Abstracts Brochure - CERN

THPLS094
THPLS096
THPLS097
THPLS098
29-Jun-06 16:00 - 18:00 THPLS — Poster Session
First Measurement Results at the LEG 100 keV Gun Test Stand
S.C. Leemann, Å. Andersson, R. Ganter, V. Schlott, A. Streun, A.F.
Wrulich (PSI)
474
In the scope of the Low Emittance Gun
Project (LEG) at PSI, a field emitter array
(FEA) cathode is being considered as an electron
source. In order to study pulsed field
emission from such a cathode and to investigate space charge compensation techniques as well as to develop diagnostic
procedures to characterize the beam resulting from an FEA cathode, it has been decided to build a 100 keV gun
test stand. The test stand gun and diagnostics have been modeled with the codes MAFIA and GPT. From extensive
parameter studies an optimized design has been derived, and construction of the gun and diagnostics have recently
been completed. We report on the commissioning of the test stand and present first measurement results.
Resonance System of RF Gun with Plasma Ferroelectric Cathode
It was demonstrated before that single cell RF
I.V. Khodak, V.A. Kushnir, V.V. Mytrochenko (NSC/KIPT)
gun with a plasma ferroelectric cathode can
generate the electron beam with peak current
up to 10 2 A/cm 2 and normalised beam emittance less than 50 mm*mrad within the current pulse duration ∼10-8 s.
The current density of electron emission in the cathode may be ∼10 3 A/cm 2 . To obtain high beam quality in such
RF guns, a multi-cell resonance system is the most preferable to be employed. There is considered in the paper the
analysis of different resonance systems of RF gun sharing the high current density emission. Results of the computer
simulation of particle beam dynamics are also referred in the paper.
Model of the CSR Induced Bursts in Slicing Experiments
In a recent experiment on ’femtoslicing’ at
G.V. Stupakov, S.A. Heifets (SLAC)
the Advanced Light Source in LBNL, it has
been observed that the beam slicing initiates
correlated bursts of coherent synchrotron radiation (CSR) of the beam. In this paper, we suggest a model describing
such bursts. The model is based on the linear theory of the CSR instability in electron rings. We describe how an
initial perturbation of the beam generated by the laser pulse evolves in time when the beam is unstable due to the
CSR wakefield. Although this model does not give quantitative predictions, it qualitatively explains the evolution of
the induced CSR bursts.
Optimum Beam Creation in Photoinjectors Using Space-charge Expansion
J.B. Rosenzweig, A.M. Cook, M.P. Dunning, C. Pellegrini (UCLA)
M. Boscolo, M. Ferrario, D. Filippetto, L. Palumbo, C. Vicario
(INFN/LNF) P. Musumeci (INFN-Roma)
It has recently been shown by Luiten* that
by illuminating a photocathode with an ultra-short
laser pulse of appropriate transverse
profile, a uniform density, ellipsoidally
shaped bunch is dynamically formed, which
then has linear space-charge fields in all dimensions inside of the bunch. We study here this process, and its marriage
to the standard emittance compensation scenario that is implemented in most modern photoinjectors. It is seen that
the two processes are compatible, with simulations indicating that a very high brightness beam can be obtained. The