HB2018 - List of Keywords (quadrupole)

Paper	Title	Other Keywords	Page
TUA1WD03	Commissioning Status and Plans of CSNS/RCS	MMI, injection, dipole, acceleration	133
	S.Y. Xu, Y.W. An, J. Chen, M.Y. Huang, H.F. Ji, Y. Li, S. Wang IHEP, Beijing, People's Republic of China X.H. Lu CSNS, Guangdong Province, People's Republic of China
	The China Spallation Neutron Source (CSNS) is an accelerator-based science facility. CSNS is designed to accelerate proton beam pulses to 1.6 GeV kinetic energy, striking a solid metal target to produce spallation neutrons. CSNS has two major accelerator systems, a linear accelerator (80 MeV Linac) and a 1.6 GeV rapid cycling synchrotron (RCS). The Beam commissioning of CSNS has been commissioned recently. Beam had been accelerated to 61 MeV at CSNS/Linac on April 24, 2017, and 1.6 GeV acceleration at CSNS/RCS was successfully accomplished on July 7, 2017 with the injection energy of 61 MeV. Beam had been accelerated to 80 MeV at CSNS/Linac on January 6, 2018, and 1.6 GeV acceleration at CSNS/RCS was successfully accomplished on January 18, 2018 with the injection energy of 80 MeV. The initial machine parameter tuning and various beam studies were completed. In this paper, the commissioning experiences are introduced.
	Slides TUA1WD03 [10.794 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-TUA1WD03
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEP1WB01	Beam Dynamics of the ESS Linac	linac, target, cavity, rfq	206
	Y. Levinsen, R. De Prisco, M. Eshraqi, N. Milas, R. Miyamoto, D.C. Plostinar, A. Ponton ESS, Lund, Sweden
	The ESS linac will deliver an unprecedented 5 MW of average beam power when completed. Beyond the 90 MeV normal conducting front-end, the acceleration is performed using SC structures up to the design energy of 2 GeV. As the ESS will send the beam to a fixed tungsten target, the emittance is not as important a factor as in injectors. However, the losses have to be studied in detail, including not only the average operational loss required to be of less than 1 W/m, but also the accidental losses, losses due to failure and other potentially damaging losses. The commissioning of the ion source and LEBT starts this year and will continue with the RFQ next year. In this contribution we will discuss the beam dynamics aspects and challenges of the ESS linac.
	Slides WEP1WB01 [2.084 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEP1WB01
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEP2PO006	Overview of the CERN PSB-to-PS Transfer Line Optics Matching Studies in View of the LHC Injectors Upgrade Project	emittance, optics, operation, injection	272
	V. Forte, S.C.P. Albright, W. Bartmann, G.P. Di Giovanni, M.A. Fraser, C. Heßler, A. Huschauer, A. Oeftiger CERN, Geneva, Switzerland
	At injection into the CERN Proton Synchrotron (PS) a significant horizontal emittance blow-up of the present high brightness beams for the LHC is observed. A partial contribution to this effect is suspected to be an important mismatch between the dispersion function in the transfer line from the PS Booster (PSB) and the ring itself. This mismatch will be unacceptable in view of the beam parameters requested by the LHC Injectors Upgrade (LIU) project with high longitudinal emittance and momentum spread. To deliver the requested beam parameters the PSB-to-PS transfer line will be upgraded and the optics in the line changed to improve the matching from all the four PSB rings. A re-matching campaign from the PSB ring 3 has been carried out to evaluate the impact of the present optics mismatch as a source of emittance growth both in simulations and measurements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEP2PO006
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEP2PO018	Magnetic Field Tracking at CSNS/RCS	controls, MMI, acceleration, dipole	306
	S.Y. Xu, S. Fu IHEP, Beijing, People's Republic of China
	Because of the differences of magnetic saturation and eddy current effects between different magnets, magnetic field tracking errors between different magnets is larger than 2.5 % at the Rapid Cycling Synchrotron (RCS) of Chinese Spallation Neutron Source (CSNS), and the induced tune shift is larger than 0.1. So larger tune shift may lead the beam to pass through the resonance lines. To reduce the magnetic field tracking errors, a method of wave form compensation for magnets of the Rapid Cycling Synchrotron was investigated on the magnets of CSNS/RCS. The wave form compensation was applied to CSNS/RCS commissioning. By performing wave form compensation, the maximum magnetic field tracking error was reduced from 2.5 % to 0.08 %, and the maximum tune shift over the ramping process was reduced from 0.1 to 0.004.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEP2PO018
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THA1WD03	Status and Beam Power Ramp-Up Plans of the Slow Extraction Operation at J-Parc Main Ring	extraction, operation, septum, proton	347
	M. Tomizawa, Y. Arakaki, T. Kimura, S. Murasugi, R. Muto, K. Okamura, Y. Shirakabe, E. Yanaoka KEK, Ibaraki, Japan
	A 30 GeV proton beam accelerated in the J-PARC Main Ring (MR) is slowly extracted by the third integer resonant extraction and delivered to the hadron experimental hall. Slow extraction from the MR has unique characteristics that can be used to obtain a low beam loss rate. Devices with electrostatic septum (ESSs) and magnetic septa are placed in the long straight section with zero dispersion. The separatrix for the resonance is independent of the momentum at the septa when the horizontal chromaticity is set to zero. The resulting beam has a large step size and small angular spread, enabling a low hit rate of the beam at the first ESS. Under these conditions, a dynamic bump scheme has been applied to reduce the beam loss further. We have attained 50 kW operation at 5.2s cycle in the latest physics run. A suppression of instability during debunch process is also essential as well as low beam loss tunings. In this paper, a current status and future plans toward a higher beam power for the slow extraction are reported. Preliminary results for a 8 GeV slow extraction test for the muon to electron conversion search experiment (COMET) will be also briefly presented.
	Slides THA1WD03 [9.174 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-THA1WD03
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THA1WE02	Requirements and Results for Quadrupole Mode Measurements	space-charge, emittance, synchrotron, pick-up	393
	A. Oeftiger CERN, Geneva, Switzerland
	Funding: Research supported by the HL-LHC project. Direct space charge may be quantified, and hence the beam brightness observed, by measuring the quadrupolar beam modes in the CERN Proton Synchrotron (PS). The spectrum of the transverse beam size oscillations (i.e. the quadrupolar beam moment) contains valuable information: the betatron envelope modes and the coherent dispersive mode indicate optics mismatch, while their frequency shifts due to space charge allow a direct measurement thereof. To measure the quadrupolar beam moment we use the Base-Band Q-meter system of the PS which is based on a four electrode stripline pick-up. Past experiments with quadrupolar pick-ups often investigated coasting beams, where the coherent betatron and dispersion modes correspond to single peaks in the tune spectrum. In contrast, long bunched beams feature bands of betatron modes: the mode frequencies shift depending on the transverse space charge strength which varies with the local line charge density. By using the new transverse feedback in the PS as a quadrupolar RF exciter, we measured the quadrupolar beam transfer function. The beam response reveals the distinct band structure of the envelope modes as well as the coherent dispersive mode.
	Slides THA1WE02 [7.315 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-THA1WE02
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

TUA1WD03

Commissioning Status and Plans of CSNS/RCS

MMI, injection, dipole, acceleration

133

S.Y. Xu, Y.W. An, J. Chen, M.Y. Huang, H.F. Ji, Y. Li, S. Wang
IHEP, Beijing, People's Republic of China
X.H. Lu
CSNS, Guangdong Province, People's Republic of China

The China Spallation Neutron Source (CSNS) is an accelerator-based science facility. CSNS is designed to accelerate proton beam pulses to 1.6 GeV kinetic energy, striking a solid metal target to produce spallation neutrons. CSNS has two major accelerator systems, a linear accelerator (80 MeV Linac) and a 1.6 GeV rapid cycling synchrotron (RCS). The Beam commissioning of CSNS has been commissioned recently. Beam had been accelerated to 61 MeV at CSNS/Linac on April 24, 2017, and 1.6 GeV acceleration at CSNS/RCS was successfully accomplished on July 7, 2017 with the injection energy of 61 MeV. Beam had been accelerated to 80 MeV at CSNS/Linac on January 6, 2018, and 1.6 GeV acceleration at CSNS/RCS was successfully accomplished on January 18, 2018 with the injection energy of 80 MeV. The initial machine parameter tuning and various beam studies were completed. In this paper, the commissioning experiences are introduced.

Slides TUA1WD03 [10.794 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-TUA1WD03

Export •

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

WEP1WB01

Beam Dynamics of the ESS Linac

linac, target, cavity, rfq

206

Y. Levinsen, R. De Prisco, M. Eshraqi, N. Milas, R. Miyamoto, D.C. Plostinar, A. Ponton
ESS, Lund, Sweden

The ESS linac will deliver an unprecedented 5 MW of average beam power when completed. Beyond the 90 MeV normal conducting front-end, the acceleration is performed using SC structures up to the design energy of 2 GeV. As the ESS will send the beam to a fixed tungsten target, the emittance is not as important a factor as in injectors. However, the losses have to be studied in detail, including not only the average operational loss required to be of less than 1 W/m, but also the accidental losses, losses due to failure and other potentially damaging losses. The commissioning of the ion source and LEBT starts this year and will continue with the RFQ next year. In this contribution we will discuss the beam dynamics aspects and challenges of the ESS linac.

Slides WEP1WB01 [2.084 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEP1WB01

Export •

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

WEP2PO006

Overview of the CERN PSB-to-PS Transfer Line Optics Matching Studies in View of the LHC Injectors Upgrade Project

emittance, optics, operation, injection

272

V. Forte, S.C.P. Albright, W. Bartmann, G.P. Di Giovanni, M.A. Fraser, C. Heßler, A. Huschauer, A. Oeftiger
CERN, Geneva, Switzerland

At injection into the CERN Proton Synchrotron (PS) a significant horizontal emittance blow-up of the present high brightness beams for the LHC is observed. A partial contribution to this effect is suspected to be an important mismatch between the dispersion function in the transfer line from the PS Booster (PSB) and the ring itself. This mismatch will be unacceptable in view of the beam parameters requested by the LHC Injectors Upgrade (LIU) project with high longitudinal emittance and momentum spread. To deliver the requested beam parameters the PSB-to-PS transfer line will be upgraded and the optics in the line changed to improve the matching from all the four PSB rings. A re-matching campaign from the PSB ring 3 has been carried out to evaluate the impact of the present optics mismatch as a source of emittance growth both in simulations and measurements.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEP2PO006

Export •

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

WEP2PO018

Magnetic Field Tracking at CSNS/RCS

controls, MMI, acceleration, dipole

306

S.Y. Xu, S. Fu
IHEP, Beijing, People's Republic of China

Because of the differences of magnetic saturation and eddy current effects between different magnets, magnetic field tracking errors between different magnets is larger than 2.5 % at the Rapid Cycling Synchrotron (RCS) of Chinese Spallation Neutron Source (CSNS), and the induced tune shift is larger than 0.1. So larger tune shift may lead the beam to pass through the resonance lines. To reduce the magnetic field tracking errors, a method of wave form compensation for magnets of the Rapid Cycling Synchrotron was investigated on the magnets of CSNS/RCS. The wave form compensation was applied to CSNS/RCS commissioning. By performing wave form compensation, the maximum magnetic field tracking error was reduced from 2.5 % to 0.08 %, and the maximum tune shift over the ramping process was reduced from 0.1 to 0.004.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEP2PO018

Export •

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

THA1WD03

Status and Beam Power Ramp-Up Plans of the Slow Extraction Operation at J-Parc Main Ring

extraction, operation, septum, proton

347

M. Tomizawa, Y. Arakaki, T. Kimura, S. Murasugi, R. Muto, K. Okamura, Y. Shirakabe, E. Yanaoka
KEK, Ibaraki, Japan

A 30 GeV proton beam accelerated in the J-PARC Main Ring (MR) is slowly extracted by the third integer resonant extraction and delivered to the hadron experimental hall. Slow extraction from the MR has unique characteristics that can be used to obtain a low beam loss rate. Devices with electrostatic septum (ESSs) and magnetic septa are placed in the long straight section with zero dispersion. The separatrix for the resonance is independent of the momentum at the septa when the horizontal chromaticity is set to zero. The resulting beam has a large step size and small angular spread, enabling a low hit rate of the beam at the first ESS. Under these conditions, a dynamic bump scheme has been applied to reduce the beam loss further. We have attained 50 kW operation at 5.2s cycle in the latest physics run. A suppression of instability during debunch process is also essential as well as low beam loss tunings. In this paper, a current status and future plans toward a higher beam power for the slow extraction are reported. Preliminary results for a 8 GeV slow extraction test for the muon to electron conversion search experiment (COMET) will be also briefly presented.

Slides THA1WD03 [9.174 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-THA1WD03

Export •

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

THA1WE02

Requirements and Results for Quadrupole Mode Measurements

space-charge, emittance, synchrotron, pick-up

393

A. Oeftiger
CERN, Geneva, Switzerland

Funding: Research supported by the HL-LHC project.
Direct space charge may be quantified, and hence the beam brightness observed, by measuring the quadrupolar beam modes in the CERN Proton Synchrotron (PS). The spectrum of the transverse beam size oscillations (i.e. the quadrupolar beam moment) contains valuable information: the betatron envelope modes and the coherent dispersive mode indicate optics mismatch, while their frequency shifts due to space charge allow a direct measurement thereof. To measure the quadrupolar beam moment we use the Base-Band Q-meter system of the PS which is based on a four electrode stripline pick-up. Past experiments with quadrupolar pick-ups often investigated coasting beams, where the coherent betatron and dispersion modes correspond to single peaks in the tune spectrum. In contrast, long bunched beams feature bands of betatron modes: the mode frequencies shift depending on the transverse space charge strength which varies with the local line charge density. By using the new transverse feedback in the PS as a quadrupolar RF exciter, we measured the quadrupolar beam transfer function. The beam response reveals the distinct band structure of the envelope modes as well as the coherent dispersive mode.

Slides THA1WE02 [7.315 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-THA1WE02

Export •

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