Detecting Cosmic Muons in a Simple Can





Introduction: Detecting Cosmic Muons in a Simple Can


This time we are trying to detect muons created through collisions of the cosmis radiation with particles of our atmosphere.

Muons are elementary particles belonging to the group of the leptons (falsely also named µ-meson) with a "middle" mass (207 times heavier than an electron). They have an average half life of just 2.2 µsek. To pass the atmosphere (20km) it takes more than 67 µsek even with the Speed of light. Therefore muons shouldn't be detected on ground, but we do. The reason is, that moving clocks go slower. For the fast muons time goes slower and so they can reach the ground. This can be seen from the two different decay-Graphs. Muons decay in electrons (Positrons) and neutrinos.

Step 1: Parts You Need

To detect the muons you just need

Step 2: Why Water?

Goes a particle through a material faster than light the so-called cherenkov-radiation is emitted. In water (refractive index n = 4/3) the speed of light is c_medium = c_vacuum / n_medium = 300.000 / (4/3) = 225.000 km/s.

So if a muon goes through water with a velocity faster than 225.000 km/s cherenkov-light will be emitted by the muon. This light can be detected with the PMT and the "light"-pulses counted.

By the way cherenkov-light can be seen in nuclear power plants too. In the cooling pool for the old fuel rods the nuclear radiation consisting of neutrons and other particles is responsable for that...

Step 3: Results

To be sure that the muons cause the peaks I made three rounds. First I took the empty can and counted the pulses within 10 minutes (53). Than I filled the can with distilled water and measured once more. Now I was able to detect 81 pulses within 10 min. After this I poured out the can and repeated the measurement with the result of 46 peaks. So water increased the number of pulses significantly, heureka ;-)

Maybe you're interested in my other Videos:

Thank's for spending your time.



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    Hello! This is awsome :)

    Could you please also send to me the circuits and the parts?


    3 replies

    I've send you the circuits ;-)

    hey, would you mind forwarding that email to me.

    I would really appreciate it.



    Hey, awesome creation.
    Could I please get a copy of the circuits? My email:

    Thank you so much

    This is excellent! I ended up making a muon counter in my dorm between semesters last year, but it used coincidence counting with two plastic scintillators and some jank homemade/dumpster-dived electronics and NIM bins. This approach with the cherenkov detector is really interesting (and I'm sure inherently has very good gamma rejection). My count rate was much lower than yours (at most 25 counts/hr, which makes getting good statistics somewhat difficult), but mine also only detected muons within a 10 degree solid angle. Hopefully sometime soon I'll get around to making a write up for my detector, but I'll attach some photos if you're interested. Thus far I have only used it to measure the zenith angle dependence of the background muon flux, but I may have some more interesting experiments in the works...

    Photo Feb 01, 6 51 41 PM (1).jpgPhoto Feb 01, 7 24 43 PM.jpgZenithAngle.png
    2 replies

    Hi! Great to hear from your experiment. I've done a similar one with three geiger Counter tubes, measuring just the coincidence-pulses. I got rates around 12 Counts/hr in vertical direction, going down to 2.7 Counts/hr in horizontal direction. Here's my Video:

    Is the last graph (flux rate vs. zenith angle) yours?

    i was wondering if you knew if using a viscous liquid would produce a faster count rate?

    Cool project, man!

    Could you send me the schematic, please?

    Thank you!

    WOW that is so cool man.
    I would love to make it.Can you please explain about the components and their connections please.

    4 replies


    First you'll Need a negative voltage, around -900V. For this you can use a CCFL-Inverter. For the Receiver you will need some OPA's to convert and amplify the Signal and count the Peaks. Maybe you can tell me your email-address, then I can send you some circuits ;-)

    Hi, could you also send them to me?

    Hey, I'm also interested in the circuits and the parts, thank you in advance!


    sure man.I'll gather around some parts and keep you updated.

    my email is

    Nice. Did you see my instructable on proving the elasticity of space time?