
Observing Ultra-High Energy Cosmic Rays with Smartphones (2014) - brahmwg
http://arxiv.org/abs/1410.2895
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cshimmin
I'm one of the leads on this project! We've been flying under the radar for a
while now, since everyone working on this has a "day job" (mostly ATLAS/CMS
physicists), and we have essentially no funding. But we are making progress
and hope to eventually do a full-scale release and produce some science! I'll
try to answer any questions in this thread.

~~~
cozzyd
Speaking of radar, many phones have FM radio receivers, which could
conceivably look for radio signatures of cosmic rays. No idea to what extent
the hardware is made available to software, but I just found another reason to
procrastinate.

Also kudos on actually going through and doing something with this; I remember
talking about using cell phone ccd's as detectors a few years ago with other
grad students, but of course it never got past the chit-chat stage (I remember
wanting a dosimeter in my pants to ring at me if I got too close to one of my
radioactive sources).

~~~
cshimmin
People have approached us with this idea! I don't think we have much/any
access at the API-level to radio signals. However are talking with another
group which is looking to build an inexpensive RF array about possibly
integrating the two networks. There is also another group which is creating a
dedicated radio device that plugs into the headphone jack of your smartphone,
but in this case you need a special piece of hardware and the phone is
basically just acting as readout/internet access. It's a cool idea but we're
trying to show that it's possible to do science with the existing hardware
that people already own!

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batbomb
Ha, we had this idea quite a long time ago (2008) when "apps" really started
becoming a thing. I think this works if you were in a densely populated area
and a significant fraction of the population was listening, but that was
always a pipe dream.

On a related note, when a 10^19 or above event hit a densely populated area,
there's a decent sized ionization column near the center of the shower that
could likely lead to cancer. Theres probably 100 to 1000 or so events like
that in an area the size of the Bay Area.

Edit: I took out a part talking about noise after I glanced at the paper, but
I would still be worried about it because the area of the detector (aka camera
sensor) is roughly equivalent to the area of the electronics (ADC, CPU,
Memory, etc...) in a smart phone, whereas most surface detectors have a huge
scintillation footprint compared to the electronics footprint.

~~~
entheon

      On a related note, when a 10^19 or 
      above event hits a densely populated 
      area, there's a decent sized ionization 
      column near the center of the shower 
      that could likely lead to cancer. 
      Theres probably 100 to 1000 or so 
      events like that in an area the size 
      of the Bay Area.
    

Ha! Oh man. That'd be the best alert a smart phone could ever show me.

    
    
      *beep* 
        You've just been irradiated by powerful 
        cosmic rays from outer space. Your risk 
        factor for certain forms of cancer has 
        increased by 0.013%.
    

I really would want to know if I was suddenly showered by cosmic rays, and my
location within the crowd-sourced area-of-effect, but I wonder if an app could
transmit it's sensor noise to a central server, and receive accurate results
aggregated from all other app instances very quickly. I figure there'd be a
lag of maybe a couple of hours or more.

Reminds me of this other site, which provides air quality stats:

[https://plumelabs.com](https://plumelabs.com)

~~~
ASalazarMX
And the alert tone could be ICQ's "Uh-oh".

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stared
When it comes to detecting radiation with smartphone, it is possible / known.
Two friends of mine made it as a scientific projects when they are still in
high-school:
[https://cds.cern.ch/journal/CERNBulletin/2014/40/News%20Arti...](https://cds.cern.ch/journal/CERNBulletin/2014/40/News%20Articles/1756279)

~~~
cshimmin
We read about them! Very cool project, especially from high-school students. A
lot of people got onto this idea about the same time. See also CellRAD, which
is an app that is supposed to act as a dosimiter to detect when you are near
radioactive sources. It's been known for quite a while that silicon pixels can
detect ionizing radiation (in fact, that's why we use pixel detectors in the
inner tracker layers of state-of-the-art particle detectors such as ATLAS and
CMS). The problem with the pixels in the CMOS camera of your smartphone is
that they are very small (in both pitch and depth) and were optimized to
respond to optical photons, rather than charged particles.

We have played around a bit with implementing these radiation-sensing
features, but the main goal for the CRAYFIS project (and which sets it apart
from other similar projects) is to create a distributed network of phones that
all work together to act as a giant telescope for UHECR events.

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privong
Have they started sending around apps to beta testers? You can sign up[0] and
I'm pretty sure I did, but I haven't heard anything.

[0] [http://crayfis.io/](http://crayfis.io/)

~~~
marvel_boy
Is the app open sourced? any link?

~~~
cshimmin
Unfortunately not open sourced (yet). The main reason is because we're
physicists, not web security experts (although I do have some background in
this). I was afraid that if we open source the code and make the protocol way
too obvious, the bar will be just too low for some troll to spam our data
acquisition servers, making it hard for us to do science. So for now we're
kind of relying on good-old "security through obscurity".

In the future we hope to harden the online system further, and eventually open
source the code for both the android/iOS apps, as well as the online website
which functions as a high-throughput distributed DAQ with online analytics.

~~~
privong
Have you thought about trying to partner with someone to do a Google Summer of
Code (or something similar) for this? It seems specific and targeted enough
that it might have a chance of getting support.

~~~
cshimmin
That's a really cool idea, I don't think we've even considered this before. If
you have information about how to get this kind of thing going, please get in
touch! (My email is my hn username at cern.ch)

~~~
privong
I've not been involved with SoC myself, but check out the website:
[https://developers.google.com/open-
source/gsoc/](https://developers.google.com/open-source/gsoc/)

Unfortunately the deadline for this summer has already passed.

------
grkvlt
From the paper: "[UHECR air shower] can be detected via [...] radio and
acoustic signatures"

Does this mean that the particles have so much energy you could _HEAR_ the
effects of them hitting the atmosphere?

