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Differential Mobility Analyzer

Half Mini

High resolution analysis of nanoparticles and molecules

Differential Mobility Analyzer image

Product Description

A portable DMA for high-resolution classification of 1 nm particles

The Half-Mini DMA is the most recent and lightest (3.2 kg) member of a class of Yale-developed supercritical DMAs, later improved by SEADM, able to isolate with high resolution aerosol particles as small as 1 nm (including molecular ions). Its broad range of particle sizes (1-30 nm) is achieved with a single DMA configuration (2 cm long working section), greatly simplifying operation. Two Half Mini systems are available: the renowned (m) model and the brand new (p) model offering extended high resolution range.

New Half Mini (p) model

The new (p) model Half mini DMA [Fernandez de la Mora, J Aer Sci Tec, 2016] introduces substantial flow improvements over the prior (m) model. It operates under near ideal flow conditions over a much wider range of aerosol and sheath gas flow rates, enabling classification of 30 nm particles with a resolving power close to the ideal. This improvement relies on a new scheme for injecting the aerosol sample flow into the sheath gas flow with greatly improved axisymmetry. A comprehensive summary of the new improvements is available at our Half Mini Cells page

Acquisition of fast size spectra: A key advantage of the Half Mini DMA over other existing DMAs is its ability to complete mobility spectra exceptionally fast without distorsion of the size distribution. This advantage is due in part to the minimal particle residence time in the classification region (0.2 -2 ms), as well as to the high resolving power of the instrument (which yields almost the same residence time to all particles over the whole size range). Undistorted size spectra from 1 nm to 30 nm can therefore be obtained every 2 s [Fernandez de la Mora, Aer. Sci. Tec., accepted, Jan-2017].

Features and advantages

  • Unmatched size range for a high resolution instrument, recently extended beyond 30 nm by the (p) model (Fernandez de la Mora 2017)
  • Highest resolutions available in the market (see results of independent studies below)
  • Excellent transmission for enhanced sensitivity, see right (internal semiconducting tube bringing the classified particles to the grounded outlet)
  • Exceptionally fast delivery of mobility spectra without distorsion of the size distribution
  • Safe operation (internally protected high voltage)
  • Optimized flow dynamics technology to ensure laminarity even at high (Re > 20,000) flow
  • Diffusion broadening minimized
  • Robust architecture, mirror polishing, total thermal control
  • Stand alone operation (control and monitorization units built-in) directly connected to PC-USB

Size distributions of T.H. Ammonium Bromide (THAB) ions obtained with Half Mini and Nano-DMA in an indepedent study (Wang et Al, see Ref. 2014). Note the higher resolution of Half Mini enabling to identify all ions present in the sample
 

Size distributions of T.H. Ammonium Bromide (THAB) ions obtained with Half Mini and Nano-DMA in an indepedent study (Wang et Al, see Ref. 2014). Note the higher resolution of Half Mini enabling to identify all ions present in the sample.


Mobility spectra of the THA+ monomer measured with the Half Mini and with Nano DMA. The resolution, defined as the ratio Full Range/FWMH is almost three times bigger for the Half mini
 

Mobility spectra of the THA+ monomer measured with the Half Mini and with Nano DMA. The resolution, defined as the ratio Full Range/FWMH is almost three times bigger for the Half mini .

Applications and sectors

The instrument has been widely used for studies of Condensation Particle Counters (CPCs) sensitive to particles smaller than 3 nm, and other investigations involving pure nanometer size standards.
For users having a charge-reduction component (not provided by SEADM), the increased size range of this DMA (relative to earlier supercritical DMAs) permits high resolution analysis of charge-reduced biomolecules and small viruses produced by electrospray.
Range of applications include:

  • Environmental/pollution research
  • Atmospheric/climate research (Ref. Kangasluoma, 2014)
  • Indoor air quality control
  • Combustion (including particles produced by road vehicles)
  • Synthesis of nano-particles via gas or wet techniques (Ref. Wang, 2014 and 2015).
  • Nano-materials development
  • Biomolecules and viruses
  • Nano-particles applications: medical imaging, drug delivery, catalysis, etc.
  • Generation of particle standards (Ref. Attoui, 2013)

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Nano-particles studies

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Medical imaging

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Atmospheric research

Videos

Application of the Half Mini for sub-23 nm nanoparticles exhausted from cars

Related publications

Solid Nucleation Mode Engine Exhaust Particles Detection at High Temperatures with an Advanced Half Mini DMA.
14th International Conference on Engines & Vehicles. Capri (Italy), Sep. 2019.

Green Vehicles.
2nd European conference on road transport research projects results. Etterbeek (Belgium), Nov. 2018.

Cai R., Attoui M., Jiang J., Korhonen F., Hao J., Petäjä T., Kangasluoma J.
Characterization of a High-Resolution Supercritical Differential Mobility Analyzer at Reduced Flow Rates.
Aerosol Science and Technology (2018) 52, 11, 1332-1343.

Understanding, Measuring and Regulating Sub-23 nm Particle Emissions from Direct Injection Engines Including Real Driving Conditions.
PMP 48th session of UNECE. Ispra (Italy), Nov. 2018.

Papaioannou E., Zarvalis D., Melas A.D., Baltzopoulou P., Konstandopoulos A.G., Zamora D., Burtscher H., Fierz M.
Understanding and Measuring Sub-23 nm Article Emissions from Direct Injection Engines Including Real Driving Conditions.
The second edition of FORM Forum. Brussels (Belgium), Oct. 2018.

Understanding, Measuring and Regulating Sub-23 nm Particle Emissions from Direct Injection Engines Including Real Driving Conditions.
1st joint workshop on Measurement and characterisation of nanoparticle emissions from powertrains. Thessaloniki (Greece), Oct. 2018.

Kangasluoma J., Ahonen L. R., Laurila T. M., Cai R., Enroth J., Mazon S.B., Korhonen F., Aalto P. P., Kulmala M., Attoui M., Petäjä T.
Laboratory Verification of a New High Flow Differential Mobility Particle Sizer, and Field Measurements in Hyytiälä.
Journal of Aerosol Science (2018) 124, 1-9.

Amo-González M., Barrios-Collado C., Delgado R., Fernández de la Mora J.
A DMA Operating at 200⁰C for the Analysis of Engine Exhaust Nanoparticles.
Aerosol Technology 2018. Bilbao (Spain), Jun. 2018.

Fernandez de la Mora J., Amo-Gonzalez M., Barrios-Collado C., Del Castillo, J.C., Konstandopoulos A.G., Baltzopoulou P., Vlachos N.D.
Half-Mini DMA Modification for High Temperature Aerosols and Evaluation on Various Combustion Exhausts.
European Aerosol Conference. Zurich (Switzerland), Aug. 2017.

Carbone F., Moslih S., Gomez A.
Probing Gas-to-Particle Transition in a Moderately Sooting Atmospheric Pressure Ethylene/Air Laminar Premixed Flame. Part II: Molecular Clusters and Nascent Soot Particle Size Distributions.
Combustion and Flame (2017) 181, 329-341.

Attoui M., Fernandez de la Mora J.
Flow Driven Transmission of Charged Particle Against an Axial Field in Antistatic Tubes at the Sample Outlet of a Differential Mobility Analyzer.
Journal of Aerosol Science (2016) 100, 91-96.

Attoui M., Paragano M., Cuevas J., Fernandez de la Mora J.
Tandem DMA Generation of Strictly Monomobile 1–3.5 nm Particle Standards.
Aerosol Science and Technology (2013) 47, 5, 499-511.

Carbone F., Attoui M., Gómez A.
Challenges of Measuring Nascent Soot in Flames as Evidenced by High-Resolution Differential Mobility Analysis.

Aerosol Science and Technology (2016) 50, 740-757.

Fernández de la Mora J., Kozlowski J.
Hand-Held Differential Mobility Analyzers of High Resolution for 1–30 nm Particles: Design and Fabrication Considerations.
Journal of Aerosol Science (2013) 57, 45–53.

Fernandez de la Mora J.,
Expanded Size Range of High-Resolution NanoDMAs by Improving the Sample Flow Injection at the Aerosol Inlet Slit.
Journal of Aerosol Science (2017) 113, 265-275.

Fernandez de la Mora J., Perez-Lorenzo L.J., Arranz G., Amo-Gonzalez M., Burtscher H.
Fast High-Resolution NanoDMA Measurements with a 25 ms Response Time Electrometer.
Aerosol Science and Technology (2017) 51, 6, 724-734.

Oberreit D. R. , McMurry P. H., Hogan C. J.
Analysis of Heterogeneous Uptake by Nanoparticles Via Differential Mobility Analysis-Drift Tube Ion Mobility Spectrometry.
Physical Chemistry Chemical Physics (2014) 16, 15, 6968–6979.

Kangasluoma J., Kuang C., Wimmer D., Rissanen M.P., Lehtipalo K., Ehn M., Worsnop D.R., Wang J., Kulmala M., Petäjä T.
Sub-3nm Particle Size and Composition Dependent Response of a Nano-CPC Battery.
Atmospheric Measurement Techniques (2014) 7, 689–700.

Wang Y., Jiaxi F., Attoui M., Chadha T.S., Wang W.H. , Biswas P.
Application of Half Mini DMA for Sub 2 nm Particle Size Distribution Measurement in an Electrospray and a Flame Aerosol Reactor.

Journal of Aerosol Science (2014) 71, 52–64.

Wang Y., Liu P., Fang J., Wang W.N., Biswas P.
Kinetics of Sub-2 nm TiO2 Particle Formation in an Aerosol Reactor during Thermal Decomposition of Titanium Tetraisopropoxide.
Journal of Nanoparticle Research (2015) 17, 147, 1-13.

Product info

New Half Mini (p) model Half Mini (m) model

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Technical brochure (includes specs)

  • New Half Mini (p) model
  • Half Mini (m) model

Contents

  • Product Description
  • New Half Mini (p) model
  • Features and advantages
  • Applications and sectors
  • Videos
  • Related publications
  • Product info
  • Related products

Read our customer review

J. Kangasluoma

University of Helsinki

(Finland)

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F. Carbone

University of Yale

(U.S.A.)

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M. Attoui

University Paris-Est Créteil

(France)

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