NAPAC2019 - List of Authors (Tantawi, S.G.)

Paper	Title	Page
TUXBA4	Rapid Radio-Frequency Beam Energy Modulator for Proton Therapy	298
WEPLM24	use link to see paper's listing under its alternate paper code
	X. Lu, G.B. Bowden, V.A. Dolgashev, Z. Li, E.A. Nanni, A.V. Sy, S.G. Tantawi SLAC, Menlo Park, California, USA
	Funding: This work is supported by US Department of Energy (DOE) Contract No. DE-AC02-76SF00515. We present the design for a rapid proton energy modulator with radio-frequency (RF) accelerator cavities. The energy modulator is designed as a multi-cell one-meter long accelerator working at 2.856 GHz. We envision that each individual accelerator cavity is powered by a 400 kW low-voltage klystron to provide an accelerating / decelerating gradient of 30 MV/m. We have performed beam dynamics simulations showing that the modulator can provide ± 30MeV of beam energy change, with an energy spread of 3 MeV for a 7 mm long (full length) proton bunch. A prototype experiment of a single cell is in preparation at the Next Linear Collider Test Accelerator (NLCTA) at SLAC.
	Slides TUXBA4 [3.275 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUXBA4
About •	paper received ※ 27 August 2019 paper accepted ※ 06 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPLS02	Simulation of a Klystron Input Cavity using a Steady-State Full-Wave Solver	768
SUPLM12	use link to see paper's listing under its alternate paper code
	A.R. Gold, S.G. Tantawi SLAC, Menlo Park, California, USA
	The simulation of vacuum electronic radio-frequency (RF) power sources is generally done through semi-analytical modeling approaches. These techniques are computationally efficient as they make assumptions on the source topology, such as the requirement that the electron beam travel longitudinally and interact with cylindrical modes. To simulate more general interactions, transient particle-in-cell (PIC) codes are currently required. We present here simulation results of a 5045 klystron using a newly developed steady state code which does not make assumptions on the beam configuration or geometry of the structure and resonant modes. As we solve directly for the steady-state system dynamics, this approach is computationally efficient yet, as demonstrated through comparison with experimental results, provides similar accuracy.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLS02
About •	paper received ※ 28 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THYBB4	High-Gradient Tests of W-Band Accelerating Structures
WEPLM46	use link to see paper's listing under its alternate paper code
	M.A.K. Othman, V.A. Dolgashev, A.A. Haase, E.A. Nanni, J. Neilson, S.G. Tantawi SLAC, Menlo Park, California, USA S. Jawla, J.F. Picard, R.J. Temkin MIT/PSFC, Cambridge, Massachusetts, USA S.C. Schaub MIT, Cambridge, Massachusetts, USA B. Spataro INFN/LNF, Frascati, Italy
	Funding: This work was supported by Department of Energy contract DE-AC02-76SF00515 (SLAC) and grant DE-SC0015566 (MIT). This work was also supported by NSF grants PHY-1734015. There is an ongoing interest in linear accelerators operating at 100s of GHz and THz frequencies due to their small size and potentially high efficiency. Vacuum RF breakdown is one of the fundamental factors limiting performance of these linacs. Accordingly, study of RF breakdown physics in mm-wave high gradient accelerating structures is needed, which includes understanding of dependencies of the breakdown rate on electromagnetic, geometric, and material properties. In our previous work, we have tested beam-driven 100 GHz and 200 GHz metallic accelerating structures. In this work we report results of high power tests of a 110 GHz single-cell standing wave accelerating cavity powered by a 1 MW gyrotron. The RF power is coupled into the accelerating structure using a "Gaussian to TM01" mode converter. In order to characterize high gradient behavior of the cavity, including the RF breakdown probability, we have measured RF signals and field-emitted currents. The cavity is driven by 10 ns, 100s of kilowatt pulses. These short pulses were cut from microsecond-long gyrotron pulses using a fast optical switch, with accelerating gradients up to 150 MV/m.
	Slides THYBB4 [4.501 MB]
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

TUXBA4

Rapid Radio-Frequency Beam Energy Modulator for Proton Therapy

298

WEPLM24

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

X. Lu, G.B. Bowden, V.A. Dolgashev, Z. Li, E.A. Nanni, A.V. Sy, S.G. Tantawi
SLAC, Menlo Park, California, USA

Funding: This work is supported by US Department of Energy (DOE) Contract No. DE-AC02-76SF00515.
We present the design for a rapid proton energy modulator with radio-frequency (RF) accelerator cavities. The energy modulator is designed as a multi-cell one-meter long accelerator working at 2.856 GHz. We envision that each individual accelerator cavity is powered by a 400 kW low-voltage klystron to provide an accelerating / decelerating gradient of 30 MV/m. We have performed beam dynamics simulations showing that the modulator can provide ± 30MeV of beam energy change, with an energy spread of 3 MeV for a 7 mm long (full length) proton bunch. A prototype experiment of a single cell is in preparation at the Next Linear Collider Test Accelerator (NLCTA) at SLAC.

Slides TUXBA4 [3.275 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUXBA4

About •

paper received ※ 27 August 2019 paper accepted ※ 06 September 2019 issue date ※ 08 October 2019

Export •

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

WEPLS02

Simulation of a Klystron Input Cavity using a Steady-State Full-Wave Solver

768

SUPLM12

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

A.R. Gold, S.G. Tantawi
SLAC, Menlo Park, California, USA

The simulation of vacuum electronic radio-frequency (RF) power sources is generally done through semi-analytical modeling approaches. These techniques are computationally efficient as they make assumptions on the source topology, such as the requirement that the electron beam travel longitudinally and interact with cylindrical modes. To simulate more general interactions, transient particle-in-cell (PIC) codes are currently required. We present here simulation results of a 5045 klystron using a newly developed steady state code which does not make assumptions on the beam configuration or geometry of the structure and resonant modes. As we solve directly for the steady-state system dynamics, this approach is computationally efficient yet, as demonstrated through comparison with experimental results, provides similar accuracy.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLS02

About •

paper received ※ 28 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019

Export •

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

THYBB4

High-Gradient Tests of W-Band Accelerating Structures

WEPLM46

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

M.A.K. Othman, V.A. Dolgashev, A.A. Haase, E.A. Nanni, J. Neilson, S.G. Tantawi
SLAC, Menlo Park, California, USA
S. Jawla, J.F. Picard, R.J. Temkin
MIT/PSFC, Cambridge, Massachusetts, USA
S.C. Schaub
MIT, Cambridge, Massachusetts, USA
B. Spataro
INFN/LNF, Frascati, Italy

Funding: This work was supported by Department of Energy contract DE-AC02-76SF00515 (SLAC) and grant DE-SC0015566 (MIT). This work was also supported by NSF grants PHY-1734015.
There is an ongoing interest in linear accelerators operating at 100s of GHz and THz frequencies due to their small size and potentially high efficiency. Vacuum RF breakdown is one of the fundamental factors limiting performance of these linacs. Accordingly, study of RF breakdown physics in mm-wave high gradient accelerating structures is needed, which includes understanding of dependencies of the breakdown rate on electromagnetic, geometric, and material properties. In our previous work, we have tested beam-driven 100 GHz and 200 GHz metallic accelerating structures. In this work we report results of high power tests of a 110 GHz single-cell standing wave accelerating cavity powered by a 1 MW gyrotron. The RF power is coupled into the accelerating structure using a "Gaussian to TM01" mode converter. In order to characterize high gradient behavior of the cavity, including the RF breakdown probability, we have measured RF signals and field-emitted currents. The cavity is driven by 10 ns, 100s of kilowatt pulses. These short pulses were cut from microsecond-long gyrotron pulses using a fast optical switch, with accelerating gradients up to 150 MV/m.

Slides THYBB4 [4.501 MB]

Export •

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