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NDIR_1Alphasense CO2 and Methane infrared sensors are supplied in the industry standard miniature (20mm diameter) gas sensor housing.

Patented optics give the best signal to noise ratio of any 20mm diameter NDIR and universal linearisation constants allow easy implementation.

The on-board temperature sensor allows for software compensation, including ideal gas law correction.


Choose between the IRC-A1 with dual channel pyroelectric detector or the IRC-AT with dual channel thermopile detector. These CO2 sensors are designed for IAQ, safety, combustion and high CO2 process control applications.

Application notes explain linearisation, temperature compensation and circuitry.

Both the IRC-A1 and IRC-AT cover the entire concentration range of measurement, simply implement the appropriate linearisation constants in software for your required range:

  • IAQ                      0 to 5,000ppm CO2
  • Safety                  0 to 5% CO2
  • Combustion          0 to 20% CO2
  • Process control     0 to 100% CO2

Methane/ Hydrocarbons

The IRM-AT uses a dual thermopile detector for measuring Methane and other Hydrocarbons in non-explosive environments. The plastic housing limits use to non-Ex environments up to 2.5% Methane.

Application notes

Download NDIR Application Notes – see application notes for full details.

Data sheets

Go to downloads page

File Name Description Type Download Link
IRM-AT Methane Infrared, thermopile Data Sheet
IRC-AT Carbon Dioxide Infrared, thermopile Data Sheet
IRC-A1 Carbon Dioxide Infrared, pyroelectric Data Sheet


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Download Data Sheets

Get data on our sensors Download Data Sheets

Download Application Notes

Get technical information Download Application Notes


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