR kicks can become distorted when calculated with non-uniform slice beam parameters. While slice beam parameters that are uniform along the centre of the bunch, do not result in distorted CSR kicks.

Poster MOPOPA12 [1.553 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOPA12

About •

Received ※ 24 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 27 August 2022 — Issue date ※ 31 August 2022

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOGE04

Cell Geometry Optimization for Dipole Kick Correction in a High-Frequency IH Structure

cavity, linac, DTL, impedance

146

R. López López, P. Calvo, D. Gavela, J. Giner Navarro, G. Moreno, C. Oliver, J.M. Pérez Morales
CIEMAT, Madrid, Spain
M.C. Battaglia, J.M. Carmona
AVS, Elgoibar, Spain
A.M. Lombardi
CERN, Meyrin, Switzerland

Funding: CIEMAT
Given the asymmetry in the stem configuration of an IH-DTL structure, an electric dipole component is always present between drift tubes, and it is especially significant for reduced dimensions in high-frequency regimes. Here we study the effect of different modifications of the drift tubes geometry of a 750 MHz IH-DTL to eliminate the impact of the dipole component in the transverse beam dynamics. Tracking simulations through a single cell are also performed to assess the outcomes in particle’s trajectory offset and angle.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE04

About •

Received ※ 24 August 2022 — Revised ※ 27 August 2022 — Accepted ※ 31 August 2022 — Issue date ※ 04 September 2022

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPORI15

Update of Adjustable PMQ Lens

quadrupole, permanent-magnet, focusing, site

262

Y. Iwashita
Kyoto University, Research Reactor Institute, Osaka, Japan
Y. Fuwa
JAEA/J-PARC, Tokai-mura, Japan
T. Hosokai
ISIR, Osaka, Japan
D. Oumbarek Espinos
Osaka University, Graduate School of Engineering, Osaka, Japan

Gluckstern’s adjustable permanent magnet quadrupole (PMQ) lens based on five rings is revisited to achieve a compact focusing system for laser-accelerated beams. The first prototype was fabricated for bore diameter of 50 mm. The integrated gradient was up to 6.8 T. A new PMQ with a bore diameter of 25 mm is under fabrication based on the same geometry. While the first prototype unit was developed for the final focus magnet of the ILC, the sec-ond unit is the first doublet element for laser-accelerated electron beam focusing to be combined with this first unit. The current status of the development is reported.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI15

About •

Received ※ 01 September 2022 — Revised ※ 03 September 2022 — Accepted ※ 05 September 2022 — Issue date ※ 15 September 2022

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOGE20

Observation of Current-Driven Features of 2.5 Mev Ion Bunch With Complete and Efficient 5D Measurements at the SNS Beam Test Facility

rfq, quadrupole, space-charge, simulation

541

K.J. Ruisard, A.V. Aleksandrov, S.M. Cousineau, A.M. Hoover, A.P. Zhukov
ORNL, Oak Ridge, Tennessee, USA

Funding: Work supported by U.S. Department of Energy, Office of Science, High Energy Physics. Authored by UT- Battelle, LLC under DOE Contract No. DE-AC05-00OR22725.
The SNS Beam Test Facility research program is focused detailed studies of beam distributions for medium-energy ion beams, with the goal of reconstructing realistic 6D bunch distributions to enable halo prediction. For complete characterization of the initial distribution, scan time scales exponentially with scan dimension. Currently, a full 6D measurement with ~10 points across most dimensions requires 30 hours. However, measurement of the 5D distribution f(x, x’,y,y’,w) can be done very rapidly using a hybrid slit/screen method. This approach requires ~4 hours to obtain at least 32 points/dimension, with very high resolution (0.5 keV) in the energy distribution. This presentation reports on the approach and results for 5D characterization of the initial RFQ-formed bunch. This includes higher-resolution views of previously reported transverse-longitudinal dependence and additional interplane dependencies that were not previously reported.

Slides TUPOGE20 [1.230 MB]

Poster TUPOGE20 [1.406 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE20

About •

Received ※ 25 August 2022 — Revised ※ 30 August 2022 — Accepted ※ 04 September 2022 — Issue date ※ 16 September 2022

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPORI25

Finding Beam Loss Locations at PIP2IT Accelerator With Oscillating Dipole Correctors

MEBT, cryomodule, linac, betatron

605

A.V. Shemyakin
Fermilab, Batavia, Illinois, USA

Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics
The PIP2IT accelerator was assembled in multiple stages in 2014 - 2021 to test concepts and components of the future PIP-II linac that is being constructed at Fermilab. In its final configuration, PIP2IT accelerated a 0.55 ms x 20 Hz x 2 mA H⁻ beam to 16 MeV. To determine location of the beam loss in the accelerator’s low-energy part, where radiation monitors are ineffective, a method using oscillating trajectories was implemented. If the beam is scraped at an aperture limitation, moving its centroid with two dipole correctors located upstream and oscillating in sync, produces a line at the corresponding frequency in spectra of BPM sum signals downstream of the loss point. Comparison of these responses along the beam line allows to find the loss location. The paper describes the method and results of its implementation at PIP2IT.

Slides TUPORI25 [0.447 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPORI25

About •

Received ※ 24 August 2022 — Revised ※ 31 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 15 September 2022

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOJO02

Commissioning of a Movable Bunch Compressor for Sub-fs Electron Bunches

electron, linac, MMI, diagnostics

695

W. Kuropka, R.W. Aßmann, F. Burkart, H. Dinter, S. Jaster-Merz, F. Lemery, F. Mayet, B. Stacey, T. Vinatier
DESY, Hamburg, Germany
R.W. Aßmann
LNF-INFN, Frascati, Italy
S. Jaster-Merz
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany

Funding: DESY is a research center within the Helmholtz association HGF.
We present the first commissioning results of the movable bunch compressor (BC) designed for the ARES linac at DESY. The development and simulated performance has been reported earlier and predicts sub-fs electron bunches with high charge densities. Commissioning results of the injector part of the ARES linac delivered promising beam quality results to achieve these numbers. The bunch compressor system is foreseen to be used to bench mark numerical models for coherent synchrotron radiation (CSR) and space charge (SC) for ultra-short electron bunches. Here we will present first measurements of the dispersion as well as calculations for the longitudinal dispersion. In the future the PolariX transverse deflecting structure (TDS) will be commissioned to fully characterize the ARES electron beam.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOJO02

About •

Received ※ 25 August 2022 — Revised ※ 23 August 2022 — Accepted ※ 31 August 2022 — Issue date ※ 15 September 2022

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOJO21

Higher Order Modes Investigation in the PERLE Superconducting RF Cavity

HOM, cavity, damping, impedance

731

C. Barbagallo, P. Duchesne, W. Kaabi, G. Olry, Z.F. Zomer
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
R.A. Rimmer, H. Wang
JLab, Newport News, Virginia, USA

The regenerative Beam Break Up (BBU) excited by the dipole Higher Order Modes (HOMs) in superconducting RF (SRF) cavities is a crucial issue for continuous-wave high-current energy recovery linacs. Beam-induced monopole HOMs can increase the cryogenic losses of the linac also. One of the ways to limit these effects is to use HOM couplers on the beam tubes of cavities to absorb and untrap cavity eigenmodes. These couplers feature antennas designed to damp dangerous HOMs and adequately reject the fundamental mode. This study illustrates an investigation of the HOMs of a 5-cell 801.58 MHz elliptical SRF cavity designed for PERLE (Powerful Energy Recovery Linac for Experiments), a multi-turn energy recovery linac (ERL) currently under study and later to be hosted at IJCLab in Orsay. Time-domain wakefield and frequency-domain eigenmode simulations have been used to calculate the cavity broadband HOM impedance spectra and identify the dangerous BBU HOMs. The transmission characteristics of several coaxial HOM couplers have been studied. The efficiencies of several HOM-damping schemes have been compared to propose a HOM endgroup to be fabricated and added to the existing bare SRF cavity.

Poster THPOJO21 [2.090 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOJO21

About •

Received ※ 24 August 2022 — Revised ※ 27 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 23 September 2022

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOJO26

Conceptual Design of the PERLE Injector

emittance, linac, space-charge, quadrupole

743

B. Hounsell, M. Klein, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
B. Hounsell, B.L. Militsyn, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
B. Hounsell, W. Kaabi
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
B.L. Militsyn
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Energy Recovery Linacs such as PERLE require high average current high brightness beams. This sets particular requirements on the kind of injectors that they can use as the injectors must be capable of producing bunches at MHz repetition rates, compressing the bunches to the specified value and transporting those bunches while they are still in the space charge dominated regime into the main ERL all while keeping the emittance low. In particular, PERLE will require a 20 mA beam consisting of 500 pC bunches with a repetition rate of 40 MHz. These bunches will be required to have rms lengths of 3mm, a total beam energy of 7 MeV, appropriate Twiss parameters to match them to the main loop and transverse emittances of < 6 mm mrad. In this paper, a DC gun based injector capable of meeting this specification will be presented with beam dynamics simulation showing the behaviour of the beam from the photocathode to the exit of the first main linac pass. The beam dynamics challenges will be discussed in terms of both the transverse emittance growth and the sources of non-linearity in the longitudinal phase space.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOJO26

About •

Received ※ 20 August 2022 — Revised ※ 24 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 15 September 2022

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOGE18

Design of a 1.3 GHz RF-Dipole Crabbing Cavity for International Linear Collider

cavity, HOM, electron, collider

832

S.U. De Silva, J.R. Delayen
ODU, Norfolk, Virginia, USA
R.A. Rimmer
JLab, Newport News, Virginia, USA

The International Liner Collider (ILC) requires crabbing systems to increase the luminosity of the colliding electron and positron bunches. There are several frequency options for the crabbing cavity. We have designed a 1.3 GHz compact 1-cell and 2-cell rf-dipole crabbing cavity to compensate for luminosity degradation due to large crossing angle. This paper presents the 1-cell and 2-cell cavities designed to meet the current specifications including the fundamental power coupler and higher order mode couplers.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOGE18

About •

Received ※ 11 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 16 September 2022

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)