Development of photoacoustic spectrometry for measurement of isotope ratio.

开发用于测量同位素比的光声光谱法。

基本信息

批准号：
10358014
负责人：
KAWASAKI Masahiro
金额：
$ 17.54万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10358014/
关键词：
water third overtone pulsed lasar photoacoustic isotope PAS microphone fourth overtone

项目摘要

A photoacoustic spectroscopy technique is applied to the isotope ratio measurement of ィイD116ィエD1O and ィイD118ィエD1O in water-vapor samples, using a pulsed tunable dye laser pumped by Nd : YAG laser. The third overtone band (3vィイD2OHィエD2) of water molecules near 950 nm was investigated, for two standard water samples, V-SMOW and SLAP. We identified the absorption lines of HィイD22ィエD2ィイD116ィエD1O and HィイD22ィエD2ィイD118ィエD1O in the photoacoustic spectra that we measured by using the HITRAN database. We measured the difference in the ィイD118ィエD1O/ィイD116ィエD1O isotope ratios for V-SMOW and SLAP, using the photoacoustic method. For each water isotope (HィイD22ィエD2ィイD116ィエD1O and HィイD22ィエD2ィイD118ィエD1O) peak we made 128 times averaging of the photoacoustic wave on the oscilloscope and scanned the laser wavelength within a selected range in 0.002 nm increments. The measurement time was 7000 s for each sample. The value obtained for the difference between the two samples is δィイD118ィエD1OィイD2SMOWィエD2=-55±10‰, whereas the value measured with a conventional isotope mass spectrometer is δィイD118ィエD1O=-55.5‰. That δ-value was certainly an improvement on the previous work. However, the obtained δ-value has a relatively large deviation, because the deviation should be less than 1-2‰ for practical use. Further improvements are necessary to reduce the deviation. The large deviation comes mainly from the low signal-to-noise ratio in the photoacoustic spectra.

使用通过ND：YAG Laser泵送的脉冲可调染料激光器，将光声光谱技术应用于水蒸气样品中D116 D1O和D118 D1O的同位素比测量。研究了两个标准水样品，即V-Smow和Slap，研究了950 nm附近的第三个泛音带（3VII D2OH D2）。我们在光声光谱中鉴定了H2D22 D2I D116 D11O和H-D22-D2-D118-D1O的吸收系，我们通过使用Hitran数据库测量了光声光谱。我们使用光声方法测量了V-Smow和Slap的Hitran D1O/I-D116-D116-D1O同位素比率的差异。对于每个水同位素（H-D22-D2-D116-D1O和H-D22-D2-D2-D118-D1O）峰，我们在示波器上平均光声波平均，并在0.002 nm增量中扫描了所选范围内的激光波长。每个样品的测量时间为7000 s。两个样品之间差的值为ΔD118ID1OI D2SMOWI D2 = -55±10‰，而使用常规同位素质谱仪测量的值为ΔD118ID1O = -55.5‰。该δ值无疑是对先前工作的改进。但是，所获得的δ值具有相对较大的偏差，因为用于实际使用的偏离应小于1-2‰。需要进一步改进以减少偏差。大偏差主要来自光声光谱中的低信噪比。