PSL spheres, standards and applications
What does PSL stand for?
PSL commonly stands for polystyrene latex. In particle metrology, PSL spheres are engineered polystyrene particles used as references or application-specific test materials.
Are PSL spheres NIST certified?
Use more precise language. A lot may include documentation supporting traceability of a stated measurement result through a documented calibration chain. NIST does not endorse commercial products, and traceability belongs to a measurement result.
What is the difference between nominal size and certified mean?
Nominal size is the catalog target or convenient designation. The certified mean or peak is the lot-specific measured result used in the technical record.
Can I use the same PSL bottle for size calibration and count verification?
Not automatically. The certificate, concentration, distribution, intended use and procedure determine whether a product fits size calibration, count control or both.
Can HEPA Test PSL particles calibrate my particle counter?
The current Applied Physics HEPA Test product page explicitly states that family is not intended for instrument calibration or diagnostic reagents.
What range of PSL spheres does Applied Physics publish?
Current family pages describe aqueous PSL size standards from 20–900 nm and approximately 1–160 µm, plus application-specific SURF-CAL, count-control and HEPA Test families.
Why does refractive index matter?
Light-scattering instruments respond to optical interaction. The reported equivalent size depends on particle and medium refractive indices, wavelength and instrument geometry.
How should aqueous PSL spheres be stored?
Use the exact label and current product documentation. Current Applied Physics aqueous PSL family pages commonly describe suggested 2–8°C storage; do not freeze unless explicitly allowed.
How do I dilute a PSL suspension?
Use a validated preparation method, calibrated volumetric equipment and a characterized diluent blank. The C1V1=C2V2 equation provides only the theoretical volumes.
What is coefficient of variation?
CV is the standard deviation divided by the mean, often expressed as a percentage. It describes relative population width, not uncertainty in the certified mean.
Are PSL spheres and silica particles interchangeable?
No. They differ in composition, refractive index, density, surface chemistry and application response.
What is SURF-CAL?
Applied Physics SURF-CAL is a selected high-concentration PSL suspension pathway for certain SSIS and wafer-deposition workflows. It is not itself a finished calibration wafer.
What information should I send for a quote?
Provide application, instrument or method, target sizes, medium, concentration, bottle volume, certificate requirements, quantity, storage and timing.
Use the technical requirement builder
The fastest way to get a useful answer is to define the application and measurement system. Generate a requirement brief and send it to Applied Physics.
Match the standard to the measurement—not the other way around.
Send the instrument, medium, target size, concentration, certificate and packaging requirements to Applied Physics for a technical recommendation.