Cerex Monitoring Solutions, LLC.

- Model Shepherd FTIR - Portable Multi-Gas Analyzer System



Real-time, laboratory quality results in a fully portable package. The Cerex Shepherd FTIR portable multi-gas analyzer represents the leading edge of portable gas analysis.

No other commercially available portable FTIR matches the Shepherd FTIR’s specifications:

  • 385 Detectable Gas Species
  • 100+ USEPA HAPs
  • Low PPB Detection Limits
  • 22 Meter Sample Path
  • Cryo-cooled MCT Detector
  • 1 Wavenumber Resolution
  • Integrated Ethernet / WiFi
  • PC or Smartphone Remote Control

Industry Leading Performance only a Cerex System can deliver...

The Shepherd FTIR utilizes an ultra-sensitive cryo-cooled MCT detector system for sensing minute changes in IR absorption due to the presence of trace concentrations of individual gases. The result of coupling our proven detection system with a 20 meter internal optical sample path and CMS real time analytic software is an industry leading FTIR multi-gas analyzer. Offering true ppb detection limits in a simple to operate portable package, in practice, only the Cerex cryo-cooled system can reliably deliver unattended, continuous real time monitoring of ultra low ppb concentrations of individual gas species with absorption features spanning the IR spectrum from 2 to 14 microns. There are no additional costs for sample handling, wet chemistry, carrier gas , sorbent filters or tedious ongoing calibrations. There are none of the constant maintenance costs or extra work associated with the handling of, or regulatory compliance issues arising from the use of liquid nitrogen coolant. Results are immediate, and the raw data containing all the information necessary for gas identification and quantification is always saved. Low cost of ownership is achieved through a three year routine maintenance cycle.

For twenty years Cerex has manufactured the premier open path FTIR analyzer: Our AirSentry FTIR. With so many installations among diverse users worldwide, Cerex has received high quality feedback from Industry, Government, Engineers, Operators, Systems Integrators and Scientists operating our FTIR analyzers. We listened - The Shepherd FTIR offers features and a variety of configurations for flexible operations. An internal cell, long life consumables, a simple user interface, simplified networking and unknown gas analysis software.

The touchscreen interface, intuitive controls, large buttons, multiple analysis routines, advanced signal smoothing and low ppb detection limits make the Shepherd FTIR ready to meet a broad spectrum of monitoring requirements, with the flexibility to meet the needs of field technicians as well scientists.

  • Integrated Computer with Windows
  • Simultaneous multi-component detection
  • Full functionality of a PC
  • Inherent calibration
  • Touchscreen Interface
  • Internal cell for QA, or user specific calibration
  • Integrated WiFi and Ethernet Networking
  • Easily configured for your application
  • .CSV data file output
  • User configurable acquisition cycles, alarms
  • Raw data files are always saved
  • Audible, Visual and Email alarm functionality
  • Software for reference file creation
  • Software for unidentified gas analysis

FTIR Principle of Operation...
The Shepherd FTIR operates by sending a beam of infrared light through a twenty meter sealed sample cell within the instrument. The IR beam is directed by a series of optics to an ultra-sensitive MCT detector where the absorption due to target gases is measured and recorded. A classical least squares regression analysis compares the measured absorption spectrum to calibrated reference absorption spectra files. Beer’s law is then used to determine gas concentrations.

Unrivaled Detection Capabilities of Individual Gases...
The Cerex detectable gas library consists of 385 compounds, including many of the most scrutinized hazardous air pollutants. The wide measurement spectrum makes detection of individual species simple. You can know the concentrations of the species you are required to monitor, without erroneous concentrations due to cross interference.


Powerful Communication Features

Internal and external USB ports make the addition of optional USB peripherals such as GPS, Cellular Modem or even a Streaming Webcam possible. This flexibility adds powerful real time monitoring, automated data reporting and automated alarm reporting functionality. The Shepherd FTIR may be deployed and environmental conditions monitored by onsite personnel as well as remote decision makers via any PC or smartphone with an internet connection.

Simplified Process Control Integration, Industrial Communication, Control Outputs, Data Acquisition Inputs

The Shepherd FTIR is available with user specific control outputs, as well as MODBUS, Serial and analog outputs to allow simple and direct integration with existing data acquisition and control systems.

Core Data Acquisition and Integrated Meteorological Monitoring

With optional inputs the Shepherd FTIR is easily configured as a data acquisition system to allow logging and communication capabilities to be extended to particulate analyzers, ancillary sensors, external analyzers, and more. Definitive source support is available by ordering a Shepherd FTIR analyzer with integrated temperature and 3-D ultrasonic wind modeling hardware. All data parameters are integrated into CMS data tables, and the anemometer is tripod mounted for rapid deployment.

External Battery Systems

The Shepherd FTIR smart charger will charge and maintain the internal lithium polymer battery while simultaneously supplying power for continuous monitoring. Ready to go at a moments notice, a variety of optional external batteries are available to extend continuous monitoring capability in the absence of power.

General parameters

  • Measuring principle: FTIR
  • Performance: Simultaneous analysis of up to 50 gas compounds
  • Response time, T90: Typically < 120s, depending on the gas flow and measurement time.
  • Operating temperature: Short term 0-40⁰C, long term 5-30⁰C, non-condensing
  • Storage temperature: -20⁰C-60⁰C non-condensing
  • Power supply: 100 to 240 VAC/50-60Hz
  • Run Time: 3 Hour Battery, Continuous AC
  • Power consumption: Average 120W; Max 300W


  • Resolution User configurable: 0.5cm-1, 2cm-1, 4cm-1, 8cm-1, 16cm-1, 32cm-1
  • Scan frequency: 6 scans/s
  • Detector: Standard: Sterling Cooled MCT, (Optional Application Dependent: 2 stage Peltier cooled MCT)
  • Source: SiC, 1550K
  • Beamsplitter: ZnSe
  • Window material: ZnSe
  • Wave number range: 600-4200 cm-1

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