The Always-On Radiation Detection Application for Android

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Protecting you from radiation even when you are not expecting radiation!

  • Uses the Phone's Camera to Detect Radiation. No External Detector Required.
  • Simple Enough for Professionals and General Public to use.
  • Noise Reduction Algorithm. Higher Sensitivity than Other Camera Based Radiation Detection Apps.
  • Runs and Alarms in Background. Continuous Protection, Continuous Dose Rate Display.
  • Logs out the data and GPS coordinates for further investigations
  • Capable of calculating Dose and Dose rate units in uSv and Rem
  • Easy Hook Up with External Detectors if desired
  • Displays Results in Widget.

As of May 2014, we have searched for an application that uses the phone's camera to detect radiation and that protects the user continuously. After downloading all the applications we could find, it was clear that such an application wasn't available. While some applications were able to detect high levels of radiation, most were unable to effectively resolve smaller radiation fields from background radiation levels. None of the applications found were suitable for continuous monitoring as the user went about their normal routine; all applications had to be running in the foreground with the screen on to operate.

So, we decided to write our own app, and GammaGuard is the result!

Our GammaGuard Android application (available now at the Google Play store) can run continuously in the background and will alarm if you are in an area with high radiation levels. The current radiation level is displayed in a widget, making this information available to the user without having to re-open the app.

GammaGuard employs your cellphone's camera to detect ionizing radiation. To use, simply cover your camera lens and start the application!

To reduce background noise, GammaGuard uses an advanced algorithm that identifies noise events and excludes them from the analysis.

What to Expect:

GammaGuard reads the brightness of the camera's pixels and compares that value to a threshold (set either manually or by the app's calibration routine). When radiation interacts with the camera, some pixels will be bright, even when the camera is covered. To discern light sources from radiation sources, no light must be allowed to enter the camera while GammaGuard is measuring. The easiest way to keep the camera dark is with a couple of strips of electrical tape. We will also sell protective cases with built-in shutters, for more popular phone models. This system is patent protected (US8766201).

The sensitivity of any radiation detector is related to its active volume. The solid state cameras in phones are quite small. Consequently, at background radiation levels, gamma rays will interact with the camera infrequently. All radiation detector apps that use the phone's camera are subject to this limitation. Any app that claims to be able to detect the radiation from the potassium in a banana is probably fake.

Depending on where you live, the size of your phone's camera, how many frames per second are analyzed, etc., you can expect anywhere from a few counts per hour, at background, to a few hours between counts. Every day objects, such as radium dial watches or thoriated TIG welding rods emit radiation fields 10 to 100 times background. When measuring these objects, one can expect a count every few seconds or minutes. Similarly, the radiation level in an air plane at 30,000 feet is around 30 times background. GammaGuard can easily detect these radiation fields, if the phone has a good camera.

While the low sensitivity of camera based radiation detectors is a limitation when measuring low levels of radiation, it is a huge advantage for protecting the user from high radiation levels. Many expensive and sensitive radiation detectors will saturate and become useless in very high radiation fields. Over exposures have occurred while using these detectors because workers responding to radiation incidents were given a false sense of security. Camera based radiation detectors do not saturate in high radiation fields, making them ideal for use by first responders.

The phone's camera uses a lot of power. By default, GammaGuard measures in "Power Save" mode, where it turns the camera on every 10 seconds, analyzes 10 frames and turns the camera off, instead of running the camera continuously. This increases battery life but reduces sensitivity. When maximum sensitivity is required, the Power Save mode can be disabled in the settings menu. In this "High Sensitivity" mode, it is a good idea to turn off other functions that draw a lot of power (turn off the screen, put your phone in flight mode etc.). Not only will this increase battery life but, it will also reduce the amount of heat produced by the phone. If the phone gets too hot, the camera gets noisier and can count bright pixels even when no radiation is present.

A single gamma ray interacting with the camera will often cause several pixels to be bright. As a result, bursts of counts are often observed.

GammaGuard performs a lot of calculations. As a result, the buttons can be somewhat sluggish. Please be patient! The idea of GammaGuard is that you set it up once and then let it run continuously in the background without having to interact with it.

GammaGuard works best on newer, higher-end phones.

Install the Widget

After installing the app, install the widget: Find the widgets on your phone. (Tap and hold on the home screen and go to Widgets.) Find GammaGuard, tap and hold on the icon until the widget appears. Drag it to your home screen or another screen that has room on it.

App Screenshots