Ionising Radiation 'stuff'

[Zad]

The uRad uses conventional ex-Russian GM tubes. Quite bulky and high power in modern terms, because of the high voltage generator it needs. I'm surprised more work hasn't been done into using power MOSFETs. They aren't easy to calibrate and obviously it depends a lot on the housing, but they are small and low power and very amenable to being embedded in mobile devices. They do have the potential for being a cheap and mass produced, ideal for monitoring big area events.

[Gary C]

Zad said:

The uRad uses conventional ex-Russian GM tubes. Quite bulky and high power in modern terms, because of the high voltage generator it needs. I'm surprised more work hasn't been done into using power MOSFETs. They aren't easy to calibrate and obviously it depends a lot on the housing, but they are small and low power and very amenable to being embedded in mobile devices. They do have the potential for being a cheap and mass produced, ideal for monitoring big area events.

But the monitoring sites have a value for dose in millisieverts. I would question the accuracy of these sort of measurements.

It's hard enought when you know the nuclide mix likely to be present, but to stick a gm tube in a box and convert cps to sieverts is riddled with difficulties.

[llewop]

Gary C said:

But the monitoring sites have a value for dose in millisieverts. I would question the accuracy of these sort of measurements.

It's hard enought when you know the nuclide mix likely to be present, but to stick a gm tube in a box and convert cps to sieverts is riddled with difficulties.

If the GM tube is energy compensated the energy response could be fairly flat over a wide energy range (perhaps losing low energy) so getting it to read Sieverts shouldn't be that hard with the right set up. Doing it accurately and consistently would of course require regular checks by an appropriate calibration centre.