Many industries require powerful neutron sources for fuel and data analysis. As its name suggests, a neutron source is any device that releases neutrons, including radioactive isotopes such as californium-252 (Cf-252), particle accelerators, and sealed-tube neutron generators. They are used for analytical and exploratory operations in physics, medicine, biology, chemistry, and nuclear power production, among other applications. Technologies that employ neutron sources can be classified as small, medium, or large devices; these device types emit various energy levels and neutron volumes. Depending on the source and its use, the overall cost of ownership and maintenance, and applicable government regulations will vary. 

As an alternative to Cf-252, some industries employ neutron generators. In this blog, we will talk about some of the differences between Cf-252 and neutron generators as neutron sources.

About Californium-252 Neutron Sources

Californium-252 Neutron Sources

Californium was originally discovered in 1950 at the University of California Radiation Laboratory in Berkeley by bombarding curium with alpha particles. While most californium radioisotopes do not have much practical value, californium-252 has become a nuclear industry standard for use in nuclear startup rods, as well as for material analysis and data collection. Cf-252 is produced by the Oak Ridge National Laboratory in Tennessee using their High Flux Isotope Reactor (HFIR). 

HFIR produces the californium-252 isotope by irradiating curium targets with alpha particles. The same end goal can be achieved through long-term irradiation of plutonium and americium, but these methods take more time and produce Cf-252 in significantly smaller amounts.

Because Cf-252 is an exceptionally strong neutron emitter, it exhibits a short half-life. It is a soft, silver-white substance with a metallic sheen and a melting point of approximately 900°C. 

Cf-252’s radioactive nature is both its greatest benefit and most critical hazard. The isotope can release 170 million neutrons per minute, which makes it an excellent neutron source for energy fuel and data analysis needs—however, this level of radiation makes it extremely hazardous to the human body. For this reason, Cf-252 must be created, transported, and stored within specialized Type-A radioactive shipping containers

Californium-252 is used in a broad range of applications and industries that can draw data from neutron emissions. Some of the most common applications include. 

  • Nuclear Reactors. Cf-252 is well-suited as a source of stable neutron emissions used to initiate nuclear chain reactions in nuclear reactors.
  • Oil Well Logging. Cf-252 neutron emissions help the oil and gas sector to map underground features for oil drilling.
  • Material Detection. Neutrons from Cf-252 can be used to detect and analyze materials and processes for defects that are not readily apparent. 

Although it is an excellent neutron source, Cf-252 does present some disadvantages. It has a 2.6-year half-life, which means that depleted sources of Cf-252 must be replaced every 2.6 years. Since the isotope is not found in nature, it must be synthetically manufactured in a highly specialized facility with very specific equipment. In addition to the necessary production conditions to ensure top quality sources, the highly radioactive nature of Cf-252 requires specialized packaging and transport methods, which contributes to higher costs. 

About Neutron Generators


Neutron generators are neutron sources that produce neutrons through the use of linear particle accelerators. While Cf-252 spontaneously radiates neutrons, neutron generators initiate fusion reactions by fusing hydrogen isotopes. Neutron generators are typically composed of a neutron source, a particle accelerator, and a target. Deuterium or tritium isotopes are propelled through the accelerator into a metal hydride target that contains the same isotopes. The resultant fusion releases neutrons which can be used in detection and analytical applications.

Neutron generators are electrically powered and can therefore yield a high number of neutrons in a steady stream when the equipment is operating reliably. Unfortunately, neutron generators are largely affected by external environmental factors such as power loss, vibration, and temperature fluctuations. In addition, the complexity of the system and number of components increase the risk of failure and problems due to part deterioration. 

Since they require a great deal more equipment than radioisotopes, neutron generators tend to take up much more space, which can make them difficult to incorporate into confinement requirements in operations such as mining and oil drilling. They also require more maintenance over time, as generator tubes tend to burn out quickly and are expensive to replace (offsetting initial lower prices). Coupled with the potential for malfunction due to shock and heat fluctuations, neutron generators may offer less reliability than radioisotope neutron sources. 

Key Differences Between Californium-252 and Neutron Generators

The primary differences between Cf-252 and neutron generators include ease-of-use and cost. Although generators may be less expensive to procure initially, they require more maintenance in the long-term and are less reliable than Cf-252 sources. The potential for error and system failure is significantly higher for neutron generators; not only does this reduce the reliability of the system, it increases overhead for time, labor, and repairs. Powerful radioisotopes such as californium-252 offer a more reliable and intense source of neutrons. Overall, Cf-252 is considered an excellent alternative to neutron generators in every aspect apart from upfront cost. 

(Click to Expand)Californium 252 vs. Neutron Generators What Are the Differences

Neutron Sources at Frontier Technology Corporation

At Frontier Technology Corporation, we offer top quality californium-252 neutron sources for industries around the world. For more than 30 years, FTC has been a premier provider of reliable, cost-effective neutron sources and Type-A shipping containers for everything from nuclear reactors to oil and gas drilling. To learn more about the differences between californium-252 and neutron generators or about our neutron sources and capabilities, reach out to us today.