JOMESA Particle standard

Microscopic counting of residue particles on filter membranes contains the following steps:
Scanning the complete filter with a scanning stage, particle detection and counting grouped in size classes.

Measurement results therefore depend on many parameters and system settings, like:
Calibration of microscope, focusing, magnification settings, adjustment of scanning stage, parameters for particle detection (thresholds), etc.

To check particle counting systems, filters taken from the production line are not suitable for the following reasons:

·          Inaccurate reproducibility, because filter transport can add or remove residues. No possibility of cleaning or conserving.

·         The actual particle sizes are unknown or not well defined.

·        Production filters contain particles with sizes close to class size boundaries.

 
The established procedure for system validation is the use of particle standards.

The JOMESA Particle standard contains defined particles according to the ISO 16232 standard.

The standard is designed such that all particle sizes are sufficiently far away from size borders, thus enabling reproducible measurements.

It is targetted for filter diameters 47mm and 25mm.

The particle standard is available with a calibration certificate, documenting the trace-ability to national standards.