Put a DSLR in the freezer with a long exposure time.[1] Instant cosmic ray detector. [1] https://www.reddit.com/r/astrophotography/comments/m1w4wv/i_...

For those who might be considering doing this, don’t unless you’re ok with destroying the camera.

How does it destroy the camera?

Most DSLRs are designed to withstand down to 0C. Most freezers are around -20C. You risk damage to the battery, condensation on interior components, contraction and mechanical damage of components with tight tolerances, etc.

Great Question. I dabble in some back yard Radio Astronomy, but now you have me wondering this too.

I wonder if there is a common substance that could be scanned for historical interactions - like some salt flats.. that might preserve, like film, a history of energetic anomalies.

One such is a Miyake event. https://en.wikipedia.org/wiki/Miyake_event

> an observed sharp enhancement of the production of cosmogenic isotopes by cosmic rays. It can be marked by a spike in the concentration of radioactive carbon isotope 14C in tree rings, as well as 10Be and 36Cl in ice cores, which are all independently dated.

Wood and ice are pretty common. :)

I don't know if there are other examples.

It's relatively easy to detect cosmic rays if you are happy with secondary muons that are produced in the atmosphere when a high energy cosmic ray is absorbed.

Detectors are relatively cheap and come out of the box for citizen science projects, this project is relatively well known: http://www.cosmicwatch.lns.mit.edu/

For high energy cosmic rays, you need to observe many of these secondary particles that are produced during the absorption with high temporal resolution, few nanoseconds, to be able to tell anything about their properties.

There are essentially five or so detection principles for measuring cosmic rays at the ground, and many observatories combine multiple techniques.

First, you can observe the secondary particles that reach the ground, mainly muons and electrons. This is possible either using water tanks with photosensors inside detecting Cherenkov light or using scintillators like in the project I linked above.

Then you can also detect very short and faint light that is also emitted in the air shower. This also comes in two variants: Cherenkov light is emitted in a cone around the charged particles and results in a "light pool" of roughly 250m diameter on the ground. Fluorescence light is emitted in all directions. We build optical telescopes with extremely fast and sensitive cameras to detect Cherenkov or fluorescence light.

Last, there is also radio emission from air showers, you can detect with antennas.

Auger in Argentina combines water tanks, scintillators and fluorescence telescopes and is investigating adding in radio antennas.

Telescope Array, the experiment which measured this event here, is using scintillators and fluorescence telescopes.

> Auger in Argentina combines water tanks, scintillators and fluorescence telescopes and is investigating adding in radio antennas.

Any thoughts about surviving the next 4 years?

Pierre Auger Observatory is a project with scientific collaborators from all over the world. The initial construction costs were shared by 15 different countries. Ongoing work and upgrades are paid by a variety of international funding sources. To get some sense of that, see [1] and the Acknowledgements section of journal papers arising from work there, such as [2].

[1] https://www.auger.org/collaboration/funding-agencies

[2] https://iopscience.iop.org/article/10.3847/1538-4357/acc862

Not that hard, Marco Reps, an excellent maker YouTube channel has a video on how to create one https://www.youtube.com/watch?v=PCB8nv4fatc

There are a couple of apps that let you detect cosmic rays on your smartphone. (One example: https://cosmicrayapp.com/)

They basically keep the camera shutter closed and look for streaks on the camera CCD.

It's really easy to build a basic visible cosmic ray detector - they're called cloud chambers. Here [1] is a random video, but you can find countless sources just searching for 'how to build a cloud chamber.'

If you haven't seen one of these before, it might sound more cool in paper than in practice. Cosmic rays are absurdly abundant to the point that dozens to hundreds are passing through you per second. So a cosmic ray detector ends up turning more into something like a really neat art show than a search for a signal. Of course there is the search for 'the big one', but somehow it's not quite so romantic when you're getting plowed by these guys constantly.

[1] - https://www.youtube.com/watch?v=gt3Ad5_Z5IA

The scintillator detectors are quite simple, but you need a whole ton of them working together to be useful.

The fluorescence detectors are more complicated.