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Determination of Low Concentration HD through Laser Thermal Lensing Spectroscopy

激光热透镜光谱法测定低浓度HD

基本信息

批准号：
10480116
负责人：
ENOKIDA Youichi
金额：
$ 3.65万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
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-10480116/
关键词：
Isotope Separation Hydrogen isotopes Laser Thermal lensing Spectroscopy Infrared Low concentration analysis HD

项目摘要

Laser-induced thermal lensing spectroscopy was studied to analyze hydrogen gas which contained natural abundance of HD, 300ppm. An infrared laser system of 1.382 μm InGaAs P type was used to excite HD molecule with a precise temperature control and frequency modulation of 1.4 to 110 kHz. At first, infrared spectrum of HD was measured with a single-path cell which contained HD gas of 100 to 800 torr and 0.8 mm long. The R(1) branch of the 2-0 band was observed with a half width of 0.02 cmィイD1-1ィエD1 at 7241.82 cmィイD1-1ィエD1, which was the same wavelength observed by Herzberg in 1950. The detection limit of HD with a normal adsorption spectroscopy was 20 torr, which was equipment to a concentration of 100 times higher than that of the natural abundance of HD. We applied a multi-path cell of 32 m in the effective path length to detect HD at the low pressure of less than 20 torr, but background noise brought about by the multi-reflection was too high detect HD absorption. In the thermal lensing spectroscopy, a reference cell which was evacuated less than 0.001 torr and 0.8 m long was placed in a parallel geometry of the sample cell contained the HD gas of 0.2 to 2 torr. Each laser beam was passed through a pinhole of 0.1 mm in diameter and detected. A difference signal was detected for a sample of 0.2 torr HD with 100kHz modulation, and it shows that we can determine HD molecule of the natural abundance with thermal lensing spectroscopy.

研究了激光诱导热透镜光谱法分析天然丰度为300 ppm的HD的氢气。采用1.382 μ mInGaAs P型红外激光系统，在1.4 ~ 110 kHz的频率范围内，对HD分子进行了精确的温度控制和频率调制。首先，HD的红外光谱是用含有HD气体的100 - 800 μ m和0.8 mm长的单光路池测量的。2-0带的R（1）分支在7241.82 cm λ D1-1 λ D1处观察到半宽为0.02 cm λ D1 - 1 λ D1，这与赫茨伯格在1950年观察到的波长相同。HD与正常的吸附光谱的检测限为20 μ g/ml，这是设备的浓度比HD的天然丰度高100倍。我们采用有效光程长为32 m的多光程池在小于20 μ m的低压下探测HD，但多次反射带来的背景噪声太高，探测HD吸收。在热透镜光谱法中，将抽真空小于0.001 μ m且0.8 m长的参比池放置在含有0.2至2 μ m HD气体的样品池的平行几何形状中。每个激光束通过直径为0.1mm的针孔并被检测。在100 kHz调制下，对0.2 μ HD的样品检测到一个差值信号，表明我们可以用热透镜光谱法测定天然丰度的HD分子。