The sensor design

structure theory

light path

theory analysis and experiment are introduced. The light absorption and scattering are related to the light distance and incidence energy

and the change of the biomass concentration makes the changes of the light absorption and scattering

and leads to the change of the receiving energy. Based on the physical phenomena and theory

a new method to measure the biomass concentration is set up. Under the constant temperature(20℃) circumstance

the biomass concentration is tested using a 760 nm lamp-house. The result indicates that the method is good for testing the bacterium liquid concentration; the maximum relative error is less than 0.2%. It is advantage in precise on-line testing

high sensitivity and long life etc and can be used in testing microbial bacterium liquid on-line.