Speaker
K.Mima
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P5.2006.pdf
Efficient ps. Laser Ion Acceleration toward High Neutron Yield
K.Mima1)*. A.Yogo2), R.Hanayama1), A.Sunahara3), T.Asahina2), H.Nagatomo2),
H.Nishimura2), Y.Arikawa2), Y.Abe2), M.Nakai2), H. Kondo3), H.Tanaka4), S.Nakai1)
and Y.Kato1)
1)
The Graduate School for C. of N. Photonics Industries (GPI), Hamamatsu,, Japan
2)
Institute of Laser Engineering (ILE), Osaka University, 565-0871, Suita, Osaka Japan
3)
Purdue University, Indiana, USA
4)
Hamamatsu Photonics K.K. (HPK), Hamamatsu, Japan,
5)
Reactor Research Institute, Kyoto University, Kumatori, Osaka, Japan
*K.Mima: k.mima@gpi.ac.jp)
Laser driven neutron sources and their applications have been explored in the projects
of the A-STEP program of the JST, since 2016 at ILE, Osaka University and GPI,
Hamamatsu. In this paper, new findings for the efficient laser ion acceleration and
neutron generation are reported.
The higher ion and neutron yield are realized by producing a pre-plasma before the
main pulse in the TNSA. According to the simulations, the short pulse laser absorption
and hot electron slope temperature are higher when a pre-plasma is formed on a solid
target surface. So, the accelerated ion number and energy are expected to be higher. But,
because of the pre-heating, the rear surface of a thin foil expands and then the TNSA field
is reduced. The new finding is to steepen the rear surface density profile by controlling
the shock breakout time, It is explored by the radiation hydro-simulation. We found that
the steepened rear surface density profile is realized by adjusting the pre-pulse intensity
and duration and the target thickness. The PIC simulations were carried out to see the
pre-pulse effects. According to the results, the total ion energy and the cut-off energy
increases by one order with a proper pre-pulse and the target thickness.
As preliminary experiments, the pitcher-catcher schemes were studied with the LFEX
laser at ILE and the repetition rate short pulse laser at HPK and GPI. In the LFEX
experiments, the 0.5-1 kJ, multi picosecond pulse irradiated a CD foil with proton
contamination for accelerating deuteron and proton. The accelerated proton and deuteron
number for the energy higher than 10 MeV reaches 1014 /shot, which is 10 times higher
than that without pre-pulse. The more discussions on the simulations and experiments
will be presented.
