Set up Your Detector for Different Gas Measurements

LASER COMPONENTS introduces five new bandpass filters for pyroelectric detectors, increasing the number of standard filters available to an outstanding seventeen versions. The new filters include reference filters (B) and filters for the detection of CO₂ (A), water vapor (M), methane (S), and alcohol (O), and are either mounted directly inside the fixed cap of the detector or available as a separate cap, which is then mounted to an existing pyroelectric detector.

A reference filter should not have any gas absorption. Filter B can be used when SO₂ is part of the gas mixture (peak wavelength = 3.86 µm, Bandwidth at half-power point (FWHM) = 90 nm).

The CO₂ filter A with an peak wavelength = 4.265 µm is the filter with the best possible signal and simple linearization (FWHM = 110 nm).

Water vapor is in almost every gas mixture, which often leads to a disturbing background noise. An attempt to measure this with a 2.94 µm filter, for example, lead to problems of cross-sensitivity with CO₂. The M filter has proven more reliable in such practical applications: peak wavelength = 5.78 µm, FWHM = 180 nm.

Methane is primarily measured at 3.33 µm; however, this is not particularly specific. An excellent alternative is the S filter, which operates at a longer-wave band: peak wavelength = 7.91 µm, FWHM = 160 nm.

With the increased popularity of breath alcohol measurement, the new standard filter (peak wavelength = 9.50 µm, FWHM = 450 nm) has become beneficial.

Further product information:
Choice of Filters for Pyroelectric Detectors

Contact:

Contact Person:	Uwe Asmus
Company:	Laser Components Germany GmbH
Address:	Werner-von-Siemens-Str. 15
ZIP / City:	82140 Olching
Phone:	+49 (0) 8142 2864-43
Fax:	+49 (0) 8142 2864-11
Email:	uwe.asmus@lasercomponents.com