MEASUREMENT OF CONVERSION RATE OF PARA-HY DROGEN TO ORTHO-HYDROGEN AND ITS REGENERATION IN RAMAN LASER FOR ISOTOPE-SEPARATION OF URANIUM

In the 16 mu m Raman laser for molecular laser isotope separation of u ranium, pure para-hydrogen gas is the Raman medium, and then natural c onversion from pure para-hydrogen to para-ortho mixture causes always serious reduction of Raman conversion efficiency. The authors have mea sured temporal decay of para-hydrogen concentration in a Raman cell an d obtained a decay time constant of 102 days. Using the Raman cell com bined with a para-hydrogen regenerator designed with the above value, they have demonstrated that the concentration of para-hydrogen was mai ntained to be high enough for the Raman conversion.