Sensors · Specialty Air Analyzers
Durridge RAD7
Specialty Air Analyzers
The DURRIDGE RAD7 is a continuous radon/thoron monitor. It collects alpha emitters electrostatically and analyzes their energy spectrum on a PIPS solid-state detector, measuring radon from 0.1 to 20,000 pCi/L (4–750,000 Bq/m³) in pCi/L, Bq/m³, or cpm, plus internal sample temperature and humidity. Discontinued by DURRIDGE in 2026 and superseded by the RAD8, but still integrated over RS-232.
Measures
What the Durridge RAD7 Measures
3 parameters, each linked to its page: the sensors, units, and standards behind it.
Connects via Thiamis
Models
Durridge RAD7 Models
1 model, with what it measures and the ranges from its datasheet.
| Model | Description | Measures & specs |
|---|---|---|
RAD7 | Continuous electronic radon/thoron detector using electrostatic collection and alpha spectroscopy on a PIPS detector (0.1–20,000 pCi/L). Offers SNIFF, NORMAL, AUTO, THORON, GRAB, and WAT modes and reports internal sample temperature and humidity. RS-232 serial (integrated at 9600 baud) plus USB adapter. Discontinued in 2026, superseded by the RAD8; existing units remain field-supported. |
Standards
Standards for What It Measures
Standards that set limits on the parameters it reports.
On the platform
What the Durridge RAD7 Gets From Aethair
Connected through Thiamis, its readings arrive in the same Environet account as Aethair's own monitors.
Live data and alerts
Environet shows the instrument live and alerts the people you choose by email, SMS, and webhook, at the thresholds you set. Noesis sets up a dashboard, a report, or an alert from a plain-text request.
Compliance reports
Aethair Reports produces scheduled or on-demand reports from the instrument's readings, as a PDF or secure link. Templates cover Aethair Blue, WELL v2, cabin air (ISO 23875), and the CMS-2567 healthcare codebook (ASHRAE 170), or you can report against custom limits such as OSHA PELs, NAAQS, EPA guidance, or your own program limits.
Dashboards and the app
Environet dashboards and the Aethair App show the instrument's readings just like any Aethair device. The occupant-facing Aethair Dashboards status display is built around Aethair IAQ and Aethair PRO.
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Questions
Durridge RAD7 FAQ
How does the RAD7 detect radon?
It draws a sample into a hemispherical chamber and electrostatically collects the charged polonium daughters of radon onto a PIPS (passivated ion-implanted planar silicon) solid-state detector. It then identifies them by alpha-particle energy (alpha spectroscopy). Separating isotopes by energy rather than simply counting lets it distinguish radon (via polonium-218/214) from thoron (via polonium-216) and reject interference.
What is the difference between SNIFF and NORMAL mode?
In SNIFF mode the RAD7 counts only polonium-218 (half-life about 3 minutes), giving fast response and recovery at lower sensitivity (~0.25 cpm per pCi/L), best for locating radon entry points. In NORMAL mode it also counts polonium-214, roughly doubling sensitivity (~0.50 cpm per pCi/L) but responding more slowly. AUTO starts in SNIFF and switches to NORMAL after three hours.
Can the RAD7 measure thoron as well as radon?
Yes. In THORON mode it measures thoron (radon-220) simultaneously and independently of radon (radon-222), separating the two by the alpha energy of their polonium daughters. The Thiamis integration ingests the radon-222 concentration channel.
What units does the RAD7 report radon in?
The integration exposes radon as pCi/L, Bq/m³, or cpm (counts per minute), selectable per device (default pCi/L). For context, the US EPA action level is 4 pCi/L and the WHO reference level is 100 Bq/m³.
How does the Thiamis integration communicate with the RAD7?
Over the RAD7's RS-232 serial port at 9600 baud. On connection the driver sets the measurement cycle, units, and mode and keeps the pump running; after each completed cycle it reads the new run with a DATA COM command and clears it from the instrument's log. Internal signals the RAD7 also reports (battery voltage, pump current, high voltage, leakage) are used for device health only and are not cataloged as measured parameters.
Is the RAD7 still available, and is its replacement supported?
The RAD7 was discontinued by DURRIDGE in 2026 and replaced by the RAD8; existing RAD7 units remain integrated over RS-232 and field-supported. The RAD8 is a redesigned instrument. It connects over USB rather than the RAD7's RS-232 serial port and does not use the RADLINK 'Special' command set this driver relies on, so it is not covered by the RAD7 integration and would need its own driver.
Sources: durridge.com
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