[aprssig] Geiger counter mobile from Indiana to Tennessee

[joe jesson]

 Hi Bob, looks like we have a nice gamma detector and testing with a calibrated 1200 cpm Uranium Ore emitter and this solar cell output is going into an amplifier and scope.

 Over the weekend I want to try different sized solar cells (again, the ambient light has to be completely blocked) to see what the Sensor capture area vs. Capacitance loading trade-offs are.  If we can get a solar cell as input to an A/D converter and give us reproduceable results, I think we have a winner! 

 Joe Jesson

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-----Original Message-----
From: Robert Bruninga <bruninga at usna.edu>
Date: Wed, 10 Oct 2012 20:52:48 
To: <jjesson at voyager.net>; TAPR APRS Mailing List<aprssig at tapr.org>
Subject: RE: [aprssig] Geiger counter mobile from Indiana to Tennessee

Tell me more about the solar cell detector.  That does make sense for
large area!
Bob


-----Original Message-----
From: joe jesson [mailto:jjesson at voyager.net]
Sent: Wednesday, October 10, 2012 8:35 PM
To: Bob Bruninga; TAPR APRS Mailing List
Subject: Re: [aprssig] Geiger counter mobile from Indiana to Tennessee


 If improving the radiation particle density detection is of interest, you
can parallel diodes to increase the surface area but it also increases the
capacitance.  Other experiments use the huge die in an old 2N3055... A
beheaded power transistor and I have tested various sizes of a solar panel
which is coated with a non-conductive black paint.

All fun experiments and the one positive advantage is you can see a
amplitude height change, which can be correlated to eV potential, as
opposed to a simple amplitude limited pulse output of a GM tube...
Click... Click...click..

  Joe Jesson



Sent via BlackBerry from T-Mobile

-----Original Message-----
From: Robert Bruninga <bruninga at usna.edu>
Date: Wed, 10 Oct 2012 18:46:00
To: <jjesson at voyager.net>; TAPR APRS Mailing List<aprssig at tapr.org>
Subject: RE: [aprssig] Geiger counter mobile from Indiana to Tennessee

> A Cheaper option is... a photodiode... and you have a
> very low-cost alpha, beta, and gamma RAD display.

But the "detector surface area is microscopic compared to the huge volume
of a geiger tube.  More like a thousand to 1?  Meaning for every ray you
detect,  you miss a thousand that do not even pass through the PN
junction?

Bob, WB4APR

-----Original Message-----
From: aprssig-bounces at tapr.org [mailto:aprssig-bounces at tapr.org] On Behalf
Of joe jesson
Sent: Wednesday, October 10, 2012 5:47 PM
To: TAPR APRS Mailing List
Subject: Re: [aprssig] Geiger counter mobile from Indiana to Tennessee


  A Cheaper option is to take a selected photodiode, or power transistor,
shield it from light, amplify, detect and display and you have a very
low-cost alpha, beta, and gamma RAD display.

Elektor has published an excellent series of articles on this and sells a
kit and I have a commercial cell/sat-based solution to sensing RAD on a
mobile asset.  APRS is a GREAT emergency backup to sensing radiation!

 I will post links if interested.  Also look at the 1,000's of RAD sensors
on the COSM network and see what the Japanese engineers have done as a
response to the nuclear disaster. What we learned from this crisis is not
to trust you government!

73,
Joe Jesson
KC2VGL





Sent via BlackBerry from T-Mobile

-----Original Message-----
From: Richard Graves <rgraves at vysystems.net>
Sender: aprssig-bounces at tapr.org
Date: Wed, 10 Oct 2012 15:47:09
To: TAPR APRS Mailing List<aprssig at tapr.org>
Reply-To: TAPR APRS Mailing List <aprssig at tapr.org>
Subject: Re: [aprssig] Geiger counter mobile from Indiana to Tennessee

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