
DIY Particle Detector - homarp
https://scoollab.web.cern.ch/diy-particle-detector
======
tzs
The parts list includes 9 resistors, 8 capacitors, a photodiode, a dual op amp
chip, a switch, and a BNC connector.

The op amp chip is in an 8 pin DIP. The capacitors, the photodiode, and 8 of
the 9 resistors are all in packages with leads. The switch and BNC connector
can easily have leads soldered to them

Then there is R3, a 40 M resistor that the parts list calls for getting as in
SMD. In fact, the parts overview link specifically calls for a _black_ SMD.

As far as I can see, R3 is the only thing that needs a PCB. Everything else
would work fine with a solderless breadboard, or any other common non-PCB
hobbyist electronics construction method.

Is there some reason R3 _has_ to be black and has to be an SMD resistor for
this thing to work? Looking at the schematic it appears to just be part of the
feedback loop to control the gain of the op amp in the first stage amplifier,
which should work no matter how one decides to get 40 M of resistance.

~~~
0zelot
Hey, project owner here. Glad you all enjoy this! :-) I've never built my
particle detectors on a breadboard. It is extremely likely that they will
oscillate or frustrate in another way. You have to keep in mind that the
amplification is enormously large, per particle only a few thousands of
charges are being generated and turned into a still tiny voltage. The lower
10M-feedback electron-detector version works if _soldered_ on a
prototyping/veroboard. Those with regular hole patterns - if the parts are put
really close together.

Please don't be put off by the circuit board requirement, I have listed it on
kitspace such that it is really easy and cheap to get one:
[https://kitspace.org/boards/github.com/ozel/diy_particle_det...](https://kitspace.org/boards/github.com/ozel/diy_particle_detector/alpha-
spectrometer/) Even if you have never ordered a PCB, it should be straight
forward using kitspace as a proxy to get it right.

For beginners, I would propose soldering the electron-detector first (on the
plus side, it has 4 times more the sensitivity) and if that works swap few
parts and upgrade to the alpha-spectrometer variant since that is a bit more
tricky to operate and get running. I've commented on the through-hole/SMD
choice and similar questions in this twitter thread
[https://twitter.com/0zelot/status/1260931205676990466](https://twitter.com/0zelot/status/1260931205676990466).

In short, I choose leaded components over SMD where possible such that it is
easy to solder. But analog signal integrity and low noise vs. signal require a
circuit board.

~~~
helsinkiandrew
Presumably this would be suitable for soldering Dead Bug or no circuit board
style - component to component.

~~~
0zelot
even the alpha-spectrometer might work if soldered wisely on a regular
prototyping grid. in any case, thoroughly cleaning after soldering with
alcohol will help. but considering the really cheap and fast PCB productions
nowadays, the hassle is most likely not worth it.

------
tambeb
I created a cloud chamber a few years ago to test out a piece of uranium ore I
bought on Amazon. It's a pretty simple design, cooled with a Peltier
(thermoelectric) device instead of dry ice. I got the idea from an
Instructable article[1] and the whole thing was pretty awesome actually. I
have a video[2] if you're interested in what it looked like. It's a few
minutes long and unedited, so heads up on that. If you watch any 10-20 second
portion of it you'll get the general idea.

[1] [https://www.instructables.com/id/Make-a-Cloud-Chamber-
using-...](https://www.instructables.com/id/Make-a-Cloud-Chamber-using-
Peltier-Coolers/)

[2] [https://youtu.be/vaRyXmMGJdk](https://youtu.be/vaRyXmMGJdk)

------
segfaultbuserr
The GitHub project page has a better and more comprehensive introduction than
the CERN page:

* [https://github.com/ozel/DIY_particle_detector/](https://github.com/ozel/DIY_particle_detector/)

Paper (Open Access, click "Download PDF"):

* _Smartphone and Tablet-Based Sensing of Environmental Radioactivity: Mobile Low-Cost Measurements for Monitoring, Citizen Science, and Educational Purposes_

[https://www.mdpi.com/1424-8220/19/19/4264](https://www.mdpi.com/1424-8220/19/19/4264)

~~~
ngold
Thank you, this diy particle detector looks pretty neat. Love more reading
material on the subject.

------
alasdair_
If you want another fun particle detector project, you can build a cloud
chamber with some dry ice and an old fish tank:
[https://www.symmetrymagazine.org/article/january-2015/how-
to...](https://www.symmetrymagazine.org/article/january-2015/how-to-build-
your-own-particle-detector)

~~~
jcims
I made a really crude one of these a long time ago. Seeing the trails live is
really strange and cool. If you can only get weak isopropyl you can remove
water pretty easily by salting it [0]. Drawing the alcohol off the top with a
turkey baster or similar is probably the best way with typical household
equipment. If you don’t have one of those, you can do it in a water bottle,
let the water settle out with a bottle upside down, poke a small hole in the
base of the bottle then just partially open the lid over sink and let it drain
until you get to the alcohol. Just remember that this stuff is now super
flammable so be careful. (Salting doesn’t really work with ethyl alcohol so
save your vodka)

Dry ice is pretty easy to get at Graeter‘s if you have one of those local.
Just don’t store it in a closed container. Gloves are a great idea of course
but I also advise wearing thick socks or slippers when you’re using it.
Stepping on even a very small piece of dry ice in bare feet is experience you
will remember.

Dry ice is a lot of fun but doesn’t last long. If you go through this, check
youtube for other experiments and things to do, and buy a little extra. Just
remember never put it in a closed container, it will almost certainly explode.
Physics doesn’t care about you, respect the material. (edit: I just checked,
heat of sublimation of CO2 is approximately 570 kJ per kilogram. A stick of
dynamite has approximately 1 MJ. There’s a lot of energy cached in those
blocks.)

Have fun!

[0] [https://youtu.be/CtwQ2aEBur4](https://youtu.be/CtwQ2aEBur4)

~~~
ohyeshedid
Jumping in to remind folks: If you notice an increasing level of panic-like
feelings when working with dry ice, seek fresh air immediately.

~~~
jcims
Great point. There have definitely been some tragedies when people play with
dry ice without understanding the dangers. Don’t throw it in the pool and go
swimming or try to cover yourself with fog, etc etc. Study up.

------
0zelot
Let me just point here again to the project entries on Kitspace.org:

[https://kitspace.org/boards/github.com/ozel/diy_particle_det...](https://kitspace.org/boards/github.com/ozel/diy_particle_detector/alpha-
spectrometer/)

[https://kitspace.org/boards/github.com/ozel/diy_particle_det...](https://kitspace.org/boards/github.com/ozel/diy_particle_detector/electron-
detector/)

Yes, this project is very much doable for electronic beginners with a knack
for science (16-year olds who have never soldered manage it well if guided a
little bit). The parts are easy to solder and ordering the circuit board will
make your life much easier in order to get it working. BTW, no one earns money
with the kitspace website above. This is community-run and intended to make
open hardware projects easier to build by simplifying the ordering procedures.
The parts and board suppliers linked on kitspace should cover most of the
world.

------
crispyambulance
Here's another "kitchen-table" project, it's a muon detector.

This one uses plastic scintillating material in front of the detector.

[https://arxiv.org/pdf/1606.01196v2.pdf](https://arxiv.org/pdf/1606.01196v2.pdf)

github: [https://github.com/spenceraxani/Desktop-Muon-
Detector](https://github.com/spenceraxani/Desktop-Muon-Detector)

~~~
0zelot
also its website:
[http://www.cosmicwatch.lns.mit.edu](http://www.cosmicwatch.lns.mit.edu)

In terms of difficulty to build and operate it, I would rate the discussed
projects such: cloud chamber < DIY particle detector (electron-detector
variant) < DIY particle detector (alpha-spectrometer variant) < desktop muon
detector

Even DIY cloud chambers can be a bit tricky to get running for the first time
(especially with too high humidity like in summer). Just don't give up! ;-) A
few tips can be found in this manual: [https://scoollab.web.cern.ch/cloud-
chamber](https://scoollab.web.cern.ch/cloud-chamber)

------
djaque
It's amazing how accessible some of these detectors can be. I wonder if you
could perform some of the classic physics lab experiments with them like muon
lifetime measurement.

------
supernova87a
Very cool -- one thing I don't understand though. I know that alpha radiation
is stopped by a piece of paper thickness. How does this then detect such
radiation through the metal of a box if the detector has to be inside?

~~~
polishdude20
Actually alpha radiation can get through a piece of paper. Check out thought
emporiums videos on it on YouTube. I remember he did a video about the
different types and had a detector between the sources and some thickness of
stuff and they seemed to go through paper just fine. I think it's his video
about those healing bracelets that actually emit radiation.

~~~
0zelot
Unfortunately, that video contained some flawed conclusions. I had left a
comment back then. Alpha particles from natural sources like an uranium stone
penetrate 50 micrometers of solid hard material at most. Let's give it maybe
100 micrometers of soft paper, but that's about it. What was most likely
observed in that video is radon, which is a radioactive gas, slowly diffusing
out of uranium or thorium stones. Since it's gaseous, it can circumvent the
paper and then do its alpha decay just behind it. I wrote a few lines on those
aspects in this article
[https://www.mdpi.com/1424-8220/19/19/4264](https://www.mdpi.com/1424-8220/19/19/4264)

~~~
polishdude20
Oh that's pretty cool! I guess the best way to check would have been to have
it in a paper box then?

~~~
0zelot
Yes, radon is pretty hilarious and spreads in very unexpected ways. Completely
wrapping sources of radon like uranium or thorium minerals (or these bracelets
containing some of that), only holds back the diffusion process for some time
unless the shielding is really thick and very dense. That's why radon
accumulates so well in household cellars, it penetrates concrete walls easily.

If you look closely in thought emporiums video (link below), the thick clouds
- representing each the full paths of individual alpha particles (from the
point of decay until full absorption in the air) - don't originate right at
the surface of his shielding materials (paper, chicken skin... whatever).
Instead, the alpha particle clouds stand by themselves in free space and can
only really stem from radon that decided to decay at those positions somewhere
outside of the shielding (transforming to "solid" polonium in that process and
sticking itself to the next closest lump of molecules/dust). If the alpha
particles would penetrate the shieldings (which they can't because of too much
material/density), we would see clouds stemming directly from the shielding
surfaces which I don't see happening:

[https://www.youtube.com/watch?v=C7TwBUxxIC0&feature=youtu.be...](https://www.youtube.com/watch?v=C7TwBUxxIC0&feature=youtu.be&t=897)
You may find and like my comment there, maybe it helps to fight some
misconceptions about natural radioactivity. ;-)

~~~
polishdude20
Awesome thanks!

------
adammunich
This is great. I am very curious what other common diodes can be used in place
of the $3000 PIN diode detectors typically used in XRF setups.

~~~
yummypaint
Alot of big power diodes can also be used, and they should have a larger
volume of silicon available. Presumably the snr will be worse. Maybe start by
filtering for diodes with low reverse bias current but high forward current on
digikey?

------
technocratia
Could this be used to create HW RNG?

~~~
0zelot
yes totally. There is a great DIY project for doing that
[https://www.fourmilab.ch/hotbits/](https://www.fourmilab.ch/hotbits/) It's
not required to have the particle energy measured for making random numbers,
detecting precisely the arrival time of particles is more important plus
having a high hit rate is usually desired. My DIY detectors are not optimized
in that way but it would work in principle. Timestamps are already recorded by
the python scripts on github, it would be just a matter of evaluating them.

------
z3t4
Would be interesting with an article describing how this works

~~~
0zelot
here you go
[https://www.mdpi.com/1424-8220/19/19/4264](https://www.mdpi.com/1424-8220/19/19/4264)

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ngcc_hk
Just place an order. Will read after it comes.

