Taiyo Nippon Sanso Corporation

Takehiro Igarashi

Takashi Kambe

Shigeru Hayashida

Hitoshi Kihara

The object of the present invention is to provide a stable isotope concentration method that reduces equipment cost and power without prolonging the start-up time and enables efficient concentration, and the present invention provides a stable isotope concentration method using multiple cascaded distillation columns (1st column to mth column; m is an integer of 2 or more), wherein the method includes a step in which one of gas and liquid is supplied from a position in the vicinity of the bottom of a (n−1)th column to a position in the vicinity of the top of an nth column (1<n≤m), and the other of liquid and gas is returned from a position in the vicinity of the top of the nth column to a position in the vicinity of the bottom of the (n−1)th column; and wherein in each distillation column, when a flow rate of an ascending gas in the column is a first flow rate and a flow rate of the gas or the liquid supplied from a previous column or a next column is a second flow rate, the second flow rate is 4% by volume or more with respect to the first flow rate.

Stable isotope concentration method

An object of the present invention is to provide an optical multipass cell that is compact and low cost, does not require the installation of a cooling mechanism around the mirror, and can increase the number of reflections of laser light, and the present invention provides an optical multipass cell comprising a container () to which a sample gas is supplied and a pair of concave mirrors (and) arranged so as to face each other inside the container (), a laser beam is incident into the container (), and the laser beam is multiply reflected between the concave mirrors (and), wherein at least one convex lens () is arranged on the optical path of the laser beam that is multiply reflected between the pair of concave mirrors (and) so that the central axis (C) thereof is inclined with respect to the central axis (C) of the concave mirrors (and), and an acute angle formed by the central axis (C) of the convex lens () and the central axis (C) of the concave mirrors (and) is equal to or less than a critical angle when the laser beam is emitted from the convex lens ().

Optical multipass cell

The present invention provides a method for enriching an oxygen isotope which enables the oxygen isotope to be enriched without requiring regular replenishment of large amounts of the nitric oxide raw material and with a small liquid NO hold-up volume, without reducing the separation efficiency for the oxygen isotope. By performing a chemical exchange between a water acquired by adding hydrogen to an oxygen having a crudely enriched oxygen isotope produced by a first distillation device, and a nitric oxide discharged from a second distillation device, a nitric oxide having an enriched concentration of the oxygen isotope and a water having a reduced concentration of the oxygen isotope are obtained, and the nitric oxide is supplied to the second distillation device, while an oxygen obtained by electrolysis of the water having a reduced concentration of the oxygen isotope is returned to the first distillation device.

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Tokyo, Japan

Takehiro Igarashi