Performance of a New Commercial Electrical Mobility Spectrometer

Figures & data

FIG. 1 Schematic drawing of the Grimm 5.4-900 DMA. All dimensions are given in millimeters.

FIG. 2 Experimental setup used for the determination of the counting efficiency.

FIG. 3 Measured counting efficiency of the TSI 3010 CPC (d ₅₀ = 10.9 nm) together with previously published data for the same instrument.

TABLE 1 Cutoff diameters for all instruments used

Model	d 50	Material	Source
TSI 3025	3.1 nm	NaCl	Kesten et al. (1991)
TSI 3010 ^a	5.7 nm	NaCl	Russell et al. (1996)
Grimm 5.403	7.5 nm	NaCl	This work
TSI 3022	8.3 nm	NaCl	Ankilov (2002b)
TSI 3010	10.9 nm	NaCl	This work
TSI 3010	10.5 nm	Ag	Mertes et al. (1995)
TSI 3010	10.3 nm	Ag	Buzorius (2001)
TSI 3010	11.9 nm	Ag	Wiedensohler et al. (1997)

FIG. 4 Counting efficiency for NaCl particles for different commercial CPCs. The two measurements for the Grimm 5.403 CPC were taken two years apart. The TSI 3010 CPC used by Russell et al. (1996) was operated with a higher temperature difference of 25 K between saturator and condenser.

FIG. 5 Experimental setup used for the determination of the concentration-dependent CPC response.

FIG. 6 Results of the concentration comparisons in the single-particle count mode. All concentrations below 10⁴ cm⁻³.

FIG. 7 Results of the concentration comparisons against a reference concentration calculated from the concentration measured by a TSI 3010 CPC in the single-particle count mode behind an injector diluter.

FIG. 8 Experimental setup used for the determination of the CPC time response.

FIG. 9 Time responses of the Grimm 5.403 CPC (the initial dead time is not shown) for a concentration step for three different starting concentrations N₀, neglecting the coincidence effect.

FIG. 10 Time response of the Grimm 5.403 CPC for a concentration step. The response can be approximated by a combination of the response for a PFR and an LFR, and it is described in Equation (2).

FIG. 11 Comparison of the step response of the Grimm 5.403, the TSI 3022 and the TSI 3010 CPCs. The solid lines represent fits according to Equation (3) based on the parameters given in Table 2.

TABLE 2 Parameters to describe the time response of three CPCs for a particle size of 100 nm according to Equation (3)

Model	a	τ PFR	τ CSTR1	τ CSTR2
Grimm 5.403	0.861	2.27 s	0.97 s	5.72 s
TSI 3022	0.859	2.03 s	0.71 s	7.32 s
TSI 3010	0.929	1.27 s	0.76 s	2.61 s

FIG. 12 Instrumental setup for the tandem measurements.

FIG. 13 Tandem signals for both Grimm 5.4-900 DMAs examined, downstream of a short Vienna DMA at a selected particle size of 52 nm.

FIG. 14 Height of the transfer function of the Grimm 5.4–900 DMA as function of the particle diameter. The solid line represents a fit to the measurement data.

FIG. 15 Area of the transfer function of the Grimm 5.4–900 DMA as function of the particle diameter. The solid line represents a fit to the measurement data.

FIG. 16 Full width at half maximum of the Grimm 5.4–900 DMA as function of the particle diameter. The solid line represents a fit to the measurement data.

FIG. 17 Comparison between loss-corrected tandem measurements (loss correction: Equation (6)) for the Grimm 5.4–900 DMA and simulated tandem signals based on Stolzenburg's diffusion-broadened transfer function for three different particle sizes and a flow rate of 0.3 l/min to 3.0 l/min.

FIG. 18 Size distribution of a NaCl Aerosol measured with the Grimm EMS system and the TSI SMPS model 3934.

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