Ercdraper
Posts: 4
Joined: Sat Jul 13, 2013 9:10 am

Cosmic Ray Detector

Sat Jul 13, 2013 9:19 am

I'm designing a cosmic ray detector using a camera - I'm exploring this camera board
To detect the rays I use the chip without any optics involved - the camera is just a convenient box for the image sensor
I then crank up the sensitivity as high as I can - the rays impact the sensor and I capture the output - got some fun ways of interpreting position and energy
Anyone got some bright suggestions as to how I can modify this camera board?
Or am I right in thinking I can do away with the optics and start afresh with my own image sensor chip on its own board?
Any help gratefully received

tenochtitlanuk
Posts: 156
Joined: Fri Jul 06, 2012 8:51 pm
Location: Taunton, Somerset, UK
Contact: Website

Re: Cosmic Ray Detector

Sat Jul 13, 2013 11:37 am

Could be interesting. I've got on order the Elektor radiation detector kit ( special offer two more days) which has a small-area sensor but useful accompanying article. Hope to add a Pi interface at some stage.
I've also got at least one Geiger tube around.
I suppose ANY webcam sensor could be used this way??
Memories of early homebrew image sensors which used DRAMs with the cover removed.
Let us know of any progress..

sharix
Posts: 200
Joined: Thu Feb 16, 2012 11:29 am
Location: Slovenia

Re: Cosmic Ray Detector

Sun Jul 14, 2013 7:44 am

Could you post a link to the Elektor kit?

tenochtitlanuk
Posts: 156
Joined: Fri Jul 06, 2012 8:51 pm
Location: Taunton, Somerset, UK
Contact: Website

Re: Cosmic Ray Detector

Sun Jul 14, 2013 8:35 am


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jbeale
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Contact: Website

Re: Cosmic Ray Detector

Sun Jul 14, 2013 4:18 pm

If you're relying on high-energy particles generating free electrons directly in the silicon of the sensor chip, you don't need to do anything. Just put a black cap over the lens so you aren't seeing visible light as well.

Remember the R-Pi camera board has a so-called 1/4" format chip, which (in this case) is actually 3.67 x 2.74 mm in size. So it is not a very large sensing surface.

Also, most people using the camera do NOT want to detect cosmic rays or other high-energy particles, which appear as momentary sparkles or hot pixels or noise. For this reason, the video and stills you get out of the camera has significant noise reduction, and it will erase most or all of the signal you are looking for. You will probably need to use RAW format. Then you will see the intrinsic noise of the sensor is pretty high. See also: http://bealecorner.org/best/RPi/

Nige C
Posts: 48
Joined: Thu Jul 19, 2012 12:22 am
Location: Hadleigh, Suffolk

Re: Cosmic Ray Detector

Tue Jul 16, 2013 12:17 am

The Elector kit is the way to go. You can buddy up sensors to increase sensitivity and add a another transistor for alpha particle detection

http://www.elektor.com/news/summer-deal ... 3672.lynkx

I have one on order arriving soon. I'll let you know how I get on.
Retired power engineer with a lot of real life experience. Life is an adventure again :)

Nige C
Posts: 48
Joined: Thu Jul 19, 2012 12:22 am
Location: Hadleigh, Suffolk

Re: Cosmic Ray Detector

Tue Jul 30, 2013 12:06 am

I received the Improved Radiation Meter kit from Elektor last week. I will build it in a few weeks with added sensors. I'm busy with other projects that involve the Pi Camera Board right now :)
Retired power engineer with a lot of real life experience. Life is an adventure again :)

selectnone
Posts: 55
Joined: Fri Jun 22, 2012 10:16 pm

Re: Cosmic Ray Detector

Fri Aug 02, 2013 11:00 am

:idea: I'm curious to see if any progress will be made with this... I'm not sure how useful it'd be as a cosmic ray detector, but could be useful as a primitive radiation dosimeter.

I've got an iphone app (http://wikisensor.com/) which uses the phone's front-facing camera as a ray-detector.

It's not the most accurate device, but can be useful to see if you need to call in professional help with proper measuring devices.

That app benefits from the fact that the phone's camera is always going to be the same model (or at least one of a small set of models) so the app knows exactly what hardware it's using.

Calibrating a radiation-sensor program to the Raspberry Pi's camera as opposed to some generic USB webcam would have the same benefit - you'll have a good idea of exactly what hardware is connected.

I'm personally interested from a novelty perspective - it'd be an appropriate use of my RaspiCam for my Pip-Boy 3000 project (http://www.raspberrypi.org/phpBB3/viewt ... 11#p384811) but this could have actual real-world human-welfare applications!

Ercdraper
Posts: 4
Joined: Sat Jul 13, 2013 9:10 am

Re: Cosmic Ray Detector

Sun Aug 04, 2013 11:35 am

This development is progressing well - while we are looking at the pi camera we are also looking at other image sensors that are a little larger

Let you know how it all goes

Nige C
Posts: 48
Joined: Thu Jul 19, 2012 12:22 am
Location: Hadleigh, Suffolk

Re: Cosmic Ray Detector

Thu Aug 15, 2013 2:43 am

The best way to go is with stacked photo diodes, to count many more cosmic gamma ray events, and also measure their mass.
Cosmic or gamma rays are damaging to human cells if they hit them. Swallowing an alpha particle is much more dangerous. Only the Russian secret service have allegedly more knowledge of this with ingested radioactive alpha particle material in the human digestive tract.
We are exposed to many gamma rays each day on Earth, they are tiny and of background radiation and hit fewer organic cells. Going into a higher field of gamma rays will lead to extreme cell damage and quick death. Like those men cleaning up after the Chernobyl accident.
Gamma rays have mass, so they are a particle? Duality again. The Pi camera will measure gamma rays, but how would you detect the difference between photons and so called gamma rays? You would need I guess to block photons from the Pi camera lens. ie with a thin metal layer over the sensor. ie gold to block the bigger particles like alpha and beta. or maybe aluminium foil at least :)
Gamma rays or particles have high energy, so they can penetrate more so called solid substances including cells., and often hit a cell and damage it. Like Xrays or radio therapy to kill cancer cells.
Retired power engineer with a lot of real life experience. Life is an adventure again :)

Ercdraper
Posts: 4
Joined: Sat Jul 13, 2013 9:10 am

Re: Cosmic Ray Detector

Sat Oct 26, 2013 4:06 pm

Hit an interesting issue

How do I maximise the exposure time on the Raspberry Pi Camera?

Using raspistill the exposure settings are very variable - and altered by history of previous settings

-ex verylong

Seems either to do nothing or hang the system

Any suggestions how I can get exposures of at least 1 second?

Any help gratefully received


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