Preparation and Raman Investigation of High Pressure ICF Targets
WEN Cheng-wei1, SHEN Chun-lei1, YU Ming-ming1, XIA Li-dong1, WANG Kai2, LI Hai-rong1*
1. Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics，Mianyang 621900, China
2. Research Center of Laser Fusion, Chinese Academy of Engineering Physics, Mianyang 621900, China
Abstract：The quantitative analysis and monitoring of hydrogen isotopes, including hydrogen (H2), hydrogen deuterium (HD), hydrogen tritium (HT), deuterium (D2), deuterium tritium (DT) and tritium (T2), are of great significance in the field of energy and environment. Due to its non-destructive and non-contact analytical characteristics, laser raman spectroscopy (LRS) has become an important analyzing method for hydrogen isotopes quantification and in-line monitering. In the international thermonuclear experimental reactor (ITER) and savannah river factory (SRF) laser raman spectroscopy has been extensively used for qualitative and quantitative analytical purposes. Promising results are also obtained in raman system at the Karlsruhe Tritium Neutrino Experiment (KATRIN), which is targeted to measure the neutrino mass by means of high precision electron spectroscopy of the β-decay of tritium. In this paper, high pressure gas targets for inertial confinement fusion (ICF) experiments were prepared and studied by Raman spectroscopy. The composition of high pressure deutrium-tritium mixtrures were obtained by analyzing the rota-vibrational spectra of above molecules as a first approximation. The obtaining results were compared with mass spectroscpy measurements and the technological parameters for target fabrication were verified. The experiments showed that a precision of 1% can be obtained for deuterium (D2), deuterium tritium (DT) and tritium (T2) when integration time increased to 1 minute using a commercial instrument (LabRAM HR800,Jobin Yvon), though modification was still needed to achieve a even higher precesion. The pressure shifts for deuterium (D2), deuterium tritium (DT) and tritium (T2) were tentatively investigated and compared with previous studies. At the same time, the composition evolution of high pressure deuterium tritium gas mixture was also monitored during 6 months’ storage time. The experimental results show ed that due to the interplay of gas permeation and tritium decay effects, the gas composition did not change though the total gas pressure within the target decreased continuously with time.
Key words：ICF；High pressure gas targets; Raman spectroscopy
