IPAC2017 - List of Authors (Hettel, R.O.)

Paper	Title	Page
TUPIK122	Bunch-by-Bunch Feedback Kickers for SPEAR3	2012
	K. Tian, W.J. Corbett, J.D. Fox, S.M. Gierman, R.O. Hettel, X. Huang, A.K. Krasnykh, N. Kurita, D.J. Martin, J.A. Safranek, J.J. Sebek SLAC, Menlo Park, California, USA Q. Lin DongHua University, Songjiang, People's Republic of China D. Teytelman Dimtel, San Jose, USA
	SPEAR3 operates with a large cross-section copper vacuum chamber, mode-damped RF cavities and low-impedance insertion devices. As a result, the beam is passively stable for 280-bunch circulating beam current up to 500ma when the background gas pressure is low. In the future, more small-gap insertion devices will be installed and plans are underway to implement resonant bunch-crabbing for the ultrafast x-ray research program. These requirements drive the need for a fast, bunch-by-bunch feedback system to control beam instabilities, remove unwanted satellite bunches and resonantly crab select bunches on demand. In this paper we present a conceptual design for the transverse bunch-by-bunch stripline kickers.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPIK122
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WEPAB115	Normal Conducting CW Transverse Crab Cavity For Producing Short Pulses In SPEAR3	2840
	Z. Li, V.A. Dolgashev, M. Dunham, K.J. Gaffney, R.O. Hettel, X. Huang, N. Kurita, J.A. Safranek, J.J. Sebek, K. Tian SLAC, Menlo Park, California, USA
	Funding: This work was supported by DOE Contract No. DE-AC02-76SF00515. The ability to produce short pulse X-rays on the scale of 1-10 ps fwhm in the SPEAR3 storage ring light source would enable enhanced timing mode studies of dynamic processes in materials as they occur. The crab cavity approach appears to be optimal for SPEAR3 to produce short pulse X-rays. Furthermore, by using a two-frequency crabbing scheme, SPEAR3 would be able to produce short-pulse bunches while supplying the high average flux needed for regular users. While supercon-ducting RF (SCRF) technology could be a natural choice for the CW crab cavity, the deflecting voltage for SPEAR3 crabbing appears to be within reach of more affordable normal conducting RF (NCRF). In this paper, we present a preliminary NCRF CW crab cavity design for SPEAR3.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB115
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THOBA3	A Compact 335 MeV Positron Damping Ring Design for FACET-II	3652
	G.R. White, Y. Cai, R.O. Hettel, M.A.G. Johansson, V. Yakimenko, G. Yocky SLAC, Menlo Park, California, USA
	Funding: This work was supported by the Department of Energy under Contract Number: DE-AC02-76SF00515. FACET-II will be a new test facility, starting construction in 2018 within the main SLAC Linac. Its purpose is to build on the decades-long experience developed conducting accelerator R&D at SLAC in the areas of advanced acceleration and coherent radiation techniques with high-energy electron and positron beams. The positron system design utilizes an existing W-Re target in Linac Sector 19, driven by 4 nC electrons bunches at 10 GeV. We present the design of a 335 MeV, 21.4 m circumference damping ring required to damp emittance from a modified positron return beamline by a factor of 500. The transverse emittance is calculated to be 6 um-rad, fully coupled, with a bunch length of 4 mm and energy spread 0.06 %, at a bunch charge of 1 nC. The arc magnets need to be especially compact due to tight space constraints (installation will be in the existing SLAC Linac tunnel, Sector 10, with 3 m width available) and were a key design challenge. We present a solution with combined function bend/quadrupole/sextupole magnets which have been modelled in 3D using Opera.
	Slides THOBA3 [8.372 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THOBA3
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Paper

Title

Page

Bunch-by-Bunch Feedback Kickers for SPEAR3

2012

K. Tian, W.J. Corbett, J.D. Fox, S.M. Gierman, R.O. Hettel, X. Huang, A.K. Krasnykh, N. Kurita, D.J. Martin, J.A. Safranek, J.J. Sebek
SLAC, Menlo Park, California, USA
Q. Lin
DongHua University, Songjiang, People's Republic of China
D. Teytelman
Dimtel, San Jose, USA

SPEAR3 operates with a large cross-section copper vacuum chamber, mode-damped RF cavities and low-impedance insertion devices. As a result, the beam is passively stable for 280-bunch circulating beam current up to 500ma when the background gas pressure is low. In the future, more small-gap insertion devices will be installed and plans are underway to implement resonant bunch-crabbing for the ultrafast x-ray research program. These requirements drive the need for a fast, bunch-by-bunch feedback system to control beam instabilities, remove unwanted satellite bunches and resonantly crab select bunches on demand. In this paper we present a conceptual design for the transverse bunch-by-bunch stripline kickers.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPIK122

Export •

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

WEPAB115

Normal Conducting CW Transverse Crab Cavity For Producing Short Pulses In SPEAR3

2840

Z. Li, V.A. Dolgashev, M. Dunham, K.J. Gaffney, R.O. Hettel, X. Huang, N. Kurita, J.A. Safranek, J.J. Sebek, K. Tian
SLAC, Menlo Park, California, USA

Funding: This work was supported by DOE Contract No. DE-AC02-76SF00515.
The ability to produce short pulse X-rays on the scale of 1-10 ps fwhm in the SPEAR3 storage ring light source would enable enhanced timing mode studies of dynamic processes in materials as they occur. The crab cavity approach appears to be optimal for SPEAR3 to produce short pulse X-rays. Furthermore, by using a two-frequency crabbing scheme, SPEAR3 would be able to produce short-pulse bunches while supplying the high average flux needed for regular users. While supercon-ducting RF (SCRF) technology could be a natural choice for the CW crab cavity, the deflecting voltage for SPEAR3 crabbing appears to be within reach of more affordable normal conducting RF (NCRF). In this paper, we present a preliminary NCRF CW crab cavity design for SPEAR3.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB115

Export •

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

THOBA3

A Compact 335 MeV Positron Damping Ring Design for FACET-II

3652

G.R. White, Y. Cai, R.O. Hettel, M.A.G. Johansson, V. Yakimenko, G. Yocky
SLAC, Menlo Park, California, USA

Funding: This work was supported by the Department of Energy under Contract Number: DE-AC02-76SF00515.
FACET-II will be a new test facility, starting construction in 2018 within the main SLAC Linac. Its purpose is to build on the decades-long experience developed conducting accelerator R&D at SLAC in the areas of advanced acceleration and coherent radiation techniques with high-energy electron and positron beams. The positron system design utilizes an existing W-Re target in Linac Sector 19, driven by 4 nC electrons bunches at 10 GeV. We present the design of a 335 MeV, 21.4 m circumference damping ring required to damp emittance from a modified positron return beamline by a factor of 500. The transverse emittance is calculated to be 6 um-rad, fully coupled, with a bunch length of 4 mm and energy spread 0.06 %, at a bunch charge of 1 nC. The arc magnets need to be especially compact due to tight space constraints (installation will be in the existing SLAC Linac tunnel, Sector 10, with 3 m width available) and were a key design challenge. We present a solution with combined function bend/quadrupole/sextupole magnets which have been modelled in 3D using Opera.

Slides THOBA3 [8.372 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THOBA3

Export •

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