Method and apparatus for characterizing microparticles and measuring their response to their environment

A process for measuring the response of a microparticle ensemble to its environment comprising the steps of:

• A. preparing a sample of said microparticles;
• B. illuminating said particles with a beam of radiation from a radiation source;
• C. measuring over a fixed period of time the intensities of radiation scattered by said particles at two sets of discrete scattering angles with respect to the direction of the incident beam, each set of angles subtending a range about each of two given angular directions;
• D. examining the variations of scattered intensity at each angular location within smaller intervals of such fixed time period and eliminating those values corresponding to large fluctuations from the mean value calculated during said fixed time period;
• E. calculating the mean scattered intensity value at each angular location member of each of the two sets of angular directions;
• F. forming a mathematical average scattered intensity of each set by combining the individual mean intensities of each element of the set yielding two characterizing values;
• G. exposing for a fixed period of time the sample of said microparticles to the test environment;
• H. repeating steps B through F to yield two averaged values characterizing the microparticle ensemble after exposure to the test environment after the fixed period of time;
• I. calculating a response of the microparticles to their environment by forming a functional combination of the two values obtained from step F with the two values obtained from step M.

An apparatus to determine two scattering values characteristic of a microparticle ensemble comprising:

• A. means to produce a collimated beam of radiation;
• B. means to hold a sample in this beam, said sample containing the microparticle ensemble;
• C. means to detect and collect radiation at two sets of angular locations each subtending a specific angle measured with respect to the direction of the incident beam;
• D. means to control the period of time during which scattered radiation is detected by said detectors;
• E. means to convert said detected values into digital representations and means to store said digital representations;
• F. means to analyse said stored digital values and suppress those values arising from spurious elements/noise of said microparticles ensemble;
• G. means to obtain an average scattered intensity value for each angular location of each of said detectors;
• H. means to calculate a weighted and averaged sum of all stored and processed digital values for each set yielding a single characterizing value for each of said two sets, said two values characteristic of detected, and weighted, and averaged scattered intensities at each of the two said principal angular locations.