Troxler 3411-B, Manual Of Operation And Instruction

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Appendix B-6
Radiation Safety
This section provides a brief discussion of general radiation
safety. The exposure profile for a 3400 series gauge is also
included, along with a discussion of the source encapsulation.
TYPES OF RADIATION
The radioactive sources in a 3400 series gauge produce three
types of radiation:
Alpha Particles
Photons
Neutrons
The alpha particles are stopped by the source capsule. Only the
photon and neutron radiation contribute to the occupational
radiation exposure.
Photon radiation is electromagnetic radiation, as are x-rays,
radio waves and visible light. Visible light and photon have no
mass, a zero electrical charge and travel at the speed of light.
Photons are energetic and penetrating. Dense materials provide
the best shielding against photon radiation.
Neutron radiation allows measurement of the hydrogen (water)
content in a material because the neutrons are slowed by
collisions with materials containing hydrogen atoms (e.g., water,
polyethylene). Neutrons have a neutral charge and are very
penetrating.