PAC2013 - List of Authors (Swinson, C.)

Paper	Title	Page
MOPAC24	Beam Pulse Shaping Experiments for Uniform High Gradient Dielectric Wakefield Acceleration	117
	D.Y. Shchegolkov, E.I. Simakov LANL, Los Alamos, New Mexico, USA S.P. Antipov Euclid TechLabs, LLC, Solon, Ohio, USA S.P. Antipov ANL, Argonne, USA M.G. Fedurin, C. Swinson BNL, Upton, Long Island, New York, USA
	Funding: Work is supported by the U.S. Department of Energy (DOE) through the Laboratory Directed Research and Development (LDRD) program at Los Alamos National Laboratory. Dielectric wakefield accelerators (DWA) can produce high accelerating gradients and are planned to be used as afterburners for the accelerators of future free electron lasers (FELs) such as X-ray FEL of the proposed Matter-Radiation Interactions in Extremes (MaRIE) experimental facility at LANL. With a double triangular drive bunch DWAs can produce a high transformer ratio. Also, by slightly customizing the time shape of the accelerated bunch it is possible to achieve high gradient uniformity along the accelerated bunch resulting in low induced energy spread. We plan to test a DWA which would incorporate all those benefits. We are going to obtain a desired current profile of the main and drive bunches from a single large-charge beam using one of the known pulse shaping techniques employing a mask.* * We will report our recent beam shaping experiments at BNL for a transformer ratio test. We used a 58 MeV energy chirped electron beam and a single dogleg with a beam mask inserted in a region where the beam transverse size was dominated by the correlated energy chirp. Both measurement results and Elegant simulation data will be presented. P. Emma, Z. Huang , et al, Phys Rev ST Accel Beams 9, 100702 (2006). P. Muggli, V. Yakimenko, et al, PRL 101, 054801 (2008). **D. Xiang and A. Chao, SLAC-PUB-14428 (2011).

MOPHO19	A Tunable Energy Chirp Correction	279
	S.P. Antipov, C.-J. Jing, A. Kanareykin, P. Schoessow Euclid TechLabs, LLC, Solon, Ohio, USA S. Baturin LETI, Saint-Petersburg, Russia M.G. Fedurin, C. Swinson BNL, Upton, Long Island, New York, USA W. Gai, A. Zholents ANL, Argonne, USA
	Funding: DOE SBIR Short (subpicosecond) pulses are central to many of the next generation light source initiatives that are based on linear accelerators. Beam compression is performed by means of a chicane utilizing a correlated linear energy chirp. The small energy chirp is kept as the beam goes through the remaining accelerating stage to compensate for wakefield effects. It is necessary to compensate the residual energy spread before the beam enters the undulator stage. We present here a concept for a passive wakefield device- the wakefield silencer- to perform this compensation. We have recently demonstrated a passive energy chirp correction by self-wakefield at the Brookhaven ATF facility. In this paper we present a progress report on development of these tunable chirp correction devices.

THPAC32	Transverse Beam Profile Diagnostic Using Fiber Optic Array	1205
	S. Wu, R.B. Agustsson, G. Andonian, T.J. Campese, A.Y. Murokh RadiaBeam, Santa Monica, USA M.G. Fedurin, K. Kusche, R. Malone, C. Swinson BNL, Upton, Long Island, New York, USA R.K. Li UCLA, Los Angeles, California, USA
	Funding: This work is supported by U.S. D.O.E Contract Number DE-SC0000870 The fiber-mesh diagnostic (FMD) is a transverse beam profile diagnostic based on the emission and detection of Cherenkov radiation produced as a relativistic electron beam traverses through an ordered bundle of fiber optics (SiO2), arranged in a hexagonal close-pack configuration. Sub-10μm transverse beam profile resolution is attainable due to fiber optic core concentricity. Adequate SNR is achieved using a standard CCD sensor. A fiber optic taper input maximizes light collection efficiency by coupling each output channel to approximately single-pixel pitch. A v-groove holder and assembly process was developed to hold many fiber layers in the desired configuration. In this paper, we present results from a fully functional FMD prototype evaluated at the BNL ATF facility that demonstrates the efficacy of this diagnostic.

Paper

Title

Page

Beam Pulse Shaping Experiments for Uniform High Gradient Dielectric Wakefield Acceleration

117

D.Y. Shchegolkov, E.I. Simakov
LANL, Los Alamos, New Mexico, USA
S.P. Antipov
Euclid TechLabs, LLC, Solon, Ohio, USA
S.P. Antipov
ANL, Argonne, USA
M.G. Fedurin, C. Swinson
BNL, Upton, Long Island, New York, USA

Funding: Work is supported by the U.S. Department of Energy (DOE) through the Laboratory Directed Research and Development (LDRD) program at Los Alamos National Laboratory.
Dielectric wakefield accelerators (DWA) can produce high accelerating gradients and are planned to be used as afterburners for the accelerators of future free electron lasers (FELs) such as X-ray FEL of the proposed Matter-Radiation Interactions in Extremes (MaRIE) experimental facility at LANL. With a double triangular drive bunch DWAs can produce a high transformer ratio. Also, by slightly customizing the time shape of the accelerated bunch it is possible to achieve high gradient uniformity along the accelerated bunch resulting in low induced energy spread. We plan to test a DWA which would incorporate all those benefits. We are going to obtain a desired current profile of the main and drive bunches from a single large-charge beam using one of the known pulse shaping techniques employing a mask.* ** *** We will report our recent beam shaping experiments at BNL for a transformer ratio test. We used a 58 MeV energy chirped electron beam and a single dogleg with a beam mask inserted in a region where the beam transverse size was dominated by the correlated energy chirp. Both measurement results and Elegant simulation data will be presented.
*P. Emma, Z. Huang , et al, Phys Rev ST Accel Beams 9, 100702 (2006).
**P. Muggli, V. Yakimenko, et al, PRL 101, 054801 (2008).
***D. Xiang and A. Chao, SLAC-PUB-14428 (2011).

MOPHO19

A Tunable Energy Chirp Correction

279

S.P. Antipov, C.-J. Jing, A. Kanareykin, P. Schoessow
Euclid TechLabs, LLC, Solon, Ohio, USA
S. Baturin
LETI, Saint-Petersburg, Russia
M.G. Fedurin, C. Swinson
BNL, Upton, Long Island, New York, USA
W. Gai, A. Zholents
ANL, Argonne, USA

Funding: DOE SBIR
Short (subpicosecond) pulses are central to many of the next generation light source initiatives that are based on linear accelerators. Beam compression is performed by means of a chicane utilizing a correlated linear energy chirp. The small energy chirp is kept as the beam goes through the remaining accelerating stage to compensate for wakefield effects. It is necessary to compensate the residual energy spread before the beam enters the undulator stage. We present here a concept for a passive wakefield device- the wakefield silencer- to perform this compensation. We have recently demonstrated a passive energy chirp correction by self-wakefield at the Brookhaven ATF facility. In this paper we present a progress report on development of these tunable chirp correction devices.

THPAC32

Transverse Beam Profile Diagnostic Using Fiber Optic Array

1205

S. Wu, R.B. Agustsson, G. Andonian, T.J. Campese, A.Y. Murokh
RadiaBeam, Santa Monica, USA
M.G. Fedurin, K. Kusche, R. Malone, C. Swinson
BNL, Upton, Long Island, New York, USA
R.K. Li
UCLA, Los Angeles, California, USA

Funding: This work is supported by U.S. D.O.E Contract Number DE-SC0000870
The fiber-mesh diagnostic (FMD) is a transverse beam profile diagnostic based on the emission and detection of Cherenkov radiation produced as a relativistic electron beam traverses through an ordered bundle of fiber optics (SiO2), arranged in a hexagonal close-pack configuration. Sub-10μm transverse beam profile resolution is attainable due to fiber optic core concentricity. Adequate SNR is achieved using a standard CCD sensor. A fiber optic taper input maximizes light collection efficiency by coupling each output channel to approximately single-pixel pitch. A v-groove holder and assembly process was developed to hold many fiber layers in the desired configuration. In this paper, we present results from a fully functional FMD prototype evaluated at the BNL ATF facility that demonstrates the efficacy of this diagnostic.