NAPAC2016 - List of Authors (Lebedev, V.A.)

Paper	Title	Page
MOPOB16	Higher Order Modes Analysis of Fermilab's Recycler Cavity	106
	M.H. Awida, J.E. Dey, T.N. Khabiboulline, V.A. Lebedev, R.L. Madrak Fermilab, Batavia, Illinois, USA
	Funding: Operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the U.S. DOE Two recycler cavities are being employed in Fermilab's Recycler Ring for the purpose of slip stacking proton bunches, where 6 batches of 8 GeV protons coming from the Booster are stacked on top of 6 circulating batches. Slip stacking requires two RF cavities operating at 52.809 and 51.545 MHz. In this paper, we report on the analysis of higher order modes in the Recycler cavity, presenting the values for R/Q and shunt impedances. Knowing the frequencies and properties of higher order modes is particularly critical for beam physics and avoidance of beam instabilities.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB16
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TUA2CO03	A Novel Technique of Power Control in Magnetron Transmitters for Intense Accelerators	271
	G.M. Kazakevich, R.P. Johnson, M.L. Neubauer Muons, Inc, Illinois, USA V.A. Lebedev, W. Schappert, V.P. Yakovlev Fermilab, Batavia, Illinois, USA
	A novel concept of a high-power magnetron transmitter allowing dynamic phase and power control at the frequency of locking signal is proposed. The transmitter compensating parasitic phase and amplitude modulations inherent in Superconducting RF (SRF) cavities within closed feedback loops is intended for powering of the intensity-frontier superconducting accelerators. The concept uses magnetrons driven by a sufficient resonant (injection-locking) signal and fed by the voltage which can be below the threshold of self-excitation. This provides an extended range of power control in a single magnetron at highest efficiency minimizing the cost of RF power unit and the operation cost. Proof-of-principle of the proposed concept demonstrated in pulsed and CW regimes with 2.45 GHz, 1kW magnetrons is discussed here. A conceptual scheme of the high-power transmitter allowing the dynamic wideband phase and mid-frequency power controls is presented and discussed.
	Slides TUA2CO03 [0.714 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUA2CO03
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WEPOA11	Frequency Manipulation of Half-Wave Resonators During Fabrication and Processing	710
	Z.A. Conway, R.L. Fischer, C.S. Hopper, M. Kedzie, M.P. Kelly, S.H. Kim, P.N. Ostroumov, T. Reid ANL, Argonne, Illinois, USA V.A. Lebedev, A. Lunin Fermilab, Batavia, Illinois, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics and High-Energy Physics, under Contract No. DE-AC02-76-CH03000 and DE-AC02-06CH11357. Argonne National Laboratory is developing a super-conducting resonator cryomodule for the acceleration of 2 mA H⁻ beams from 2.1 to 10.3 MeV for Fermi National Accelerator Laboratory's Proton Improvement Plan II. The cryomodule contains 8 superconducting half-wave resonators operating at 162.500 MHz with a 120 kHz tuning window. This paper reviews the half-wave resonator fabrication techniques used to manipulate the resonant frequency to the design goal of 162.500 MHz at 2.0 K. This also determines the target frequency at select stages of resonator construction, which will be discussed and supported by measurements. This research used resources of ANL's ATLAS facility, which is a DOE Office of Science User Facility.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOA11
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WEPOA17	On the Possibility of Using Nonlinear Elements for Landau Damping in High-Intensity Beams	729
	E. Gianfelice-Wendt, Y.I. Alexahin, V.A. Lebedev, A. Valishev Fermilab, Batavia, Illinois, USA
	Funding: Work supported by Fermi Research Alliance, LLC under Contract DE-AC02-07CH11359 with the U.S. DOE Direct space-charge force shifts the incoherent tunes down from the coherent ones switching off Landau damping of coherent oscillations at high beam intensity. To restore it the nonlinear elements can be employed which move back tunes of large amplitude particles. In the present report we consider the possibility of creating a "nonlinear integrable optics" insertion in the Fermilab Recycler to host either octupoles or hollow electron lens for this purpose. For comparison we also consider the classic scheme with distributed octupole families. It is shown that for the Proton Improvement Plan II parameters the required nonlinear tuneshift can be created without destroying the dynamic aperture.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOA17
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WEPOA20	Numerical Simulations of Collimation Efficiency for Beam Collimation System in the Fermilab Booster	735
	V.V. Kapin, V.A. Lebedev, N.V. Mokhov, S.I. Striganov, I.S. Tropin Fermilab, Batavia, Illinois, USA
	A two-stage beam collimation (2SC) system has been installed in the Fermilab Booster more than 10 years ago. It consists of two primary collimators (horizontal and vertical) and three 1.2m-long secondary collimators. The two-stage collimation has never been used in Booster operations due to uncontrolled beam orbit variations produced by radial cogging (it is required for beam accumulation in Recycler). Instead, only secondary collimators were used in the single-stage collimation (1SC). Recently introduced magnetic cogging resulted in orbit stabilization in the course of almost entire accelerating cycle and created a possibility for the 2SC. In this paper, the 2SC performance is evaluated and compared the 1SC. Several parameters characterizing collimation efficiency are calculated in order to compare both schemes. A combination of the MADX and MARS15 codes is used for proton tracking in the Booster with their scattering in collimators being accounted. The dependence of efficiency on the primary collimators foil thickness is presented. The efficiency dependence on the proton energy is also obtained for the optimal foil. The feasibility of the 2SC scheme for the Booster is discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOA20
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WEPOA38	Optically Based Diagnostics for Optical Stochastic Cooling	779
SUPO59	use link to see paper's listing under its alternate paper code
	M.B. Andorf Northern Illinois University, DeKalb, Illinois, USA V.A. Lebedev, P. Piot, J. Ruan Fermilab, Batavia, Illinois, USA
	An Optical Stochastic Cooling (OSC) experiment with electrons is planned in the Integrable Optics Test Accelerator (IOTA) ring currently in construction at Fermilab. OSC requires timing the arrival of an electron and its radiation generated from the upstream pickup undulator into the downstream kicker undulator to a precision on the order of less than a fs. The interference of the pickup and kicker radiation suggests a way to diagnose the arrival time to the required precision.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOA38
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WEB3CO03	650 MHz Elliptical Superconducting RF Cavities for PIP-II Project	859
	V. Jain, E. Borissov, I.V. Gonin, C.J. Grimm, S. Kazakov, T.N. Khabiboulline, V.A. Lebedev, C.S. Mishra, D.V. Mitchell, T.H. Nicol, Y.M. Pischalnikov, A.M. Rowe, N.K. Sharma, V.P. Yakovlev Fermilab, Batavia, Illinois, USA
	Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. Proton Improvement Plan-II at Fermilab is an 800 MeV superconducting pulsed linac which is also capable of running in CW mode. The high energy section operates from 185 MeV to 800 MeV instigated using 650 MHz elliptical cavities. The low-beta (LB) βG =0.61 portion will accelerate protons from 185 MeV-500 MeV, while the high-beta (HB) βG = 0.92 portion of the linac will acceler-ate from 500 to 800 MeV. The development of both LB and HB cavities is taking place under the umbrella of the Indian Institutions Fermilab Collaboration (IIFC). This paper presents the design methodology adopted for both low-beta and high-beta cavities starting from the RF design yielding mechanical dimensions of the cavity cells and, then moving to the workable dressed cavity design. Designs of end groups (main coupler side and field probe side), helium vessel, coupler, and tuner are the same for both cavities everywhere where it is possible. The design, analysis and integration of dressed cavity are presented in detail.
	Slides WEB3CO03 [11.396 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEB3CO03
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WEA4CO04	Suppression of Half-Integer Resonance in FNAL Booster and Space Charge Losses at Injection
	A. Valishev, Y.I. Alexahin, V.A. Lebedev Fermilab, Batavia, Illinois, USA
	Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. The particle losses at injection in the FNAL Booster are one of the major factors limiting the machine performance. The losses are caused by motion non-linearity due to direct space charge and due to non-linearity introduced by large values of chromaticity sextupoles required to suppress transverse instabilities. The report aims to address the former - the suppression of incoherent space charge effects by reducing deviations from the perfect periodicity of linear optics functions. It should be achieved by high accuracy optics measurements with subsequent optics correction and by removing known sources of optics perturbations. The study shows significant impact on half-integer stop band with subsequent reduction of particle loss. We use realistic Booster lattice model to understand the present limitations, and investigate the possible improvements which would allow high intensity operation with PIP-II parameters.
	Slides WEA4CO04 [3.828 MB]
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Higher Order Modes Analysis of Fermilab's Recycler Cavity

106

M.H. Awida, J.E. Dey, T.N. Khabiboulline, V.A. Lebedev, R.L. Madrak
Fermilab, Batavia, Illinois, USA

Funding: Operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the U.S. DOE
Two recycler cavities are being employed in Fermilab's Recycler Ring for the purpose of slip stacking proton bunches, where 6 batches of 8 GeV protons coming from the Booster are stacked on top of 6 circulating batches. Slip stacking requires two RF cavities operating at 52.809 and 51.545 MHz. In this paper, we report on the analysis of higher order modes in the Recycler cavity, presenting the values for R/Q and shunt impedances. Knowing the frequencies and properties of higher order modes is particularly critical for beam physics and avoidance of beam instabilities.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB16

Export •

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

TUA2CO03

A Novel Technique of Power Control in Magnetron Transmitters for Intense Accelerators

271

G.M. Kazakevich, R.P. Johnson, M.L. Neubauer
Muons, Inc, Illinois, USA
V.A. Lebedev, W. Schappert, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

A novel concept of a high-power magnetron transmitter allowing dynamic phase and power control at the frequency of locking signal is proposed. The transmitter compensating parasitic phase and amplitude modulations inherent in Superconducting RF (SRF) cavities within closed feedback loops is intended for powering of the intensity-frontier superconducting accelerators. The concept uses magnetrons driven by a sufficient resonant (injection-locking) signal and fed by the voltage which can be below the threshold of self-excitation. This provides an extended range of power control in a single magnetron at highest efficiency minimizing the cost of RF power unit and the operation cost. Proof-of-principle of the proposed concept demonstrated in pulsed and CW regimes with 2.45 GHz, 1kW magnetrons is discussed here. A conceptual scheme of the high-power transmitter allowing the dynamic wideband phase and mid-frequency power controls is presented and discussed.

Slides TUA2CO03 [0.714 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUA2CO03

Export •

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WEPOA11

Frequency Manipulation of Half-Wave Resonators During Fabrication and Processing

710

Z.A. Conway, R.L. Fischer, C.S. Hopper, M. Kedzie, M.P. Kelly, S.H. Kim, P.N. Ostroumov, T. Reid
ANL, Argonne, Illinois, USA
V.A. Lebedev, A. Lunin
Fermilab, Batavia, Illinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics and High-Energy Physics, under Contract No. DE-AC02-76-CH03000 and DE-AC02-06CH11357.
Argonne National Laboratory is developing a super-conducting resonator cryomodule for the acceleration of 2 mA H⁻ beams from 2.1 to 10.3 MeV for Fermi National Accelerator Laboratory's Proton Improvement Plan II. The cryomodule contains 8 superconducting half-wave resonators operating at 162.500 MHz with a 120 kHz tuning window. This paper reviews the half-wave resonator fabrication techniques used to manipulate the resonant frequency to the design goal of 162.500 MHz at 2.0 K. This also determines the target frequency at select stages of resonator construction, which will be discussed and supported by measurements.
This research used resources of ANL's ATLAS facility, which is a DOE Office of Science User Facility.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOA11

Export •

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

WEPOA17

On the Possibility of Using Nonlinear Elements for Landau Damping in High-Intensity Beams

729

E. Gianfelice-Wendt, Y.I. Alexahin, V.A. Lebedev, A. Valishev
Fermilab, Batavia, Illinois, USA

Funding: Work supported by Fermi Research Alliance, LLC under Contract DE-AC02-07CH11359 with the U.S. DOE
Direct space-charge force shifts the incoherent tunes down from the coherent ones switching off Landau damping of coherent oscillations at high beam intensity. To restore it the nonlinear elements can be employed which move back tunes of large amplitude particles. In the present report we consider the possibility of creating a "nonlinear integrable optics" insertion in the Fermilab Recycler to host either octupoles or hollow electron lens for this purpose. For comparison we also consider the classic scheme with distributed octupole families. It is shown that for the Proton Improvement Plan II parameters the required nonlinear tuneshift can be created without destroying the dynamic aperture.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOA17

Export •

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

WEPOA20

Numerical Simulations of Collimation Efficiency for Beam Collimation System in the Fermilab Booster

735

V.V. Kapin, V.A. Lebedev, N.V. Mokhov, S.I. Striganov, I.S. Tropin
Fermilab, Batavia, Illinois, USA

A two-stage beam collimation (2SC) system has been installed in the Fermilab Booster more than 10 years ago. It consists of two primary collimators (horizontal and vertical) and three 1.2m-long secondary collimators. The two-stage collimation has never been used in Booster operations due to uncontrolled beam orbit variations produced by radial cogging (it is required for beam accumulation in Recycler). Instead, only secondary collimators were used in the single-stage collimation (1SC). Recently introduced magnetic cogging resulted in orbit stabilization in the course of almost entire accelerating cycle and created a possibility for the 2SC. In this paper, the 2SC performance is evaluated and compared the 1SC. Several parameters characterizing collimation efficiency are calculated in order to compare both schemes. A combination of the MADX and MARS15 codes is used for proton tracking in the Booster with their scattering in collimators being accounted. The dependence of efficiency on the primary collimators foil thickness is presented. The efficiency dependence on the proton energy is also obtained for the optimal foil. The feasibility of the 2SC scheme for the Booster is discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOA20

Export •

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

WEPOA38

Optically Based Diagnostics for Optical Stochastic Cooling

779

SUPO59

use link to see paper's listing under its alternate paper code

M.B. Andorf
Northern Illinois University, DeKalb, Illinois, USA
V.A. Lebedev, P. Piot, J. Ruan
Fermilab, Batavia, Illinois, USA

An Optical Stochastic Cooling (OSC) experiment with electrons is planned in the Integrable Optics Test Accelerator (IOTA) ring currently in construction at Fermilab. OSC requires timing the arrival of an electron and its radiation generated from the upstream pickup undulator into the downstream kicker undulator to a precision on the order of less than a fs. The interference of the pickup and kicker radiation suggests a way to diagnose the arrival time to the required precision.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOA38

Export •

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

WEB3CO03

650 MHz Elliptical Superconducting RF Cavities for PIP-II Project

859

V. Jain, E. Borissov, I.V. Gonin, C.J. Grimm, S. Kazakov, T.N. Khabiboulline, V.A. Lebedev, C.S. Mishra, D.V. Mitchell, T.H. Nicol, Y.M. Pischalnikov, A.M. Rowe, N.K. Sharma, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
Proton Improvement Plan-II at Fermilab is an 800 MeV superconducting pulsed linac which is also capable of running in CW mode. The high energy section operates from 185 MeV to 800 MeV instigated using 650 MHz elliptical cavities. The low-beta (LB) βG =0.61 portion will accelerate protons from 185 MeV-500 MeV, while the high-beta (HB) βG = 0.92 portion of the linac will acceler-ate from 500 to 800 MeV. The development of both LB and HB cavities is taking place under the umbrella of the Indian Institutions Fermilab Collaboration (IIFC). This paper presents the design methodology adopted for both low-beta and high-beta cavities starting from the RF design yielding mechanical dimensions of the cavity cells and, then moving to the workable dressed cavity design. Designs of end groups (main coupler side and field probe side), helium vessel, coupler, and tuner are the same for both cavities everywhere where it is possible. The design, analysis and integration of dressed cavity are presented in detail.

Slides WEB3CO03 [11.396 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEB3CO03

Export •

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

WEA4CO04

Suppression of Half-Integer Resonance in FNAL Booster and Space Charge Losses at Injection

A. Valishev, Y.I. Alexahin, V.A. Lebedev
Fermilab, Batavia, Illinois, USA

Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
The particle losses at injection in the FNAL Booster are one of the major factors limiting the machine performance. The losses are caused by motion non-linearity due to direct space charge and due to non-linearity introduced by large values of chromaticity sextupoles required to suppress transverse instabilities. The report aims to address the former - the suppression of incoherent space charge effects by reducing deviations from the perfect periodicity of linear optics functions. It should be achieved by high accuracy optics measurements with subsequent optics correction and by removing known sources of optics perturbations. The study shows significant impact on half-integer stop band with subsequent reduction of particle loss. We use realistic Booster lattice model to understand the present limitations, and investigate the possible improvements which would allow high intensity operation with PIP-II parameters.

Slides WEA4CO04 [3.828 MB]

Export •

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