All radium and radon in the earth comes from uranium. Therefore, radium and radon are more than pathfinders: they are direct indicators of uranium.

  • With half-lives of 1622 years and 3.8 days respectively, radium and radon are so short-lived that any originally present when the earth formed billions of years ago has decayed and what we find now is all a direct product of uranium.

  • It's the same nucleus, just a few protons and neutrons have been lost.

  • The same is true for all the other members of the uranium and thorium decay series, except for helium and some of the isotopes of lead, which are stable.

  • Each of the elements in these decay series has a different chemical behaviour. Lead is a metal, radium is an alkaline earth, and radon and helium are noble gases. Each has a different half-life.

  • The different chemistry and half-life means that each of these elements follows a different process in its separation from an orebody and formation of a geochemical anomaly, giving us a wide variety of geochemical techniques for uranium exploration. Radium and radon are particularly easy to analyse for.

  • Sometimes radon and radium are called pathfinders for uranium, as in mercury being a pathfinder for base metals, but it's more than that. As the same nucleus, they are direct indicators of uranium, just as direct as measuring the element uranium itself.

  • We measure: radon - radium - thoron - radon daughters - alpha radiation.
  • The Lucas cell is recognized as the most sensitive and reliable method for these elements.
  • Intrinsically safe functions.
  • Sensitive to geochemical trace levels necessary for radon in lake water and for radon-thoron isotope ratios.
  • immune to beta and gamma radiation.
  • one monitor works with a number of (less expensive) detectors.
  • Our instruments are used around the world in exploration for uranium, oil & gas, groundwater and hydrothermal, and in environmental protection, health physics, earthquake prediction, and evaluation of hydrocarbon and NAPL contamination etc.
  • Same instruments used for radon and radium in soil, sediment, plant parts, rocks, water, soil gas, air, snow, food, and for radon and thoron daughters in air.
  • Winter and summer, from the Sahara Desert to the Canadian Shield, our instruments have faced up to severe field conditions.
  • In the radon business since 1968, our instruments are updated regularly with the most recent major re-design in 2015. Modern, low-power, field-rugged electronics. Some earlier versions still working after 40 years.
  • Continuous real-time monitoring and data recording.
  • RS232 port/pc software.
  • User programmable measurement intervals, sample and count periods and alarm level settings.
  • Can work in a tent without electricity or be carried from point to point in the field.
  • 50 readings per day. Results available immediately.
  • Portable. Rechargeable battery pack good for a long day in the field and recharges in a few hours.
  • Can be operated by junior personnel if carefully supervised.
  • EPA and CE Mark compliant.
  • Click here ( for more details of our radon instruments, and for other instruments, components and accessories we provide.
  • Technical specification sheets and pictures of our instruments provided on request.
  • Multilingual consulting and training (if required).
For instruments contact

Robert H. Morse, Ph.D., P.Eng.
March 21, 2010
Click here for technical details and other applications of our radon instruments.

Copyright 1968 - 2018, R.H. Morse & Associates Ltd., all rights reserved.