# RadioactivityCounter > Mobile Geiger counter app using camera sensor to measure radiation. (iPhone/iPad app by Dipl.-Ing. Rolf-Dieter Klein.) - Source: https://appshunter.io/ios/app/radioactivitycounter/id464004677 (this page in markdown: same URL + `.md`) - Developer: [Dipl.-Ing. Rolf-Dieter Klein](https://appshunter.io/developer/309148367) - Category: Utilities, Health & Fitness - Price: $4.99 - Rating: 3.10/5 from 10 App Store ratings · 19 written reviews indexed - Age rating: 4+ - Requires: iOS 8.0 · 11 MB - Languages: American English - Released: 2012-02-01 - Data updated: 2026-08-24 - Monetization: paid - User reviews in markdown: https://appshunter.io/ios/app/radioactivitycounter/id464004677/reviews.md ## What is RadioactivityCounter? RadioactivityCounter This application is a real working radioactivity counter without any extra hardware needed ! It will turn your phone into a Geiger Müller Counter to measure radioactivity after proper calibration. ** Attention after upgrading iOS to a higher iOS do the calibrate again, as camera data properties might have changed ** Disclaimer: The type of radiation picked up by the camera can be dangerous/detrimental to the user's health as well as cause damage to the device. Important note: The camera sensor can measure gamma radiation (CS137 for example) and some beta radiation (depends on the energy if the beta rays can pass through the plastic parts - for example H3 or K14 are weak sources). It cannot measure alpha rays (PO210) For AM241 though its primary a Alpha source also some gamma radiation is emitted and might be detectable for a longer measurement. Please check our homepages for examples and hints on how to measure. We did calibrations with several iPod2*, IPhone 3GS*, iPhone 4*, iPhone 4S, iPhone5, iPhone 5S iPhone 6, 6s and iPad 2, iPad 3* devices at the Helmholtz Research Centre, Munich. we used a CS137 test source from 10 µGy/h till 1 Sv/h for each of the phones we had. The values are stored for a rough start on the application (all devices differ a little bit). For precise professional measurement the devices must be adjusted to the sensor which is possible with the expert setup. For personal use the defaults should be sufficient (please give us feedback). * = Attention some phone might not be compatible due the new version of iOS or missing features (gps precision using sim cards)- please try to use an older rev of the App which should be available according to my settings (1.3). ## Key features - Real radioactivity counter functionality - Converts phone into Geiger Müller Counter - Measures gamma and some beta radiation - Requires calibration for accuracy - Expert setup for precise measurements - Supports various iPhone and iPad models ## Recent user reviews (10 of 19) All indexed reviews: https://appshunter.io/ios/app/radioactivitycounter/id464004677/reviews.md ### 5/5 — works well *2023-03-30* detects uranium glass and microwave ### 1/5 — Failed me in my time of need *2021-12-11* I am in an intro to nuclear engineering class and I had to detect the number of gamma counts that a smoke detector would give off. I used this app, thinking nothing of it, but the second I put the tape on the cameras, I was greeted by 0 CPM constantly. It never deviated from that, which makes me believe that this was never a good app, and the reviews saying it was are lying. Either that or it worked on past phone builds but something has changed in the technology. I had to write my report on if this worked or not instead of finding the quantitative values I had to. Just very disappointed in it. ### 1/5 — None of this made sense! *2021-02-24* I tried to use the app to check to see if any of the rocks I have been collecting show any signs of radiation. This description made this app look like what I needed. I dropped the $7, and have NEVER been so disappointed. Nothing is in any sort of easy to decipher on the app. No idea how to use it, or even what it is for. I would like a refund please! ### 1/5 — Did not work for me on iPhone 11 Pro *2020-09-06* I believe the app needs updating to Support iPhone 11 Pro. I tried multiple ways it did not work as expected to me. ### 1/5 — Zero stars *2019-08-30, version 2.2* It does NOT work! I’ve just had I-131 treatment. I put my phone right next to the pill and there was no reaction whatsoever. The nuclear medicine technician told me that phone cameras cannot detect gamma rays. So don’t waste your time and money. ### 5/5 — Awesome information *2019-08-10* I just had radiation treatment for my thyroid and it has been helpful to know how much radiation remains in my neck and watch it as it dissipates. It provides warning quite well when the phone is near my neck. ### 5/5 — Radiation therapy patient is impressed. *2019-02-14* I doubted the validity of this app, so I tested in the linear accelerator room during my morning radiation therapy. 10 feet off to the side, It worked and actually sounded alarms when the beam was activated. ### 5/5 — Seems legit *2017-12-21* I learned of this app from James mahaffey’s book, atomic adventures. I work inside a nuclear power plant and have tested this app a few times in front of known and unknown sources. It seems to function as described and I look forward to comparing its results to that of other calibrated detection equipment. ### 5/5 — Amazing sensor usage; not fake *2017-01-01* Hats off to the developer for implementing a real measurement tool for radioactivity. Visit his website to see his calibration data, I know that measurements from my iPhone 6p matched my 'real' instrument by detecting faint radiation from my granite countertops. ### 1/5 — Tyler *2016-07-11* Waste money and it doesn't even open. I've even done two resets and it still won't work. Don't buy ## Frequently asked questions about RadioactivityCounter ### What can RadioactivityCounter measure? RadioactivityCounter can measure gamma radiation and some beta radiation. It cannot measure alpha rays. Examples of detectable sources include CS137 for gamma and H3 or K14 for weak beta radiation. ### How accurate is RadioactivityCounter? The app provides a rough start for measurements with default values, which should be sufficient for personal use. For precise professional measurements, an expert setup to adjust to the specific sensor is possible. ### Does RadioactivityCounter require calibration? Yes, proper calibration is required to turn your phone into a working radioactivity counter. It is recommended to recalibrate after iOS upgrades as camera data properties may change. ### Is RadioactivityCounter safe to use? The disclaimer states that the type of radiation picked up by the camera can be dangerous or detrimental to user health and device. Users should exercise caution and refer to provided resources for safe measurement practices. ### What devices are compatible with RadioactivityCounter? The app has been calibrated on various iPhone and iPad models, including iPhone 3GS through iPhone 6s, and iPad 2 and 3. However, some older phones might not be compatible due to new iOS versions or missing features. ### How much does RadioactivityCounter cost? RadioactivityCounter is a paid application priced at $4.99. There are no in-app purchases or advertisements associated with this app. ### When was RadioactivityCounter last updated? The latest version of RadioactivityCounter, 2.2, was last updated on July 28, 2016. The initial release date was February 1, 2012. ### Does RadioactivityCounter have ads? No, RadioactivityCounter does not contain advertisements. It is a paid application with a one-time purchase price. ## Version history (last 4 releases) ### 2.2 — 2016-07-28 This update from Apple will improve the functionality of this app. No new features are included. Rev 2.2. New algorithm for more stable camera cold starts, needs less recalibration, bugfix on unkown devices, and experimental upload function for statistics., new devices supported up to iPhone 6 - attention some feature made it incompatible to older devices or not having a sim card -- we work on this for the next version -- stay on the old version 1x when affected. ### 1.3 — 2014-01-21 iOS7 support, several compatibility problems were solved, so iOS7 can be used now. iPhone 5S added to the predefined calibration tables. More infos in the CSV file, new name scheme, email default can be changed now. ### 1.1 — 2012-10-16 1 .Support for iPad 3 and iPhone 5. 2. Now you can switch between frontcam and backcam we measured all our devices for both cameras if available. 3. New log file format with more information in the CSV format. 4. Attention some problems on iOS7.0x reported - we work on this (log filename and info crash) ### 1.0 — 2012-02-01 No release notes. ## More apps by Dipl.-Ing. Rolf-Dieter Klein - [PortOfCallL](https://appshunter.io/ios/app/portofcalll/id313835253) All apps by Dipl.-Ing. Rolf-Dieter Klein: https://appshunter.io/developer/309148367 --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-24.*