Link: https://thebulletin.org/2026/06/what-if-the-smartphone-in-your-pocket-was-also-a-radiation-detector/

Thermodynamics has given us the concept of emergent behavior. There are properties that billions of particles possess that thousands do not. As the saying goes, “Quantity has a quality all its own.” Nowhere is this more true than in cell-phone radiological detection. The ubiquity and density of many millions of phones would give rise to two-dimensional image tracking, instead of simple zero-dimensional thresholding. And once the real-time geographic background has been recorded, innumerable machine learning and astronomy algorithms could compete for detection supremacy in ways we could not have anticipated two decades ago; this democratizes the stopping of nuclear terrorism and converts the problem into a machine learning competition.

Convincing a society is a slow percolation problem. Years ago, Japan’s MEXT was interested, and Chiyoda Technol Corp was curious. Eventually, SoftBank released a phone with a small dosimeter in it and an app for putting push-pins on map locations. While we researchers were grateful for these increments, we failed to persuade our colleagues on central points: large detection aperture, spectroscopy, ubiquity, real-time reporting, automatic 2D geo-mapping, without human intervention, with server-side algorithmic source detection, are all required components. But so far, the systems that have been built have had only unconnected pieces of that puzzle.

Systems of thousands of nodes have been done as demonstrators. The Defense Advanced Research Projects Agency, or DARPA (the folks who funded the internet, and did much of the early research into satellite navigation, among other things) showed the effectiveness of this approach at first, with 100 detectors, and then 1,000 detectors around the year 2016. By 2018, there was a roll-out to state, local, and federal authorities, but these likely remain in the thousands of nodes. We applaud every baby step, but we wish to be clear that life begins in the tens of millions. Tens of thousands won’t cut it. We will keep insisting after every future radiological crisis that ubiquitous, real-time, internet reporting, gamma-ray spectroscopy, has to be on every smartphone if you want to save the world from nuclear terrorism.

I understand this is potentially dystopian, I get that, but also just focusing on a distributed capacity for Nuclear Radiation Detection that is impossible to completely sabotage and that requires little additional build out and maintenance (since everyone already has a smartphone) could genuinely change how a Nuclear Emergency might unfold. Even if large Nuclear Radiation detection systems were able to get a message out through centralized systems, the ability of individuals to monitor it themselves would decrease panic and uncertainty even if it didn't actually change the message or conclusion being conveyed to the civilian population to flee or take shelter. This also reduces the potential benefit from a bad actor to sabotaging centralized state run emergency responses to a Nuclear radiation emergency since at the very least everyone has a detector to give them some ground truth to the wildly frightening things being said about a force that is mostly invisible to the human eye. Wild fabricated claims using AI generated footage deployed to manipulate and spread panic would be far less effective if people generally knew how to check themselves what the environment was like around them.

Outside the context of disaster, radon buildup in houses is also a thing...

What’s the difference between a gamma-ray spectrometer and a Geiger counter? A Geiger-Mueller counter is sort of like a bucket that provides one count of all the baseballs it catches. In contrast, a gamma-ray spectrometer measures the speed, and counts up fastballs, slowballs, curveballs, and sometimes measures their spin, of all the baseballs it catches. And a gamma ray spectrometer measures each photon by its frequency, which means that you can discern radioactive material composition at a distance.

TIL

Very cool idea. Now I want a radiation sensor in my smartphone.

What I dont like is the tone of the article. It pretends as though the act of civillians smuggling highly radioactive material in order to conduct terrorism is a trend that is so common, that we must implement complete and total spectroscopic surveillience using all smartphones in the world in order to stand a chance of combatting it.

Quite frankly the idea is ridiculous on many levels. First, that we cant track such acts any other way, and secondly, that this stuff happens in the first place. From the article repeatedly stating that the physics community needs to understand the necessity of this, I can tell that even their own colleges arent convinced.

The part where they state that nuclear terrorism will be conducted using cartel owned "drug mules" makes me think they watched too many movies with that plot.

Other than that I think radiation sensors in smartphones is a really cool idea :)

It already is. Its sensor is just limited to a very specific band of frequencies in the visual spectrum.