IPAC2012 - List of Authors (Romanov, G.V.)

Paper	Title	Page
MOPPC081	Simulation of RF Cavity Dark Current in Presence of Helical Magnetic Field	325
	G.V. Romanov, V.S. Kashikhin Fermilab, Batavia, USA
	In order to produce muon beam of high enough quality to be used for a Muon Collider, its large phase space must be cooled several orders of magnitude. This task can be accomplished by ionization cooling. Ionization cooling consists of passing a high-emittance muon beam alternately through regions of low-Z material, such as liquid hydrogen, and very high accelerating RF cavities within a multi-Tesla solenoidal focusing channel. But first high power tests of an RF cavity with beryllium windows in a solenoidal magnetic field showed a dramatic drop in accelerating gradient due to RF breakdowns. It has been concluded that external magnetic fields parallel to the RF electric field significantly modifies the performance of RF cavities. However, the magnetic field in a Helical Cooling Channel has a strong dipole component in addition to a solenoidal one. The dipole component essentially changes electron motion in a cavity compared to a pure solenoidal case, making dark current less focused at field emission sites. The simulation of a dark current dynamic in HCC performed with CST Studio Suite is presented in this paper.

MOPPC082	Beam Dynamics Simulations inProject X RFQ with CST Studio Suite	328
	G.V. Romanov Fermilab, Batavia, USA
	Typically the RFQs are designed using the Parmteq, DesRFQ and other similar specialized codes, which produces the files containing the field and geometrical parameters for every cell. The beam dynamic simulations with these analytical fields are, of course, ideal realizations of the designed RFQs. The new advanced computing capabilities made it possible to simulate beam and even dark current in the realistic 3D electromagnetic fields in the RFQs that may reflect cavity tuning, presence of tuners and couplers, RFQ segmentation etc. The paper describes the utilization of full 3D field distribution obtained with CST Studio Suite for beam dynamic simulations using both PIC solver of CST Particle Studio and the beam dynamic code TRACK.

TUPPD010	Helical Muon Beam Cooling Channel Engineering Design	1425
	G. Flanagan, R.P. Johnson, G.M. Kazakevich, F. Marhauser, M.L. Neubauer Muons, Inc, Batavia, USA V.S. Kashikhin, M.L. Lopes, G.V. Romanov, M.A. Tartaglia, K. Yonehara, M. Yu, A.V. Zlobin Fermilab, Batavia, USA
	Funding: Supported in part by DOE STTR Grant DE-SC0006266 The Helical Cooling Channel (HCC), a novel technique for six-dimensional (6D) ionization cooling of muon beams, has shown considerable promise based on analytic and simulation studies. However, the implementation of this revolutionary method of muon cooling requires new techniques for the integration of hydrogen-pressurized, high-power RF cavities into the low-temperature superconducting magnets of the HCC. We present the progress toward a conceptual design for the integration of 805 MHz RF cavities into a 10 T Nb3Sn based HCC test section. We include discussions on the pressure and thermal barriers needed within the cryostat to maintain operation of the magnet at 4.2 K while operating the RF and energy absorber at a higher temperature. Additionally, we include progress on the Nb3Sn helical solenoid design

THPPC032	Conditioning and Future Plans for a Multi-purpose 805 MHz Pillbox Cavity for Muon Acceleration	3353
	G.M. Kazakevich, A. Dudas, G. Flanagan, R.P. Johnson, F. Marhauser, M.L. Neubauer, R. Sah Muons, Inc, Batavia, USA S.S. Kurennoy LANL, Los Alamos, New Mexico, USA A. Moretti, M. Popovic, G.V. Romanov, K. Yonehara Fermilab, Batavia, USA Y. Torun IIT, Chicago, Illinois, USA
	Funding: Supported in part by grant 4735 · 10 LANL and Dept. of Energy STTR grant DE-FG02-08ER86352. An 805 MHz RF pillbox cavity has been designed and constructed to investigate potential muon beam acceleration and cooling techniques for a Muon Collider or Neutrino Factory. The cavity can operate in vacuum or under pressure to 100 atmospheres, at room temperature or in a liquid nitrogen bath at 77 K. The cavity has been designed for easy assembly and disassembly with bolted construction using aluminum seals. To perform vacuum and high pressure breakdown studies of materials and geometries most suitable for the collider or factory, the surfaces of the end walls of the cavity can be replaced with different materials such as copper, aluminum, beryllium, or molybdenum, and with different geometries such as shaped windows or grid structures. The cavity has been designed to fit inside the 5-Tesla solenoid in the MuCool Test Area at Fermilab. In this paper we present the vacuum conditioning results and discuss plans for testing in a 5-Tesla magnetic field. Additionally, we discuss the testing plan for beryllium (a material research has shown to be ideal for the collider or factory) end walls.

THPPC034	Design and Analysis of the PXIE CW Radio-frequency Quadrupole (RFQ)	3359
	S.P. Virostek, M.D. Hoff, A.R. Lambert, D. Li, J.W. Staples LBNL, Berkeley, California, USA G.V. Romanov Fermilab, Batavia, USA C. Zhang IAP, Frankfurt am Main, Germany
	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) will be a prototype front end of the Project X accelerator proposed by Fermilab. PXIE will consist of 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 that will accelerate the beam from 30 keV to 30 MeV. LBNL has developed an RFQ design for PXIE with fabrication scheduled to begin before the end of CY 2012. The chosen baseline design is a four-vane, 4.4 m long CW RFQ with a resonant frequency at 162.5 MHz (2.4 wavelengths long). The RFQ will provide bunching and acceleration of a nominal 5 mA H⁻ beam to 2.1 MeV. The relatively low wall power density results in wall power losses that are less than 100 kW. The beam dynamics design has been optimized to allow for more than 99% beam capture with exceptionally low longitudinal emittance. The RFQ mechanical design and the results of RF and thermal analyses are presented here.

THPPP063	CW Room Temperature Re-buncher for the Project X Front End	3880
	G.V. Romanov, M.H. Awida, M. Chen, I.V. Gonin, S. Kazakov, R.A. Kostin, V.A. Lebedev, N. Solyak, V.P. Yakovlev Fermilab, Batavia, USA
	At Fermilab there is a plan to construct the Project X Injector Experiment (PXIE) facility - a prototype of the front end of the Project X, a multi-MW proton source based on a superconducting linac. The construction and successful operations of this facility will validate the concept for the Project X front end, thereby minimizing the primary technical risk element within the Project. The front end of the linac contains a cw room-temperature MEBT section which comprises an ion source, RFQ, and high-bandwidth bunch selective chopper. The length of the MEBT exceeds 9 m, so three re-bunching cavities are used to support the beam longitudinal dynamics. The paper reports RF design of the re-bunchers along with preliminary beam dynamic and thermal analysis of the cavities.

THPPP064	Project X RFQ EM Design	3883
	G.V. Romanov Fermilab, Batavia, USA M.D. Hoff, D. Li, J.W. Staples, S.P. Virostek LBNL, Berkeley, California, USA
	Project X is a proposed multi-MW proton facility at Fermi National Accelerator Laboratory (FNAL). The Project X front-end would consist of an H⁻ ion source, a low-energy beam transport (LEBT), a cw 162.5 MHz radio-frequency quadrupole (RFQ) accelerator, and a medium-energy beam transport (MEBT). Lawrence Berkeley National Laboratory (LBNL) and FNAL collaboration is currently developing the designs for various components in the Project X front end. This paper reports the detailed EM design of the cw 162.5 MHz RFQ that provides bunching of the 1-10 mA H⁻ beam with acceleration from 30 keV to 2.1 MeV.

THPPP092	Progress of the Front-End System Development for Project X at LBNL	3951
	D. Li, M.D. Hoff, Q. Ji, A.R. Lambert, T. Schenkel, J.W. Staples, S.P. Virostek LBNL, Berkeley, California, USA S. Nagaitsev, L.R. Prost, G.V. Romanov, A.V. Shemyakin Fermilab, Batavia, USA C. Zhang IAP, Frankfurt am Main, Germany
	Funding: This work is supported by the Office of Science, United States Department of Energy under DOE contract DE-AC02-05CH11231. A multi-MW proton facility, Project X has been proposed and is currently under development at Fermilab. Project X is a key accelerator complex for intensity frontier of future high energy physics programs in the US. In collaboration with Fermilab, LBNL takes the responsibility in the development and design studies of the front-end system for Project X. The front-end system would consist of H⁻ ion source(s), low-energy beam transport (LEBT), 162.5 MHz normal conducting CW Radio-Frequency-Quadrupole (RFQ) accelerator, medium-energy beam transport (MEBT), and beam chopper(s). In this paper, we will review and present recent progress of the front-end system studies, which will include the RFQ beam dynamics design, RF structure design, thermal and mechanical analyses and fabrication plan, LEBT simulation studies and concept for LEBT chopper.

Paper

Title

Page

Simulation of RF Cavity Dark Current in Presence of Helical Magnetic Field

325

G.V. Romanov, V.S. Kashikhin
Fermilab, Batavia, USA

In order to produce muon beam of high enough quality to be used for a Muon Collider, its large phase space must be cooled several orders of magnitude. This task can be accomplished by ionization cooling. Ionization cooling consists of passing a high-emittance muon beam alternately through regions of low-Z material, such as liquid hydrogen, and very high accelerating RF cavities within a multi-Tesla solenoidal focusing channel. But first high power tests of an RF cavity with beryllium windows in a solenoidal magnetic field showed a dramatic drop in accelerating gradient due to RF breakdowns. It has been concluded that external magnetic fields parallel to the RF electric field significantly modifies the performance of RF cavities. However, the magnetic field in a Helical Cooling Channel has a strong dipole component in addition to a solenoidal one. The dipole component essentially changes electron motion in a cavity compared to a pure solenoidal case, making dark current less focused at field emission sites. The simulation of a dark current dynamic in HCC performed with CST Studio Suite is presented in this paper.

MOPPC082

Beam Dynamics Simulations inProject X RFQ with CST Studio Suite

328

G.V. Romanov
Fermilab, Batavia, USA

Typically the RFQs are designed using the Parmteq, DesRFQ and other similar specialized codes, which produces the files containing the field and geometrical parameters for every cell. The beam dynamic simulations with these analytical fields are, of course, ideal realizations of the designed RFQs. The new advanced computing capabilities made it possible to simulate beam and even dark current in the realistic 3D electromagnetic fields in the RFQs that may reflect cavity tuning, presence of tuners and couplers, RFQ segmentation etc. The paper describes the utilization of full 3D field distribution obtained with CST Studio Suite for beam dynamic simulations using both PIC solver of CST Particle Studio and the beam dynamic code TRACK.

TUPPD010

Helical Muon Beam Cooling Channel Engineering Design

1425

G. Flanagan, R.P. Johnson, G.M. Kazakevich, F. Marhauser, M.L. Neubauer
Muons, Inc, Batavia, USA
V.S. Kashikhin, M.L. Lopes, G.V. Romanov, M.A. Tartaglia, K. Yonehara, M. Yu, A.V. Zlobin
Fermilab, Batavia, USA

Funding: Supported in part by DOE STTR Grant DE-SC0006266
The Helical Cooling Channel (HCC), a novel technique for six-dimensional (6D) ionization cooling of muon beams, has shown considerable promise based on analytic and simulation studies. However, the implementation of this revolutionary method of muon cooling requires new techniques for the integration of hydrogen-pressurized, high-power RF cavities into the low-temperature superconducting magnets of the HCC. We present the progress toward a conceptual design for the integration of 805 MHz RF cavities into a 10 T Nb3Sn based HCC test section. We include discussions on the pressure and thermal barriers needed within the cryostat to maintain operation of the magnet at 4.2 K while operating the RF and energy absorber at a higher temperature. Additionally, we include progress on the Nb3Sn helical solenoid design

THPPC032

Conditioning and Future Plans for a Multi-purpose 805 MHz Pillbox Cavity for Muon Acceleration

3353

G.M. Kazakevich, A. Dudas, G. Flanagan, R.P. Johnson, F. Marhauser, M.L. Neubauer, R. Sah
Muons, Inc, Batavia, USA
S.S. Kurennoy
LANL, Los Alamos, New Mexico, USA
A. Moretti, M. Popovic, G.V. Romanov, K. Yonehara
Fermilab, Batavia, USA
Y. Torun
IIT, Chicago, Illinois, USA

Funding: Supported in part by grant 4735 · 10 LANL and Dept. of Energy STTR grant DE-FG02-08ER86352.
An 805 MHz RF pillbox cavity has been designed and constructed to investigate potential muon beam acceleration and cooling techniques for a Muon Collider or Neutrino Factory. The cavity can operate in vacuum or under pressure to 100 atmospheres, at room temperature or in a liquid nitrogen bath at 77 K. The cavity has been designed for easy assembly and disassembly with bolted construction using aluminum seals. To perform vacuum and high pressure breakdown studies of materials and geometries most suitable for the collider or factory, the surfaces of the end walls of the cavity can be replaced with different materials such as copper, aluminum, beryllium, or molybdenum, and with different geometries such as shaped windows or grid structures. The cavity has been designed to fit inside the 5-Tesla solenoid in the MuCool Test Area at Fermilab. In this paper we present the vacuum conditioning results and discuss plans for testing in a 5-Tesla magnetic field. Additionally, we discuss the testing plan for beryllium (a material research has shown to be ideal for the collider or factory) end walls.

THPPC034

Design and Analysis of the PXIE CW Radio-frequency Quadrupole (RFQ)

3359

S.P. Virostek, M.D. Hoff, A.R. Lambert, D. Li, J.W. Staples
LBNL, Berkeley, California, USA
G.V. Romanov
Fermilab, Batavia, USA
C. Zhang
IAP, Frankfurt am Main, Germany

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) will be a prototype front end of the Project X accelerator proposed by Fermilab. PXIE will consist of 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 that will accelerate the beam from 30 keV to 30 MeV. LBNL has developed an RFQ design for PXIE with fabrication scheduled to begin before the end of CY 2012. The chosen baseline design is a four-vane, 4.4 m long CW RFQ with a resonant frequency at 162.5 MHz (2.4 wavelengths long). The RFQ will provide bunching and acceleration of a nominal 5 mA H⁻ beam to 2.1 MeV. The relatively low wall power density results in wall power losses that are less than 100 kW. The beam dynamics design has been optimized to allow for more than 99% beam capture with exceptionally low longitudinal emittance. The RFQ mechanical design and the results of RF and thermal analyses are presented here.

THPPP063

CW Room Temperature Re-buncher for the Project X Front End

3880

G.V. Romanov, M.H. Awida, M. Chen, I.V. Gonin, S. Kazakov, R.A. Kostin, V.A. Lebedev, N. Solyak, V.P. Yakovlev
Fermilab, Batavia, USA

At Fermilab there is a plan to construct the Project X Injector Experiment (PXIE) facility - a prototype of the front end of the Project X, a multi-MW proton source based on a superconducting linac. The construction and successful operations of this facility will validate the concept for the Project X front end, thereby minimizing the primary technical risk element within the Project. The front end of the linac contains a cw room-temperature MEBT section which comprises an ion source, RFQ, and high-bandwidth bunch selective chopper. The length of the MEBT exceeds 9 m, so three re-bunching cavities are used to support the beam longitudinal dynamics. The paper reports RF design of the re-bunchers along with preliminary beam dynamic and thermal analysis of the cavities.

THPPP064

Project X RFQ EM Design

3883

G.V. Romanov
Fermilab, Batavia, USA
M.D. Hoff, D. Li, J.W. Staples, S.P. Virostek
LBNL, Berkeley, California, USA

Project X is a proposed multi-MW proton facility at Fermi National Accelerator Laboratory (FNAL). The Project X front-end would consist of an H⁻ ion source, a low-energy beam transport (LEBT), a cw 162.5 MHz radio-frequency quadrupole (RFQ) accelerator, and a medium-energy beam transport (MEBT). Lawrence Berkeley National Laboratory (LBNL) and FNAL collaboration is currently developing the designs for various components in the Project X front end. This paper reports the detailed EM design of the cw 162.5 MHz RFQ that provides bunching of the 1-10 mA H⁻ beam with acceleration from 30 keV to 2.1 MeV.

THPPP092

Progress of the Front-End System Development for Project X at LBNL

3951

D. Li, M.D. Hoff, Q. Ji, A.R. Lambert, T. Schenkel, J.W. Staples, S.P. Virostek
LBNL, Berkeley, California, USA
S. Nagaitsev, L.R. Prost, G.V. Romanov, A.V. Shemyakin
Fermilab, Batavia, USA
C. Zhang
IAP, Frankfurt am Main, Germany

Funding: This work is supported by the Office of Science, United States Department of Energy under DOE contract DE-AC02-05CH11231.
A multi-MW proton facility, Project X has been proposed and is currently under development at Fermilab. Project X is a key accelerator complex for intensity frontier of future high energy physics programs in the US. In collaboration with Fermilab, LBNL takes the responsibility in the development and design studies of the front-end system for Project X. The front-end system would consist of H⁻ ion source(s), low-energy beam transport (LEBT), 162.5 MHz normal conducting CW Radio-Frequency-Quadrupole (RFQ) accelerator, medium-energy beam transport (MEBT), and beam chopper(s). In this paper, we will review and present recent progress of the front-end system studies, which will include the RFQ beam dynamics design, RF structure design, thermal and mechanical analyses and fabrication plan, LEBT simulation studies and concept for LEBT chopper.