It is quite important to control and observe the concentration and total amount of tritium when nuclear fusion is utilized like ITER project. There are many kinds of molecular species, conditions, amount, and concentration in the environment and it is desirable to have multiple ways of observation. Tritium is often found as hydrogen, water and methane molecules. Their behavior differs by the molecular species and detection of molecular species is therefore important. Near-infrared spectroscopy can be a good molecular species sensitive method for this purpose. However, since basic spectroscopic information of tritiated water (HTO or T2O) is unavailable, in this study we prepared tritiated water of high concentration, and carried out frequency modulation near-infrared spectroscopy.

The tritiated water was synthesized by the oxidation reaction of 1 Ci of T2. Near-infrared spectra at 1.3 micron were recorded. Many lines were observed which are not due to normal water. They are strong candidates of tritiated water spectral lines.