Speaker
Description
We have begun searching for the new super-heavy
element (SHE) with Z=119 at RIKEN Heavy Ion
LINAC (RILAC). To overcome the small production
cross section of vanadium (V) beam on the curium
target, the project requires a very powerful V beam.
In order to optimize the beam intensity of V with the
charge state of 13+, we have investigated the effects
of the amount of V vapor, the power of 18- and 28-
GHz microwaves, and the strength of the mirror field.
While no significant effect was seen by changing the
mirror field Bext from 1.4 T to 1.6 T, the amount of V
vapor and the microwave power strongly affected.
Based on the correlation between the V-vapor and
the microwave power, we obtained a 600-euA V(13+)
beam with the V consumption rate of 24 mg/h and
the microwave power of 2.9 kW in order to execute
about 1-month SHE experiment. Furthermore,
because such strong mirror field enhances the
transverse beam emittance, it is important to control
the emittance with small reduction of the intensity.
We have successfully controlled the beam emittance
by using three pairs of slits (triplet slits) in LEBT by
eliminating the peripheral beam components in both
of the x-x' and y-y' phase spaces.