D. Covert et al., PARTICLE CHARGING AND TRANSMISSION EFFICIENCIES OF AEROSOL CHARGE NEUTRALIZERS, Aerosol science and technology, 27(2), 1997, pp. 206-214
Diffusion losses and charging efficiency were measured for three types
of charge neutralizers commonly used in aerosol research: two with Kr
-85 and one with Po-210 as radiation sources. The diffusion losses wer
e characterized at flows of 0.5-6.1 min(-1) typically used in atmosphe
ric aerosol physics measurements. All of the neutralizers tested exhib
ited high transmission efficiencies, with losses up to 25% at the smal
lest tested size of 3 nm, varying with size and how in general agreeme
nt with diffusion loss theory. Charging efficiency was measured for a
singly charged, monodisperse aerosol at the same hows and at concentra
tions of 10(3)-10(4) particles cm(-3). Neither of the Kr-85 chargers b
rought the charge distribution close to equilibrium at 2 l min(-1), ex
cept at concentrations less than or equal to 10(3) cm(-3). The Po-210
charger produced the theoretically expected fraction of singly charged
particles within the uncertainty of the experiment. (C) 1997 American
Association for Aerosol Research.