HB2018 - List of Keywords (betatron)

Paper	Title	Other Keywords	Page
MOP1WA01	J-PARC RCS: Effects of Emittance Exchange on Injection Painting	emittance, operation, injection, space-charge	20
	H. Hotchi JAEA/J-PARC, Tokai-mura, Japan
	The J-PARC RCS is a high-power rapid cycling synchrotron aiming for a 1-MW output beam power. This talk reports the recent progress of the J-PARC RCS beam commissioning and operation especially focusing on our efforts for beam dynamics issues that we faced during the process of the beam power ramp-up.
	Slides MOP1WA01 [4.081 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-MOP1WA01
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOP2WA01	Beam Physics Limitations for Damping of Instabilities in Circular Accelerators	damping, pick-up, emittance, kicker	26
	V.A. Lebedev Fermilab, Batavia, Illinois, USA
	Funding: Work supported by D.O.E. Contract No. DE-AC02-07CH11359 The paper considers a beam interaction with a feedback system and major limitations on the beam damping rate. In particular, it discusses: limitations on the system gain and damping rate, feedback system noise and its effect on the beam emittance growth, x-y coupling effect on damping, suppression of high order modes and damping of slip-stacked beams.
	Slides MOP2WA01 [0.408 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-MOP2WA01
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOP2WA03	Experiments and Theory on Beam Stabilization with Second-Order Chromaticity	impedance, damping, experiment, simulation	32
	M. Schenk, X. Buffat, L.R. Carver, K.S.B. Li, E. Métral CERN, Geneva, Switzerland A. Maillard ENS, Paris, France
	This study reports on an alternative method to generate transverse Landau damping to suppress coherent instabilities in circular accelerators. The incoherent betatron tune spread can be produced through detuning with longitudinal rather than transverse action. This approach is motivated by the high-brightness, low transverse emittance beams in future colliders where detuning with transverse amplitude will be less effective. Detuning with longitudinal action can be introduced with a radio frequency (rf) quadrupole, or similarly, using second-order chromaticity. The latter was enhanced in the Large Hadron Collider (LHC) at CERN and experimental results on single-bunch stabilization are briefly recapped. The observations are interpreted analytically by extending the Vlasov formalism to include nonlinear chromaticity. Finally, the newly developed theory is benchmarked against circulant matrix and particle tracking models.
	Slides MOP2WA03 [3.374 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-MOP2WA03
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEP2PO001	Upgraded Transverse Feedback for the CERN PS Booster	feedback, kicker, hardware, booster	256
	A. Blas, G. Kotzian CERN, Geneva, Switzerland
	A new transverse feedback system is being used for the 4 rings of the CERN Proton Synchrotron Booster (PSB). In addition to transverse instabilities mitigation - within the range of 100 kHz to 100 MHz - the system allows for controlled beam emittance blow-up, machine tune measurement and other optic studies. The system was upgraded in order to multiply by 8 its power (800 W instead of 100 W on each of the 4 kicker electrodes) and in order for its electronic core to employ a digital processing. The transverse feedback adapts automatically to a factor 3 change in the beam revolution period and to any change of the machine tune. It includes an excitation source that combines up to 9 selectable harmonics of the revolution frequency with a selectable amplitude for each. The excitation may be dipolar or quadrupolar. Future possible upgrades will be presented including a setup to tackle half-integer tune values and a digital processing using a fixed clock frequency instead of the revolution frequency clock.
	Poster WEP2PO001 [1.794 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEP2PO001
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEP2PO024	Resonance Stop-bands Compensation at Booster Ring of HIAF	resonance, alignment, injection, coupling	315
	J. Li, J.C. Yang IMP/CAS, Lanzhou, People's Republic of China
	Booster Ring (BRing) of the new approved High Intensity heavy-ion Accelerator Facility (HIAF) in China is designed to stack 0.3-1.0·10¹¹ number of 238U³⁵⁺ ions by painting injection and deliver over such intensity beam in extraction. However, depressed tune spread caused by space charge effect crosses the low-order resonance stop-bands after bunching the storage beam. To keep a low beam loss during crossing, stop-band compensation scheme is proposed covering the whole process of RF capture and early acceleration.
	Poster WEP2PO024 [1.218 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEP2PO024
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THP2WC02	LLRF Studies for HL-LHC Crab Cavities	cavity, feedback, emittance, luminosity	440
	P. Baudrenghien CERN, Geneva, Switzerland T. Mastoridis CalPoly, San Luis Obispo, California, USA
	The HL-LHC upgrade includes sixteen Crab Cavities (CC) to be installed on both sides of the high luminosity experiments, ATLAS and CMS. Two issues have been highlighted for the Low Level RF: transverse emittance growth (and associated luminosity drop) caused by CC RF noise, and large collimator losses following a CC trip. A prototype cryomodule with two CCs has been installed in the SPS, and tests have started in May 2018 with beam. This paper briefly reports on preliminary results from the SPS tests. It then presents emittance growth calculations from cavity field phase and amplitude noise, deduces the maximum RF noise compatible with the specifications and presents a possible cure consisting of a feedback on CC phase and amplitude. To reduce the losses following a CC trip we propose to implement transverse tail cleaning via the injection of CC noise with an optimized spectrum, which selectively excites the particles of large transverse oscillation amplitudes.
	Slides THP2WC02 [1.943 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-THP2WC02
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

MOP1WA01

J-PARC RCS: Effects of Emittance Exchange on Injection Painting

emittance, operation, injection, space-charge

20

H. Hotchi
JAEA/J-PARC, Tokai-mura, Japan

The J-PARC RCS is a high-power rapid cycling synchrotron aiming for a 1-MW output beam power. This talk reports the recent progress of the J-PARC RCS beam commissioning and operation especially focusing on our efforts for beam dynamics issues that we faced during the process of the beam power ramp-up.

Slides MOP1WA01 [4.081 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-MOP1WA01

Export •

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

MOP2WA01

Beam Physics Limitations for Damping of Instabilities in Circular Accelerators

damping, pick-up, emittance, kicker

26

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

Funding: Work supported by D.O.E. Contract No. DE-AC02-07CH11359
The paper considers a beam interaction with a feedback system and major limitations on the beam damping rate. In particular, it discusses: limitations on the system gain and damping rate, feedback system noise and its effect on the beam emittance growth, x-y coupling effect on damping, suppression of high order modes and damping of slip-stacked beams.

Slides MOP2WA01 [0.408 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-MOP2WA01

Export •

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

MOP2WA03

Experiments and Theory on Beam Stabilization with Second-Order Chromaticity

impedance, damping, experiment, simulation

32

M. Schenk, X. Buffat, L.R. Carver, K.S.B. Li, E. Métral
CERN, Geneva, Switzerland
A. Maillard
ENS, Paris, France

This study reports on an alternative method to generate transverse Landau damping to suppress coherent instabilities in circular accelerators. The incoherent betatron tune spread can be produced through detuning with longitudinal rather than transverse action. This approach is motivated by the high-brightness, low transverse emittance beams in future colliders where detuning with transverse amplitude will be less effective. Detuning with longitudinal action can be introduced with a radio frequency (rf) quadrupole, or similarly, using second-order chromaticity. The latter was enhanced in the Large Hadron Collider (LHC) at CERN and experimental results on single-bunch stabilization are briefly recapped. The observations are interpreted analytically by extending the Vlasov formalism to include nonlinear chromaticity. Finally, the newly developed theory is benchmarked against circulant matrix and particle tracking models.

Slides MOP2WA03 [3.374 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-MOP2WA03

Export •

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

WEP2PO001

Upgraded Transverse Feedback for the CERN PS Booster

feedback, kicker, hardware, booster

256

A. Blas, G. Kotzian
CERN, Geneva, Switzerland

A new transverse feedback system is being used for the 4 rings of the CERN Proton Synchrotron Booster (PSB). In addition to transverse instabilities mitigation - within the range of 100 kHz to 100 MHz - the system allows for controlled beam emittance blow-up, machine tune measurement and other optic studies. The system was upgraded in order to multiply by 8 its power (800 W instead of 100 W on each of the 4 kicker electrodes) and in order for its electronic core to employ a digital processing. The transverse feedback adapts automatically to a factor 3 change in the beam revolution period and to any change of the machine tune. It includes an excitation source that combines up to 9 selectable harmonics of the revolution frequency with a selectable amplitude for each. The excitation may be dipolar or quadrupolar. Future possible upgrades will be presented including a setup to tackle half-integer tune values and a digital processing using a fixed clock frequency instead of the revolution frequency clock.

Poster WEP2PO001 [1.794 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEP2PO001

Export •

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

WEP2PO024

Resonance Stop-bands Compensation at Booster Ring of HIAF

resonance, alignment, injection, coupling

315

J. Li, J.C. Yang
IMP/CAS, Lanzhou, People's Republic of China

Booster Ring (BRing) of the new approved High Intensity heavy-ion Accelerator Facility (HIAF) in China is designed to stack 0.3-1.0·10¹¹ number of 238U³⁵⁺ ions by painting injection and deliver over such intensity beam in extraction. However, depressed tune spread caused by space charge effect crosses the low-order resonance stop-bands after bunching the storage beam. To keep a low beam loss during crossing, stop-band compensation scheme is proposed covering the whole process of RF capture and early acceleration.

Poster WEP2PO024 [1.218 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEP2PO024

Export •

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

THP2WC02

LLRF Studies for HL-LHC Crab Cavities

cavity, feedback, emittance, luminosity

440

P. Baudrenghien
CERN, Geneva, Switzerland
T. Mastoridis
CalPoly, San Luis Obispo, California, USA

The HL-LHC upgrade includes sixteen Crab Cavities (CC) to be installed on both sides of the high luminosity experiments, ATLAS and CMS. Two issues have been highlighted for the Low Level RF: transverse emittance growth (and associated luminosity drop) caused by CC RF noise, and large collimator losses following a CC trip. A prototype cryomodule with two CCs has been installed in the SPS, and tests have started in May 2018 with beam. This paper briefly reports on preliminary results from the SPS tests. It then presents emittance growth calculations from cavity field phase and amplitude noise, deduces the maximum RF noise compatible with the specifications and presents a possible cure consisting of a feedback on CC phase and amplitude. To reduce the losses following a CC trip we propose to implement transverse tail cleaning via the injection of CC noise with an optimized spectrum, which selectively excites the particles of large transverse oscillation amplitudes.

Slides THP2WC02 [1.943 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-THP2WC02

Export •

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