What is a neutron probe and how does it work?

What is a neutron probe and how does it work?


muddy soil

Used to measure moisture levels in the ground

When it comes to trying to understand how much water is present within the ground, a neutron probe can be the perfect tool. This instrument is widely used across industries such as Geologging and farming, proving fundamental to the successful operating and management of their related processes.

How does a Neutron Probe work?

A neutron probe is a clever device which contains a pellet of americium and beryllium. The alpha particles from americium collide with that of the beryllium nuclei. This allows the detection of slow neutrons to take place, enabling the calculation of the amount of hydrogen present in the ground to take place.

Using such a device comes with both positives and negatives. Before you use a neutron probe it is important to try and understand exactly how it works and what to expect.


  • Soil moisture can be measured regardless of its physical state, meaning there are few limitations when undertaking the process
  • A neutron probe can read average moisture levels in an incredibly effective manner, as it has huge depth reaching abilities
  • The probe is highly coefficient with stored date, allowing the interfacing of automatic downloading of said data
  • Soil moisture changes are logged and measured to provide accurate information
  • Any sudden, unexpected or rapid changes can be detected very easily through its technological capability
  • Soil moisture changes can be logged and measured to give accurate information
  • The data that is recorded by neutron probes can be profiled in a safe and reliable manner through integration of other equipment


  • Depth resolution can create a measurement of moisture content a little harder, especially in heavily layered soils
  • Moisture measurements may be dependent on physical and chemical properties that have historically been difficult to measure with complete ease
  • There is associated health and safety risk with the process used with neutron probes, as dealing with probes that contain radioactive sources can prove dangerous if handled incorrectly
  • Immediate soil moisture towards the top of may not be reached in the neutron probes sphere of reach that could mean inaccurate results could be presented and cause problems associated with the top layers


Neutron probes are essential pieces of equipment that must be used by those needing to know the amount of water in the ground. For both oil/well/ wireline logging and farming process’ it is important that those that use this process understand the advantages and disadvantages, ensuring they can make required preparations and adjustments to ensure a smooth, safe process. There are a number of expert well and oil logging firms that can offer their services and advice in situations whereby you may be experiencing unfamiliar territory.


Image by 'wwarby' / Licence