7th Asia-Pacific Conference on Plasma Physics, 12-17 Nov, 2023 at Port Messe Nagoya

Fabrication of cupper containing deuterated material target for laser plasma
diagnostics
K. Yamanoi1
1Institute of Laser Engineering, Osaka university
e-mail (speaker):yamanoi.kohei.ile@osaka-u.ac.jp
Fast ignition (FI) is an advance concept of Inertial
Confinement Fusion to realize Inertial Fusion Energy(IFE) which can optimize fuel implosion and heatingprocesses, respectively to achieve high gain. In FI, theunderstanding the mechanisms of the energy transfer fromfast electrons to the compressed plasma core is critical for
efficient fusion fuel heating. In these experiments,characteristic X-rays produced by the laser-accelerated
fast electrons are utilized to understand the mechanismsof the electron transport in dense plasma and neutrons
generated during the IFE experiment are utilized toinvestigate the fusion reaction as well as the temperatureof the core compressed. Characteristic X-rays andneutrons are measured by using fuel targets containing
tracer atoms that generate a specific signal during a fusion
reaction in the IFE experiment. The amount of tracer isimportant to avoid resonant self-absorption of the X-ray.
The deuterated ratio of target materials is also essential for
efficient fusion reaction. For these purposes, several
targets such as high deuterium concentration, metal foams,
and low Z materials with transparency had beendeveloped.[1-3] The type of tracer atom contained in thetarget depends on the purpose of the experiment.
It has been pointed out that experiments involving X-rays
and neutrons require different experimental conditions
mainly because inorganic materials such as Cu andorganic materials with deuterium are generallyincompatible with each other. However, the simultaneousachievement of Cu doping, deuterated polymer,
mechanical toughness and chemical robustness for thefabrication process is not so simple. The glow discharge
polymer (GDP) method was applied for a Cu-doped
deuterated target. GDP method polymerize deuterated
Copper (II) acetylacetonate radically on a solid sphere byvapor deposition. However, this method has a problem
that the complicated shape of the target is difficult to befabricated, because it requires a base part to deposit thetarget. Therefore, there is no bead target that contains bothCu and deuterium and no simultaneous measurements
involving both characteristic X-rays and neutrons. Herewe will introduce an example to satisfy thesespecifications with chemical and laser plasma
characterizations. The target material will open new
characterizations of the next fast ignition progress.
Doping inorganic elements into organic compounds isdifficult because the interface between an inorganic andan organic substance generally has a poor affinity, and it
is also difficult to combine the two substances in thecondition with a large interfacial effect such as adispersion system of fine particles. The concentration oftracer atoms should be adjustable from 1 to10 wt.%
depending on the experimental conditions since too much
Cu concentration more than 10 wt.% leads to weak CuKα emission due to resonant self-absorption and X-ray
measurement will be difficult. In this regard, we report thefabrication of Cu-doped deuterated methyl methacrylate(MMA) and methacrylic acid (MAA) targets (Cu-dMAtargets) as a novel target for laser fusion experiments. The
Cu-dMA is soluble in the solvents to facilitate processing
into various shapes as shown in fig.1.[4] The Cu
concentration in the Cu-dMA targets is studied using
inductively coupled plasma optical emission spectrometry(ICP-OES). The Cu-dMA targets is characterized bysimple dissolution tests, differential scanning calorimetry(DSC), and fourier transform infrared spectroscopy(FTIR). Our results suggest that the Cu-dMA targets canbe used as targets to provide valuable insights in the IFE
experiments.
References[1] N.G. Borisenko et al, EPJ Web of Conf. 59, 03014(2013)[2] N.G. Borisenko et al, Fusion Sci. Technol. 38, 161165 (2017)[3] A.V. Pastukhov et al, J. Appl. Polym. Sci. 139,e52997 (2022)[4] T. Ikeda et al, Nucl. Fusion 63, 016010 (2023)

Figure 1. (a) Cu-dMA (left) and Cu-hMA (right) samples
taken from the oven and the test tube. (b) Cu-dMA thinfilm with a thickness of 10 μm cut to a size of 1 mm × 1mm. (c) photograph of the Cu-hMA spheres fabricatedby dropping the Cu-hMA solution into 10wt.% PVA
aqueous solution.