The DURRIDGE RAD7 is a truly versatile radon and thoron detector used by research scientists and professionals worldwide. Its mature and yet still state-of-the-art design match or exceed those of the most expensive radon measurement devices in the world. At the same time, it incorporates a number of exclusive features that are found in no other radon detector, regardless of price. Incredibly, the RAD7 is affordable.

The RAD7 is a sophisticated measuring instrument widely used in laboratories and research work around the globe. It is used by professional radon testers, mitigators and home inspectors, as well as by research scientists studying groundwater, mines, deserts, the ocean and volcanoes at extreme temperature. A rugged carrying case encloses the instrument, ensuring reliability in the field.

The RAD7 is the easiest electronic radon detector to use, with preprogrammed setups for common tasks. The instrument comes complete with a built-in air pump, rechargeable batteries, and a detachable wireless printer. The RAD7 can store large amounts of radon data for later printing and/or for graphing and analysis on a computer using DURRIDGE's powerful and free CAPTURE software.

The RAD7 is a Sniffer that detects the 3-minute alpha decay of a radon daughter, without interference from other radiations. It also detects the instantaneous alpha decay of a thoron daughter for rapid thoron measurements. The instrument can sniff for entry points and radon gushers, and it recovers from high radon exposures in minutes. The RAD7 is also a Continuous Radon Monitor which can measure the EPA action level of 4 pCi/L, with 10% standard deviation, in under two hours. At the end of each run, the detector prints out a complete report.

The included accessories are sufficient for the measurement of radon and thoron in air. Additional, optional accessories are available for the measurement of radon in soil gas and water, for the measurement of the emission of radon from surfaces, objects and bulk materials, and for other specialized applications. See the Products Overview page for details.

RAD7 Advantages

Precision and Performance

• Fastest response and recovery times of any electronic monitor/sniffer on the market.
• Measures EPA action level of 4 pCi/L in under two hours.
• Recovers from radon highs in minutes - not hours.
• Spectrum printout verifies correct operation of instrument in field.

Convenience and Ease of Use

• All-in-one complete, compact, portable unit in rugged carrying case.
• The instrument directs you step by step, so you can do what you want to do.
• Programmed set-ups for often-used tests.
• Audible radon and thoron counts lets you hear the hot spots.

Security and Flexibility

• Tamper-proof key-lock command secures your RAD7 and assures uninterrupted testing.
• Easily portable: The RAD7 weighs 9.6 pounds (4.35 kg).
• Displays, prints, and downloads radon data in your choice of units.
• Immunity to build-up of 210pb.

Expandability and Value

• Includes wireless printer and infrared data link for on-the-spot printouts.
• Available with a wide range of optional accessories for measuring radon in water and below ground.
• Versatile connectivity with an RS-232 port and USB adaptor
• Includes CAPTURE software for data retrieval and analysis. Full Windows and macOS compatibility.
• Includes rechargeable batteries and extensive documentation.

Testing for radon in soil gas with the RAD7. Research overseen by Kizito M. Opondo, Kenya Electricity Generating Co. Ltd.

Geologist Kenneth Sims using a RAD7 on the rim of a volcano. Photo by John Catto.

Operating the RAD7

The RAD7 is remarkably easy to use. When you turn it on you will see current settings listed on the LCD display. This allows you to check that the instrument is configured as needed for your intended use. Presets are available for 1-day and 2-day tests, and you can also establish a custom preset for your particular job. When you arrive at the testing site just select a preset and the RAD7 will start collecting data immediately.

An exclusive RAD7 feature is the ability to automatically switch between "Sniff" and "Normal" modes. The instrument starts in "Sniff" mode, providing a quick response, base-line reading. After 3 hours enough radon progeny will have accumulated on the detector for the RAD7 to be able to switch to "Normal" mode, providing higher statistical precision.

Once started, the RAD7 can be "locked" to prevent it from being tampered with until you return. When the RAD7 is locked it will become unresponsive to user input, but the radon test in progress will continue without interruption.

Thoron Measurement Capabilities

The RAD7 is capable of making a direct and specific measurement of thoron, which is a short-lived isotope of radon. Testing for thoron is a great way to identify the points at which radon is entering a building, because the thoron is localized to those entry points. The RAD7’s response to thoron is virtually instantaneous, and compared to other instruments the RAD7 is much less susceptible to radon-thoron interference, thanks to its ability to distinguish the isotopes by their unique alpha particle energies. See Section 4.5 of the RAD7 Manual and the following Application Note for details:
Application Note: Sniffing for Thoron (HTML)

USB and Bluetooth Connectivity

Stored RAD7 data may be downloaded to a computer using a USB or serial connection. DURRIDGE offers a dedicated RAD7 communications software package called CAPTURE, which automatically transfers RAD7 data to disk, displays radon graphs, and produces a variety of supplementary information. CAPTURE can also monitor a RAD7 in real time with its Chart Recorder. Learn more about CAPTURE here.

For situations where the RAD7 can not be directly connected to a computer, DURRIDGE offers the Parani SD1000 Serial to Bluetooth Adaptor. This adaptor offers a 100 meter wireless range, and it comes pre-configured for plug and play compatibility with the RAD7 and CAPTURE. An optional 16 hour battery allows the adaptor to be used even in the absence of a reliable power source.

RAD7 Specifications