Abstracts Brochure - CERN

TUPLS100
TUPLS103
27-Jun-06 16:00 - 18:00 TUPLS — Poster Session
creation of the extended resonance zone in a comparatively compact ECRIS. For this purpose the axial magnetic field
is formed with a flat minimum by mounting only one additional solenoid coil to the classical CAPRICE magnetic
structure. In this case the superposition of the axial magnetic field and the radial field of the permanent magnet
hexapole, made from NdFeB, allows one to create a larger resonance volume. First results of the ion source tests show
that in this resonance volume electrons are heated very efficiently which allows to produce intense beams of medium
charge state ions with comparatively low level of input microwave power. The basic design features, construction
issues and the first results of ion source tests are presented.
Generation of Highly Charged Ions Using ND-glass Laser
A. Kondrashev (ITEP) T. Kanesue (Kyushu University) M. Okamura
(RIKEN) K. Sakakibara (RLNR)
250
Parameters of ions (charge state distributions,
currents and pulse durations) were
measured in laser plasma generated by 3 J/
30 ns Nd-glass laser for wide range of ele-
ments from 12C to 181Ta and for different laser power densities at the target surface. It is shown that such a laser can
effectively generate highly charged ions for elements from 12C to 56Fe. Registered ion charge states significantly drops
for heavier elements because of recombination losses of highly charged ions during laser produced plasma expansion
into vacuum. Absolute currents and numbers of ions with different charge states were obtained by normalization of
charge state distributions summary on total ion currents measured by Faraday cup for 2.7*10 13 W/cm2 and 2.9*10 12
W/cm2 laser power densities at the target surface. The results obtained are very useful for Laser Ion Source (LIS)
development, in particular, for Direct Plasma Injection Scheme (DPIS) study*.
*M. Okamura et al. Laser and Particle Beams, 20, 2002, pp. 451 - 454.
Further Development of a Low Inductance Metal Vapor Vacuum Arc (LIZ-MeV) Ion
Source
B. Johnson (APS) E. Garate, R. McWilliams, J.P. Sprunck, A. van
Drie (University of California IIrvine) A. Hershcovitch (BNL)
A Low Impedance Z-Discharge Metal Vapor
Vacuum Arc (LIZ-MeV) ion source* is being
explored as an alternate pre-injector for the
Brookhaven Relativistic Heavy Ion Collider
(RHIC). With the vacuum arc operating at tens of kiloamperes and an aluminum electrode, LIZ-MeV has been run
in two regimes: an LC dominated "ringing" arc of period 4.1 microseconds, which decays after about 6 cycles, and a
1-3 microsecond wide "pulsed" arc, where a small series resistance has been added to critically damp ringing. Metal
ions are extracted from the plasma using a two-grid system with a triggered, variable-delay voltage of up to 10 kV.
Time-of-Flight (TOF) measurements are taken using a Faraday cup located at the end of a 15-76 cm drift tube. TOF
measurements from both arc regimes have been obtained suggesting generation of about a billion ions per pulse of
charge states +1 and +2, and occasionally +3 states. TOF results are compared with simple theoretical models.
*B. M. Johnson, et al. Two approaches to electron beam enhancement of the metal vapor vacuum arc ion source. Laser
and Particle Beams 21, 103 (2003).