水溶液の中の重水をトレ−サ−として利用する方式が最近注目されている。水中の重水の含有率を測定するとき、比重計では水の比重（１．００）と重水の比重（１．１１）が近いので、１０数％以下の含有率では比重計の１％以下の精度誤差の範囲に入る。即ち、重水の有無が判定し難くなる。また、最近開発されたガスクロマトグラフィ−は重水素を強調した測定方法ではなく、一般のガスを共通して測定する。従って重水をトレ−サ−として水溶液中で使用する場合には、一般性の分だけ効果が低下し、複雑、高価になり、誤差の範囲が増大する。重水がトレ−サ−の場合には、重水を選択的に強調できる方法が望ましい。重水は高価なので、この点からも必要である。
この発明では平板コンデンサ−の絶縁膜と負電極の間に重水含有の水を染ませた紙を挟み、負電極板に小穴を開けてコンデンサ−の正、負極間に電圧を加えた。このコンデンサ−を真空容器に入れ、回転ポンプで排気し、５Ｐａ〜１０２Ｐａにすると紙の中でその水、重水が分極して、コンデンサ−の端子電圧で加速された水素正イオンＨ＋、重水素正イオンＤ＋がその小穴から発生する。これ等を簡単な９０′曲げ磁場型質量分析器で分析するとＨ＋，Ｄ＋が判明しそれ等の強弱に応じた正イオン電流が分析器のビ−ムコレクタ−の電流計に現れる。ここで驚くべきことに先の圧力範囲５Ｐａ〜１０２ＰａではＤ＋の分極効果がＨ＋より著しく大きいことが発見された。この現象は、純水Ｈ２Ｏに市販の重水Ｄ２Ｏを加えて、紙に染ませて実験すれば正確に判明する。その結果Ｈ２Ｏに１％のＤ２Ｏを加えて上の方法を試したとき、５Ｐａ〜１０２ＰａではＨ＋とＤ＋の質量分析の磁場特性が同程度になった。即ち、Ｈ＋とＤ＋のビ−ムコレクタ−への正電流のピ−ク値〜１０ｎＡが同じになった。Ｈ２Ｏ５０％とＤ２Ｏ５０％を同程度の基準とすれば、この方法ではＤ２ＯのＤ＋検出能力がＨ２ＯのＨ＋より５０倍大きいことを示している。Ｄ２Ｏの０．０２％（自然水の重水濃度）でも明確に検出できたことは重水トレ−サ−の検出能力としては画期的である。重水は放射性物質でなく、毒性も小さいのでトレ−サ−としてこの発明は今後期待される。なお、重水の反ミュ−ニュ−トリノによる水からの人工的製法は、既に特願２００４−３８２７０４に発表してあり、２０％近くの濃度があり（上の方法で正確に決定）価格も安価なので、この発明の検出装置に活用できる。A method of using heavy water in an aqueous solution as a tracer has recently attracted attention. When measuring the content of heavy water in water, the specific gravity of water (1.00) and the specific gravity of heavy water (1.11) are close to each other in the hydrometer, so if the content is less than 10%, it is less than 1% of the hydrometer. It is within the range of accuracy error. That is, it becomes difficult to determine the presence or absence of heavy water. Further, recently developed gas chromatography is not a measurement method that emphasizes deuterium, but commonly measures general gases. Therefore, when heavy water is used as a tracer in an aqueous solution, the effect is reduced by the generality, it becomes complicated and expensive, and the range of error increases. When heavy water is a tracer, a method that can selectively emphasize heavy water is desirable. Since heavy water is expensive, it is necessary from this point.
In the present invention, a paper impregnated with heavy water is sandwiched between the insulating film of the flat capacitor and the negative electrode, a small hole is made in the negative electrode plate, and a voltage is applied between the positive and negative electrodes of the capacitor. When this capacitor is put in a vacuum vessel, evacuated with a rotary pump, and when it is set to 5 Pa to 10 2 Pa, the water and heavy water are polarized in the paper, and hydrogen positive ions H + accelerated by the terminal voltage of the capacitor, Deuterium positive ions D + are generated from the small holes. When these are analyzed by a simple 90 'bending magnetic field type mass spectrometer, H + and D + are found, and positive ion currents corresponding to the strengths appear in the ammeter of the beam collector of the analyzer. Here Surprisingly previous pressure range 5Pa~10 2 Pa at D + polarization effect was found that H + and more significantly greater. This phenomenon can be accurately determined by adding commercially available heavy water D 2 O to pure water H 2 O and dyeing it on paper for experiments. As a result, when 1% D 2 O was added to H 2 O and the above method was tested, the magnetic field characteristics of H + and D + mass spectrometry became comparable at 5 Pa to 10 2 Pa. That is, the peak values of 10 nA of positive currents to the beam collectors of H + and D + are the same. If H 2 O 50% and D 2 O 50% comparable criteria, in this way indicates that D 2 O of D + detection capability is 50 times more of H 2 O H + large. The clear detection even with 0.02% of D 2 O (heavy water concentration of natural water) is epoch-making as the detection capability of the heavy water tracer. Since heavy water is not a radioactive substance and has low toxicity, the present invention is expected in the future as a tracer. In addition, the artificial production method from water by heavy water anti-Mu-Turino has already been published in Japanese Patent Application No. 2004-382704, and has a concentration of nearly 20% (determined accurately by the above method) and is inexpensive. Therefore, it can be utilized for the detection apparatus of the present invention.
［図１］水と重水を染ませた紙を挟んだコンデンサ−と質量分析器
［図２］水に対する重水の含有率と質量分析図[Fig. 1] Capacitor and mass analyzer sandwiching paper soaked with water and heavy water [Fig. 2] Content of heavy water with respect to water and mass analysis diagram
符号の説明Explanation of symbols
［図１］
［Ｃ］：平面コンデンサ−、［ＭＡ］：磁場型質量分析器、Ｍ：金属板、Ｉｎｓ：コンデンサ−の絶縁膜（誘電膜）、Ｐ：水と重水を染ませた紙、Ｖ：コンデンサ−の端子電圧、Ｈ２Ｏ：純水、Ｄ２Ｏ：重水、ＢＣ：ビ−ムコレクタ−、ＢＭ：垂直磁場、Ｉ＋：ＢＣへの正電流、［ＶＣ］：真空容器、［Ｐｕｍｐ］：排気ポンプ（回転ポンプ）、Ｈ＋：水素正イオン、 Ｄ＋：重水素正イオン
［図２］
Ｄ２Ｏ／Ｈ２Ｏ：重水の水に対する比率（体積比）
ａ：Ｄ２Ｏ／Ｈ２Ｏ＝１０％
ｂ：Ｄ２Ｏ／Ｈ２Ｏ＝ １％
ｃ：Ｄ２Ｏ／Ｈ２Ｏ＝０．１％[Figure 1]
[C]: planar capacitor, [MA]: magnetic field mass analyzer, M: metal plate, Ins: insulating film (dielectric film) of the capacitor, P: paper stained with water and heavy water, V: capacitor Terminal voltage, H 2 O: pure water, D 2 O: heavy water, BC: beam collector, B M : vertical magnetic field, I + : positive current to BC, [VC]: vacuum vessel, [Pump]: Exhaust pump (rotary pump), H + : hydrogen positive ion, D + : deuterium positive ion [Fig. 2]
D 2 O / H 2 O: ratio of heavy water to water (volume ratio)
a: D 2 O / H 2 O = 10%
b: D 2 O / H 2 O = 1%
c: D 2 O / H 2 O = 0.1%
