DEVELOPMENT OF DETECTION METHOD FOR MEASURING AMBIENT NO CONCENTRATION USING HIGH SENSITIVE LASER SPECTROSCOPIC TECHNIQUE

高灵敏激光光谱技术测量环境中NO浓度检测方法的研制

• 批准号: 07454147
• 负责人: KAJII Yoshizumi
• 金额: $ 4.86万
• 依托单位: RESEACH CENTER FOR ADVANCED SCIENCE AND TECHNOLOGY,THE UNIVERSITY OF TOKYO
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07454147/
• 关键词: SUPER SONIC FREE JET; RETPI; UV-PULSE LASER; ROTATIONAL TEMPERATURE; INTERFERENCE OF NO_2; COUNTING TECHNIOUE; LIMIT OF DETECTION; NO; 2光子共鳴イオン化(RE2PI); 大気測走; 高感度測走; レーザーイオン化; 超音速分子線法

we designed and constructed vacuum chamber and vacuum system for measuring ambient NO concentration. The laser system of tunable dye laser pumped by 3rd harmonic of pulsed nd : YAG laser was constructed. The out-put of dye laser was doubled to excite NO molecule into single ro-vibronic level. The analysis of rotationnal temperature was done to determine rotational temperature to be 25 K under X/D of 70. we reconfirmed resonance enhanced two photon ionization (RETPI) process rom the laser power dependence experiment showing index of 1.75. we employed ion counting system for detection of ion signals to increase S/N ratio. we found almost of two order of magnitude improvement of sensitivity by replacement of detection system from analog-to-digital operation to ion counting operation. we confirmed linear response of ion signal with NO concentration up to 200 ppb. In the chemical. interference of NO_2, the sensitivity of NO_2 is ca.2% compared to that of NO.This shows the improvement of selectivity by the cooling process. The limit of detection was estimated to be 16 pptv with an integration time of 1 min.

我们设计和构建了真空室和真空系统，以测量环境无浓度。构建了由脉冲和YAG激光的第三谐波泵送的可调染料激光器的激光系统。将染料激光的倒入量加倍，以将无分子激发到单个RO-Evibronic水平。进行旋转温度的分析以确定旋转温度在70的X/D下为25K。我们重新确认了共振增强了两个光子电离（RETPI）过程ROM激光功率依赖性实验，显示指数为1.75。我们使用离子计数系统来检测离子信号以增加S/N比。我们发现，通过替换检测系统从类似物到数字操作到离子计数操作，几乎有两个数量级提高了灵敏度。我们证实了离子信号的线性响应，无浓度高达200 ppb。在化学物质中。 NO_2的干扰，NO_2的灵敏度为Ca.2％，而No_2则显示了通过冷却过程提高选择性的敏感性。估计检测极限为16 PPTV，整合时间为1分钟。