2011 Particle Accelerator Conference - List of Authors (Dolgashev, V.A.)

Paper

Title

Page

Ultra-High Gradient Compact S-Band Accelerating Structure

127

L. Faillace, R.B. Agustsson, P. Frigola, A.Y. Murokh
RadiaBeam, Santa Monica, USA
V.A. Dolgashev
SLAC, Menlo Park, California, USA
J.B. Rosenzweig
UCLA, Los Angeles, California, USA
V. Yakimenko
BNL, Upton, Long Island, New York, USA

Funding: Dept. of Energy DE-SC0000866
In this paper, we present the radio-frequency design of the DECA (Doubled Energy Compact Accelerator) S-band accelerating structure operating in the pi-mode at 2.856 GHz, where RF power sources are commonly available. The development of the DECA structure will offer an ultra-compact drop-in replacement for a conventional S-band linac in research and industrial applications such as drivers for compact light sources, medical and security systems. The electromagnetic design has been performed with the codes SuperFish and HFSS. The choice of the single cell shape derives from an optimization process aiming to maximize RF efficiency and minimize surface fields at very high accelerating gradients, i.e. 50 MV/m and above. Such gradients can be achieved utilizing shape-optimized elliptical irises, dual-feed couplers with the "fat-lip" coupling slot geometry, and specialized fabrication procedures developed for high gradient structures. The thermal-stress analysis of the DECA structure is also presented.
* V. Dolgashev, "Status of X-band Standing Wave Structure Studies at SLAC", SLAC-PUB-10124, (2003).
** C. Limborg et al., "RF Design of LCLS Gun", LCLS-TN-05-03 (2005).

MOP242

Evaluation of Temporal Diagnostic Techniques for Two-bunch FACET Beam

568

M.D. Litos, M.R. Bionta, V.A. Dolgashev, R.J. England, D. Fritz, A. Gilevich, P. Hering, M.J. Hogan
SLAC, Menlo Park, California, USA

Funding: Work supported by the U.S. Department of Energy under contract number DE-AC02-76SF00515
Three temporal diagnostic techniques are considered for use in the FACET facility at SLAC, which will incorporate a unique two-bunch beam for plasma wakefield acceleration experiments. The results of these experiments will depend strongly on the the inter-bunch spacing as well as the longitudinal profiles of the two bunches. A reliable, single-shot, high resolution measurement of the beam’s temporal profile is necessary to fully quantify the physical mechanisms underlying the beam driven plasma wakefield acceleration. In this study we show that a transverse deflecting cavity is the diagnostic which best meets our criteria.

THOBN5

Design and Testing of Advanced Photonic Bandgap (PBG) Accelerator Structures

2071

B.J. Munroe, M.A. Shapiro, R.J. Temkin
MIT/PSFC, Cambridge, Massachusetts, USA
V.A. Dolgashev, S.G. Tantawi, A.D. Yeremian
SLAC, Menlo Park, California, USA
R.A. Marsh
LLNL, Livermore, California, USA

Photonic Band-gap (PBG) structures continue to be an area of promising research for high gradient accelerators with wakefield suppression. Experimental results on an 11.4 GHz PBG structure tested at high power and high repetition rate at SLAC have shown that high gradients can be achieved in these structures. For PBG structures with thin rods, however, pulsed heating of the inner row of rods is a problem. Following these preliminary results, two new PBG structures have been designed. One structure, designated 1C-SW-A5.65-T4.6-Cu-PBG2-SLAC1, utilizes elliptical inner rods to reduce pulsed heating to an acceptable level; it will be tested at SLAC. A second PBG structure with round rods will be tested at 17.1 GHz at MIT. The MIT research will use the improved diagnostic access of the PBG structure to obtain a better understanding of the breakdown process. We will present preliminary results for the design and testing of these PBG structures.

Slides THOBN5 [0.752 MB]

THP050

Normal Conducting Radio Frequency X-band Deflecting Cavity Fabrication and Validation

2211

R.B. Agustsson, S. Boucher, L. Faillace, P. Frigola, A.Y. Murokh, S. Storms
RadiaBeam, Santa Monica, USA
D. Alesini
INFN/LNF, Frascati (Roma), Italy
V.A. Dolgashev, R.J. England
SLAC, Menlo Park, California, USA
J.B. Rosenzweig
UCLA, Los Angeles, California, USA
V. Yakimenko
BNL, Upton, Long Island, New York, USA

An X-band Traveling wave Deflector mode cavity (XTD) has been developed at Radiabeam Technologies to perform longitudinal characterization of the sub-picosecond ultra-relativistic electron beams. The device is optimized for the 100 MeV electron beam parameters at the Accelerator Test Facility (ATF) at Brookhaven National Laboratory, and is scalable to higher energies. The XTD is designed to operate at 11.424 GHz, and features short filling time, femtosecond resolution, and a small footprint. RF design, fabrication and RF validation and tuning will be presented.

Paper	Title	Page
MOP012	Ultra-High Gradient Compact S-Band Accelerating Structure	127
	L. Faillace, R.B. Agustsson, P. Frigola, A.Y. Murokh RadiaBeam, Santa Monica, USA V.A. Dolgashev SLAC, Menlo Park, California, USA J.B. Rosenzweig UCLA, Los Angeles, California, USA V. Yakimenko BNL, Upton, Long Island, New York, USA
	Funding: Dept. of Energy DE-SC0000866 In this paper, we present the radio-frequency design of the DECA (Doubled Energy Compact Accelerator) S-band accelerating structure operating in the pi-mode at 2.856 GHz, where RF power sources are commonly available. The development of the DECA structure will offer an ultra-compact drop-in replacement for a conventional S-band linac in research and industrial applications such as drivers for compact light sources, medical and security systems. The electromagnetic design has been performed with the codes SuperFish and HFSS. The choice of the single cell shape derives from an optimization process aiming to maximize RF efficiency and minimize surface fields at very high accelerating gradients, i.e. 50 MV/m and above. Such gradients can be achieved utilizing shape-optimized elliptical irises, dual-feed couplers with the "fat-lip" coupling slot geometry, and specialized fabrication procedures developed for high gradient structures. The thermal-stress analysis of the DECA structure is also presented. * V. Dolgashev, "Status of X-band Standing Wave Structure Studies at SLAC", SLAC-PUB-10124, (2003). ** C. Limborg et al., "RF Design of LCLS Gun", LCLS-TN-05-03 (2005).

MOP242	Evaluation of Temporal Diagnostic Techniques for Two-bunch FACET Beam	568
	M.D. Litos, M.R. Bionta, V.A. Dolgashev, R.J. England, D. Fritz, A. Gilevich, P. Hering, M.J. Hogan SLAC, Menlo Park, California, USA
	Funding: Work supported by the U.S. Department of Energy under contract number DE-AC02-76SF00515 Three temporal diagnostic techniques are considered for use in the FACET facility at SLAC, which will incorporate a unique two-bunch beam for plasma wakefield acceleration experiments. The results of these experiments will depend strongly on the the inter-bunch spacing as well as the longitudinal profiles of the two bunches. A reliable, single-shot, high resolution measurement of the beam’s temporal profile is necessary to fully quantify the physical mechanisms underlying the beam driven plasma wakefield acceleration. In this study we show that a transverse deflecting cavity is the diagnostic which best meets our criteria.

THOBN5	Design and Testing of Advanced Photonic Bandgap (PBG) Accelerator Structures	2071
	B.J. Munroe, M.A. Shapiro, R.J. Temkin MIT/PSFC, Cambridge, Massachusetts, USA V.A. Dolgashev, S.G. Tantawi, A.D. Yeremian SLAC, Menlo Park, California, USA R.A. Marsh LLNL, Livermore, California, USA
	Photonic Band-gap (PBG) structures continue to be an area of promising research for high gradient accelerators with wakefield suppression. Experimental results on an 11.4 GHz PBG structure tested at high power and high repetition rate at SLAC have shown that high gradients can be achieved in these structures. For PBG structures with thin rods, however, pulsed heating of the inner row of rods is a problem. Following these preliminary results, two new PBG structures have been designed. One structure, designated 1C-SW-A5.65-T4.6-Cu-PBG2-SLAC1, utilizes elliptical inner rods to reduce pulsed heating to an acceptable level; it will be tested at SLAC. A second PBG structure with round rods will be tested at 17.1 GHz at MIT. The MIT research will use the improved diagnostic access of the PBG structure to obtain a better understanding of the breakdown process. We will present preliminary results for the design and testing of these PBG structures.
	Slides THOBN5 [0.752 MB]

THP050	Normal Conducting Radio Frequency X-band Deflecting Cavity Fabrication and Validation	2211
	R.B. Agustsson, S. Boucher, L. Faillace, P. Frigola, A.Y. Murokh, S. Storms RadiaBeam, Santa Monica, USA D. Alesini INFN/LNF, Frascati (Roma), Italy V.A. Dolgashev, R.J. England SLAC, Menlo Park, California, USA J.B. Rosenzweig UCLA, Los Angeles, California, USA V. Yakimenko BNL, Upton, Long Island, New York, USA
	An X-band Traveling wave Deflector mode cavity (XTD) has been developed at Radiabeam Technologies to perform longitudinal characterization of the sub-picosecond ultra-relativistic electron beams. The device is optimized for the 100 MeV electron beam parameters at the Accelerator Test Facility (ATF) at Brookhaven National Laboratory, and is scalable to higher energies. The XTD is designed to operate at 11.424 GHz, and features short filling time, femtosecond resolution, and a small footprint. RF design, fabrication and RF validation and tuning will be presented.