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Mercury isotope ratio change in CFLs

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Conundrum

Tue May 28 2013, 05:45AM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062

As far as I know, this is peer reviewed and suggests that something strange is going on within the bulb(s).

The current theory is that mercury is being absorbed into the glass so obviously the lightest isotopes would diffuse further leading
to a bias towards heavier isotopes.

Any ideas?

This might also be a viable way to enrich isotopes such as K-40, albeit in a very inefficient energy intensive way.
See

Proud Mary

Tue May 28 2013, 06:20PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

There's quite a bit of excitement in the LENR community about this - hopes that an unambiguous proof of LENR might at last be hand.

Mercury has some funny isotopes - Hg-180 can fission spontaneously, and rather than getting a 90-90 split as you'd expect, there is an assymmetric split 100-80.

Conundrum

Tue May 28 2013, 08:41PM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062

I had a discussion with someone about this today, it is more likely that a mundane explanation exists such as differential absorption in the phosphor or amalgamation of Hg to the filament supports.

HG180 unstable? Interesting, so if I put some of those Hg containing switches next to a shielded GM tube versus some in a control shielded container then some difference would be seen over a long time?

EDIT: Sort of a poor man's neutrino detector, as in the unlikely event of a neutrino hitting an Hg nucleus in just the right way it gets destabilised and fissions.
Not sure how I'd compensate for ambient radiation and the much larger signal in the tube itself, perhaps supercooling?

I noticed something interesting about these ZP1313's, there appears to be an exposed sealing pip.
Would shining UV light on this affect the count rate much?

-A

Proud Mary

Tue May 28 2013, 09:57PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Conundrum wrote ...

I noticed something interesting about these ZP1313's, there appears to be an exposed sealing pip.
Would shining UV light on this affect the count rate much?

I doubt that ordinary daylight will cause obvious spurious counts - as you get with some sensitive clear glass GM tubes - but for the sake of accuracy, put a spot of black paint on it just to be sure.

Conundrum

Thu May 30 2013, 05:12AM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062

OK thanks for the tip.
What I wanted to try is intentionally exposing the tube to UV LED light in order to boost the sensitivity at the cost of overall accuracy ie for locating radioactive materials prior to a proper scan with the diode disabled.
An alternate method I came up with is to pulse the LED with very short (ie hundreds of nanoseconds) pulses at 30mA so that the tube never gets the chance to fully ionise, tuned to the current count rate so as CR increases the LED pulse width decreases.

Another interesting idea I had, upon examining the raw output from the tube it seems that there may be multiple pulse heights.
Despite the literature saying that GR energy levels aren't linked to pulse width, pulse height might be a factor.
Was thinking about using an MK484 as a pickup here, with a tuned filter to remove everything below say 10 kHz so it doesen't pick up Rugby and motor noise etc.

RE. mercury 180, see

-A

Proud Mary

Thu May 30 2013, 07:14AM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

I don't follow how injecting UV photons into a GM tube will increase its sensitivity. Some of the UV photons will get counted, though. GM tube sensitivity is strongly related, amongst other things, to size - the cross-sectional area of sensitive space presented to inbound gamma photons.

The counting efficiency of GM tubes to gamma rays is very low - more than 99% of gamma rays will just sail through the detector without the interactions needed to produce a Townsend avalanche. As more low energy photons will interact than high energy ones, the energy response of GM tubes is extremely non-linear below about 120 kV, giving the impression that there is ten times more radiation about than there in fact is.

ZP1313 has an energy compensating filter built into its metal jacket. The cost of this more linear response is less sensitivty, as lower energy photons are selectively filtered out.

Carbon_Rod

Thu May 30 2013, 08:06AM

Registered Member #65 Joined: Thu Feb 09 2006, 06:43AM
Location:
Posts: 1155

Proud Mary is correct regarding the UV issue,
some alpha sensitive tubes with Mica exposure aperture windows are completely transparent below 400nm.

Anecdotally, the larger Pancake sensors seem somewhat more sensitive to erroneous events.

Bored Chemist

Thu May 30 2013, 08:12PM

Registered Member #193 Joined: Fri Feb 17 2006, 07:04AM
Location: sheffield
Posts: 1022

Proud Mary wrote ...

There's quite a bit of excitement in the LENR community about this - hopes that an unambiguous proof of LENR might at last be hand.

Mercury has some funny isotopes - Hg-180 can fission spontaneously, and rather than getting a 90-90 split as you'd expect, there is an assymmetric split 100-80.

Why would you expect 50:50?
Uranium doesn't, nor does plutonium

Incidentally, the original article gives a plausible explanation and it doesn't require any weird nuclear physics- just optics and chemistry.

Wolfram

Thu May 30 2013, 09:24PM

Registered Member #33 Joined: Sat Feb 04 2006, 01:31PM
Location: Norway
Posts: 971

Conundrum wrote ...

HG180 unstable? Interesting, so if I put some of those Hg containing switches next to a shielded GM tube versus some in a control shielded container then some difference would be seen over a long time?

Hg180 has a half life of 2.58 seconds so I doubt you will find any in common mercury. Things like this are easy to check before posting.

Proud Mary

Thu May 30 2013, 09:46PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Bored Chemist wrote ...

Why would you expect 50:50?
Uranium doesn't, nor does plutonium

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