Miniaturized Scanning Electrical Mobility Sizer

Model 9404


The miniaturized Scanning Electrical Mobility Sizer (mSEMS) allows you to perform ultra-fast particle number size distribution measurements on-board Unmanned Aerial Vehicles (UAV) and other mobile platforms where high time resolution is critical. The rapid time response is the result of a miniaturized differential mobility analyzer design coupled with the 0.18 sec response time of the aMCPC detector. Capable of scan times down to 5 seconds and a scan size range between 5 and 300 nm, the system is compact, light and uses minimal power. The size range has been optimized to provide overlap with the Model 9405 mOPC. Development of the mSEMS is built upon BRECHTEL’s decades of experience with traditional SEMS instruments and aircraft field studies. Deploy the 9404 in conjunction with our other portable instruments to get a more complete picture of the aerosol under study.

Key features:

  • Few nanometer to 300 nm particle size range
  • High size resolution
  • Compact, lightweight, low power use
  • Rapid scan times down to 5 seconds
  • Fast-response aMCPC detector
  • Good size overlap with mOPC
  • Self-contained with on-board data storage
  • No external pumps required

Technical Specs

9404 mSEMS Technical Specs

parameter value
Selectable particle diameter size range 0.005-0.3 μm
Size resolution (set by Qaer/Qsheath) Variable (10:1 typical)
Scan time range 5 secs to several mins
Sheath flow range 1 to 4 lpm
Aerosol sample flow range 0.36 or 0.72 lpm
Particle concentration range with aMCPC 1-10⁸ cm⁻³
Range of high voltage 0-3,000 Volts
Communications RS-232
aMCPC butanol use 1.9 ml/hr
Operating temperature -20-35°C
Operating Pressure (unpressurized cabin) 200-1,000 mb
Physical size ≈ 8.8 x 5.3 x 8 in/22.4 x 13.5 x 20.3 cm
Weight ≈ 4.85 lbs/2.2 kg
Supply voltage 12 VDC
Power usage with aMCPC ≈ 60 watts
Specifications subject to change. Expected release in 2018.

Copyright ©2017 All specifications are subject to change without notice. BMI assumes no responsibility for inaccuracies in this document or for any obligation to update information in this document. BMI reserves the right to change, modify, transfer or otherwise revise this publication without prior notice.

*Some products may be shown with optional accessories, which are sold separately. Items shown may not be to scale.

Applications and Solutions

  • Mobile platform sampling: UAVs, Balloons, Aircraft, Vehicles
  • Personal exposure monitoring
  • Climate change field studies
  • Air quality monitoring


Integrated software drives each ACCESS module from the inside – the built-in microprocessor and sensors are able to sense, control, and report on instrument performance. A serially-communicated stream of data provides real-time user access to all the fundamental operating parameters and measurement values. An on-board micro-SD card can be used to store data locally.

Add the Base Module option to your ACCESS package to benefit from a graphical user interface (GUI) that allows you to easily interact with the instrument so you can change parameter settings, configure outputs and view measurements on the screen of the PC. Multiple ACCESS modules can be connected via a micro-USB hub to the GUI allowing the system configuration to be easily changed. This feature also allows each of the connected modules to be remotely controlled via a single RS232 connection.The GUI software automatically recognizes which instruments are attached to the Base Module and adjusts accordingly. It is provided to facilitate configuration and monitoring of the ACCESS instruments on the

The GUI software automatically recognizes which instruments are attached to the Base Module and adjusts accordingly. It is provided to facilitate configuration and monitoring of the ACCESS instruments on the ground, but is not required to operate the unit and acquire data. The external GUI software is only available pre-loaded on a ruggedized tablet PC supplied by BRECHTEL.

What’s Included

  • Model 9404
  • LED Display
  • External 12 VDC power supply
  • Communication and power cables
  • Operating manual
  • Weatherproof shipping case


The following optional accessories are available:

9404 mSEMS Accessories

Part Number Description
ACC-PWR External 12VDC power supply for ground operation of any 94XX series instrument
ACC-mSEMSKit Maintenance kit for 9404-mSEMS
ACC-PC Computer with 94XX series control software
8008 Particle Round Jet Impactor, 0.5 μm cut size, 0.7 lpm flow
8009 Particle Round Jet Impactor, 1.0 μm cut size, 0.7 lpm flow
9000 Aerosol charge neutralizer body
9001 Non radioactive aerosol charging system (release date late 2018)
9002 Soft-Xray Charger
SEMS-DrySize Dry sizing package for SEMS, 110-230 V

Related Products

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