Review: Excel Physics - APOC mini radiation detector

I'm a scientist by training and inclination, if no longer by profession. I love measuring things. My phone has all manner of measuring and mapping apps.

When I saw on Kickstarter that a pocket-sized radiation detector was coming up, I was thrilled. Following on from the 2011 Tōhoku earthquake and tsunami,
and subsequent Fukushima Daiichi nuclear disaster, it seemed that having my own gamma and high energy x-ray detector would be a great addition to my burgeoning toolkit.

The APOC Mini Radiation Detector Kickstarter fit that bill perfectly. The people of Excel-Physics put together a very compact, and easy to use package, which they offered in kit, or "built" forms. Being  pretty much devoid of electronics experience, I opted for the "built" kit.

When it arrived, I was delighted to find a very robust package, with a couple of connector cable, and a bridge component (which came in handy, as I needed to add it to make the device iPhone compatible.)

The clear plexi-case allows you to see right into the device, the circuit-board, wiring, batter pack, speaker and LED indicators, along with the copper-foil covered detector.

It features both a human readable LED/ speaker setup, with blinks and a "click" for each measured event, as well as a "data" setting that feeds to a device via a 3.5mm mic jack.

A simple Off/On/Data switch lets you change between settings, and on the other side, the data-port for the data cable. Access to in innards ( to change the 9V battery, or to adjust the sensitivity, if needed, is by unscrewing four little screws.

A cut-away on the bottom (in classic radiation trefoil format) gives a nice accent to the detector array.

I connect my detector up to my iPhone, using several apps, (Spectrogram and iOS7 Voice Memos) to track the "clicks", although I am waiting on a purpose built app to be put out by Excel Physics ...

Primarily a gamma and x-ray detector, it will also detect alpha particles (such as found in household smoke detectors) but can pick up interference from Bluetooth devices, according to Excel Physics. The old brick building I work on gives me more background clicks than the even older weatherboard I live in, as expected.

I have used this at home, and been pleased to see the LED flash every minute and a half, or so with its characteristic "click", but wanted to give it a real test, so took the whole lot into work, and visited the Diagnostic Imaging / Radiology department, and spoke to my pals in the "hot lab". They were bemused at the idea I had my own personal radiation detector, so were happy to point me at some "sources" to scan.





So, as you can see, I had a lot of fun with it. Between the rather rapidly decaying medical radionuclides and the strong but slow long half life Cs137 we got some great signals. I'm still trying to work out the best way to record and display the signals I get, but at least I have a portable, cheep to run detector for all my Mad Max water testing needs!