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The light blocking optical particle counter method is typically useful for detecting and sizing particles greater than 1 micrometre in size and is based upon the amount of light a particle blocks when passing through the detection area of the particle counter. This type of technique allows high resolution and reliable measurement.
ISO/DIS 14644-1.2(2014): Classification of air cleanliness by particle concentration [4] ISO 14644-2: Specifications for testing and monitoring to prove continued compliance with ISO 14644-1 [3] ISO/DIS 14644-2.2(2014): Monitoring to provide evidence of cleanroom performance related to air cleanliness by particle concentration [5]
The particle counter determines the concentration and the size distribution of the particles. Therefore, the accuracy of the liquid particle counter has to be established through calibration. According to ISO 11171 for the primary particle-sizing calibration NIST SRM 2806 suspension [clarification needed] has to be used. In annex "F" of ISO ...
Counting efficiency varies for different isotopes, sample compositions and scintillation counters.Poor counting efficiency can be caused by an extremely low energy to light conversion rate, (scintillation efficiency) which, even optimally, will be a small value.
The direction this light is emitted is on a cone with angle θ c about the direction in which the particle is moving, with cos(θ c) = c / nv (c = the vacuum speed of light, n = the refractive index of the medium, and v is the speed of the particle). The angle of the cone θ c thus is a direct measure
A condensation particle counter or CPC is a particle counter that detects and counts aerosol particles by first enlarging them by using the particles as nucleation centers to create droplets in a supersaturated gas. [2] Three techniques have been used to produce nucleation: Adiabatic expansion using an expansion chamber.
A Visible Light Photon Counter (VLPC) is a photon counting photodetector based on impurity-band conduction in arsenic-doped silicon. They have high quantum efficiency and are able to detect single photons in the visible range of the electromagnetic spectrum .
Liquid scintillation counter. Samples are dissolved or suspended in a "cocktail" containing a solvent (historically aromatic organics such as xylene or toluene, but more recently less hazardous solvents are used), typically some form of a surfactant, and "fluors" or scintillators which produce the light measured by the detector.