Radiation dosimeter help

[pisoiu]

I have purchased recently a set of radiation dosimeters used by german troops, type FH39. The set has two types of pen dosimeters, one with 50 roentgen scale and other with 500 roentgen scale. These dosimeters were basically designed to measure total ionized radiation over a long period of time, say a day or two. What I'm interested is if it is possible to convert one such dosimeter to a device which measure instantaneous radiation by attaching an amplification circuit to its ionization chamber. I'm interested to build something similar with geiger counter. I have 20 pens available so sacrificing one or two for this project would not be a problem. The problem is that I don't understand very well the physics around this subject and there may be some details that I miss. Another problem would be the calibration of such home built device. Obviously, I do not have and I will not be able to procure radiation sources so the only available source, in the best case, is to ask for help at a medical x-ray facility. I want to know if such device could be built in these conditions.

Regards,

 

[bluehole]

Well it is a wild guess... Do you have a (OLD) CRT TV??? that can provide you with some radiation. X-Ray and Beta ray i guess
Next few smoke detectors have a nuclear material too.
But to calibrate you need a reference or a already calibrated meter.

You may find this useful

 

[DeepOne]

Recently collected such scheme

Another scheme:


I think more simply to gain Geyger tube than try to force to work in this quality еlectrometer.
Though I tried as sensor neon lamp with coaxial electrode, like works, but sensitivity very low (voltage begin count around 50V). But for checking needs source to radiation too, may be useful some old luminous tumbler or instrument..

 

[bluehole]

Then Check for Cloud-chamber here.

If a simple electroscope is not good then ionization chamber is good and less costly.

 

[pisoiu]

Thank you. I admit the CRT idea never crossed my mind, even if it is so obvious...

 

[Kripton2035]

I just started a geiger repository - may be you can find some schematic ideas in it ?
regards,

**broken link removed**

 

[bluehole]

I just started a geiger repository - may be you can find some schematic ideas in it ?
regards,

**broken link removed**

Hey very nice repo .
Do you have sources where can I get cheaper but sensitive Geiger tube?
Or else Do you know some Cheaper Solidstate radiation detector circuits which can be assembled and tested by school students?
If so please put those in your repo please.

 

[Kripton2035]

I bought a sbm20 tube on ebay for some $20...
the other tubes are really more expansive...
if it is to detect some cloud above you, the sbm20 is really enought !

 

[dick_freebird]

There are dosimeter IC products out there that operate
roughly this way, short-term integrating a photocurrent
and incrementing a counter / resetting the integrator. But
the tube you show appears to be an optically read, charge
bleed type of scheme with no electrical connections.

A known-response plain diode and integrator could do the
same thing, the details of calibration and consistency
(especially how to resolve a small radiation rate against
a significant temperature-dependent leakage) are a key
technical hurdle that requires somebody put forth effort.
Dosimetry at high dose rates is easier. But those kind of
dose rates mean you're walking dead by the time you read
it.