Optimal for Particle Counters:     Calibration Standards - LS Series

These NIST traceable particle size standards fully accomplish the requirements of particle counting instruments:
The particle concentration to measure may not be to low to guarantee statistical count security. It also may not be to high to avoid the   Coincidence Effect   which leads to definitely wrong measurement results. To overcome these problems we designed the solids content of each size standard in dependance of its diameter. The bigger the particles are the higher the solids content has to be to keep the particle concentration itself constant.
By this you will get with an approximately identical number of drops (listed in each certificate) a particle concentration of appr. 5000 particles per mL. This means you can start to calibrate or measure immediately with no need for time consuming consecutive dilutions of the size standard.

Scope of Delivery and Shelf Life....

5ml or 20mL dropper-tipped-bottle with a certificate which also comprises the particle size distribution as a graph aditionally.
As an budget-priced alternative 6 sets are availble, too. These sets contain useful compilations of the mostly needed calibrants and their certificates. The Sets are protected by a stable box containing either 7 bottles of 5mL or 5 bottles of 20ml each.
The documented shelf life is 3 years from date of delivery.