Pinnick R G, Hofmann D J
Appl Opt. 1973 Nov 1;12(11):2593-7. doi: 10.1364/AO.12.002593.
The counting efficiency as a function of particle size has been calculated for a particular forward scattering aerosol particle counter that uses white light illumination for spherical particles with indexes of refraction 1.33-0i, 1.40-0i, 1.50-0i, 1.592-0i, 1.50-0.05i, 1.50-0.1i, 1.50-0.5i, and 1.95-0.66i. The counting efficiency differs from 100% because of statistical effects: photoelectron statistical broadening, variation in aerosol speed through the illuminated volume, nonuniform illumination of the sampled aerosol, and nonuniformity of the photomultiplier tube photo cathode surface. These spectra broadening effects have been determined for the particle counter by measurement of monodisperse aerosols, and the efficiency calculation is based on these measurements. For the particle counter studied, the efficiencies vary from 70%; to slightly over 100% in the size ranges where the counter response is single valued. The efficiency for materials for which the response is not single-valued fluctuates wildly in those size ranges from about 20% to more than 10,000%. The efficiency as a function of particle size discriminator level setting is sensitive to particle refractive index and to the aerosol size distribution locally about that particle size. The method for calculation of the efficiency can be applied to light-scattering aerosol counters available commercially.
对于一台特定的前向散射气溶胶粒子计数器，已计算出其作为粒径函数的计数效率。该计数器使用白光照射，用于折射率为1.33 - 0i、1.40 - 0i、1.50 - 0i、1.592 - 0i、1.50 - 0.05i、1.50 - 0.1i、1.50 - 0.5i和1.95 - 0.66i的球形粒子。由于统计效应，计数效率不同于100%：光电子统计展宽、气溶胶通过照明体积时速度的变化、采样气溶胶的不均匀照明以及光电倍增管光电阴极表面的不均匀性。通过测量单分散气溶胶确定了粒子计数器的这些光谱展宽效应，效率计算基于这些测量结果。对于所研究的粒子计数器，在计数器响应为单值的粒径范围内，效率从70%变化到略高于100%。在那些响应不是单值的粒径范围内，材料的效率在约20%到超过10000%之间剧烈波动。作为粒径鉴别器水平设置函数的效率对粒子折射率以及该粒径附近局部的气溶胶粒径分布敏感。效率的计算方法可应用于市售的光散射气溶胶计数器。
