The PASCO TD-8553 Radiation Sensor (Figure 1)
measures the relative intensities of incident thermal
radiation. The sensing element, a miniature thermopile,
produces a voltage proportional to the intensity of
the radiation. The spectral response of the thermopile
is essentially flat in the infrared region (from 0.5 to 40
μm), and the voltages produced range from the microvolt
range up to around 100 millivolts. (A good
millivolt meter is sufficient for all the experiments
described in this manual. See the current PASCO
catalog for recommended meters.)
The Sensor can be hand held or mounted on its stand
for more accurate positioning. A spring-clip shutter is
opened and closed by sliding the shutter ring forward
or back. During experiments, the shutter should be
closed when measurements are not actively being
taken. This helps reduce temperature shifts in the
thermopile reference junction which can cause the
sensor response to drift.