[Ian Scott (OP)]

I was wondering about Chernobyl and it would be cool to visit but I might want a XRAY, gamma ray etc detector for a motorbike drive through. Could Neon bulbs be uses as a detector for ionizing radiation.

I was thinking of biasing at about 70 V and detecting pulses - would this work and what efficiency if it did?


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[Soul Surfer]

I agree that a gieger tube is very similar to a neon tube and if it was biassed just below the point of breakdown it shuld be possible to detect penetrating ionising radiation.  there are several things that count against it.

The geometry of the discharge is not good, the glass is probably too thick and would absorb most of the radiation you want to detect and the sensitivity would be too low because the volume of gas is not great enough.  A GM tube should produce a pulse ot two a second from normal background radiation.  Proper GM tubes are available from electronics hobby stores and counters themselves aren't all that expensive

[Ian Scott (OP)]

kewl Ill look up on this Soul Surfer

[RD]

Colour-changing radiation-exposure badge...
http://www.jplabs.com/html/sirad.HTM

If you use a film camera on your Chernobyl trip and your photos are fogged then you're in trouble  []

[Ian Scott (OP)]

Hi RD

Thanks for the web link - it is interesting.

I might buy a radiation monitor patch from them.

[Bored chemist]

People have (according to the web, though I haven't got a reference) used neon bulbs as radiation detectors. They are not very good but they can be made to work. A real GM tube is a much better bet.

[Ian Scott (OP)]

Thanks Bored Chemist

I wonder if a compact fluorescent tube would be better due to its larger volume.

I guess maybe a neon sign - no need to heat filaments. Mercury might be useful as an ionized gas.

I know some PIN diodes are radiation sensitive but have a small die area 1mm^2 etc - so I guess these must be poor detectors.

The problem with patches is that they seen to accrue dosage so periodic exposures time by time are not provided. This integration is better done with s/w but it would be better to see sites that get "hot" and then move to a "colder" place.

People in a stable nuclear site would benefit from accumulated dosage devices but those that adventure may be better provided with instantaneous measurements. This is why I asked about gas ionizing tubes - is the gas mass the issue wrt probability of a neutron colliding - so more mass the better? Or is a silicon PIN diode just more likely to stop a neutron and record a charge given its much higher density.

[lyner]

A proper GM tube has a very thin window of mica at the end so it is much more likely to record you dosage. If you are interested in Health and Safety then there would be a risk in relying on what would be a selective detector.
However, as an experiment, it could be worth trying. You would need a high value damping resistor in series to kill each strike when it occurs or the neon would stay on once it has struck.