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I recently acquired a Geiger counter to feed my raging paranoia curiosity.

However, I am wondering if it could harm the Geiger–Müller tube to leave it energized continuously?

I know a couple places (spark fun, for one) Have continuously operating Geiger tubes.

However, my understanding of how they work is that when the gas inside gets struck by a high-energy particle, it causes an ionization path to form between the electrodes. This makes me think that it might cause pitting and evaporation of the anode over time.

Do Geiger–Müller tubes wear out over time? And if so, what it the mechanism that causes the wear?

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  • \$\begingroup\$ Wikipedia notes: The halogen GM tube was invented ... in 1947 ... discharge mechanism takes advantage of a metastable state of the inert gas atom to more-readily ionize a halogen molecule, enabling the tube to operate at typically 400–600 volts instead of 900–1200 volts. This type of GM tube is therefore by far the most common form now. It has a longer life than tubes quenched with organic compounds, because the halogen ions can recombine while the organic vapor is gradually destroyed by the discharge process (giving the latter a life of around 10^8 events). || What voltage is yours? \$\endgroup\$
    – Russell McMahon
    Feb 28, 2012 at 11:11
  • \$\begingroup\$ @Russell McMahon - It's a modern tube, for what it's worth. I think it's around 500V. \$\endgroup\$ Feb 28, 2012 at 11:14
  • \$\begingroup\$ Also, what is the decay mechanism for the halogen-filled tubes? \$\endgroup\$ Feb 28, 2012 at 11:15
  • \$\begingroup\$ @Kellenjb - It would probably be more accurate to say I need to work on asking questions which have an available answer. \$\endgroup\$ Mar 5, 2012 at 1:30

1 Answer 1

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Best guess based on a Gargoyling skim consensus seems to be that

  • Lifetime is probably finite but largish.
    Years to 10+ years of continuous operation in a non lethal environment seems very likely.

  • Modern tubes (since about 1950~) tend to be halogen quenched.

    • Particle impacts cause destruction of quench targets BUT halogen recombines subsequently leading to semi-infinite life
  • Many references refer to "extended" life rather than infinite. Some older one say infinite.

  • Older organic quenched tubes had a lifetime of about 10^8 events. So you could expect a "longer life tube to have say 10^10+ events life.

  • 1 year = 8765 hours =~~ 3 x 10^7 seconds. So:

    • 1 year life at 10^10 events ~= 300+ events / second average.
    • = 10 years at 30+ events/second.

A Gargoyle search using

  • geiger muller halogen quenched lifetime

produces results that look useful.

This is a 1957! paper that discusses the early days of Halogen quenched tubes. It thus tends to less gloss over things that may be taken for granted nowadays - and also he doesn't know things that nave been learned in the last 55 years :-). Useful and interesting though.
Firing cahatcteristics of halogen quenched Geiger muller tubes

1999 lab notes - but useful

Wow! 1972 Airforce Institute of Technology :-)
... investigation into ... short lifetime ...
No doubt pople havce long since come to grips with the problems described, but they give insight - lead solder reaction with Bromine and general Bromine attack causing depletion of the halogen quench gas.

Book Extract pages 103-104 especiall but generally fascinating


1960's halogen quenched tube:

Only passing relevance, but interest guaranteed :-)

enter image description here


Passing relevance. Page 53. BY James Van Allen :-) :-) :-) :-) !!!

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From 1999 lab notes mentioned above - pages one & two

enter image description here

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