Radon detectors - alpha track detectors, continuous radon monitors, scintillation devices, etc. - give us an idea of the concentration of Radon in the atmosphere. This is an important metric as radon harms the human body and can cause many serious illnesses including lung cancer.
To avoid over-exposure, you first have to know how much radon you are exposed to. To discover that, you need to perform a radon measurement. Many homeowners often get radon testing kits, or radon monitors, set up in their property. But how do Radon detectors work?
Keep on reading to find out!
How Do Radon Detectors Work?
Charcoal radon test kits absorb radon gas over a period of 2-90 days and are then sent for sampling in a lab. This is the cheapest method you can use to detect radon. However, this is also the most inaccurate as radon gas concentrations may rise/fall overtime depending upon the weather, humidity, etc.
Another tool used for radon detection is a continuous radon monitor. This device measures the radon gas in pCi/L and alerts the user if the value is above the set standard (4 pCi/L).
This technology relies on sensors that pick up the alpha particles released by radon gas into the air. This information is then converted into representable data which is shown on the digital display of your detector.
Detectors usually have a Teflon disc which is statically charged and stimulates when an ion generated from radon decay strikes it. This Teflon layer is then chemically treated to make the ion tracks visible.
Unlike test kits that need to be sent out to labs, there are many radon detectors which take continuous readings and show the real-time findings on the screen.
Properties of Radon Gas
Now that we know how a radon detector works, let us find out more about some properties of radon which makes it so unique.
Radon gas is invisible, odorless, and tasteless; thus, detection becomes quite tricky unless one uses a tool instead of relying on their senses. The United States Environmental Protection Agency advises having your house tested for radon before purchasing or renting it.
You can test for radon using "DIY" test kits or you can contact professional technicians and testers. However, any test you choose for detecting radon should be officially certified.
You can do the testing on a short-term basis (two to ninety days) or a long-term basis (90 days to a year). Keeping an interval between tests is essential as radon levels fluctuate depending on the time of day, the season, weather patterns, and the changes in pressure.
Suppose you need the findings of a test immediately. In that case, conducting a short-term test is preferable. That said, long term testing will provide more accurate results. These detection systems are usually installed in the basement since radon gas typically seeps into a house via the basement.
Radon Detector: Working Principle
Radon detectors detect alpha particles that fire off from the radon gas in order to calculate the concentration of radon gas. In other words, radon emits alpha particles, which are then detected by devices that come with a sensors tuned to catch the presence of alpha particles.
The sensor, termed a "photodiode," is the digital equivalent of film, producing a "radon image" based on the number of particles that strike the sensor.
Afterwards, the lab examines the alpha track by triggering a chemical change and then calculates the markings on the foil in order to determine the radon concentration and give you an accurate reading.
Types of Radon Detectors
There are a plethora of Radon detectors available on the market and this section will help you understand the inner-workings of different detectors to help you choose the type tailored for your needs.
Alpha Particle Detectors
A radon-tight device is a tiny piece of specially manufactured plastic substrate encased within a filtration chamber that prevents radon penetration.
Whenever the photodiode sensor picks up traces of radon, they mark areas of damage on the foil called residual alpha traces.
Chemical peeling from the foil magnifies the alpha traces and renders them visible under an optical microscope. It is then counted with an atom sensor to get an accurate Radon concentration in the desired location.
Continuous Radon Monitoring Systems
Continuous Radon Monitors (CRMs) utilize sensors like scintillation chambers and pulse ionization to detect Radon.
These radon monitors scan the environment for radon with a tiny pump or by letting air permeate into the detector’s sensor compartment.
These monitors come with an electrical circuit that keeps a log of data and calculates the cumulative radon content after specific time intervals.
Electronic Radon Detectors
Most electric radon detectors use a silicon sensor for detecting alpha particles released by the radon. Due to the small diffusing cell, constant waiting periods are necessary for detecting accurate radon levels.
The electric detectors use the high-voltage output mechanism to capture chargeable radon, allowing the silicon sensors to work at higher sensitivity for precise radon readings.
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I am a professional radon technician who enjoys writing about radon to spread awareness of this harmful, radioactive gas.