High Altitude Radiation

Support forum for the mightyohm.com Geiger Counter.
http://mightyohm.com/geiger
Post Reply
NickB
Posts: 2
Joined: Fri May 11, 2012 10:07 am

High Altitude Radiation

Post by NickB »

The geiger counter went on a high altitude mission last week.
It traveled together with a (arduino) transmitter under a high altitude balloon up to an altitude of 30km.
The following data got send back:
http://img705.imageshack.us/img705/5038 ... 052015.jpg
Unfortunately it started to behave a bit strange above 20km (gave CPM values around 8000).
I think it might be because of arcing due to high vacuum.

User avatar
mightyohm
Site Admin
Posts: 1028
Joined: Fri Apr 03, 2009 10:29 pm
Location: Seattle, WA
Contact:

Re: High Altitude Radiation

Post by mightyohm »

Nick,

Wow, this is really cool! Do you have any pictures of the balloon or the payload?

The curve flattens out above 15km, do you think the radiation level becomes constant, or is this related to the malfunction above 20km?

Regarding the results above 20km, it's hard to say what is going on, but arcing is one possibility. Is there any possibility of condensation? If the board gets wet that will almost certainly cause problems.

Thanks for sharing this!

NickB
Posts: 2
Joined: Fri May 11, 2012 10:07 am

Re: High Altitude Radiation

Post by NickB »

Here are some pictures:
Balloon
Launch
Ascent
Descent
The geiger counter was housed in the bottom payload.
Here is a picture of the arduino tracker.
I designed a shield for the arduino mega containing a GPS, SD, Temp Sensor, 433Mhz transmitter and some IO.
I'm now working on a single board version.
Condensation could indeed be a problem as temperature rises again at this altitude.
Going to look into it :).
The radiation should keep rizing with altitude as its cosmic radiation.
But its also something I have to look into.
Thanks for building such a great and affordable geiger counter!

dcgonzal
Posts: 2
Joined: Mon Sep 03, 2012 4:22 am

Re: High Altitude Radiation

Post by dcgonzal »

Hello Nick,

I see that you used the Mega and the Geiger Counter, I am trying to connect an Arduino Uno to a MightyOhm Geiger Counter, do you think you could share your code and schematic?

David

sharpcoordinator
Posts: 1
Joined: Sat Sep 08, 2012 8:12 am

Re: High Altitude Radiation

Post by sharpcoordinator »

I too am looking to connect the mightyohm geiger counter to an R3 arduino via an SD card logger shield to log data on a high altitude balloon (HAB). Do any of you know how to connect the two devices and where i could get a script to log cpm data on the logger shield? David, has anyone answered your question, cause mine is the same.

dcgonzal
Posts: 2
Joined: Mon Sep 03, 2012 4:22 am

Re: High Altitude Radiation

Post by dcgonzal »

No, I have not gotten a reply, but I think it involves using a 74LS04 connected to the serial out of the Geiger into the Serial in of the Arduino (I am not sure if this is true but that seems to be the case if you follow what he says on this website:

http://mightyohm.com/blog/2012/05/pics- ... ker-faire/

If you get a response let me know. Thanks,

David

User avatar
mightyohm
Site Admin
Posts: 1028
Joined: Fri Apr 03, 2009 10:29 pm
Location: Seattle, WA
Contact:

Re: High Altitude Radiation

Post by mightyohm »

You can use a 74LS04 as a buffer (put 2 of the inverters in series). The idea is to level shift the 3V outputs of the geiger kit up to 5V levels that the Arduino can read. I don't have a schematic handy, and I also haven't verified that the circuit works with very low battery voltages (but it should, since Vih for TTL is 2V).

Lunar_Lander
Posts: 1
Joined: Sun Jun 30, 2013 11:03 am

Re: High Altitude Radiation

Post by Lunar_Lander »

A late addition to this thread: I have tested my kit at University in the vacuum chamber we have. For that I took the circuit board from my March 5 balloon flight (with an Arduino Pro Mega 3.3V) and soldered on a cable to the Serial3 port to be connected to the Geiger's Serial output. I used a code that NickB wrote to read the serial data stream to extract the CPM value and integrated that into a code that transmitted the pressure measured by a Bosch BMP085 pressure sensor and the CPM value via the radio to the outside of the chamber. The values were also stored on a microSD card.

The pressure was reduced to 10 mbar, which corresponds to an altitude of about 31 km. This plot then was obtained.
Image
(Bigger Version here: http://oernen2balloon.files.wordpress.c ... 06-261.jpg)

As can be seen, there is no real change in CPM at the lowest pressures, i.e. not significantly, like the count rate getting astronomically high or breaking down altogether (like in this 2011 Balloon Flight from South-West Germany, but they had a different Geiger Counter): http://p56.de/ballonprojekt/20110605/strahlung900.jpg

As the count rate breaks down but rises again at roughly the same altitude, I had the idea, like NickB, that the problem is pressure related. Seems it is not so easy after all :(.

Spiruel
Posts: 1
Joined: Fri Jul 19, 2013 12:17 pm

Re: High Altitude Radiation

Post by Spiruel »

Hi,

We recently launched a GM tube up to an altitude of 31km on the 28 June this year.

You may be interested in our results!

Here is a profile histogram of what we recorded: https://www.dropbox.com/s/e38b9plxvrjic ... essure.pdf

As you can see, the peak on the graph confirmed the Pfotzer maximum almost perfectly! If you haven't heard of the Pfotzer maximum, here's the explanation:
'With increasing depth in the atmosphere, the primary cosmic radiation component decreases, whereas the secondary radiation component increases. This complex situation results in a maximum of the dose rate at an altitude of 20 to 25 km, the so-called Pfotzer maximum. From this altitude to earth surface, the dose rate decreases continuously. Besides of the dependence of the radiation field on the altitude, its parameters vary with the geomagnetic latitude and the solar cycle.'

You may like to read an interesting article from 1936 about it here: https://www.dropbox.com/s/ckdrwd0ouzrgt ... phere.docx

Post Reply