The object of the present invention is to provide an
oxygen isotope concentration method capable of concentrating the stable
oxygen isotopes of 17O and 18O which can be carried out using a simple device configuration. The present invention relates to a method for concentrating an
oxygen isotope in separated oxygen by irradiating
ozone with light, selectively dissociating an isotopomer of
ozone containing an oxygen
isotope in its molecule into oxygen, followed by dissociating the
ozone and separating the formed oxygen from the non-dissociated ozone. The basic configuration of the device is provided with an ozone formation unit 11 that forms ozone from
raw material oxygen, an ozone separation unit 12 that separates ozone formed with said ozone generation unit and
raw material oxygen, an ozone
photodissociation unit 13 that radiates light of a specific
wavelength onto the ozone separated by said ozone separation unit 12 and selectively dissociates ozone containing an oxygen isotope in its molecule into oxygen, and an oxygen separation unit that separates the oxygen formed by dissociating ozone in said ozone
photodissociation unit 13 and non-dissociated ozone to concentrate the oxygen isotope in the oxygen. The present invention also relates to a method for concentrating an oxygen isotope comprising an ozone
photodissociation step, in which light is radiated onto a
rare gas-ozone
mixed gas containing ozone and at least one type of
rare gas selected from
krypton,
xenon and
radon to selectively dissociate ozone containing a specific oxygen isotope in its molecule into oxygen, and an oxygen isotope concentration step, in which the oxygen separated from ozone in said ozone photodissociation step is separated from non-dissociated ozone and
rare gas to concentrate the oxygen isotope present in the separated oxygen. An oxygen isotope may also be concentrated in a
dissociation reaction product by irradiating a gas containing a
peroxide selected from hydroperoxides, (di)
alkyl peroxides, peroxyacids including peracids, (di)acyl peroxides, peroxy esters, peroxycarbonates, peroxydicarbonates, diperoxycarbonates, peroxalates, cyclic peroxides, ozonides and endoperoxides,
nitrite esters and
nitrate esters, and selectively dissociating a
peroxide containing a specific oxygen isotope in its molecule.