Amplified InAsSb Detector
Chapter 2: Description
Page 2
TTN010624-D02
Chapter 2
Description
The PDA10PT is an amplified, thermoelectrically cooled, switchable-gain, switchable-bandwidth, InAsSb
photoconductive detector. The detector is AC coupled and requires a chopped or pulsed input source. It is
sensitive over a wavelength range from 1.0 to 5.8 µm. Two eight-position rotary switches allow the user to vary
the gain in 6 dB steps and select low-pass filter bandwidth settings from 12.5 kHz to 1600 kHz. A buffered output
drives 50 Ω load impedances up to 5 V.
The detector is mounted on a thermoelectric cooler and factory set to cool the detector to -30 °C with a thermistor
providing feedback to maintain a constant temperature. This cooling provides higher detectivity (D*), which results
in a lower offset at the output and allows higher gains. It also reduces thermally generated noise. The housing is
used as a heat sink and includes a fan to increase the cooling capacity. It is important to note that the cooling fan
will keep the heat sink at room temperature. Without it, the heat sink will warm up, causing a higher temperature
drop from the heat sink to the detector element, resulting in larger TEC currents. Without the fan, the TEC current
will operate at its limit (~820 mA) and the detector element will no longer be temperature stabilized. Offsets will
increase and fluctuate, and output noise will increase. For best results do not block, limit airflow to, or stop the
cooling fan.
The detector housing has an internally SM1-threaded (1.035"-40) mounting aperture around the diode, which is
compatible with any SM1-threaded accessory. The device ships with a SM1RR Retaining Ring allowing
convenient mounting of optics, light filters, apertures, etc. The SM1-threaded mount can be easily integrated into
our cage and lens tube systems.
The PDA10PT has two 8-32 (M4) tapped holes for mounting the detector on a Ø1/2" optical post in one of two
perpendicular directions. The detector includes a 100 - 240 V, 50 - 60 Hz power supply.
