HgCdTe (photovoltaic) 1 - 5.5 µm
The application field is equal to InSb, but without LN2 cooling. The typical 1/f noise does not occur with PV MCT detectors and are therefore ideally suited for distributed current and low frequency a
HgCdTe Detectors
Infrared detectors of the J19TE series by JUDSON are made of mercury cadmium telluride (MCT) and function according to the photovoltaic principle (PV), that is as a source of current.
This offers several advantages. For example, contrary to the photoconductive detectors we normally use, infrared detectors do not need a bias voltage. The 1/f noise that is characteristic of photoconductors does not occur. Therefore these detectors are especially well suited for DC and low frequency applications. They do not require a mechanical chopper and achieve a good linearity.
Versions
The detectors can be delivered with one-, two-, three-, or four-level Peltier coolers. Cooling reduces the noise and increases the detectivity (D*).
The high-end model of the series features an evacuated TO-3 can with an integrated four-level Peltier cooler and achieves D* values of up to 1 x 1011 at an operating temperature of -95 ºC. This comes close to the LN2 cooled InSb detector. A built-in thermistor watches the temperature.
Applications
Applications can be found in industrial process controlling, spectroscopy, and radiometry.
J19 Series
The J19 series has just been expanded to include the J19D11 option. These diodes come in a dewar, achieve a detectivity of at least 3.5 E10 (typically 4.5 E10), and are available with a 0.25 or a 1 mm active diameter. The 50% cut-off is at 10.5 µm.
