Radon and radon-thoron ratios can help indicate distance of glacial transport of radioactive material.

  • Airborne and ground gamma-ray and gamma-ray spectrometer surveys find "boulder trains", trains of radioactive material transported "down-ice" from bedrock sources.
  • Boulders are commonly transported further than finer material. Also, as transport distance increases, finer material is mixed with other non-radioactive fine material. The radioactivity is diluted and not easily detected.
  • High values of radon and radon-thoron ratios are due to radioactivity in fine grained material (local).
    High gamma-ray values are more likely due to larger chunks and boulders (distant).
  • Just west of the Midwest Lake deposit boulders of radioactive pegmatite are exposed on the top of an esker. These boulders give an airborne gamma-ray anomaly that is unrelated to the Midwest deposit and far down ice from the bedrock source. The real boulder train, which led to the discovery, is immediately south, "down-ice" of the Midwest deposit. The radioactive boulders here are angular, friable and weathered, and visual inspection reveals that they have not travelled far. This valuable boulder train contains sufficient fine-grained radioactive material to give a strong radon anomaly, reinforcing the conclusion that the bedrock source was not far "up-ice".
  • When examining these glacial dispersion trains by soil geochemistry, we expect that, at least in the case of organic soils, radium would give a better indication of nearby uranium mineralization than would uranium. Radon in soil gas would, in turn, reflect the radium content of the soil.

  • 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 (www.finderschoice.com/rn) 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.
January 27, 2010
Click here for technical details and other applications of our radon instruments.

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