Does the classifier remove all the particles of certain size from an aerosol?
No. The classifier will only remove particles of a certain size that also are carrying a positive charge after neutralization, generally about 10% to 20% of the total particles in that size range.
How long is the neutralizer good for and how do I dispose of it?
The half-life of the neutralizer is 10.4 years and we recommend that it is replaced at that time. TSI is responsible for disposal of the neutralizer. Simply call TSI's shipping department and they will instruct you on how to return the neutralizer to us for disposal.
Is the radioactive neutralizer in the classifier dangerous and do I need a special license to purchase it?
We use Kr-85 gas as the radioactive source in the neutralizer. Safety wise this is a very wise choice. Since it is a gas, should leakage occur the gas will diffuse into the air and the radioactivity will go to a background level very rapidly. Also, Kr-85 is an inert gas and will not readily combine with other substances. This means if you were to inhale the gas you would just exhale it right back out. Calculated radiation dosage levels for a user who literally spends all day, 5 days a week within 6 inches of a neutralizer are well below allowed exposure limits. TSI holds a Nuclear Regulatory Agency (NRC) General License for the neutralizers under which the user of device is listed as a “General Licensee.” This is why we require the end users name and address when a 3071A is purchased. There are no other license requirements from the (NRC), but their may be additional state, local or institutional license requirements. The user is responsible for checking for these.
Why is the upper limit of the classifier 1.0 µm?
Particles larger than 1.0 µm will carry too many multiple charges even after neutralization for this technique to be effective. Along with particles of the size you wanted, the classifier would also give you particles of other sizes that carry multiple charges, making it no longer a monodisperse generator.