Indium Antimonide Short Form Catalog in PDF Format
Click on any drawing on this page to
see enlarged version.
(Must have Adobe Reader to view these PDF drawings.)
J10D Series Indium Antimonide Detectors
J10D Series detectors are high quality Indium
Antimonide (InSb)photodiodes, providing excellent performance in the 1
to 5.5 µm wavelength region. Single crystal p–n junction technology
yields high speed, low noise detectors with excellent uniformity,
linearity and stability.
Applications
- Thermal Imaging
- Heat-Seeking Guidance
- Radiometers
- Spectrometry
- FTIR
InSb detectors are photovoltaic and generate current
when exposed to infrared radiation. Figure 2 shows the equivalent
circuit for InSb, including the shunt resistance RD, junction
capacitance CD and shot noise. The shot noise results from the DC
current IBG produced by the background infrared radiation. Because IBG
is proportional to the detector active area (Fig. 5), smaller detectors
have less shot noise and lower values of NEP.
|
|
|
Figure 1
|
Figure 2
|
Figure 3
|
Field of View: A standard cold field of view
(FOV) is provided at no extra charge. A custom field of view can be
supplied for a small extra charge. Detectivity can be improved and IBG
reduced by restricting the FOV angle. The FOV cold stop angle should be
chosen to restrict unwanted background radiation while still accepting
all desired radiation from the optical system. A 60° (full-angle) FOV,
corresponding to 1/F optics, is provided unless otherwise specified.
Cold Filters: Optional cold filters can improve
detectivity by eliminating background radiation in unwanted wavelength
regions. The D* performance with the SP28 cold filter (0.5-2.8µm) and
the SP35 cold filter (1.7-3.5µm ±0.3µm) is shown in Figure 1. Other
bandpass filters are available on a custom basis.
Dewar Packages: All J10D Series InSb detectors require
77°K operating temperatures. The detector comes mounted in the standard
M204 or M205 metal dewar with a sapphire window and a 60° field of view.
Other window and dewar options are available. All InSb detectors can be
provided in the LC1 Dewar Cooler Assembly or the RC2 Detector Cooler
Assembly for operation without bulk liquid nitrogen.
|
|
|
Figure 4
|
Figure 5
|
Figure 6
|
Custom Detectors: InSb detectors in any size up to 7mm
diameter and in any configuration can be provided on a custom basis.
Contact Judson for specifications for linear position sensors, quad
cells, and two-color (sandwich) detectors.
Preamplifiers: Optimum performance is achieved when
the InSb detector is coupled into a Judson transimpedance gain
preamplifier, which converts detector output current to voltage while
maintaining the detector at the optimum zero volt bias (Fig. 3).
The PA-9 preamplifier is specifically matched to each
InSb detector to provide maximum sensitivity, gain and bandwidth. The
lower-cost, adjustable gain PA-7 preamplifier is suitable for lower
frequency applications (DC-10KHz). When selecting preamp gain, choosing
the largest practical value of RF results in the lowest overall noise.
However, the detector IBG must be considered to avoid DC saturation of
the preamp.
Example: The J10D-M204-R01M has a background current (IBG)
of 7µA (from Fig. 5). Choosing RF= 1MW would result in a gain of 10E6,
for a DC output of (7µA x 10E6 V/A) or 7V. This is near the saturation
level of both the PA-7 and PA-9. Consequently, a gain of 10E6 is the
maximum useable DC gain with this detector. An AC-coupled second stage
may be added for further amplification. The background current IBG may
be reduced by adding a cold filter or reducing the field of view.
Click here to view table
Click for more information on HgCdTe/InSb sandwich detectors. |