Sunday 4 March 2018

Is Your Gaming CRT Exposing You to X-Rays?

Motivated by this discussion at UKVAC I decided to run a little experiment to find out if your typical gaming CRT leaks any measurable X-rays. Tan while having fun? Let's find out.

Test Setup 

My setup involved testing three tubes in my collection used from time to time for testing arcade pcbs, retro consoles, as well as micro computers. I believe these models are also commonly found among the gaming community and they should be somehow representative.

In front of each tube an X-ray sensor is placed at different distances: 3cm, 30cm, 60cm. X-ray activity is sampled during 180 seconds during each run, then compared against ambient readings (tube turned off).

Initially the X-ray sensor is left to warm up for a good 10 minutes to obtain constant ambient reads.


Sony BVM-20F1E

Toshiba A68 CRT (NANAO MS9) on a New Astro City cab

The Results

I'm afraid to break the news but... there's no such thing as a free tan while retro gaming. At no time any of the tubes tested presented any abnormal sensor reads indicating the presence of X-rays. To put things into perspective I have included a table below comparing the different scenarios together with reads of the sensor exposed to radiation from a controlled x-ray source.

I'm no expert on this matter, but even if the energies inside the tube are high enough to produce X-rays, the glass in your CRT has lead in it to block those from reaching you. Perhaps someone with enough expertise could confirm these assumptions.

Happy safe gaming.


  1. it's people miss-understanding old problems.
    crt's originally leaked radiation from the back where the glass is much thinner.
    this was dealt with eventually first by putting a metal shield on the back of the tube - like on electrohome G07 arcade monitors,
    then by putting the shield inside the tube.

    to talk about radiation from crt's you really have to be talking pre-1970's

    the only other way is if the chassis fails and puts far too much HT onto the anode.
    but again, that's been dealt with by the 1980's with over-voltage sensing and shutdown.

  2. Thanks for putting my fears to rest. Kudos, mate!