Photographing Cosmic Rays

29/Dec/24 

1. Method
2. Results
3. Other Odd Finds

SpaceHey still doesn't have a blog category for sciences yet, so you're dealing with some amateur astronomy bullshit today guys. 

Cutting right to the chase, in simple terms, Cosmic Rays are high energy sub-atomic particles expelled from deep space, as well as the sun,  at ridiculously high speeds. Rubbish name really, since they're not electromagnetic rays, just boring old Protons, Alpha Particles, Electrons — and in small amounts, more complicated stuff like positrons, which are irrelevant to this and are things I know nothing about. Anyway, these particles are theorised to come from plenty of places, though so far the only extra-solar source that has been fully proven to my knowledge is from supernovae, both inside the Milky Way and beyond. 

Billions of these not-rays hit Earth every minute, though it is very rare that this happens in their original 'Primary' forms. When a cosmic ray reaches Earth's atmosphere, more often than not it will collide with Oxygen or Nitrogen atoms in an 'air shower', releasing massive amounts of energy and secondary particles. One of these secondary particles, the muon, is what I will be attempting to record.

Muons are charged particles, having a charge of -1e, equal to that of an electron. This charge can interfere with electronics if the particle collides with them, a notable example being the Super Mario 64 Bit Flip Speedrun, during which it is speculated that a similarly charged, high-power cosmic ray was able to cause a 'single-event upset', a binary bit flipping from a 0 to a 1. With some incredibly lucky timing, this led to a near irreplicable glitch, shaving off a grand total of 3-ish seconds from the run. This same concept can be applied to a far more sensitive camera sensor, found in pretty much any piece of tech that can access the internet nowadays. When a muon hits the sensor, its electrical charge lights up the pixels it hits, forming either dots or longer streaks of light, depending on the angle of incidence of the particle. The brightness of the pixel correlates to the energy of the particle, in the same way that light receptors would convert a large amount of photons entering the camera to a more powerful electrical signal. 

I am using a Canon EOS 2000D, a relatively cheap APS-C sensor DSLR (Any camera with a decently sized sensor should work). It is set up on a tripod at an angle of roughly 40°, with a body cap covering the body. The angle is set as such to increase the number of 'streaks', since they're far more interesting to see than 'dots'. If you are solely interested in capturing a large number of rays, feel free to just leave the camera pointing straight up.

From here I'm ready to start recording, taking 30 second long exposures with an ISO of 1600, providing ample sample size and light sensitivity. I just keep taking exposures until I feel like I have enough, then dump the SD card onto my laptop for processing. Now I have to spend however long it takes to scour through every image, looking for any signs of cosmic rays. Ridiculously tedious, but hopefully worth it.

After a day of waiting for an SD card reader to arrive for my new laptop, I was ready to look through all the shots I had taken. Of the 78 frames I had taken, I'd managed to find a grand total of...

1 muon artifact candidate.  ---->

Statistically that made absolutely zero sense, so I'm just gonna presume that the others were just very conspicuous dots. So I decided to run another volley of shots. 

90 more photos later, and I am absolutely blown away. I'll let the images speak for themselves!!

Okay, okay, not exactly the most visually incredible photos. But these are just amazing to me, those streaks are our potentially intergalactic muons smashing into a bit of silicon after travelling for god knows how many tens of thousands of years across the universe; potentially 8 minutes as well, but we'll never really know. I'd say it's about as cool as physics can get really, just be grateful I didn't bring any calculations into it.

Alongside our Muon artifacts, hot pixels, and noise, I also stumbled across a couple of other curious phenomena that I thought to mention:

Electron

Another charged particle that can be picked up while recording! because of their low mass, they have a sort of wonky trajectory, this one is all over the place. I have been led to believe that these free electrons are a result of gamma rays dislodging them from their atoms due to the Compton Effect. Whilst some particles produced during an Air Shower do appear to be able to decay into photons, becoming gamma radiation, I think this is an unlikely origin, rather just arising from background radiation. Cool nonetheless! 

???

I just don't know what this is. There were a few across the images, this particular one was only found on one frame. I'm guessing it's something within the sensor, not any other sort of subatomic particle. It's a little blurry, but consists of this 3x3 pixel shape, almost like a star or FPS crosshair. Couldn't even begin to guess what it could be, so make your bets in the comments.

Anyway, this has been really fun to put together over the past 2 days, and I could have experimented so much more. It's incredibly simple to replicate if you have an hour or two on hand, so let me know if you spot any cosmic rays of your own!

Also check out Adrian Zhang's blog post on the same experiment HERE! He's plenty smarter at all of this than me, and his other posts are great reads too :)

(And don't forget to drop some kudos so I can feel nice)