AmBe Americium-Beryllium neutron source
Published: Oct 22, 2023
An AmBe (Americium-Beryllium) source is a special type of industrial neutron source. It is made in the form of a capsule which contains a finely blended powder of radioactive Am-241 (Americium) and Beryllium (Be). The AmBe source works on the interaction of the alpha particles from the Am-241 with Beryllium:
The neutrons formed are emitted in the energy range of 0.1 - 11 MeV, with an average energy of 4.2 MeV.
Typical neutron output can be specified as 2.2 x 106neutrons/s per 37 GBq (1 Ci). The half-life of the source is 432 years (i.e. based on Am-241); the source usually has a recommended working life of 15 years.
Typical dose rates will be in the order of 0.7 micro Sv/hr at 1 m per GBq (gamma) and 0.6-0.7 micro Sv/hr at 1 m per GBq (neutron). Knowing the neutron and gamma dose rates per known activity is useful when determining the transport index (TI) - this is required when transporting the packaged source around.
Typical applications include:
- Well logging
- Industrial gauges
- Porosity / moisture measurements
- Prompt Gamma Neutron Activation Analysis (PGNAA) - security applications
Typical source activities available range from around 37 MBq-740 GBq (1 mCi to 20 Ci). Note that where the Am-214 activity exceeds 60 GBq then the source becomes a High Activity Sealed Source (HASS). More Ionactive resource on HASS sources can be found here: 5. High Activity Sealed Sources (HASS).