My DIY nuclear-powered calculator: A writeup

I'd like to share this project I built this summer in my free time. This is a simple 100% nuclear-powered calculator, deriving all of its energy from a nuclear beta decay reaction in which Tritium (Hydrogen-3) decays into Helium-3, an electron anti-neutrino, and a high energy electron. I posted this to Hackaday.io awhile back but I think it would also go well here on Steemit.

In spite of sounding complicated, the design is actually very very simple. The energy source is a small tritium light tube. These are legal to purchase online in the USA, and contain a decent amount of Tritium, a radioactive gas (a hydrogen isotope) that decays with a half life of a bit over 12 years into Helium-3 and 0-15 keV electrons. Relative to other radioactive isotopes, the decay products are actually very low energy, resulting in no detectable or harmful radiation leaving the tube other than ordinary green light, produced when the emitted electrons slam into a phosophor coating on the inner wall of the tube. The result is a pale green light that produces a constant stream of green light for decades. And, where there is light, there is energy that can be extracted.

I originally produced the power source a year and a half ago with a crude nuclear battery made using the tube. After several experiments to try and get a reasonable voltage out, I managed to find that solar cells derived from dollar store calculators worked extremely well at producing a usable voltage (about 1.6V) off of just the light coming the tritium reactions. I'm sure some of you have seen the popular youtube video about building one of these batteries, but I produced my original nuclear battery about 6 months before that video was made.

The calculator uses a new, much smaller tritium battery that directly wraps the tube in aluminum foil and electrical tape without the large mint box. This actually ended up boosting the power output by around 20% due to the additional reflecting surfaces on the inside of the battery.

By using a small electrolytic capacitor to store charge produced by the tritium cell, the calculator is able to run for over one minute before screen brightness drops and the capacitor has to be recharged. Considering that the battery is producing power on the order of nanowatts, I consider this kind of battery life a success.

The super-simple design is shown below.

As mentioned before, there is no harmful radiation emitted from this tube. Using both my CDV-700 geiger counter and my homemade detector, I was not able to pick up any emissions. This is to be expected - the beta radiation and the x-ray byproducts produced by its collisions are both far too low energy to escape the glass tube. The only particles that the escape the tube are green-light photons (obviously harmless) and keV energy antineutrinos (even more harmless, given how impossible they are to detect). The device is only even remotely dangerous if you break the internal Tritium tube.

This is the first nuclear-powered device I've been able to make. It's very very difficult to extract energy from radioactive decay, since tritium is the only radioisotope you can legally buy in reasonable energy producing quantities without a permit and tons of money. I spent a lot of time trying to get detectable energy from Am-241 smoke alarm sources, but those produce power several orders of magnitude than the tiny tritium tube so it may be a long time before I succeed. I have, however, been able to build a device that detects Am-241 (namely, my crude geiger counter).

If you'd like to contribute to my radiation/high-voltage experiments, my various crypto addresses are posted below. I appreciate any donations! My long-term goal is to produce electrically-driven nuclear reactions (the easiest of which is D-D fusion in a fusor), but that is a long way and a lot of money out.

ARK: AXQN61RkAPsJXAkv17YipQKk4MQZCMAUJF

BTC: 1MV7pvR9PGzYBMbSpAyRQbMBonJxZyBnrT

VTC: Vi9o5HMgzwqDEnhVZTksCNRy3JxeatNkQr