Patent ID: 8337802

Claim:
A method for concentrating an oxygen isotope or isotopes, comprising: an oxygen distillation step in which a starting material oxygen comprising 16 O 16 O, 16 O 17 O, 16 O 18 O, 17 O 17 O, 17 O 18 O and 18 O 18 O distilled using a distillation column to generate a 17 O-enriched oxygen in which at least one of 17 O-oxygen components selected from the group consisting of 16 O 17 O, 17 O 17 O and 17 O 18 O is enriched an ozone generation step in which the 17 O-enriched oxygen is used to generate an ozone; a 17 O-selective ozone photodissociation step in which a 17 O-containing ozone within the ozone is selectively decomposed to generate the 17 O-enriched oxygen in which at least one of the 17 O-oxygen components selected from the group consisting of 16 O 17 O, 17 O 17 O and 17 O 18 O is enriched; a 18 O-selective ozone photodissociation step in which a 18 O-containing ozone within the ozone is selectively decomposed to generate a 18 O-enriched oxygen in which at least one of 18 O-oxygen components selected from the group consisting of 16 O 18 O, 17 O 18 O and 18 O 18 O is enriched; and an oxygen returning step in which a part of oxygen, to be obtained by decomposing the remained ozone after the 17 O-selective ozone photodissociation step and the 18 O-selective ozone photodissociation step, is returned to the distillation column which is used in the oxygen distillation step.