FAQ-NANO

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What is the Nano Division?

The Nano Division is in charge of the research, development and support of the equipment to measure airborne Nanoparticles. Most importantly, our Nano staff enables you to experience unrivalled results in precision, durability and flexibility of your measuring solution. Our systems measure in the Himalayas as well as in the jungles and deserts, on airplanes as well as on ships. Of course they also provide you with scientific data in your laboratory. Numerous comparisons have proven the reliability of this kind of measurement. GRIMM provides particle counters and sizers as well as particle generators ranging from 0.9 nm to >30 µm. Every single unit sold is fit to your personal needs and you will be advised by our specialists and by their knowledge due to our long expertise of measuring the smallest detectable aerosols.

What are the basic instruments and how can I combine them?

Grimm offers as basic modules:
Detection systems: Condensation Particle Counters (CPC) and a Faraday Cup Electrometer (FCE).
Classifiers, i.e. Differential Mobility Analyzers (DMA). We offer three different DMAs to cover different particle size ranges.
A unique feature is, that any DMA can be combined with any detection system. The new software supports all combinations. You can also combine any DMA with a sampling system (electrostatic precipitator).

What is a SMPS?

The Scanning Mobility Particle Sizer (SMPS) is an instrument for measuring size distributions of airborne Nanoparticles. It consists of a DMA and a detector (either a CPC or an FCE).

What is a CPC?

The Condensation Particle Counter (CPC), also called Condensation Nuclei Counter (CNC), is used to count individual Nanoparticles in air. The CPC enlarges the particles by condensation in order to enable the detection by an optical system.

What is a DMA?

A Differential Mobility Analyzer (DMA) classifies Nanoparticles. The applied voltage corresponds to a particle mobility (particle size) that passes through the DMA.

What is a FCE?

The Faraday Cup Electrometer measures the electric current carried by an aerosol flow. It is usually operated downstream the DMA to measure the concentrations of single charged particles.

What are the advantages of the new stationary CPC line compared to competitor models?

High concentration ranges with full accuracy in single count mode (0-150,000 particles/ccm). Operable in a wide range of ambient conditions (5 - 40°C). Activation of hydrophobic and hydrophilic particles down to a size of ~4 nm. Flexible configuration (with or without pumps, with or without SMPS controller, rack version or stand-alone). Comprehensive monitoring of instrument parameters to guarantee most reliable data

What are the advantages of the mobile CPC line compared to competitor models?

Three simple, but convincing facts: It is the only mobile high precision counter on the market, it is battery powered, and it is also extendable to a complete SMPS-system.

What are the advantages of a bipolar charger ("neutralizer") compared to an unipolar charger?

For a classical radioactive bipolar charger, charging probabilities do not depend on instrument parameters and the charger is considered as reference. The theoretical charging probabilities are well known and the unwanted contribution of multiple charged particles is low. Consequently, the calculated size distributions feature highest accuracy. A neutralizer using Am241 needs almost no maintenance and features a lifetime of many years.

When should I use a SMPS with CPC as detection system ("SMPS+C") and when a SMPS with electrometer ("SMPS+E")

This depends on the concentration range of the size distribution to be measured. The tresholds are roughly:
SMPS+E: ~104 - 108 1/ccm
SMPS+C (with CPC 541x) : ~102 - 107 1/ccm
SMPS+C (with CPC 5403) : ~102 - 106 1/ccm

An SMPS+E is normally used for emission measurements, an SMPS+C for measurements in ambient air. If your concentration range allows both SMPS+C and SMPS+E, consider the following advantages of an SMPS+E:

• More flexible size range due to the variable sheath air.
• Adjustable concentration range due to variable sample air.
• No consumables needed.
• Faster scan time (> ~1 min as compared to ~2 min for the SMPS+C).
• Cheaper (Contact your dealer).

Can I measure size distributions for concentrations higher than 106 - 108 1/ccm?

YES. However, such high concentrations have to be diluted before measuring. Therefore we developed the ESS hot gas dilution system with a dilution ratio of 1:10 or 1:100 at sample air flow of 1 l/pm.

Can I measure size distributions with sub-second time resolution?

YES, with the FAPES instrument. It is particularly designed for emission measurements with an integrated diluter and requires only a minimum concentration of ~104 1/ccm. Contact the Grimm office for further information.

Can I analyse the data any way I want?

The GRIMM Universal Nano Software calculates number-, surface-, and mass size distributions and for each type of distribution a variety of statistical data: Total concentration, mode diameter, median diameter, arithmetic and geometric mean diameter, diameter of mean surface and mean mass. The correction of CPC efficiency, DMA efficiency, and multiple charged particles can be switched on or off. The data can be easily exported as text files or as spreadsheet files.

Are there mobile units too?

YES, GRIMM offers mobile versions of the CPC and the SMPS which feature the same technical highlights and advantages like the stationary instruments.