Polystyrene Latex (PSL) spheres are the industry standard for calibrating airborne particle counters (LPCs), testing HEPA filters, and validating cleanroom environments.
Selecting the correct sphere size ensures that your instrumentation provides accurate, repeatable data that aligns with international cleanliness standards.
Using the wrong particle size can lead to faulty calibration curves, missed contamination risks, and compliance failures.
To pick the right PSL size, you must match the sphere dimensions to your hardware specifications and target testing goals. Follow these three selection steps.
Your laser particle counter (LPC) has fixed sizing channels (e.g., 0.1 µm, 0.3 µm, 0.5 µm, 1.0 µm). You must choose a PSL size that directly matches the specific channel you want to calibrate or verify.
Different industries require different testing sizes.
Laser counters identify size based on light scattering. Because PSL spheres have a stable refractive index of 1.59, ensure your counter’s configuration matches this specific material profile before running the test.
Use this reference table to select the exact PSL sphere size range based on your specific testing application and industry.
| Target PSL Sphere Size | Specific Testing Application | Industry Standard |
| 20 nm to 50 nm | Wafer inspection system calibration, CNC testing | Semiconductor Node Testing |
| 0.1 µm to 0.3 µm | Laser particle counter calibration, laser diode checks | Microelectronics / Electronics |
| 0.3 µm to 0.5 µm | HEPA filter efficiency testing, filter leak detection | Cleanroom Validation / Ventilation |
| 0.5 µm to 1.0 µm | Environmental monitoring, room classification | ISO 14644-1 / Pharma GMP |
| 2.0 µm to 10.0 µm | Coarse particle checks, liquid counter validation | Medical Devices / Industrial Labs |
Once you select the correct size, use these preparation steps to ensure accurate testing data:
Storage Rule: Store all PSL suspensions between 2°C and 8°C. Do not freeze the solution, as freezing permanently damages the sphere distribution.
Selecting the correct PSL sphere size is essential for accurate particle counter calibration and strict cleanroom compliance.
Matching the sphere dimensions directly to your equipment channels and industry standards prevents critical data errors.
Proper dilution and sonication further guarantee reliable, repeatable testing results. Choosing the right size ultimately secures your system’s validation accuracy and operational integrity.
Focus on the 0.1 µm, 0.3 µm, or 0.5 µm sizes. You must select the exact size that matches the specific particle channels your target cleanroom class requires to be verified.
Your laser particle counter will misinterpret the light scattering data. This leads to faulty calibration curves, inaccurate particle counts, and potential audit or compliance failures.
PSL spheres naturally clump together in solution. Sonication breaks up these clusters, ensuring the aerosol generator delivers single, accurate sphere sizes to the particle counter.
Since 1992, Applied Physics Corporation has been a leading global provider of precision contamination control and metrology standards. We specialize in airflow visualization, particle size standards, and cleanroom decontamination solutions for critical environments.
