双散射角光学粒子计数器的研制

Development of optical particle counter with double scattering angles

为了实现同时测量气溶胶粒子的谱分布和折射率,研制了一种新的双角度光学粒子计数器(D-OPC),该计数器采用60°和110°双散射角系统对气溶胶谱分布进行测量。利用Mie散射理论定义敏感函数,选取两个最佳的散射角,使其既对折射率敏感又不线性相关。然后,利用气溶胶折射率对两个散射角系统敏感性的差异来反演气溶胶折射率。最后,利用该仪器对大气气溶胶谱分布以及折射率进行实际测量。与TSI公司黑炭仪和浊度计测量的吸收系数和散射系数对比表明,双散射角光学粒子计数器测量气溶胶折射率和谱分布结果合理,测量误差<20%,可以满足同时测量气溶胶粒子谱分布和折射率的需要。

A new Optical Particle Counter（OPC） with 60° and 110° double-scattering angles was developed in the paper for measuring aerosol refractive indexes and size distributions synchronously. On the basis of defining a sensitive function by Mie scattering theory,two optimum scattering angles were selected,then,the difference of two sattering angles sensitive to aerosol refractive indexes was used to inverse the aerosol refractive indexes. Finally, a prototype with 60° and 110° double scattering-angle of OPC （D-OPC） was used in the experiments at Hefei for measuring aerosol refractive indexes and size distributions. The scattering and absorption coefficient values measured by the D-OPC were compared with that measured by an Aethalometre and an Integrating Nephelometer（designed by TSI）. The comparison results indicate that measured data by the D-OPC are reasonable and the measuring error is less than 20 % ,which shows the D-OPC can satisfy the requirements of measurement of aerosol refractive indexes and size distributions synchronougly.