Inversion of electrical mobility measurements using bipolar or unipolar chargers for the arbitrary distribution of channels--颗粒学报PARTICUOLOGY

Domat, M., Kruis, F. E., Azong-Wara, N. L., & Fernandez-Diaz, J. M. (2015). Inversion of electrical mobility measurements using bipolar or unipolar chargers for the arbitrary distribution of channels. Particuology, 20, 114–123. https://doi.org/10.1016/j.partic.2014.08.007

Inversion of electrical mobility measurements using bipolar or unipolar chargers for the arbitrary distribution of channels

M. Domat ^a *, F.E. Kruis ^b, N.L. Azong-Wara ^b, J.M. Fernandez-Diaz ^a

a Department of Physics, University of Oviedo, C/ Calvo Sotelo, s/n, E-33007 Oviedo, Spain
b Institute of Technology for Nanostructures (NST) and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Bismarckstr. 81, D-47057 Duisburg, Germany

10.1016/j.partic.2014.08.007

Volume 20, June 2015, Pages 114-123

Received 16 March 2014, Revised 1 August 2014, Accepted 15 August 2014, Available online 6 January 2015.

E-mail: maida.dro@gmail.com

Highlights

• Inversion of particle size distributions from electrical mobility data was analyzed.

• The transfer function in each size interval was geometrically estimated.

• Arbitrary voltage steps resulted in non-adjoining and overlapping transfer functions.

• Multiply charging was corrected to retrieve the singly charged particle distribution.

• Retrieval of the mean charge from a tandem DMA configuration was obtained.

Abstract

The inversion of the particle size distribution from electrical mobility measurements is analyzed. Three different methods are adapted for a dot-matrix approach to the problem, especially for non-square or singular matrices, and applied to electrical mobility measurements from fixed or scanning voltages. Multiply charged particles, diffusion losses, arbitrary voltage steps and noise were considered, which results in non-adjoining and overlapping transfer functions. The individual contribution of the transfer functions in each size interval was geometrically estimated, which requires only its characteristic mobilities. The methodology is applied to mobility measurements from particles charged with unipolar and bipolar chargers. However, the method can be extrapolated to any charging method with a defined charge distribution, and retrieval of the singly charged particle distribution and mean charge from a tandem differential mobility analysis configuration was successfully demonstrated.

Graphical abstract

Keywords

Tandem differential mobility analysis; Inverse problem; Regularization methods; Size distribution; Transfer function; Unipolar charger

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