PAC2013 - List of Authors (Yakimenko, V.)

Paper

Title

Page

Subpicosecond Bunch Train Production for High Power Tunable THz Source

604

S.P. Antipov, C.-J. Jing, A. Kanareykin, P. Schoessow
Euclid TechLabs, LLC, Solon, Ohio, USA
M.G. Fedurin
BNL, Upton, Long Island, New York, USA
W. Gai, A. Zholents
ANL, Argonne, USA
V. Yakimenko
SLAC, Menlo Park, California, USA

Funding: DOE SBIR
An effective method of introducing an energy modulation in an electron bunch by passing it through a dielectric-lined waveguide was recently demonstrated. In the follow up experiment we successfully converted this energy modulation into a density modulation by means of a chicane beamline. The density modulated beam was sent through a foil target, producing THz transition radiation which was characterized using interferometeric techniques. By changing the initial energy chirp of the beam we tuned the center frequency of the generated THz radiation in the range 0.5 - 1 THz. A table top high power narrowband tunable THz source based on this technique is proposed

THYAA2

Latest Plasma Wakefield Acceleration Results from the FACET Project

1101

M.D. Litos, E. Adli, C.I. Clarke, S. Corde, J.-P. Delahaye, R.J. England, A.S. Fisher, J.T. Frederico, S.J. Gessner, M.J. Hogan, S.Z. Li, D.R. Walz, G.R. White, Z. Wu, V. Yakimenko
SLAC, Menlo Park, California, USA
E. Adli
University of Oslo, Oslo, Norway
W. An, C.E. Clayton, C. Joshi, W. Lu, K.A. Marsh, W.B. Mori, N. Vafaei-Najafabadi
UCLA, Los Angeles, California, USA
P. Muggli
MPI, Muenchen, Germany

SLAC’s new FACET facility had its second user run in April–June, 2013. Several new milestones were reached during this run, including the achievement of beam driven plasma wakefield acceleration of a discrete witness bunch for the first time, and energy doubling in a noble gas plasma source. The FACET beam is a 20 GeV electron bunch with a charge of 3.2 nC that can be compressed and focused to a size of 20 μm × 20 μm × 20 μm rms. To create the two-bunch, drive/witness beam structure, a chirped and over-compressed beam was dispersed horizontally in a chicane and a bite was taken from its middle with a tantalum finger collimator, corresponding to a longitudinal notching of the beam due to the head-tail energy correlation. A new 10 terawatt Ti:Sapphire laser was commissioned and used during this run to pre-ionize the plasma source in order to increase the efficiency of energy transfer from the beam to the wake. Ultimately, a witness beam of hundreds of pC in charge was accelerated by a drive beam of similar charge in a pre-formed lithium plasma with a density of 5×10¹⁶ cm^−3, experiencing gradients reaching several GeV/m in magnitude.

Slides THYAA2 [22.217 MB]

THPAC33

Scintillator Diagnostics for the Detection of Laser Accelerated Ion Beams

1208

N.M. Cook
Stony Brook University, Stony Brook, USA
R.S. Lefferts
SBUNSL, Stony Brook, New York, USA
O. Tresca
BNL, Upton, Long Island, New York, USA
V. Yakimenko
SLAC, Menlo Park, California, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Radiation pressure acceleration with ultraintense laser pulses presents an exciting new scheme for accelerating ions. One of the advantages conferred by using a gaseous laser and target is the potential for a fast (several Hz) repetition rate. This requires diagnostics which are not only comprehensive for a single shot, but also capable of repeated use. We consider several scintillators as candidates for an imaging diagnostic for protons accelerated to MeV energies by a CO2 laser focused on a gas jet target. We have measured the response of chromium-doped alumina (Chromox), CsI:Tl, and two polyvinyl toluene (PVT) screens to protons in the 2 – 8 MeV range using a CCD camera. We have calibrated the luminescent yield in terms of photons emitted per incident proton for each scintillator. We also discuss how light scattering and material properties affect detector resolution. Furthermore, we consider material damage and the presence of an afterglow under intense exposures. Our analysis reveals a near order of magnitude greater yield from Chromox in response to proton beams at > 5 MeV energies, while scattering effects favor PVT at lower energies.
Many thanks are due to M. Babzien, A. Drees, K. Kusche, and A. Lipski for their contributions to this work.

Paper	Title	Page
TUPMA08	Subpicosecond Bunch Train Production for High Power Tunable THz Source	604
	S.P. Antipov, C.-J. Jing, A. Kanareykin, P. Schoessow Euclid TechLabs, LLC, Solon, Ohio, USA M.G. Fedurin BNL, Upton, Long Island, New York, USA W. Gai, A. Zholents ANL, Argonne, USA V. Yakimenko SLAC, Menlo Park, California, USA
	Funding: DOE SBIR An effective method of introducing an energy modulation in an electron bunch by passing it through a dielectric-lined waveguide was recently demonstrated. In the follow up experiment we successfully converted this energy modulation into a density modulation by means of a chicane beamline. The density modulated beam was sent through a foil target, producing THz transition radiation which was characterized using interferometeric techniques. By changing the initial energy chirp of the beam we tuned the center frequency of the generated THz radiation in the range 0.5 - 1 THz. A table top high power narrowband tunable THz source based on this technique is proposed

THYAA2	Latest Plasma Wakefield Acceleration Results from the FACET Project	1101
	M.D. Litos, E. Adli, C.I. Clarke, S. Corde, J.-P. Delahaye, R.J. England, A.S. Fisher, J.T. Frederico, S.J. Gessner, M.J. Hogan, S.Z. Li, D.R. Walz, G.R. White, Z. Wu, V. Yakimenko SLAC, Menlo Park, California, USA E. Adli University of Oslo, Oslo, Norway W. An, C.E. Clayton, C. Joshi, W. Lu, K.A. Marsh, W.B. Mori, N. Vafaei-Najafabadi UCLA, Los Angeles, California, USA P. Muggli MPI, Muenchen, Germany
	SLAC’s new FACET facility had its second user run in April–June, 2013. Several new milestones were reached during this run, including the achievement of beam driven plasma wakefield acceleration of a discrete witness bunch for the first time, and energy doubling in a noble gas plasma source. The FACET beam is a 20 GeV electron bunch with a charge of 3.2 nC that can be compressed and focused to a size of 20 μm × 20 μm × 20 μm rms. To create the two-bunch, drive/witness beam structure, a chirped and over-compressed beam was dispersed horizontally in a chicane and a bite was taken from its middle with a tantalum finger collimator, corresponding to a longitudinal notching of the beam due to the head-tail energy correlation. A new 10 terawatt Ti:Sapphire laser was commissioned and used during this run to pre-ionize the plasma source in order to increase the efficiency of energy transfer from the beam to the wake. Ultimately, a witness beam of hundreds of pC in charge was accelerated by a drive beam of similar charge in a pre-formed lithium plasma with a density of 5×10¹⁶ cm^−3, experiencing gradients reaching several GeV/m in magnitude.
	Slides THYAA2 [22.217 MB]

THPAC33	Scintillator Diagnostics for the Detection of Laser Accelerated Ion Beams	1208
	N.M. Cook Stony Brook University, Stony Brook, USA R.S. Lefferts SBUNSL, Stony Brook, New York, USA O. Tresca BNL, Upton, Long Island, New York, USA V. Yakimenko SLAC, Menlo Park, California, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Radiation pressure acceleration with ultraintense laser pulses presents an exciting new scheme for accelerating ions. One of the advantages conferred by using a gaseous laser and target is the potential for a fast (several Hz) repetition rate. This requires diagnostics which are not only comprehensive for a single shot, but also capable of repeated use. We consider several scintillators as candidates for an imaging diagnostic for protons accelerated to MeV energies by a CO2 laser focused on a gas jet target. We have measured the response of chromium-doped alumina (Chromox), CsI:Tl, and two polyvinyl toluene (PVT) screens to protons in the 2 – 8 MeV range using a CCD camera. We have calibrated the luminescent yield in terms of photons emitted per incident proton for each scintillator. We also discuss how light scattering and material properties affect detector resolution. Furthermore, we consider material damage and the presence of an afterglow under intense exposures. Our analysis reveals a near order of magnitude greater yield from Chromox in response to proton beams at > 5 MeV energies, while scattering effects favor PVT at lower energies. Many thanks are due to M. Babzien, A. Drees, K. Kusche, and A. Lipski for their contributions to this work.