Quantitative Study on the Extinction Efficiency Error Caused by the Refractive Index During the Particulate Measurement

ABSTRACT

The quantitative errors of extinction efficiency during the particulate measurement caused by the refractive index are studied. And the quantitative results are acquired when the real part of the refractive index and the imaginary part change respectively. The change ranges of the real part are 1+0.5 i to 2+0.5 i at a 0.1 interval and 1.5+0.5 i to 1.59+0.5 i at a 0.01 interval. Another the change ranges of the imaginary part are 1.57+0.1 i to 1.57+1 i at a 0.1 i interval and 1.57+1 i to 1.57+10 i at a 1 i interval. Firstly, the result shows the extinction efficiency change is linear with the real part change of the refractive index, but not linear with the imaginary part change. Secondly, when both the real part and the imaginary part change, the extinction efficiency will go to a constant value about 2.24 with the size parameter x infinitely increasing. Thirdly, the errors are different with the change of x when the real part changes. The maximal error value is 1.168% at x =2 and the end constant value is about 0.05%. Also the extinction efficiency errors are 0.67% and 0.036% when the size of x are 1 and 20 respectively when the imaginary part changes.