APDCAM User’s Guide
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1. Introduction
APDCAM is a 4x8 pixel Avalanche Photodiode Detector camera containing all detec-
tor infrastructure and data acquisition in one compact package. This type of detector is
designed for special applications where low light level has to be measured with extreme
high speed (up to several MHz). The detector pixels have large area (1.6x1.6 mm) com-
pared to CCD sensors therefore they are easier to match to low f-number optics used in
low light applications. All pixels of the detector are read out simultaneously; therefore the
throughput is not limited by readout time. The intrinsic gain of the detector allows meas-
urement under conditions where photodiodes would not be applicable. Stable gain is pro-
vided by the temperature stabilised detector and the calibration process is made easy by
the built-in shutter and calibration light source.
The digital part of the camera contains individual Analog to Digital Converters for all
32 channels. These ADCs continuously digitize data with 14 bit resolution and 10-50
MHz frequency. The resulting data stream can be digitally filtered and downsampled in
the camera to provide an output data stream with a frequency band matching the final
sampling rate. Various triggering and sampling schemes are available for the data acqui-
sition, including external, internal, post-trigger, external sample control. The resampled
data stream is transferred to a Personal Computer via standard 1 Gbit Ethernet communi-
cation, either over UTP or fibre cable. The same connection is used for camera control.
Technical specifications of the system are shown in
Table 1
and
Table 2
.
Figure 1.
shows photos of APDCAM where the location of its elements are indicated.
1.1.
Using this document
Section 2 briefly describes the information needed for setting up and operating the
camera. Section 3. contains a detailed reference documentation intended for software
developers and for advanced users.