Particle size measurement method, particle size measurement apparatus, and particle size measurement program

A particle size measurement apparatus, comprising:

• a measurement unit comprising a light source, a sample holder, pin holes, and a light receiving unit, wherein the measurement unit is configured to:
• irradiate a sample with light during a test measurement time period including a plurality of measurement timings set in advance, to thereby measure a test measurement intensity of scattered light scattered by the sample;
• a central processing unit configured to:
• calculate an autocorrelation function representing a relationship between an autocorrelation of the test measurement intensity and time;
• set a part of the plurality of measurement timings set in advance as measurement timings to be used for main measurement, based on a time period required until the autocorrelation function falls below a predetermined threshold value and a preliminary time period set and added to the time period;
• wherein the measurement unit is further configured to irradiate the sample with light during a main measurement time period including the part of the plurality of measurement timings, to thereby measure a main measurement intensity of the scattered light scattered by the sample;
• and
• the central processing unit is further configured to calculate a particle size of the sample based on the main measurement intensity.

A particle size measurement program for causing a computer, which is used in a particle size measurement apparatus configured to measure a particle size of a sample, to execute:

• a test measurement step of irradiating the sample with light during a test measurement time period including a plurality of measurement timings set in advance, to thereby measure a test measurement intensity of scattered light scattered by the sample;
• an autocorrelation function calculation step of calculating an autocorrelation function representing a relationship between an autocorrelation of the test measurement intensity and time;
• a setting step of setting a part of the plurality of measurement timings set in advance as measurement timings to be used for main measurement, based on a time period required until the autocorrelation function falls below a predetermined threshold value and a preliminary time period set and added to the time period;
• a main measurement step of irradiating the sample with light during a main measurement time period including the part of the plurality of measurement timings, to thereby measure a main measurement intensity of the scattered light scattered by the sample;
• and
• a particle size calculation step of calculating the particle size of the sample based on the main measurement intensity.