Anybody know if it's still possible to get thorium mantles of the sort
fitted to tilley lamps from any place there days?

It's actually for testing an old Geiger counter that was a Maplin kit.

I'd have guessed that the thorium has been replaced by some other
material these days, but I could be wrong.

--
John

Anybody know if it's still possible to get thorium mantles of the sort
fitted to tilley lamps from any place there days?

It's actually for testing an old Geiger counter that was a Maplin kit.

Don't know, but do you have an old luminous watch or, best of all, the
standard War Dept prismatic compass? Mine gives about 500 counts per second.
The natural K40 in high potash fertiliser will give you about double the
natural background.

On Mon, 19 Jun 2006 20:11:49 GMT, John Nickum wrote:

Anybody know if it's still possible to get thorium mantles of the sort
fitted to tilley lamps from any place there days?

It's actually for testing an old Geiger counter that was a Maplin kit.

I'd have guessed that the thorium has been replaced by some other
material these days, but I could be wrong.

Try a smoke alarm. The disc is Americium (alpha source)
--
Jim
Tyneside UK
http://www.jimscot.plus.com

The message
from Jim Scott contains these words:

Try a smoke alarm. The disc is Americium (alpha source)

Just remember to crimp it back again afterwards!

--
Skipweasel
Pay no attention to that man behind the curtain.

"Newshound" wrote:

Anybody know if it's still possible to get thorium mantles of the sort
fitted to tilley lamps from any place there days?

It's actually for testing an old Geiger counter that was a Maplin kit.

Don't know, but do you have an old luminous watch or, best of all, the
standard War Dept prismatic compass? Mine gives about 500 counts per second.
The natural K40 in high potash fertiliser will give you about double the
natural background.

Thanks for the suggestion. I've looked on ebay, and WWII luminous
watches are about £20-£30, which is a bit expensive. I didn't know
about the potash fertiliser.

--
John

Jim Scott wrote:

On Mon, 19 Jun 2006 20:11:49 GMT, John Nickum wrote:

Anybody know if it's still possible to get thorium mantles of the sort
fitted to tilley lamps from any place there days?

It's actually for testing an old Geiger counter that was a Maplin kit.

I'd have guessed that the thorium has been replaced by some other
material these days, but I could be wrong.

Try a smoke alarm. The disc is Americium (alpha source)

Thanks. I've just tried monitoring a smoke alarm, but of course, alpha
particles can't go through its plastic case. At least smoke alarms are
cheap, so I'll try breaking one open tomorrow.

--
John

"John Nickum" wrote

Thanks. I've just tried monitoring a smoke alarm, but of course, alpha
particles can't go through its plastic case. At least smoke alarms are
cheap, so I'll try breaking one open tomorrow.

Careful now, you will have the anti-terrorist squad kicking your door in
(and maybe shooting you) for trying to build an improvised dirty nuclear
device :-)

H

"John Nickum" wrote in message ...
Anybody know if it's still possible to get thorium mantles of the sort
fitted to tilley lamps from any place there days?

It's actually for testing an old Geiger counter that was a Maplin kit.

I'd have guessed that the thorium has been replaced by some other
material these days, but I could be wrong.

Most valves (out of a nold Telly etc) have thoriated tungsten cathodes in
'em, which might be enough of a source? I'd guess that the electron gun in a
tube might be a source, too. IIRC, camping gas lamp mantles are thoriated,
TAAW.

I used to work in a big transmitter cabin which had fibre-optics for the
control gear, and wondered why we had to replace them every few years, only
to be told "Oh, the radiation from the TWT [1] makes them go cloudy..." 0

Dave H.
(The engineer formerly known as Homeless)

[1] Travelling Wave Tube, a big (ie several KW) broadband microwave
transmitting amplifier. With a 5KV, 5A power supply. Dangerous. VERY
Dangerous.

John Nickum wrote:

Anybody know if it's still possible to get thorium mantles of the sort
fitted to tilley lamps from any place there days?

It's actually for testing an old Geiger counter that was a Maplin kit.

I'd have guessed that the thorium has been replaced by some other
material these days, but I could be wrong.

http://www.mindfully.org/Nucs/Radioa...cout1nov98.htm

;-)


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Mon, 19 Jun 2006 20:11:49 GMT, John Nickum
wrote:

|Anybody know if it's still possible to get thorium mantles of the sort
|fitted to tilley lamps from any place there days?
|
|It's actually for testing an old Geiger counter that was a Maplin kit.
|
|I'd have guessed that the thorium has been replaced by some other
|material these days, but I could be wrong.

If you live in a granite area, Cornwall, Scotland etc, the rock is mildly
radioactive. Are you traveling to a granite area sometime soon?
--
Dave Fawthrop dave hyphenologist co uk Google Groups is IME the *worst*
method of accessing usenet. GG subscribers would be well advised get a
newsreader, say Agent, and a newsserver, say news.individual.net. These
will allow them: to see only *new* posts, a killfile, and other goodies.

On Mon, 19 Jun 2006 20:11:49 GMT, John Nickum wrote:

Anybody know if it's still possible to get thorium mantles of the sort
fitted to tilley lamps from any place there days?

Yes. The cheap Chinese mantles contain thorium, expect 500-600 Becquerel.

Anchor and Egret are mantle brands that are radioactive, Luxor and Petromax
aren't.

Just take you Geiger counter into the shop!


Thomas Prufer

Owain wrote:

John Nickum wrote:
Anybody know if it's still possible to get thorium mantles of the sort
fitted to tilley lamps from any place there days?
It's actually for testing an old Geiger counter that was a Maplin kit.

Would tritium dials from Trimphones be an acceptable alternative source
of radioactivity?

According to the article referenced by John Ruum, the tritium would be
mixed into a waxy substance - and presumably sealed in glass which
would prevent escape of the alpha particles.

Breaking it open could be messy, so I think I'll pass on that one. :-)

--
John

"Dave H." wrote:

Most valves (out of a nold Telly etc) have thoriated tungsten cathodes in
'em, which might be enough of a source? I'd guess that the electron gun in a
tube might be a source, too. IIRC, camping gas lamp mantles are thoriated,
TAAW.

Thanks. I guess I could go into the local electonics shack and ask if
they've got anyold valves that they were going to throw away.

I used to work in a big transmitter cabin which had fibre-optics for the
control gear, and wondered why we had to replace them every few years, only
to be told "Oh, the radiation from the TWT [1] makes them go cloudy..." 0

Jeez.

--
John

John Rumm wrote:

http://www.mindfully.org/Nucs/Radioa...cout1nov98.htm

I'd heard of the story, but not at that level of detail. Really
astonishing and quite frightening.

--
John

Dave Fawthrop wrote:

If you live in a granite area, Cornwall, Scotland etc, the rock is mildly
radioactive. Are you traveling to a granite area sometime soon?

I'm in the Midlands, so it's a long way to travel either way.

--
John

Thomas Prufer wrote:

On Mon, 19 Jun 2006 20:11:49 GMT, John Nickum wrote:

Anybody know if it's still possible to get thorium mantles of the sort
fitted to tilley lamps from any place there days?

Yes. The cheap Chinese mantles contain thorium, expect 500-600 Becquerel.

Anchor and Egret are mantle brands that are radioactive, Luxor and Petromax
aren't.

Just take you Geiger counter into the shop!

Thanks for the info. But using the Geiger counter to select a mantle
might not be too clever. ;-)

--
John

"John Nickum" wrote :

According to the article referenced by John Ruum, the tritium would be
mixed into a waxy substance - and presumably sealed in glass which
would prevent escape of the alpha particles.



Getting tritium to emit alpha particles would be a really neat trick, and
worthy of a Nobel Prize :-)

Steve S

"HLAH" wrote:

"John Nickum" wrote
Thanks. I've just tried monitoring a smoke alarm, but of course, alpha
particles can't go through its plastic case. At least smoke alarms are
cheap, so I'll try breaking one open tomorrow.

Careful now, you will have the anti-terrorist squad kicking your door in
(and maybe shooting you) for trying to build an improvised dirty nuclear
device :-)

Aaagh! ;-)

Anyway, I've broken open the smoke detector and found that it's more
than enough to prove that the Geiger counter is working.

Job done.

If I hold the Geiger counter just 1cm from the source, it really does
thunder, and I have to switch it to its uppermost range, but if I hold
it 5cm away, then it's back to background levels. So it seems that the
smoke detector emits low-energy alpha particles that have low
penetration even through the air, so it's a nice safe test.

--
John

"Steve S" wrote:

"John Nickum" wrote :
According to the article referenced by John Ruum, the tritium would be
mixed into a waxy substance - and presumably sealed in glass which
would prevent escape of the alpha particles.

Getting tritium to emit alpha particles would be a really neat trick, and
worthy of a Nobel Prize :-)

Errr... ummm... beta particles, I meant beta particles.

I guess that they must be very low energy beta particles, because if
they were able to penetrate the glass, they'd never have gone on the
market, even in the 70s.

--
John

John Nickum wrote:

I guess that they must be very low energy beta particles, because if
they were able to penetrate the glass, they'd never have gone on the
market, even in the 70s.

So called "traser" key fobs and watches have tritium contained in
phosphor lined glass vial, the beta particles as you say don't make it
out unless you break the glass

http://www.glowrings.com/

"John Nickum" wrote :

Errr... ummm... beta particles, I meant beta particles.

I'll let you off :-)

I guess that they must be very low energy beta particles, because if
they were able to penetrate the glass, they'd never have gone on the
market, even in the 70s.


Yes, low energy, 0.018590 MeV. Cannot even penetrate skin, so only dangerous
if inhaled or ingested. The difficulty is that tritium is hard to contain
due to its propensity for diffusing through solids such as plastics, rubber
and even some steels.

Tritium decays to helium-3, which is non-radioactive, so you don't have to
worry about other decays down the line. Contrast with thorium, for example,
one of whose decay products is radon.

Steve S

Newshound wrote:


It's actually for testing an old Geiger counter that was a Maplin kit.

The natural K40 in high potash fertiliser will give you about double the
natural background.

I was told that the radiation detectors at Sellafield/Windscale were
sensitive enough to trigger an alarm if somebody went past them
carrying a pack of cigarettes - the potassium nitrate in them from (a)
tobacco being fertilised and (b) being added to ensure they don't go
out when lit being radioactive enough. I could never find a source for
that story, 'though, despite a lot of searching. It seems unlikely, if
you read the article in the reference URL below.

The natural radioactivity of the normal isotopic mixture of potassium
on Earth is interesting - it being the major source of radioactivity
within the human body.

See
URL:http://www.fas.harvard.edu/~scdiroff/lds/QuantumRelativity/RadioactiveHumanBody/RadioactiveHumanBody.html

Cheers,

Sid

On Tue, 20 Jun 2006 07:55:12 GMT, John Nickum wrote:

Thanks for the info. But using the Geiger counter to select a mantle
might not be too clever. ;-)

I had a bunch of my mantles tested at a nuclear lab. Some were radioactive, some
weren't; they documented them, and were very nice about it.

Trouble was walking out through the exit -- the contamination alarm went off,
security guards came out, explaining to do...



Thomas Prufer

wrote:
Newshound wrote:


It's actually for testing an old Geiger counter that was a Maplin kit.

The natural K40 in high potash fertiliser will give you about double the
natural background.

I was told that the radiation detectors at Sellafield/Windscale were
sensitive enough to trigger an alarm if somebody went past them
carrying a pack of cigarettes - the potassium nitrate in them from (a)
tobacco being fertilised and (b) being added to ensure they don't go
out when lit being radioactive enough. I could never find a source for
that story, 'though, despite a lot of searching. It seems unlikely, if
you read the article in the reference URL below.

The natural radioactivity of the normal isotopic mixture of potassium
on Earth is interesting - it being the major source of radioactivity
within the human body.

See
URL:http://www.fas.harvard.edu/~scdiroff/lds/QuantumRelativity/RadioactiveHumanBody/RadioactiveHumanBody.html

Following up on the above, buy a pack of Lo-Salt, which is about 66%
Potassium Chloride. Its radioactivity (due to the potassium 40) will
be significantly above background levels. See here
URL:http://www.blackcatsystems.com/science/radprod.html

Cheers,

Sid.

In message .com,
writes
Newshound wrote:


It's actually for testing an old Geiger counter that was a Maplin kit.

The natural K40 in high potash fertiliser will give you about double the
natural background.

I was told that the radiation detectors at Sellafield/Windscale were
sensitive enough to trigger an alarm if somebody went past them
carrying a pack of cigarettes -

Sounds like ******** to me

--
geoff

On Tue, 20 Jun 2006 21:04:39 GMT, raden wrote:

In message .com,
writes
Newshound wrote:


It's actually for testing an old Geiger counter that was a Maplin kit.

The natural K40 in high potash fertiliser will give you about double the
natural background.

I was told that the radiation detectors at Sellafield/Windscale were
sensitive enough to trigger an alarm if somebody went past them
carrying a pack of cigarettes -

Sounds like ******** to me

Do they set it off as well then???

:O

"EricP" wrote :


I was told that the radiation detectors at Sellafield/Windscale were
sensitive enough to trigger an alarm if somebody went past them
carrying a pack of cigarettes -

Sounds like ******** to me

Do they set it off as well then???


Dunno, but what I want to know is: do cats have eighteen half-lives?

Steve S

On Tue, 20 Jun 2006 21:16:29 GMT, Steve S wrote:

"EricP" wrote :

I was told that the radiation detectors at Sellafield/Windscale were
sensitive enough to trigger an alarm if somebody went past them
carrying a pack of cigarettes -

Sounds like ******** to me

Do they set it off as well then???


Dunno, but what I want to know is: do cats have eighteen half-lives?

Steve S

I think you'll find that they have an infinite number! )
--
Jim
Tyneside UK
http://www.jimscot.plus.com

On Tue, 20 Jun 2006 22:19:18 +0100, Jim Scott
wrote:

On Tue, 20 Jun 2006 21:16:29 GMT, Steve S wrote:

"EricP" wrote :

I was told that the radiation detectors at Sellafield/Windscale were
sensitive enough to trigger an alarm if somebody went past them
carrying a pack of cigarettes -

Sounds like ******** to me

Do they set it off as well then???


Dunno, but what I want to know is: do cats have eighteen half-lives?

Steve S

I think you'll find that they have an infinite number! )

Sounds a purrfect situation either way.

raden wrote:
In message .com,
writes
Newshound wrote:


It's actually for testing an old Geiger counter that was a Maplin kit.

The natural K40 in high potash fertiliser will give you about double the
natural background.

I was told that the radiation detectors at Sellafield/Windscale were
sensitive enough to trigger an alarm if somebody went past them
carrying a pack of cigarettes -

Sounds like ******** to me

--
geoff

Not completely, as far as I can tell. Do a bit of googleing for
cigarettes and polonium 210 for some interesting data on the radiation
dosage to the lungs from smoking cigarettes. However, as polonium-210
is an alpha emitter, it's not detectable by a portal monitor, which
will look for gamma emmissions, and maybe neutrons. However, (again) -
as potassium-40 is a gamma-emitter, it is just about feasible to detect
raised concentrations of potassium in the environment by looking for
the characteristic signature of K-40 emissions, which are at a
particular energy - however, an expensive multi-spectral monitor is
needed. The Americans have tried using just this technique to detect
contraband tobacco & marijuana in freight in 1992 see
URL:http://spiedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PSISDG002276000001000 374000001&idtype=cvips&gifs=yes
so it is possible that a portal monitor - especially the 'pause for 5
seconds while being measured' type would notice elevated K-40 levels.

If a nuclear worker reads this newsgroup, they might be able to say
definitively.

Cheers,

Sid

Jim Scott wrote:
Steve S wrote:
"EricP" wrote :
I was told that the radiation detectors at Sellafield/Windscale were
sensitive enough to trigger an alarm if somebody went past them
carrying a pack of cigarettes -
Sounds like ******** to me
Do they set it off as well then???

Dunno, but what I want to know is: do cats have eighteen half-lives?

I think you'll find that they have an infinite number!

Not like radioactive substances, then, which don't have an
infinite number.

unopened wrote:
raden wrote:
unopened writes
I was told that the radiation detectors at Sellafield/Windscale were
sensitive enough to trigger an alarm if somebody went past them
carrying a pack of cigarettes -
Sounds like ******** to me

Not completely, as far as I can tell. Do a bit of googleing for
cigarettes and polonium 210 for some interesting data on the radiation
dosage to the lungs from smoking cigarettes. However, as polonium-210
is an alpha emitter

Interestingly, smokers are less likely to suffer from certain
radiation damage to the lungs, as the mucous coating is thicker
in theirs, due to the reduced functionality of the cilia and
irritant effect of all the gunk inhaled.

On 21 Jun 2006 13:18:53 +0200, Chris Bacon wrote:

Jim Scott wrote:
Steve S wrote:
"EricP" wrote :
I was told that the radiation detectors at Sellafield/Windscale were
sensitive enough to trigger an alarm if somebody went past them
carrying a pack of cigarettes -
Sounds like ******** to me
Do they set it off as well then???

Dunno, but what I want to know is: do cats have eighteen half-lives?

I think you'll find that they have an infinite number!

Not like radioactive substances, then, which don't have an
infinite number.

Where did you learn your atomics then?
--
Jim
Tyneside UK
http://www.jimscot.plus.com

Jim Scott wrote:
Chris Bacon wrote:
Jim Scott wrote:
Steve S wrote:
"EricP" wrote :
I was told that the radiation detectors at Sellafield/Windscale were
sensitive enough to trigger an alarm if somebody went past them
carrying a pack of cigarettes -
Sounds like ******** to me
Do they set it off as well then???

Dunno, but what I want to know is: do cats have eighteen half-lives?
I think you'll find that they have an infinite number!
Not like radioactive substances, then, which don't have an
infinite number.

Where did you learn your atomics then?

Suppose you've got a known number of atoms of something
radioactive. Can the number of half-lives before they
decay to some other substance be infinite?

On 21 Jun 2006 14:40:00 +0200, Chris Bacon wrote:

Jim Scott wrote:
Chris Bacon wrote:
Jim Scott wrote:
Steve S wrote:
"EricP" wrote :
I was told that the radiation detectors at Sellafield/Windscale were
sensitive enough to trigger an alarm if somebody went past them
carrying a pack of cigarettes -
Sounds like ******** to me
Do they set it off as well then???

Dunno, but what I want to know is: do cats have eighteen half-lives?
I think you'll find that they have an infinite number!
Not like radioactive substances, then, which don't have an
infinite number.

Where did you learn your atomics then?

Suppose you've got a known number of atoms of something
radioactive. Can the number of half-lives before they
decay to some other substance be infinite?

Yes because each time you go through a half-life then the rate of decay
halves too.
Imagine a frog crossing a road. His first jump is half way, his next jump is
half of that and so on. How long before he reaches the other side?
--
Jim
Tyneside UK
http://www.jimscot.plus.com

EricP wrote:

On Tue, 20 Jun 2006 21:04:39 GMT, raden wrote:

In message .com,
writes

snip

I was told that the radiation detectors at Sellafield/Windscale were
sensitive enough to trigger an alarm if somebody went past them
carrying a pack of cigarettes -

Sounds like ******** to me

Do they set it off as well then???

Only if you've been sitting on boulders in Cornwall...



I'll get me coat...

"Jim Scott" wrote in message
...
On 21 Jun 2006 14:40:00 +0200, Chris Bacon wrote:

Jim Scott wrote:
Chris Bacon wrote:
Jim Scott wrote:
Steve S wrote:
"EricP" wrote :
I was told that the radiation detectors at Sellafield/Windscale
were
sensitive enough to trigger an alarm if somebody went past them
carrying a pack of cigarettes -
Sounds like ******** to me
Do they set it off as well then???

Dunno, but what I want to know is: do cats have eighteen half-lives?
I think you'll find that they have an infinite number!
Not like radioactive substances, then, which don't have an
infinite number.

Where did you learn your atomics then?

Suppose you've got a known number of atoms of something
radioactive. Can the number of half-lives before they
decay to some other substance be infinite?

Yes because each time you go through a half-life then the rate of decay
halves too.
Imagine a frog crossing a road. His first jump is half way, his next jump
is
half of that and so on. How long before he reaches the other side?


Distance is infinitely divisible. Atoms are discrete so once you get down
(and you will) to one it either goes or it doesn't, it can't half go. The
progression will not be infinite therefore (although it might take a while
) )


--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)

Only if you've been sitting on boulders in Cornwall...

I'll get me coat...

Since Radon gas is emitted from granite, it collects under floors in
Cornwall, and you can get a grant to fit an extractor fan.

I believe the highest concentration found was in the toilets of a health
centre.
--
Jim
Tyneside UK
http://www.jimscot.plus.com

"Chris Bacon" wrote in message
...
Jim Scott wrote:
Chris Bacon wrote:
Jim Scott wrote:
Steve S wrote:
"EricP" wrote :
I was told that the radiation detectors at Sellafield/Windscale
were
sensitive enough to trigger an alarm if somebody went past them
carrying a pack of cigarettes -
Sounds like ******** to me
Do they set it off as well then???

Dunno, but what I want to know is: do cats have eighteen half-lives?
I think you'll find that they have an infinite number!
Not like radioactive substances, then, which don't have an
infinite number.

Where did you learn your atomics then?

Suppose you've got a known number of atoms of something
radioactive. Can the number of half-lives before they
decay to some other substance be infinite?

No. The exponential theory of radioactive decay does not apply to small
numbers of atoms, as it is essentially a statistical theory. With small
numbers the randomness of the decay becomes very apparent.

Steve S

Jim Scott wrote:
Only if you've been sitting on boulders in Cornwall...

I'll get me coat...

Since Radon gas is emitted from granite, it collects under floors in
Cornwall, and you can get a grant to fit an extractor fan.

I believe the highest concentration found was in the toilets of a health
centre.

This could well be of interest for those wondering about whether
they be exposed to a radon hazard:

http://www.hpa.org.uk/radiation/publ.../1996/ern8.pdf