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DensityPRO User Manual
A Cesium (Cs-137) radioisotope source is used for most applications, and a Cobalt
(Co-60) source is available for applications requiring a higher energy source. The
radioisotope is bound in ceramic or glass pellets and doubly encapsulated in a pair of
sealed stainless steel containers. The resulting source capsule is highly resistant to
vibration and mechanical shock.
The source capsule is further enclosed in the source head, a lead-filled, welded steel
housing. A shaped opening in the lead shielding directs the gamma radiation beam
through the process material towards the detector. Outside of the beam path, the
energy escaping the source head is very low and well within prescribed limits. Closing
the source shutter allows the beam to be turned off (the shutter blocks the radiation)
during installation or servicing of the gauge. All source housings meet or exceed the
safety requirements of the U.S. Nuclear Regulatory Commission (NRC) and
Agreement State regulations. Refer to the gamma radiation safety guide (P/N 717904).
The gauge uses a scintillator-type detector to measure the radiation reaching the
detector from the source. The detector consists of either a special NaI (sodium iodide)
scintillator material or a PVT (polyvinyl toluene) scintillator material coupled to a
photomultiplier tube with the associated electronics. When radiation strikes the
scintillator material, small flashes of light are emitted. As the density of the process
material increases, more gamma radiation is absorbed by the process material and fewer
light pulses are generated by the scintillator material. The photomultiplier tube and
associated detector electronics convert the light pulses into electrical pulses that are
processed to determine the process material density and related measurement values.
Communication with the gauge is via the RS485 and RS232 serial ports, USB, or
Ethernet from a PC running EZ Cal II software. Once the gauge is set up, the primary
measurement (density) can be viewed on the display and on the EZ Cal II software.
The display on the DensityPRO units provides measurement data to the user.
Figure 1-2. Measurement Data Display
Thermo Scientific
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