IPAC2018 - List of Authors (Schaub, S. C.)

Paper	Title	Page
TUZGBE4	Toward High-Power High-Gradient Testing of mm-Wave Standing-Wave Accelerating Structures	1224
	E.A. Nanni, V.A. Dolgashev, A.A. Haase, J. Neilson, S.G. Tantawi SLAC, Menlo Park, California, USA S. Jawla, R.J. Temkin MIT/PSFC, Cambridge, Massachusetts, USA S. C. Schaub MIT, Cambridge, Massachusetts, USA B. Spataro INFN/LNF, Frascati (Roma), Italy
	Funding: This work is supported in part by Department of Energy contract DE-AC02-76SF00515 (SLAC) and DE-SC0015566 (MIT). We will preliminary testing results for single-cell accelerating structures intended for high-gradient testing at 110 GHz. The purpose of this work is to study the basic physics of ultrahigh vacuum RF breakdown in high-gradient RF accelerators. The accelerating structures consist of pi-mode standing-wave cavities fed with TM01 circular waveguide mode. We fabricated of two structures one in copper and the other in CuAg alloy. Cold RF tests confirm the design RF performance of the structures. The geometry and field shape of these accelerating structures is as close as practical to single-cell standing-wave X-band accelerating structures more than 40 of which were tested at SLAC. This wealth of X-band data will serve as a baseline for these 110 GHz tests. The structures will be powered with a MW gyrotron oscillator that produces microsecond pulses. One megawatt of RF power from the gyrotron may allow us to reach a peak accelerating gradient of 400 MeV/m.
	Slides TUZGBE4 [4.644 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUZGBE4
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPML015	Dielectric Multipactor Discharges at 110 GHz	4684
	S. C. Schaub MIT, Cambridge, Massachusetts, USA M.A. Shapiro, R.J. Temkin MIT/PSFC, Cambridge, Massachusetts, USA
	A 1.5 MW, 110 GHz gyrotron has been used to experimentally measure the maximum sustainable fields on dielectric materials in vacuum. The purpose of this work is to evaluate the suitability of these materials for future applications in high frequency linear accelerators and high power terahertz components. To our knowledge, these are the first measurements of multipactor phenomena in the millimeter wave or terahertz frequency range. Materials tested include alumina, sapphire, fused quartz, crystal quartz, and high resistivity silicon. Dielectric samples were tested both as windows, with electric fields parallel to the surface, and sub-wavelength dielectric rod waveguides, with electric fields perpendicular to the surface. Surface electric fields in excess of 52 MV/m were achieved in 3 microsecond pulses. Visible light emission, absorbed/scattered microwave power, and emitted electrons were measured to characterize the discharges on the dielectric surfaces. The results of these experiments have been compared to theoretical calculations of multipactor discharges, testing these theories at significantly higher frequencies than has been done before.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML015
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Toward High-Power High-Gradient Testing of mm-Wave Standing-Wave Accelerating Structures

1224

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

Funding: This work is supported in part by Department of Energy contract DE-AC02-76SF00515 (SLAC) and DE-SC0015566 (MIT).
We will preliminary testing results for single-cell accelerating structures intended for high-gradient testing at 110 GHz. The purpose of this work is to study the basic physics of ultrahigh vacuum RF breakdown in high-gradient RF accelerators. The accelerating structures consist of pi-mode standing-wave cavities fed with TM01 circular waveguide mode. We fabricated of two structures one in copper and the other in CuAg alloy. Cold RF tests confirm the design RF performance of the structures. The geometry and field shape of these accelerating structures is as close as practical to single-cell standing-wave X-band accelerating structures more than 40 of which were tested at SLAC. This wealth of X-band data will serve as a baseline for these 110 GHz tests. The structures will be powered with a MW gyrotron oscillator that produces microsecond pulses. One megawatt of RF power from the gyrotron may allow us to reach a peak accelerating gradient of 400 MeV/m.

Slides TUZGBE4 [4.644 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUZGBE4

Export •

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

THPML015

Dielectric Multipactor Discharges at 110 GHz

4684

S. C. Schaub
MIT, Cambridge, Massachusetts, USA
M.A. Shapiro, R.J. Temkin
MIT/PSFC, Cambridge, Massachusetts, USA

A 1.5 MW, 110 GHz gyrotron has been used to experimentally measure the maximum sustainable fields on dielectric materials in vacuum. The purpose of this work is to evaluate the suitability of these materials for future applications in high frequency linear accelerators and high power terahertz components. To our knowledge, these are the first measurements of multipactor phenomena in the millimeter wave or terahertz frequency range. Materials tested include alumina, sapphire, fused quartz, crystal quartz, and high resistivity silicon. Dielectric samples were tested both as windows, with electric fields parallel to the surface, and sub-wavelength dielectric rod waveguides, with electric fields perpendicular to the surface. Surface electric fields in excess of 52 MV/m were achieved in 3 microsecond pulses. Visible light emission, absorbed/scattered microwave power, and emitted electrons were measured to characterize the discharges on the dielectric surfaces. The results of these experiments have been compared to theoretical calculations of multipactor discharges, testing these theories at significantly higher frequencies than has been done before.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML015

Export •

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