IPAC2015 - List of Authors (Romanov, G.V.)

Paper	Title	Page
MOPMA018	Simulation of Multipacting in SC Low Beta Cavities at FNAL	579
	G.V. Romanov, P. Berrutti, T.N. Khabiboulline Fermilab, Batavia, Illinois, USA
	Proton Improvement Plan-II at Fermilab is a plan for improvements to the accelerator complex aimed at providing a beam power capability of at least 1 MW on target at the initiation of LBNE (Long Base Neutrino Experiment) operations. The central element of the PIP-II is a new 800 MeV superconducting linac, injecting into the existing Booster. Multipacting affects superconducting RF cavities in the entire range from high energy elliptical cavities to coaxial resonators for low-beta applications. This work is focused on multipacting study in the low-beta 325 MHz spoke cavities; namely SSR1 and SSR2, which are especially susceptible to the phenomena. The extensive simulations of multipacting in the cavities with updated material properties and comparison of the results with experimental data helped us to improve overall reliability and accuracy of these simulations. Our practical approach to the simulations is described in details. For SSR2, which has a high multipacting barrier right at the operating power level, some changes of the cavity shape to mitigate this harmful phenomenon are proposed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMA018
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WEPTY037	A Perpendicular Biased 2nd Harmonic Cavity for the Fermilab Booster	3358
	C.-Y. Tan, J.E. Dey, R.L. Madrak, W. Pellico, G.V. Romanov, D. Sun, I. Terechkine Fermilab, Batavia, Illinois, USA
	Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. A perpendicular biased 2nd harmonic cavity is currently being designed for the Fermilab Booster. Its purpose cavity is to flatten the bucket at injection and thus change the longitudinal beam distribution so that space charge effects are decreased. It can also work at transition to help beam cross it. The choice of perpendicular biasing over parallel biasing is that the Q of the cavity is much higher and thus allows the accelerating voltage to be a factor of 2 higher than a similar parallel biased cavity. This cavity will also provide a higher accelerating voltage per meter than the present folded transmission line cavity. However, this type of cavity presents technical challenges that need to be addressed. The two major issues are cooling of the garnet material from the effects of the RF and the cavity itself from eddy current heating because of the 15 Hz bias field ramp. This paper will address the technical challenge of preventing the garnet from overheating.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY037
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WEPTY045	High-Intensity Proton RFQ Accelerator Fabrication Status for PXIE	3375
	A.R. Lambert, A.J. DeMello, M.D. Hoff, D. Li, T.H. Luo, J.W. Staples, S.P. Virostek LBNL, Berkeley, California, USA R. Andrews, C.M. Baffes, P. Berrutti, T.N. Khabiboulline, G.V. Romanov, D. Snee, J. Steimel Fermilab, Batavia, Illinois, USA
	Funding: Work supported by the Office of Science, U.S. Department of Energy under DOE contract number DE-AC02-05CH11231 PXIE is a prototype front end system for the proposed PIP-II accelerator upgrade at Fermilab. An integral component of the front end is a 162.5 MHz, normal conducting, CW (continuous wave), radio-frequency quadrupole (RFQ) cavity that was designed and is being fabricated by LBNL. This RFQ will accelerate a continuous stream of up to 10mA of H⁻ ions from 30 keV to 2.1 MeV. The four-vane, 4.45 meter long RFQ consists of four modules, each constructed from 2 pairs of identical modulated vanes. Vane modulations are machined using a custom carbide cutter designed at LBNL. Other machined features include ports for slug tuners, pi-mode rods, sensing loops, vacuum pumps and RF couplers. Vanes at the entrance and exit possess cutbacks for RF matching to the end plates. The vanes and pi-mode rods are bonded via hydrogen brazing with Cusil wire alloy. The brazing process mechanically bonds the RFQ vanes together and vacuum seals the module along its length. Vane fabrication is successfully completed, and the braze process has proved successful. Delivery of the full RFQ beam-line is expected in the middle of 2015.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY045
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Simulation of Multipacting in SC Low Beta Cavities at FNAL

579

G.V. Romanov, P. Berrutti, T.N. Khabiboulline
Fermilab, Batavia, Illinois, USA

Proton Improvement Plan-II at Fermilab is a plan for improvements to the accelerator complex aimed at providing a beam power capability of at least 1 MW on target at the initiation of LBNE (Long Base Neutrino Experiment) operations. The central element of the PIP-II is a new 800 MeV superconducting linac, injecting into the existing Booster. Multipacting affects superconducting RF cavities in the entire range from high energy elliptical cavities to coaxial resonators for low-beta applications. This work is focused on multipacting study in the low-beta 325 MHz spoke cavities; namely SSR1 and SSR2, which are especially susceptible to the phenomena. The extensive simulations of multipacting in the cavities with updated material properties and comparison of the results with experimental data helped us to improve overall reliability and accuracy of these simulations. Our practical approach to the simulations is described in details. For SSR2, which has a high multipacting barrier right at the operating power level, some changes of the cavity shape to mitigate this harmful phenomenon are proposed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMA018

Export •

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

WEPTY037

A Perpendicular Biased 2nd Harmonic Cavity for the Fermilab Booster

3358

C.-Y. Tan, J.E. Dey, R.L. Madrak, W. Pellico, G.V. Romanov, D. Sun, I. Terechkine
Fermilab, Batavia, Illinois, USA

Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
A perpendicular biased 2nd harmonic cavity is currently being designed for the Fermilab Booster. Its purpose cavity is to flatten the bucket at injection and thus change the longitudinal beam distribution so that space charge effects are decreased. It can also work at transition to help beam cross it. The choice of perpendicular biasing over parallel biasing is that the Q of the cavity is much higher and thus allows the accelerating voltage to be a factor of 2 higher than a similar parallel biased cavity. This cavity will also provide a higher accelerating voltage per meter than the present folded transmission line cavity. However, this type of cavity presents technical challenges that need to be addressed. The two major issues are cooling of the garnet material from the effects of the RF and the cavity itself from eddy current heating because of the 15 Hz bias field ramp. This paper will address the technical challenge of preventing the garnet from overheating.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY037

Export •

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

WEPTY045

High-Intensity Proton RFQ Accelerator Fabrication Status for PXIE

3375

A.R. Lambert, A.J. DeMello, M.D. Hoff, D. Li, T.H. Luo, J.W. Staples, S.P. Virostek
LBNL, Berkeley, California, USA
R. Andrews, C.M. Baffes, P. Berrutti, T.N. Khabiboulline, G.V. Romanov, D. Snee, J. Steimel
Fermilab, Batavia, Illinois, USA

Funding: Work supported by the Office of Science, U.S. Department of Energy under DOE contract number DE-AC02-05CH11231
PXIE is a prototype front end system for the proposed PIP-II accelerator upgrade at Fermilab. An integral component of the front end is a 162.5 MHz, normal conducting, CW (continuous wave), radio-frequency quadrupole (RFQ) cavity that was designed and is being fabricated by LBNL. This RFQ will accelerate a continuous stream of up to 10mA of H⁻ ions from 30 keV to 2.1 MeV. The four-vane, 4.45 meter long RFQ consists of four modules, each constructed from 2 pairs of identical modulated vanes. Vane modulations are machined using a custom carbide cutter designed at LBNL. Other machined features include ports for slug tuners, pi-mode rods, sensing loops, vacuum pumps and RF couplers. Vanes at the entrance and exit possess cutbacks for RF matching to the end plates. The vanes and pi-mode rods are bonded via hydrogen brazing with Cusil wire alloy. The brazing process mechanically bonds the RFQ vanes together and vacuum seals the module along its length. Vane fabrication is successfully completed, and the braze process has proved successful. Delivery of the full RFQ beam-line is expected in the middle of 2015.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY045

Export •

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