Abstracts Brochure - CERN

THPCH188
THPCH189
THPCH190
29-Jun-06 16:00 - 18:00 THPCH — Poster Session
kicker power supply. Analyses of the EMI
source and the propagation path are the beginning missions. The radiated and conducted EMI both affected the
Integral Current Transformer (ICT) normal operation because of the space limitation for TLS in NSRRC. The ICT is to
measure injection efficiency, thus, ICT located just behind the kickers and using the common girder. The EMI signals
therefore are much higher than the electron beam currents, and the integral values of the sensor are not correct. For
reducing and eliminating the interference of electromagnetic waves, a hybrid segregation and grounding method was
used. The EMI wrapper was enclosed the ICT and its high frequency amplifier separately to prevent the radiated
EMI from the space. The grounding paths provided the possible stray current dredge to the ground loop. It reduced
the stray current spread to the subsystems next to the kickers. The EMI therefore reduced 99%, and the injection
efficiency could be calculated successfully. The elimination of the EMI from kicker itself will be the next step in the
future.
On Maximal Current Density in the Secondary Emission Magnetron Injection Gun
Progress in the accelerator techniques ad-
S.A. Cherenshchykov, E.V. Bulyak (NSC/KIPT)
joins with necessity to increase of the brightness
of electron beams and to transit to higher
frequency of high-power microwave sources. In some cases conventional electron guns cannot attain required density
of current. One of the alternative sources of intensive beams is the secondary emission magnetron injection gun. The
density of current in such a gun increases with electric field strength at the cathode surface. The allowed maximum
of the field is equal to the threshold to the uncontrollable explosive emission. The space charge of electrons decreases
the field strength and thus prevents the explosive emission. In the report, numerical evaluations of the threshold
are presented based on experimental data on the beam current and its cross section. The problem is solved within
the approximation of an azimuthally uniform beam. The electron trajectories are evaluated back stream, from the
position of the beam at the collector. Estimation of the maximal current of the secondary emission is derived with
account for the space charge.
Influence of "Long-range" Couplings on Dispersion Properties of Accelerating Structures
The analysis of influence of cross-cavity cou-
K. Kramarenko, M.I. Ayzatskiy (NSC/KIPT)
plings on dispersion properties of S-band
accelerating structures is carried out. It is
shown that the increasing of cavity length is not the sufficient condition for the weakening of the "long-range" couplings.
Results of our calculations have shown that the dependence of cross-cavity coupling coefficient on the cell
length substantially differs from the analogous one for coupling coefficient of adjacent cells. The coupling coefficients
are calculated using the rigorous electrodynamic approach.
Electron Beam Formation in the Secondary-emission Sources with a Uniform and Nonuniform
Electric Azimuthal
V. Zakutin, M.I. Ayzatskiy, A. Dovbnya, N.A. Dovbnya, V.
Mitrochenco, N.G. Reshetnyak, V.P. Romas’ko (NSC/KIPT)
442
The paper reports the results of experimental
studies on the formation of electron beams in
three types of secondary-emission sources.