chemical neutron source — Oil & Gas Glossary

An encapsulated radioactive material that emits neutrons for use in neutron porosity measurements. The most common source relies on alpha-beryllium reactions in a 241Am-Be mixture. Beryllium releases a neutron of approximately 4 MeV when struck by an alpha particle. The americium is the source of alpha particles. 253Californium fission is an intense source of 2.3 MeV neutrons but is used