Low-energy x-rays and GMC 300e Plus Geiger Counter

[Fraser]

Sadly I do not know the actual keV level coming out of the tube and hitting the DUT. Again, the problem is finding a keV meter that works at such low energy levels. Sadly I do not have access to such a meter. I do own a couple of Faxitron MX-20 units that can apply 10 to 35kvp to the Microfocus tube. Great for checking low energy response of a meter but again, I have no idea what keV is emitted from the tube.

Sorry I can't help more. It's an interesting subject but sadly low energy X-Ray can be a little challenging when it comes to materials penetration and measurement. Interestingly Mammography X-Ray test and compliance equipment is often designed to measure low levels of energy. I have a Radcal 2025 meter that is fitted with very sensitive ionisation chambers. It goes berserk when it's probe is placed inside the Tel-X-Ometer. I need to build a battery eliminator for the 300V chamber bias though as the original zinc carbon battery is down to 145 Volts now due to age. I have the parts, just need the time and inclination.

Fraser

[Fraser]

I shall do some more testing of the GMC-300E in the Tel-X-Ometer (because I can easily see the display) I only tested it when sat on its back and the energy entering the tube through the bottom of the plastic case. The front panel has slots cut in it behind the label in order to improve detection of low energy sources.

As you will know, low energy X-Ray is attenuated by dense materials and it would be good to see where the GMC-300E is most sensitive to low energies.

I will update you on the results for your reference.

Fraser

[Plat]

I shall do some more testing of the GMC-300E in the Tel-X-Ometer (because I can easily see the display) I only tested it when sat on its back and the energy entering the tube through the bottom of the plastic case. The front panel has slots cut in it behind the label in order to improve detection of low energy sources.

As you will know, low energy X-Ray is attenuated by dense materials and it would be good to see where the GMC-300E is most sensitive to low energies.

I will update you on the results for your reference.

Fraser

Now I want an x-ray machine! It is so cool to be able to play with this stuff safely and in a controlled manor like with your machines. Your real-world testing of this stuff is fantastic, it really answers allt of my questions that the physics people cannot. I bet the GMC didn't click because it was overloaded and the logic couldn't handle the input fast enough.

I am thinking it will read nothing at 10kvp, and by 15kvp should show a significant reading. Thin glass should start allowing a large fractions of photons through there.