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Reference to GPT: Please quote http://www.pulsar.nl/gpt
in papers containing GPT simulation results. If the simulations are obtained with the 3D mesh-based space-charge routine,
the following references are appropriate:
S.B. van der Geer, O.J. Luiten, M.J. de Loos, G. Pöplau,
U. van Rienen, 3D space-charge model for GPT simulations of high
brightness electron bunches, Institute of Physics Conference Series, No.
175, (2005), p. 101.
Gisela Pöplau, Ursula van Rienen, Bas van der Geer, and Marieke de Loos,
Multigrid algorithms for the fast calculation of space-charge effects in
accelerator design, IEEE Transactions on magnetics, Vol 40, No. 2,
(2004), p. 714. |
Highlights: Below are
a few publication highlights directly or indirectly related to the GPT
project. Alternatively, see all publications and our
most cited papers.
Ultracold Electron
Source for Single-Shot, Ultrafast Electron Diffraction
Microscopy and Microanalysis 15, p. 282-289 (2009).
DOI: 10.1017/S143192760909076X
S.B. van der Geer, M.J. de Loos, E.J.D. Vredenbregt, and O.J. Luiten
Ultrafast electron diffraction (UED) enables studies of
structural dynamics at atomic length and timescales, i.e., 0.1 nm and 0.1 ps,
in single-shot mode. At present UED experiments are based on femtosecond
laser photoemission from solid state cathodes. These photoemission sources
perform excellently, but are not sufficiently bright for single-shot studies
of, for example, biomolecular samples. We propose a new type of electron
source, based on near-threshold photoionization of a laser-cooled and
trapped atomic gas. The electron temperature of these sources can be as low
as 10 K, implying an increase in brightness by orders of magnitude. We
investigate a setup consisting of an ultracold electron source and standard
radio-frequency acceleration techniques by GPT tracking simulations. The
simulations use realistic fields and include all pairwise Coulomb
interactions. We show that in this setup 120 keV, 0.1 pC electron bunches
can be produced with a longitudinal emittance sufficiently small for
enabling sub-100 fs bunch lengths at 1% relative energy spread. A transverse
root-mean-square normalized emittance of εx=10
nm is obtained, significantly better than from photoemission sources.
Correlations in transverse phase-space indicate that the transverse
emittance can be improved even further, enabling single-shot studies of
biomolecular samples.
Low-Energy-Spread Ion Bunches from a Trapped Atomic Gas
Physical Review Letters 102, 034802 (2009)
DOI: 10.1103/PhysRevLett.102.034802
M. P. Reijnders, P. A. van Kruisbergen, G. Taban, S. B. van
der Geer, P.H.A. Mutsaers, E. J. D. Vredenbregt, and O. J. Luiten
We present time-of-flight measurements of the
longitudinal energy spread of pulsed ultracold ion beams, produced by
near-threshold ionization of rubidium atoms captured in a magneto-optical
atom trap. Well-defined pulsed beams have been produced with energies of
only 1 eVand a root-mean-square energy spread as low as 0.02 eV, 2 orders of
magnitude lower than the state-of-the-art gallium liquid-metal ion source.
The low energy spread is important for focused ion beam technology because
it enables milling and ion-beam-induced deposition at sub-nm length scales
with many ionic species, both light and heavy. In addition, we show that the
slowly moving, low-energy-spread ion bunches are ideal for studying
intricate space charge effects in pulsed beams. As an example, we present a
detailed study of the transition from space charge dominated dynamics to
ballistic motion. |
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