PAC2013 - List of Authors (Virostek, S.P.)

Paper	Title	Page
WEPMA03	Tuner System Assembly and Tests for the 201-MHz MICE Cavity	987
	L. Somaschini INFN-Pisa, Pisa, Italy A.J. DeMello, D. Li, S.P. Virostek LBNL, Berkeley, California, USA P.M. Hanlet IIT, Chicago, Illinois, USA A. Moretti, R.J. Pasquinelli, D.W. Peterson, Y. Torun Fermilab, Batavia, USA
	Funding: Supported by the US Department of Energy. The MICE cavities include a mechanical tuning system consisting of stainless steel flexure forks attached to the cavity body and driven by pneumatic actuators. The first of these systems was assembled and tested at Fermilab for use at the MuCool Test Area. The actuators were calibrated on a test hoop. The cavity body was measured and the fork contact pads machined to fit. Actuators were mounted on the vacuum vessel housing the cavity. The transfer function of the tuning system was measured and frequency control software implemented.

WEPMA16	Assembly and Testing of the First 201-MHz MICE Cavity at Fermilab	1016
	Y. Torun Illinois Institute of Technology, Chicago, IL, USA D.L. Bowring, A.J. DeMello, D. Li, T.H. Luo, S.P. Virostek LBNL, Berkeley, California, USA P.M. Hanlet IIT, Chicago, Illinois, USA M.A. Leonova, A. Moretti, R.J. Pasquinelli, D.W. Peterson, R.P. Schultz, J.T. Volk Fermilab, Batavia, USA T.H. Luo UMiss, University, Mississippi, USA L. Somaschini INFN-Pisa, Pisa, Italy
	Funding: Supported by the US Department of Energy. The International Muon Ionization Cooling Experiment (MICE) includes two linear accelerator sections with four RF cavities each within a shared vacuum vessel. Ten cavity bodies have been fabricated for MICE including two spares and one was electropolished. A special vacuum vessel was built to house this cavity and form the 201-MHz Single-Cavity Module. The module was assembled, instrumented and tested at Fermilab for installation and operation in the MuCool Test Area.

WEPMA19	Progress on the Fabrication of a CW Radio-frequency Quadrupole (RFQ) for the Project X Injector Experiment (PXIE)	1019
	M.D. Hoff, A.J. DeMello, A.R. Lambert, D. Li, J.W. Staples, S.P. Virostek LBNL, Berkeley, California, USA
	Funding: * This work is supported by the Office of Science, United States Department of Energy under DOE contract DE-AC02-05CH11231. The Project X Injector Experiment (PXIE), a prototype front end of the Project X accelerator [1] proposed by Fermilab, is currently under construction. The complete PXIE beamline [2] is made up of an H⁻ ion source, a low-energy beam transport (LEBT), a 2.1 MeV, 162.5 MHz radio-frequency quadrupole (RFQ) accelerator, a medium-energy beam transport (MEBT) and a 30 MeV section of superconducting cryomodules. The 4.45 m long CW RFQ consists of four separate modules that are joined by means of specially designed bolted joints. Each module consists of four solid copper vanes that are brazed together to form a 4-quadrant accelerating cavity. The ~80 kW of total wall power heat is removed by means of gun drilled water cooling passages. Mode stabilization is provided by a series of brazed, water cooled pi-mode rods. Tuning is achieved using a total of 80 fixed slug tuners. Fabrication of the PXIE RFQ is now under way at LBNL. Details of the RFQ mechanical design and an update of the fabrication progress are presented in this paper.

WEPMA20	RF, Thermal, and Structural Finite Element Analysis of the Project X Injector Experiment (PXIE) CW Radio-frequency Quadrupole (RFQ)	1022
	A.R. Lambert, M.D. Hoff, D. Li, J.W. Staples, S.P. Virostek LBNL, Berkeley, California, USA
	Funding: This work is supported by the Office of Science, United States Department of Energy under DOE contract DE-AC02-05CH11231. PXIE (Project X Injector Experiment) is a prototype front end system for the proposed Project X accelerator complex at Fermilab. An integral component of the front end is a 162.5 MHz normal conducting CW (continuous wave) radio-frequency quadrupole (RFQ) accelerator that has been designed and will be fabricated by LBNL. The RFQ will accelerate H⁻ ions from 30 keV to 2.1 MeV [2]. The four-vane RFQ will consist of four modules with a total length of 4.45 meters. Through rigorous application of finite element analysis (FEA), the electromagnetic fields and their resultant effect on the RFQ body temperature and the subsequent deformations due to thermal expansion have been simulated. The analysis methodology developed at LBNL allows for quick evaluation of RFQ temperature, stress, deformation and the resulting effect on frequency without requiring the construction of a prototype. The technique has been applied to the following: RFQ body, RFQ cutbacks, fixed slug tuners, and pi-mode rods. The analysis indicates that the total heat load on the RFQ walls will be approximately 80 kW, which is removed via water-cooled passages.

WEPMA21	Final Design of a CW Radio-frequency Quadrupole (RFQ) for the Project X Injector Experiment (PXIE)	1025
	S.P. Virostek, A.J. DeMello, M.D. Hoff, A.R. Lambert, D. Li, J.W. Staples LBNL, Berkeley, California, USA
	Funding: This work is supported by the Office of Science, United States Department of Energy under DOE contract DE-AC02-05CH11231. The Project X Injector Experiment (PXIE) now under construction at Fermilab is a prototype front end of the proposed Project X accelerator [1]. PXIE will consist of the following: an H⁻ ion source, a low-energy beam transport (LEBT), a radio-frequency quadrupole (RFQ) accelerator, a medium-energy beam transport (MEBT) and a section of superconducting cryomodules [2]. The PXIE system will accelerate the beam from 30 keV to 30 MeV. The four-vane, brazed, solid copper design is a 4.45 m long CW RF accelerator with a resonant frequency of 162.5 MHz. The RFQ will provide bunching and acceleration of a nominal 5 mA H⁻ beam to an energy of 2.1 MeV. The average power density on the RFQ cavity walls is <0.7 W/sq. cm such that the total wall power losses are ~80 kW. LBNL has completed the final design of the PXIE RFQ, and fabrication is now under way. The completed PXIE RFQ will be assembled at LBNL and tested with low-level RF prior to shipping to Fermilab. Several aspects of the final RFQ mechanical design along with associated fabrication techniques are presented in this paper.

WEPMA26	Multipacting Study for the RF Test of the MICE 201 MHz RF Cavity at Fermilab MTA	1037
	T.H. Luo, D.J. Summers UMiss, University, Mississippi, USA A.J. DeMello, D. Li, P. Pan, S.P. Virostek, M.S. Zisman LBNL, Berkeley, California, USA
	One 201 MHz RF cavity for the Muon Ionization Cooling Experiment (MICE) will be tested at Muon Test Area (MTA) in Fermilab. Before the Coupling Coil is ready, we will use the fringe field of the Lab G magnet to study the cavity performance in external B field, which can significantly change the multipacting situation in cavities. In this report, we present the multipacting study of the MICE 201 MHz cavity with the fringe field of Lab G magnet. We will survey the co-axial waveguide, the cavity body and the loop coupler region at different power levels and different fringe field magnitudes.

Paper

Title

Page

Tuner System Assembly and Tests for the 201-MHz MICE Cavity

987

L. Somaschini
INFN-Pisa, Pisa, Italy
A.J. DeMello, D. Li, S.P. Virostek
LBNL, Berkeley, California, USA
P.M. Hanlet
IIT, Chicago, Illinois, USA
A. Moretti, R.J. Pasquinelli, D.W. Peterson, Y. Torun
Fermilab, Batavia, USA

Funding: Supported by the US Department of Energy.
The MICE cavities include a mechanical tuning system consisting of stainless steel flexure forks attached to the cavity body and driven by pneumatic actuators. The first of these systems was assembled and tested at Fermilab for use at the MuCool Test Area. The actuators were calibrated on a test hoop. The cavity body was measured and the fork contact pads machined to fit. Actuators were mounted on the vacuum vessel housing the cavity. The transfer function of the tuning system was measured and frequency control software implemented.

WEPMA16

Assembly and Testing of the First 201-MHz MICE Cavity at Fermilab

1016

Y. Torun
Illinois Institute of Technology, Chicago, IL, USA
D.L. Bowring, A.J. DeMello, D. Li, T.H. Luo, S.P. Virostek
LBNL, Berkeley, California, USA
P.M. Hanlet
IIT, Chicago, Illinois, USA
M.A. Leonova, A. Moretti, R.J. Pasquinelli, D.W. Peterson, R.P. Schultz, J.T. Volk
Fermilab, Batavia, USA
T.H. Luo
UMiss, University, Mississippi, USA
L. Somaschini
INFN-Pisa, Pisa, Italy

Funding: Supported by the US Department of Energy.
The International Muon Ionization Cooling Experiment (MICE) includes two linear accelerator sections with four RF cavities each within a shared vacuum vessel. Ten cavity bodies have been fabricated for MICE including two spares and one was electropolished. A special vacuum vessel was built to house this cavity and form the 201-MHz Single-Cavity Module. The module was assembled, instrumented and tested at Fermilab for installation and operation in the MuCool Test Area.

WEPMA19

Progress on the Fabrication of a CW Radio-frequency Quadrupole (RFQ) for the Project X Injector Experiment (PXIE)

1019

M.D. Hoff, A.J. DeMello, A.R. Lambert, D. Li, J.W. Staples, S.P. Virostek
LBNL, Berkeley, California, USA

Funding: * This work is supported by the Office of Science, United States Department of Energy under DOE contract DE-AC02-05CH11231.
The Project X Injector Experiment (PXIE), a prototype front end of the Project X accelerator [1] proposed by Fermilab, is currently under construction. The complete PXIE beamline [2] is made up of an H⁻ ion source, a low-energy beam transport (LEBT), a 2.1 MeV, 162.5 MHz radio-frequency quadrupole (RFQ) accelerator, a medium-energy beam transport (MEBT) and a 30 MeV section of superconducting cryomodules. The 4.45 m long CW RFQ consists of four separate modules that are joined by means of specially designed bolted joints. Each module consists of four solid copper vanes that are brazed together to form a 4-quadrant accelerating cavity. The ~80 kW of total wall power heat is removed by means of gun drilled water cooling passages. Mode stabilization is provided by a series of brazed, water cooled pi-mode rods. Tuning is achieved using a total of 80 fixed slug tuners. Fabrication of the PXIE RFQ is now under way at LBNL. Details of the RFQ mechanical design and an update of the fabrication progress are presented in this paper.

WEPMA20

RF, Thermal, and Structural Finite Element Analysis of the Project X Injector Experiment (PXIE) CW Radio-frequency Quadrupole (RFQ)

1022

A.R. Lambert, M.D. Hoff, D. Li, J.W. Staples, S.P. Virostek
LBNL, Berkeley, California, USA

Funding: This work is supported by the Office of Science, United States Department of Energy under DOE contract DE-AC02-05CH11231.
PXIE (Project X Injector Experiment) is a prototype front end system for the proposed Project X accelerator complex at Fermilab. An integral component of the front end is a 162.5 MHz normal conducting CW (continuous wave) radio-frequency quadrupole (RFQ) accelerator that has been designed and will be fabricated by LBNL. The RFQ will accelerate H⁻ ions from 30 keV to 2.1 MeV [2]. The four-vane RFQ will consist of four modules with a total length of 4.45 meters. Through rigorous application of finite element analysis (FEA), the electromagnetic fields and their resultant effect on the RFQ body temperature and the subsequent deformations due to thermal expansion have been simulated. The analysis methodology developed at LBNL allows for quick evaluation of RFQ temperature, stress, deformation and the resulting effect on frequency without requiring the construction of a prototype. The technique has been applied to the following: RFQ body, RFQ cutbacks, fixed slug tuners, and pi-mode rods. The analysis indicates that the total heat load on the RFQ walls will be approximately 80 kW, which is removed via water-cooled passages.

WEPMA21

Final Design of a CW Radio-frequency Quadrupole (RFQ) for the Project X Injector Experiment (PXIE)

1025

S.P. Virostek, A.J. DeMello, M.D. Hoff, A.R. Lambert, D. Li, J.W. Staples
LBNL, Berkeley, California, USA

Funding: This work is supported by the Office of Science, United States Department of Energy under DOE contract DE-AC02-05CH11231.
The Project X Injector Experiment (PXIE) now under construction at Fermilab is a prototype front end of the proposed Project X accelerator [1]. PXIE will consist of the following: an H⁻ ion source, a low-energy beam transport (LEBT), a radio-frequency quadrupole (RFQ) accelerator, a medium-energy beam transport (MEBT) and a section of superconducting cryomodules [2]. The PXIE system will accelerate the beam from 30 keV to 30 MeV. The four-vane, brazed, solid copper design is a 4.45 m long CW RF accelerator with a resonant frequency of 162.5 MHz. The RFQ will provide bunching and acceleration of a nominal 5 mA H⁻ beam to an energy of 2.1 MeV. The average power density on the RFQ cavity walls is <0.7 W/sq. cm such that the total wall power losses are ~80 kW. LBNL has completed the final design of the PXIE RFQ, and fabrication is now under way. The completed PXIE RFQ will be assembled at LBNL and tested with low-level RF prior to shipping to Fermilab. Several aspects of the final RFQ mechanical design along with associated fabrication techniques are presented in this paper.

WEPMA26

Multipacting Study for the RF Test of the MICE 201 MHz RF Cavity at Fermilab MTA

1037

T.H. Luo, D.J. Summers
UMiss, University, Mississippi, USA
A.J. DeMello, D. Li, P. Pan, S.P. Virostek, M.S. Zisman
LBNL, Berkeley, California, USA

One 201 MHz RF cavity for the Muon Ionization Cooling Experiment (MICE) will be tested at Muon Test Area (MTA) in Fermilab. Before the Coupling Coil is ready, we will use the fringe field of the Lab G magnet to study the cavity performance in external B field, which can significantly change the multipacting situation in cavities. In this report, we present the multipacting study of the MICE 201 MHz cavity with the fringe field of Lab G magnet. We will survey the co-axial waveguide, the cavity body and the loop coupler region at different power levels and different fringe field magnitudes.