Low Level Gamma Radiation...

[Mike Monett]

\"John Miles, KE5FX\" <jmiles@gmail.com> wrote:

On Saturday, June 25, 2022 at 11:16:45 AM UTC-7, Mike Monett wrote:
I tried to order one. Does not ship to Canada. Can you order one and
mail it to me? I can pay you via Paypal. Thanks.

Maybe. I\'ll have to surf through the Commerce and ITAR lists to see if
there\'s a reason why the seller doesn\'t ship to Canada. Shifty folk,
Canadians.

(It\'ll be a few days before I have time to deal with it, for various
reasons.)

-- john, KE5FX

That\'s fantastic. Thanks.

A lot of US vendors don\'t want to ship to Canada. But the majority do ship
with no problem. Spending time to find out why may give mixed results. I
can probably ask the vendor what his reasons are. In the meantime, my main
goal is to get a copy of his model before he runs out or gives up.

I will send my name and address to your gmail address. Again, thanks.

Mike



--
MRM

 

[Phil Hobbs]

Mike Monett wrote:

\"John Miles, KE5FX\" <jmiles@gmail.com> wrote:

On Sunday, June 5, 2022 at 4:07:22 PM UTC-7, Mike Monett wrote:
My Radiascan Radiacode finally arrived from Russia. After the
sanctions, I was surprised to see it made it.

This listing is also very interesting:

https://www.ebay.com/itm/194659036410

Basically 2000+ PMT+CsI(Tl) assemblies for sale at around $20 each.
Wonder how they\'d compare to the solid-state CsI(Tl) detector assembly
in the Radiacode unit?

-- john, KE5FX

I tried to order one. Does not ship to Canada. Can you order one and mail it
to me? I can pay you via Paypal. Thanks.

For any serious use, I\'d budget for a replacement PMT. They age out
after several years, which is probably why these assemblies were
replaced. They also wear out on account of photocurrent--the usual rule
is that you can get an integrated anode charge of about 1000 C/cm**2 of
photocathode area before the gain drops by ~half.

If you\'re going to use an ionic scintillator in contact with an end-on
PMT (one where the photocathode is deposited directly on the faceplate)
you\'ll need to keep the cathode near ground to avoid ions migrating
through the glass and corroding the PC. That means running the anode at
high voltage and coupling the pulses out with a cap or transformer or
something.

Using an air gap between scintillator and tube allows you to keep the
anode near ground, which is much more convenient, but costs you about
half your light. (The collection efficiency goes like the etendue,
which has a factor of n**2 in it.)

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Mike Monett]

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

Mike Monett wrote:
\"John Miles, KE5FX\" <jmiles@gmail.com> wrote:

On Sunday, June 5, 2022 at 4:07:22 PM UTC-7, Mike Monett wrote:
My Radiascan Radiacode finally arrived from Russia. After the
sanctions, I was surprised to see it made it.

This listing is also very interesting:

https://www.ebay.com/itm/194659036410

Basically 2000+ PMT+CsI(Tl) assemblies for sale at around $20 each.
Wonder how they\'d compare to the solid-state CsI(Tl) detector assembly
in the Radiacode unit?

-- john, KE5FX

I tried to order one. Does not ship to Canada. Can you order one and
mail it to me? I can pay you via Paypal. Thanks.

For any serious use, I\'d budget for a replacement PMT. They age out
after several years, which is probably why these assemblies were
replaced. They also wear out on account of photocurrent--the usual rule
is that you can get an integrated anode charge of about 1000 C/cm**2 of
photocathode area before the gain drops by ~half.

If you\'re going to use an ionic scintillator in contact with an end-on
PMT (one where the photocathode is deposited directly on the faceplate)
you\'ll need to keep the cathode near ground to avoid ions migrating
through the glass and corroding the PC. That means running the anode at
high voltage and coupling the pulses out with a cap or transformer or
something.

Using an air gap between scintillator and tube allows you to keep the
anode near ground, which is much more convenient, but costs you about
half your light. (The collection efficiency goes like the etendue,
which has a factor of n**2 in it.)

Cheers

Phil Hobbs

Good information. Thanks.

I\'m not planning on heavy use. The idea is to compare the scintillator
againt the Radiacode, and try to measure any Radon gas in the basement.
Then it will probably go into storage.



--
MRM

 

[Chris Jones]

On 28/06/2022 08:01, Mike Monett wrote:

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

Mike Monett wrote:
\"John Miles, KE5FX\" <jmiles@gmail.com> wrote:

On Sunday, June 5, 2022 at 4:07:22 PM UTC-7, Mike Monett wrote:
My Radiascan Radiacode finally arrived from Russia. After the
sanctions, I was surprised to see it made it.

This listing is also very interesting:

https://www.ebay.com/itm/194659036410

Basically 2000+ PMT+CsI(Tl) assemblies for sale at around $20 each.
Wonder how they\'d compare to the solid-state CsI(Tl) detector assembly
in the Radiacode unit?

-- john, KE5FX

I tried to order one. Does not ship to Canada. Can you order one and
mail it to me? I can pay you via Paypal. Thanks.

For any serious use, I\'d budget for a replacement PMT. They age out
after several years, which is probably why these assemblies were
replaced. They also wear out on account of photocurrent--the usual rule
is that you can get an integrated anode charge of about 1000 C/cm**2 of
photocathode area before the gain drops by ~half.

If you\'re going to use an ionic scintillator in contact with an end-on
PMT (one where the photocathode is deposited directly on the faceplate)
you\'ll need to keep the cathode near ground to avoid ions migrating
through the glass and corroding the PC. That means running the anode at
high voltage and coupling the pulses out with a cap or transformer or
something.

Using an air gap between scintillator and tube allows you to keep the
anode near ground, which is much more convenient, but costs you about
half your light. (The collection efficiency goes like the etendue,
which has a factor of n**2 in it.)

Cheers

Phil Hobbs

Good information. Thanks.

I\'m not planning on heavy use. The idea is to compare the scintillator
againt the Radiacode, and try to measure any Radon gas in the basement.
Then it will probably go into storage.

If you have radon, try running a CRT television for a few hours and then
wipe down the screen with a damp piece of tissue that has been folded to
about the size of your geiger tube (or its end window if it has one). I
find the dust on my CRT screen is quite radioactive but it has a short
half-life. I\'m guessing it is some polonium isotopes. The dust that
collects on the screen doesn\'t end up in my lungs, so perhaps CRTs are
healthier to have in the house than flatscreens.

 

[Clifford Heath]

On 28/6/22 13:31, Chris Jones wrote:

If you have radon, try running a CRT television for a few hours and then
... The dust that
collects on the screen doesn\'t end up in my lungs, so perhaps CRTs are
healthier to have in the house than flatscreens.

Not as healthy as having no TV. That crap bypasses the lungs and goes
straight to the brain

 

[Jan Panteltje]

On a sunny day (Tue, 28 Jun 2022 13:31:26 +1000) it happened Chris Jones
<lugnut808@spam.yahoo.com> wrote in <eCuuK.190184$pqD1.30751@fx01.ams4>:

If you have radon, try running a CRT television for a few hours and then
wipe down the screen with a damp piece of tissue that has been folded to
about the size of your geiger tube (or its end window if it has one). I
find the dust on my CRT screen is quite radioactive but it has a short
half-life. I\'m guessing it is some polonium isotopes. The dust that
collects on the screen doesn\'t end up in my lungs, so perhaps CRTs are
healthier to have in the house than flatscreens.

Some CRTs from sets that came in for repair had collected tar from smokers.. nicotine.
Wiping clean with alcohol increased brightness considerably
So yes, functioned as air filter ;-)

 

[Jan Panteltje]

On a sunny day (Tue, 28 Jun 2022 17:03:04 +1000) it happened Clifford Heath
<no_spam@please.net> wrote in
<16fcb6d40dd74681$1$391142$70dd7a6b@news.thecubenet.com>:

On 28/6/22 13:31, Chris Jones wrote:
If you have radon, try running a CRT television for a few hours and then
... The dust that
collects on the screen doesn\'t end up in my lungs, so perhaps CRTs are
healthier to have in the house than flatscreens.

Not as healthy as having no TV. That crap bypasses the lungs and goes
straight to the brain

There are some informative science related programs on (sat) TV Astra1
and there is (at least on the continent) tetelext / ceefax / videotext
Caesar: give the people bread and TeeFee
or was it games?

Its a shame UK dropped Ceefax. no way to see the program schedule other then
internet, talk about a DANGEROUS medium ? Just read this group!

Radon detectors and test kits are 14 USD upwards on Amazon...

I was looking for a sold state PMT diode .. for that tomshardware link I gave,
delivery November, about 56 Euro 1 piece

I will hang on to my good old PMTs for now, have also many plastic scintillators.
Big PMT will likely last to WW3 (2024??). After that all lights up in the dark anyways

BTW I have a nice scintillation screen too.

 

[Phil Hobbs]

Mike Monett wrote:

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

Mike Monett wrote:
\"John Miles, KE5FX\" <jmiles@gmail.com> wrote:

On Sunday, June 5, 2022 at 4:07:22 PM UTC-7, Mike Monett wrote:
My Radiascan Radiacode finally arrived from Russia. After the
sanctions, I was surprised to see it made it.

This listing is also very interesting:

https://www.ebay.com/itm/194659036410

Basically 2000+ PMT+CsI(Tl) assemblies for sale at around $20 each.
Wonder how they\'d compare to the solid-state CsI(Tl) detector assembly
in the Radiacode unit?

-- john, KE5FX

I tried to order one. Does not ship to Canada. Can you order one and
mail it to me? I can pay you via Paypal. Thanks.

For any serious use, I\'d budget for a replacement PMT. They age out
after several years, which is probably why these assemblies were
replaced. They also wear out on account of photocurrent--the usual rule
is that you can get an integrated anode charge of about 1000 C/cm**2 of
photocathode area before the gain drops by ~half.

If you\'re going to use an ionic scintillator in contact with an end-on
PMT (one where the photocathode is deposited directly on the faceplate)
you\'ll need to keep the cathode near ground to avoid ions migrating
through the glass and corroding the PC. That means running the anode at
high voltage and coupling the pulses out with a cap or transformer or
something.

Using an air gap between scintillator and tube allows you to keep the
anode near ground, which is much more convenient, but costs you about
half your light. (The collection efficiency goes like the etendue,
which has a factor of n**2 in it.)


Good information. Thanks.

I\'m not planning on heavy use. The idea is to compare the scintillator
againt the Radiacode, and try to measure any Radon gas in the basement.
Then it will probably go into storage.

It ought to work fine for light-duty use like that, though you\'ll need
the PMT supply and bias string. If you know the tube P/N, I can
probably tell you what to use.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Mike Monett]

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

> Mike Monett wrote:

[...]

I\'m not planning on heavy use. The idea is to compare the scintillator
againt the Radiacode, and try to measure any Radon gas in the basement.
Then it will probably go into storage.

It ought to work fine for light-duty use like that, though you\'ll need
the PMT supply and bias string. If you know the tube P/N, I can
probably tell you what to use.

Cheers

Phil Hobbs

I don\'t think the PMT P/N is available. I also assume the bias string is
buried inside the assembly. I\'ll probably have to find the operating voltage
by experimenting, a time-honored tradition among hackers.



--
MRM

 

[Phil Hobbs]

Mike Monett wrote:

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

Mike Monett wrote:

[...]

I\'m not planning on heavy use. The idea is to compare the scintillator
againt the Radiacode, and try to measure any Radon gas in the basement.
Then it will probably go into storage.

It ought to work fine for light-duty use like that, though you\'ll need
the PMT supply and bias string. If you know the tube P/N, I can
probably tell you what to use.

Cheers

Phil Hobbs

I don\'t think the PMT P/N is available. I also assume the bias string is
buried inside the assembly. I\'ll probably have to find the operating voltage
by experimenting, a time-honored tradition among hackers.

Turns out the p/n is (more or less) in the listing title: it\'s some
flavour of R7400, whose datasheet is here, courtesy of Jeroen & Co:
<https://ctf3-tbts.web.cern.ch/instr/PMT/R7400U_TPMH1204E07.pdf>.

CsI(Tl) emits in the visible (the peak is around 550 nm), so the tube is
probably an R7400-02 or -20.

It\'s an 8-stage tube that likes about 75-100V per stage, and is
interestingly fast at 800 ps FWHM. That\'s fast like an APD, and much
faster than a SiPM/MPPC. I ordered a few of them to try out, probably
without the scintillator.

For scintillation counting, you don\'t need brilliant linearity, so a
resistor string is probably fine for the dynode bias. I\'d start with a
current-limited -1 kV variable supply and some 1M resistors, with a
2.2-nF cap across each of the bottom two or three resistors. That way,
at 800V you\'ll be dissipating about 80 mW.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Mike Monett]

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

[...]

Turns out the p/n is (more or less) in the listing title: it\'s some
flavour of R7400, whose datasheet is here, courtesy of Jeroen & Co:
https://ctf3-tbts.web.cern.ch/instr/PMT/R7400U_TPMH1204E07.pdf>.

CsI(Tl) emits in the visible (the peak is around 550 nm), so the tube is
probably an R7400-02 or -20.

It\'s an 8-stage tube that likes about 75-100V per stage, and is
interestingly fast at 800 ps FWHM. That\'s fast like an APD, and much
faster than a SiPM/MPPC. I ordered a few of them to try out, probably
without the scintillator.

For scintillation counting, you don\'t need brilliant linearity, so a
resistor string is probably fine for the dynode bias. I\'d start with a
current-limited -1 kV variable supply and some 1M resistors, with a
2.2-nF cap across each of the bottom two or three resistors. That way,
at 800V you\'ll be dissipating about 80 mW.

Cheers

Phil Hobbs

Very valuable information. Thanks.



--
MRM

 

[Mike Monett]

\"John Miles, KE5FX\" <jmiles@gmail.com> wrote:

On Sunday, June 5, 2022 at 4:07:22 PM UTC-7, Mike Monett wrote:
My Radiascan Radiacode finally arrived from Russia. After the
sanctions, I was surprised to see it made it.

This listing is also very interesting:

https://www.ebay.com/itm/194659036410

Basically 2000+ PMT+CsI(Tl) assemblies for sale at around $20 each.
Wonder how they\'d compare to the solid-state CsI(Tl) detector assembly
in the Radiacode unit?

-- john, KE5FX

I tried to order one. Does not ship to Canada. Can you order one and mail it
to me? I can pay you via Paypal. Thanks.



--
MRM

 

[John Miles, KE5FX]

On Sunday, June 26, 2022 at 5:23:43 PM UTC-7, Mike Monett wrote:
> I will send my name and address to your gmail address. Again, thanks.

Go ahead and send your address to me at john (at) miles.io if you\'d
still like one, and I\'ll throw one in a padded envelope next time I go to
the post office. My GMail account is almost unusable due to people
confusing their email address with mine and signing me up for
all kinds of junk mail. Right now there are 217,959 unread messages
and I don\'t see yours anywhere.

I powered one up just now and took a video:

http://www.ke5fx.com/r7400u.htm

Hopefully I\'m looking at a lot of dark counts or other PMT artifacts,
because jeez, that sure seems like a lot of pulses.

-- john, KE5FX

 

[Mike Monett]

\"John Miles, KE5FX\" <jmiles@gmail.com> wrote:

On Sunday, June 26, 2022 at 5:23:43 PM UTC-7, Mike Monett wrote:
I will send my name and address to your gmail address. Again, thanks.

Go ahead and send your address to me at john (at) miles.io if you\'d
still like one, and I\'ll throw one in a padded envelope next time I go to
the post office. My GMail account is almost unusable due to people
confusing their email address with mine and signing me up for
all kinds of junk mail. Right now there are 217,959 unread messages
and I don\'t see yours anywhere.

I powered one up just now and took a video:

http://www.ke5fx.com/r7400u.htm

Hopefully I\'m looking at a lot of dark counts or other PMT artifacts,
because jeez, that sure seems like a lot of pulses.

-- john, KE5FX

Hi John,

Very nice page !

That is a very nice offer. Thanks.

Various sources say the PMT voltage is critical and must be adjusted
individually for each PMT. One way to do this is to find a known
radioactive source and generate a spectrum, then adjust the PMT voltage so
the source lines up with the known energies in KeV or Mev.

Getting samples of thorium has turned out to be impossible, except for
traces in welding rods. However, radium is readily available in the form of
watch hands painted with radium. These are for sale extremely cheap on
Ebay.

The watch hands no longer glow in the dark since the phosphor will have
worn out. However, the radium will still be active since it has a half-life
of 1600 years. Below is the radioactive series of radium-226. You can see
the first step is radon, which releases alpha particles and gamma
radiation:

https://www.ld-
didactic.de/software/524221en/Content/Appendix/Ra226Series.htm

Radon gas is extremely dangerous. There is a small amount in every
basement. You breath it into your lungs, where it emits alpha particles,
which are the nucleus of helium-4. This causes lung cancer and you die.

We need to be able to monitor the amount of radon in our basements and be
certain it doesn\'t increase, such as during the winter when most
ventilation is shut off.

So it pays to learn a bit about gamma spectrometers to be able to protect
yourself and your family.

Regular radon detectors are very expensive, but gamma spectrometers can be
quite modest in cost. You can get the Radiacode, which is a very nice unit,
or build the Hamamatsu R7400U PMT version as a backup and verification.



--
MRM

 

[Anthony William Sloman]

On Saturday, July 16, 2022 at 8:25:08 PM UTC+10, Mike Monett wrote:

\"John Miles, KE5FX\" <jmi...@gmail.com> wrote:
On Sunday, June 26, 2022 at 5:23:43 PM UTC-7, Mike Monett wrote:
I will send my name and address to your gmail address. Again, thanks.

Go ahead and send your address to me at john (at) miles.io if you\'d
still like one, and I\'ll throw one in a padded envelope next time I go to
the post office. My GMail account is almost unusable due to people
confusing their email address with mine and signing me up for
all kinds of junk mail. Right now there are 217,959 unread messages
and I don\'t see yours anywhere.

I powered one up just now and took a video:

http://www.ke5fx.com/r7400u.htm

Hopefully I\'m looking at a lot of dark counts or other PMT artifacts,
because jeez, that sure seems like a lot of pulses.

Very nice page !

That is a very nice offer. Thanks.

Various sources say the PMT voltage is critical and must be adjusted
individually for each PMT. One way to do this is to find a known
radioactive source and generate a spectrum, then adjust the PMT voltage so
the source lines up with the known energies in KeV or Mev.

The photomultiplier voltage just adjusts the gain of the photomultiplier tube - photons hitting the photocathode produce electrons in the cathode space, and the voltage drop across the dynode chain just adjusts the number of electrons that each electron hitting the first dynode ends up delivering to the anode.

Getting the energy of individual particles coming out of the radiation source takes rather more than fiddling with the gain of the electron multiplication stages inside the photomultiplier tube. Because you\'ve got a lot of stages of multiplication - anything from 10 to 14 - you can vary that gain a lot.

Getting samples of thorium has turned out to be impossible, except for
traces in welding rods. However, radium is readily available in the form of
watch hands painted with radium. These are for sale extremely cheap on
Ebay.

The watch hands no longer glow in the dark since the phosphor will have
worn out. However, the radium will still be active since it has a half-life
of 1600 years. Below is the radioactive series of radium-226. You can see
the first step is radon, which releases alpha particles and gamma
radiation:

https://www.ld-
didactic.de/software/524221en/Content/Appendix/Ra226Series.htm

Radon gas is extremely dangerous. There is a small amount in every
basement.

If your house is built above granite rocks, or any other kind of rock that contains uranium, you can get radon gas leaking into the basement. If it is, put in an extractor fan to move it out before it can drift up to diffuse through the floor into the rest of the house.

> You breath it into your lungs, where it emits alpha particles, which are the nucleus of helium-4. This causes lung cancer and you die.

Helium four won\'t do any damage at all, but energetic alpha particles can cause mutations in any cell that they hit, and some mutations can make cell cancerous

We need to be able to monitor the amount of radon in our basements and be
certain it doesn\'t increase, such as during the winter when most
ventilation is shut off.

If there\'s uranium - or the like - in the rocks under your basement it makes sense to monitor for radon. If there is, it makes sense to ventilate that space, even in winter.

> So it pays to learn a bit about gamma spectrometers to be able to protect yourself and your family.

Learning about geology is cheaper.

Regular radon detectors are very expensive, but gamma spectrometers can be
quite modest in cost. You can get the Radiacode, which is a very nice unit,
or build the Hamamatsu R7400U PMT version as a backup and verification.

Radon itself decays by emitting a 4.6 Mev alpha particle. This isn\'t any kind of gamma ray, but it is energetic enough that if it hits an adjacent atom it may generate a gamma ray (an energetic photon) which is likely to have a longer range.

The Radiacode 101 monitor uses a scintillation detector - the chunk of thallium doped cesium iodide - which produces a flash of light when hit by a gamma ray photon (or anything else that can get at it).

crystal CsI (Tl) of cesium iodide doped with thallium in a sealed container;
silicon photomultiplier;

Also called an avalanche photodiode.

> optical interface between scintillator and photomultiplier;

A window, so the photons emerging from the transparent can get at the sensitive face of the photodiode

> precision temperature-compensated power supply for photomultiplier;

Avalanche photodiodes are tricky to bias.

> high-speed analog-digital circuit for processing pulses from a photomultiplier.

The pulses do tend to be narrow. You need fast op amps and comparators, but they are widely available and not that expensive.

https://ctf3-tbts.web.cern.ch/instr/pmt/r7400u_tpmh1204e07.pdf

The minature Hamamatsu R7400U photomultiplier tubes are pretty compact (but not as compacts as an avalanche photodode) and need a higher voltage supply, but they aren\'t quite as tricky to bias as an avalanche photodiode.

--
Bill Sloman, Sydney

 

[Dave Platt]

In article <XnsAED63FC6A8982idtokenpost@88.198.57.247>,
Mike Monett <spamme@not.com> wrote:

Getting samples of thorium has turned out to be impossible, except for
traces in welding rods. However, radium is readily available in the form of
watch hands painted with radium. These are for sale extremely cheap on
Ebay.

Also on eBay, you can find \"quantum energy\" or \"scalar energy\" or
\"negative ion\" pendants made out of a black volcanic rock. They\'re
often touted as a way of protecting oneself from the (supposed)
harmful effects of electromagnetic radiation.

They do generate \"negative ions\", in the form of beta-decay
electrons... these are not your gentle after-the-rainstorm negative
ions by any means!

By one report the radiation level is high enough that wearing one next
to the skin for a year can exceed safe exposure levels and might even
cause a mild radiation burn. I understand that Singapore has banned
the import of such products for this reason.

The rock from which they are made appears to be rich in thorium and
its decay products (perhaps something like monazite?).

I measured one on my home-made gamma spectrometry system and got
a very recognizable thorium-decay signature (the isotope markers
are from a best-efforts calibration).

https://www.radagast.org/~dplatt/gamma/quantum-pendant.png

Another useful calibration source (for higher-energy gammas from
potassium-40) is a sack of potassium chloride water-softener recharge
crystals from your local big-box home/hardware store (or, on a smaller
scale, a box of Morton \"Lite Salt\" which is about half potassium
chloride).

And, one can still find orange Fiestaware and green uranium glass at
the occasional estate or garage sale or antique store.

 

[a a]

On Saturday, 16 July 2022 at 16:16:38 UTC+2, Dave Platt wrote:

In article <XnsAED63FC6A8...@88.198.57.247>,
Mike Monett <spa...@not.com> wrote:
Getting samples of thorium has turned out to be impossible, except for
traces in welding rods. However, radium is readily available in the form of
watch hands painted with radium. These are for sale extremely cheap on
Ebay.
Also on eBay, you can find \"quantum energy\" or \"scalar energy\" or
\"negative ion\" pendants made out of a black volcanic rock. They\'re
often touted as a way of protecting oneself from the (supposed)
harmful effects of electromagnetic radiation.

They do generate \"negative ions\", in the form of beta-decay
electrons... these are not your gentle after-the-rainstorm negative
ions by any means!

By one report the radiation level is high enough that wearing one next
to the skin for a year can exceed safe exposure levels and might even
cause a mild radiation burn. I understand that Singapore has banned
the import of such products for this reason.

The rock from which they are made appears to be rich in thorium and
its decay products (perhaps something like monazite?).

I measured one on my home-made gamma spectrometry system and got
a very recognizable thorium-decay signature (the isotope markers
are from a best-efforts calibration).

https://www.radagast.org/~dplatt/gamma/quantum-pendant.png

Another useful calibration source (for higher-energy gammas from
potassium-40) is a sack of potassium chloride water-softener recharge
crystals from your local big-box home/hardware store (or, on a smaller
scale, a box of Morton \"Lite Salt\" which is about half potassium
chloride).

And, one can still find orange Fiestaware and green uranium glass at
the occasional estate or garage sale or antique store.

-Low Level Gamma Radiation is all fake

 

[John Miles, KE5FX]

On Saturday, July 16, 2022 at 7:16:38 AM UTC-7, Dave Platt wrote:

I measured one on my home-made gamma spectrometry system and got
a very recognizable thorium-decay signature (the isotope markers
are from a best-efforts calibration).

https://www.radagast.org/~dplatt/gamma/quantum-pendant.pn

Resolution of that setup looks really good -- is it written up anywhere?

-- john, KE5FX

 

[Mike Monett]

dplatt@coop.radagast.org (Dave Platt) wrote:

In article <XnsAED63FC6A8982idtokenpost@88.198.57.247>,
Mike Monett <spamme@not.com> wrote:
Getting samples of thorium has turned out to be impossible, except for
traces in welding rods. However, radium is readily available in the form
of watch hands painted with radium. These are for sale extremely cheap
on Ebay.

Also on eBay, you can find \"quantum energy\" or \"scalar energy\" or
\"negative ion\" pendants made out of a black volcanic rock. They\'re
often touted as a way of protecting oneself from the (supposed)
harmful effects of electromagnetic radiation.

They do generate \"negative ions\", in the form of beta-decay
electrons... these are not your gentle after-the-rainstorm negative
ions by any means!

By one report the radiation level is high enough that wearing one next
to the skin for a year can exceed safe exposure levels and might even
cause a mild radiation burn. I understand that Singapore has banned
the import of such products for this reason.

The rock from which they are made appears to be rich in thorium and
its decay products (perhaps something like monazite?).

I measured one on my home-made gamma spectrometry system and got
a very recognizable thorium-decay signature (the isotope markers
are from a best-efforts calibration).

https://www.radagast.org/~dplatt/gamma/quantum-pendant.png

Another useful calibration source (for higher-energy gammas from
potassium-40) is a sack of potassium chloride water-softener recharge
crystals from your local big-box home/hardware store (or, on a smaller
scale, a box of Morton \"Lite Salt\" which is about half potassium
chloride).

And, one can still find orange Fiestaware and green uranium glass at
the occasional estate or garage sale or antique store.

Thanks for the information. I will try to find the black volcanic rock
products. I recall an article describing these that got them kicked off
Amazon (I think).

Your gamma spectrometry system sounds very interesting. Can you supply more
information, such as what kind of scintillator crystal do you use, how big
is it, and do you use a PMT or diode for the detector, what software do you
use to generate the spectrum, how do you drive it, and any other details
that might be interesting.

I use pure potassium chloride (KCl) in the form of Windsor Salt Free
seasoning, but my Radiacode is not sensitive enough to detect the decay
products. I left it sitting on three containers for several days but had no
luck. I need a more sensitive detector, which is why yours is so
interesting.

On a related topic, I have been trying to find out why the background gamma
spectrum has a sharp rise at low energies, and where does it come from? Do
you have any ideas?

Thanks,

Mike



--
MRM

 

[Sjouke Burry]

On 16.07.22 20:43, John Miles, KE5FX wrote:

On Saturday, July 16, 2022 at 7:16:38 AM UTC-7, Dave Platt wrote:
I measured one on my home-made gamma spectrometry system and got
a very recognizable thorium-decay signature (the isotope markers
are from a best-efforts calibration).

https://www.radagast.org/~dplatt/gamma/quantum-pendant.pn

Resolution of that setup looks really good -- is it written up anywhere?

-- john, KE5FX

why did somebody snip off the last letter of .PNG????