TM 5-3610-285-14
a. The densitometer employs a technique whereby density of an unknown sample is converted to a time period. The
time period is precisely proportional to the density of the sample. Measurement of the time period results in a digital
readout which is calibrated in terms of density. The entire measurement cycle occurs within 1/60 of a second (60 Hz
power operation).
b.
A regulated power supply provides low voltage power for the filament lamp located within the reflection probe
housing. It also supplies low voltage power for the filament lamp located within the transmission probe housing when the
transmission probe is in use.
c.
Within the probe housing, light from the prefocused lamp is directed by a lens and mirror and caused to strike the
unknown sample. The light strikes the sample at a 900 angle relative to the surface. Diffused light that is reflected back
from the surface of the sample is collected by a group of fiber optic bundles. The bundles are spaced evenly between 0°
and 3600 at a 450 angle relative to the surface. Light collected by the fiber optic bundles is directed back to the
densitometer. The light then passes through a filter system, and is directed on the photosensitive cathode of the
photomultiplier tube.
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