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.

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

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

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

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

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

"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

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.

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

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

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

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????

Mike Monett <spamme@not.com> wrote:

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

>> 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

> 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).

> Thanks,
> Mike

Ebay was a bust. Quantum Energy turned out to be a fishing reel. Scalar
energy was some patterns on a piece of paper.

However, Amazon turned up lots of volcanic rock emi protectors. I got one
titled

"Volcanic Stone Pendant,Energy Necklace Fashionable Health Care for Women
for Daily Wear Quantum Science Scalar Energy Necklace Round Pendant for Men
Woman Tourmaline Volcanic Stone Jewelry",

$15.86 FREE delivery August 22 - September 16

https://www.amazon.ca/gp/product/B09V9Y7359/

This one sounds like it will do the job. Thanks.

Mike

--
MRM

On Saturday, 16 July 2022 at 21:25:19 UTC+2, Mike Monett wrote:
> Mike Monett <spa...@not.com> wrote:
> > dpl...@coop.radagast.org (Dave Platt) wrote:
>
> >> 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.
> >> 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
> > 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).
> > Thanks,
>
> > Mike
>
> Ebay was a bust. Quantum Energy turned out to be a fishing reel. Scalar
> energy was some patterns on a piece of paper.
>
> However, Amazon turned up lots of volcanic rock emi protectors. I got one
> titled
>
> "Volcanic Stone Pendant,Energy Necklace Fashionable Health Care for Women
> for Daily Wear Quantum Science Scalar Energy Necklace Round Pendant for Men
> Woman Tourmaline Volcanic Stone Jewelry",
>
> $15.86 FREE delivery August 22 - September 16
>
> https://www.amazon.ca/gp/product/B09V9Y7359/
>
> This one sounds like it will do the job. Thanks.
>
> Mike
>
>
> --
> MRM
Gamma Radiation is never Low Level
beware of cancer

On Sat, 16 Jul 2022 18:48:41 -0000 (UTC), Mike Monett <spamme@not.com>
wrote:

>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

The classic radiation test source was a thoriated Coleman lantern
mantle.

In article <7cc8f810-1325-4542-bda7-63c76d4195a0n@googlegroups.com>,
John Miles, KE5FX <jmiles@gmail.com> 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?

I don't think I've written up anything in detail - it's been a few
years since I played with it much.

I have a couple of probes, both built with surplus commercial PMTs,
one with a NaI(Tl) crystal and another with a BGO crystal.

The signal processing uses a charge-sensitive amplifier with some
pulse shaping built in (I like the CSA architecture because it's not
particularly sensitive to the cable length and capacitance). The
original design was done by Richard Hester; I did some tweaks for my
version and did a custom board layout. The files are in the
https://www.radagast.org/~dplatt/gamma/ directory.

The biggest disadvantage to this circuit is that if I forget, and
connect or disconnect the probe cable with the power on (or without
letting it discharge to zero) the spike usually blows out the
front-end JFET, and I have to cuss and pull it out of the
air-wire socket and replace it :-)

The high-voltage supply is based on a flyback with diode voltage
multiplier, based on a circuit I found some years ago intended for
use with GM tubes.

The output of the CSA goes into a moderately-priced USB sound card
line input.

I wrote the pulse detection and filtering code myself. The first
version was strictly command-line (record audio to a .WAV file, then
post-process to detect and bin the pulses and generate data files which
could be fed to gnuplot). I then wrote a Linux GUI based on the FLTK
toolkit which can read/process/display in real time.

The trickiest part was handling high pulse rates, where one pulse
starts while the CSA is still recovering from the previous one.
At some point I may sit down and try writing some DSP code to
de-convolve the CSA's pulse shaping and turn the signal back
into narrow impulses.

In article <XnsAED696ABEA7D1idtokenpost@88.198.57.247>,
Mike Monett <spamme@not.com> wrote:

>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?

As I understand it, you're seeing is largely Compton radiation and
X-ray fluorescence. When naturally occurring gammas (from K40 decay,
transuranincs, and cosmic rays) smack into atmosphere or into solid
matter, the energy of the gamma is scattered... it's dissipated a bit
at a time as the gamma photon interacts with electrons or the nucleus
of the impacted materials.

If a gamma scatters off of an electron, some of the energy is
transferred to the electron. If the electron is bumped up to a
higher-energy orbital and then decays back to its ground state, the
decay can cause the emission of an X-ray photon - fluorescence. This
necessarily has a lower energy than the gamma, and its energy will
depend on just what element was involved in the scattering. The
original scattered gamma will have less energy than it did before, of
course.

So, the rise you see in the spectrum is probably the sum of a whole
bunch of Compton scattering events which involved gammas that were
originally of higher energy.

From what I've read, skyglow (gammas and X-rays originating from
cosmic-ray impacts on the atmosphere) is a big part of this.
NORM is another big part.

A few years ago I collected a box of monazite sand from a local
beach. It definitely shows a thorium signature, but the peaks are
nowhere near as sharp as the ones in the "quantum pendant" data.
I believe this is because the thorium is diffused throughout a
much larger amount of base material (I have to use a couple of
pounds of it to get a good reading) and most of the decay gammas
end up Compton-scattering at least once as they work their way
through the sand to the sensor crystal. As a result, the
sharp peaks from the original decay events are weakened, and
blurred by the Compton scattering effect.

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

> In article <7cc8f810-1325-4542-bda7-63c76d4195a0n@googlegroups.com>,
> John Miles, KE5FX <jmiles@gmail.com> 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?
>
> I don't think I've written up anything in detail - it's been a few
> years since I played with it much.
>
> I have a couple of probes, both built with surplus commercial PMTs,
> one with a NaI(Tl) crystal and another with a BGO crystal.

How big are the crystals?

--
MRM

On Saturday, July 16, 2022 at 5:38:44 PM UTC-7, Dave Platt wrote:

> The trickiest part was handling high pulse rates, where one pulse
> starts while the CSA is still recovering from the previous one.
> At some point I may sit down and try writing some DSP code to
> de-convolve the CSA's pulse shaping and turn the signal back
> into narrow impulses.

The analog-days solution was a delay line amplifier; the long recovery tail
is exponential, so a difference amplification of V(t) - (1+epsilon)V(t-s)
flattens the recovery when (1+epsilon) equals the diminution of the signal
during 's' seconds. The infinite-impulse response or FIR filter is relatively easy
work to do that.

Some good info here:
<https://www.ortec-online.com/-/media/ametekortec/manuals/4/460-mnl.pdf>

Thanks to Phil and John, I will soon have a PMT gamma detector to compare
with the Radiacode. Hopefully, it will be more sensitive so I can be more
certain of measuring Radon in the basement as well as other radiation
sources.

Assembling the electronics turned out to be much easier than some DIY pages
describe on the web. There is a company in Israel that supplies complete
Gamma Spectroscopy electronics. The company is RH-Electronics at

http://rhelectronics.net

I got the PIC18 MCA Module for $95.00 plus shipping at $17.95:

https://www.rhelectronics.store/diy-pic18-mca-kit-for-gamma-spectroscopy

Generating the high voltage for the PMT turned out to be easy. Amazon sells
CCFL inverter boards very cheap. I got one for $13.46 at

https://www.amazon.ca/gp/product/B07YM68GVM/

The last item is a fast high voltage diode to supply the PMT. This turned
out to be the hardest problem until I found Dean Technology in Dallas,
Texas, 75370

They sell a 5KV 100ns diode for a couple of bucks:

https://www.deantechnology.com/products/hl500

The total price is CDN $95.00 + $17.95 + $13.46 + $2.50 = $128.91, not
including the PMT that the seller refuses to sell to Canada.

The US price is about $120 USD including the PMT, so nobody has any excuse
for not being able to detect radon in their basement.

--
MRM

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

> In article <XnsAED696ABEA7D1idtokenpost@88.198.57.247>,
> Mike Monett <spamme@not.com> wrote:
>
>>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?
>
> As I understand it, you're seeing is largely Compton radiation and
> X-ray fluorescence. When naturally occurring gammas (from K40 decay,
> transuranincs, and cosmic rays) smack into atmosphere or into solid
> matter, the energy of the gamma is scattered... it's dissipated a bit
> at a time as the gamma photon interacts with electrons or the nucleus
> of the impacted materials.
>
> If a gamma scatters off of an electron, some of the energy is
> transferred to the electron. If the electron is bumped up to a
> higher-energy orbital and then decays back to its ground state, the
> decay can cause the emission of an X-ray photon - fluorescence. This
> necessarily has a lower energy than the gamma, and its energy will
> depend on just what element was involved in the scattering. The
> original scattered gamma will have less energy than it did before, of
> course.
>
> So, the rise you see in the spectrum is probably the sum of a whole
> bunch of Compton scattering events which involved gammas that were
> originally of higher energy.
>
> From what I've read, skyglow (gammas and X-rays originating from
> cosmic-ray impacts on the atmosphere) is a big part of this.
> NORM is another big part.
>
> A few years ago I collected a box of monazite sand from a local
> beach. It definitely shows a thorium signature, but the peaks are
> nowhere near as sharp as the ones in the "quantum pendant" data.
> I believe this is because the thorium is diffused throughout a
> much larger amount of base material (I have to use a couple of
> pounds of it to get a good reading) and most of the decay gammas
> end up Compton-scattering at least once as they work their way
> through the sand to the sensor crystal. As a result, the
> sharp peaks from the original decay events are weakened, and
> blurred by the Compton scattering effect.

A very lucid explanation. Thanks.

I was able to find out what NORM is without having to ask you: "Naturally
ocurring radioactive materials." I'm so proud of myself:)

How big are your scintillator crystals?

--
MRM

On Sunday, 17 July 2022 at 20:01:52 UTC+2, Mike Monett wrote:
> dpl...@coop.radagast.org (Dave Platt) wrote:
>
> > In article <XnsAED696ABEA...@88.198.57.247>,
> > Mike Monett <spa...@not.com> wrote:
> >
> >>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?
> >
> > As I understand it, you're seeing is largely Compton radiation and
> > X-ray fluorescence. When naturally occurring gammas (from K40 decay,
> > transuranincs, and cosmic rays) smack into atmosphere or into solid
> > matter, the energy of the gamma is scattered... it's dissipated a bit
> > at a time as the gamma photon interacts with electrons or the nucleus
> > of the impacted materials.
> >
> > If a gamma scatters off of an electron, some of the energy is
> > transferred to the electron. If the electron is bumped up to a
> > higher-energy orbital and then decays back to its ground state, the
> > decay can cause the emission of an X-ray photon - fluorescence. This
> > necessarily has a lower energy than the gamma, and its energy will
> > depend on just what element was involved in the scattering. The
> > original scattered gamma will have less energy than it did before, of
> > course.
> >
> > So, the rise you see in the spectrum is probably the sum of a whole
> > bunch of Compton scattering events which involved gammas that were
> > originally of higher energy.
> >
> > From what I've read, skyglow (gammas and X-rays originating from
> > cosmic-ray impacts on the atmosphere) is a big part of this.
> > NORM is another big part.
> >
> > A few years ago I collected a box of monazite sand from a local
> > beach. It definitely shows a thorium signature, but the peaks are
> > nowhere near as sharp as the ones in the "quantum pendant" data.
> > I believe this is because the thorium is diffused throughout a
> > much larger amount of base material (I have to use a couple of
> > pounds of it to get a good reading) and most of the decay gammas
> > end up Compton-scattering at least once as they work their way
> > through the sand to the sensor crystal. As a result, the
> > sharp peaks from the original decay events are weakened, and
> > blurred by the Compton scattering effect.
> A very lucid explanation. Thanks.
>
> I was able to find out what NORM is without having to ask you: "Naturally
> ocurring radioactive materials." I'm so proud of myself:)
>
> How big are your scintillator crystals?
>
>
>
> --
> MRM
Gamma Radiation is never Low Level
since
what matters is
long-term exposure to cancerogenic Gamma Radiation
so
Long-term Low Level exposure
turns into
High Level Gamma Radiation

On Sunday, July 17, 2022 at 1:00:00 PM UTC-7, a a wrote:

> Gamma Radiation is never Low Level

False, of course.
> since
> what matters is
> long-term exposure to cancerogenic Gamma Radiation

Not at all; for human health, what matters is the generation of ion pairs
and gamma radiation includes energies that go right through a human
body without much likelihood of interaction.

> Long-term Low Level exposure
> turns into
> High Level Gamma Radiation

That's just nonsense; word salad, plus some capitalizations.

On Monday, 18 July 2022 at 00:34:05 UTC+2, whit3rd wrote:
> On Sunday, July 17, 2022 at 1:00:00 PM UTC-7, a a wrote:
>
> > Gamma Radiation is never Low Level
> False, of course.
> > since
> > what matters is
> > long-term exposure to cancerogenic Gamma Radiation
> Not at all; for human health, what matters is the generation of ion pairs
> and gamma radiation includes energies that go right through a human
> body without much likelihood of interaction.
> > Long-term Low Level exposure
> > turns into
> > High Level Gamma Radiation
> That's just nonsense; word salad, plus some capitalizations.
you are exactly stupid dog

--
Gamma Radiation Sterilization: What You Need to Know
https://int-enviroguard.com/blog/what-is-the-gamma...

Gamma Radiation Sterilization ExplainedAdvantages of Gamma Radiation SterilizationDisadvantages of Gamma Radiation Sterilization

Image
As the name implies, this is a sterilization process, and it's commonly used to kill bacteria and microorganisms that may be living on the surface of products, packaging, or goods. Powered by Cobalt-60, the low-dose process is administered when high-energy photons are emitted from a radiation source, which works to io…

---
Gamma Radiation - an overview | ScienceDirect Topics
https://www.sciencedirect.com/.../gamma-radiation

Gamma rays are a form of electromagnetic radiation, whereby gamma radiation kills microorganisms by destroying cellular nucleic acid [1]. The use of gamma irradiation is relatively widespread and was first described in the British Pharmacopeia in 1963 and in the

---

What are gamma rays and how dangerous are they?
Gamma rays are ionizing radiation and are thus biologically hazardous. Due to their high penetration power, they can damage bone marrow and internal organs. Unlike alpha and beta rays, they pass easily through the body and thus pose a formidable radiation protection challenge.

---

Gamma Radiation: A brief background Gamma particles consist of energy photons and were discovered by Paul Villard in 1900 when he was researching gamma radiation that comes from radium. These particles are a form of ionizing radiation and can be dangerous to humans, animals and plant life. The decay of the atomic nucleus downgrades from high levels of energy to lower energy. This process is call gamma decay which is what gives birth to radiation gamma. The nucleus releases particles decreasing its energy. Gamma radiation Radiation gamma How Gamma Radiation is Produced Typically, the gamma particles that are released during gamma decay are radioactive so there is enough power in them to do harm. It has the ability to damage physical structure and cause genetic mutations. Because of the ability to break natural bonds in the human body, it can potentially do a high level of harm and cause many severe health problems. Some of the health concerns can be acute and the damage cannot be repaired through the body’s natural repair process. This is commonly the case with high exposure that is long term and will accumulate to cause serious health problems. What can Stop Radiation Gamma? Gamma radiations can travel very fast at the speed of light and chances of penetration are very high. It can penetrate even through metal and do damage. Even though these rays are dangerous with high exposure, they are still used in the medical field for cancer treatment and for imaging equipment such as x-rays. Your exposure amount can only be measured using a Geiger counter and to determine what can stop gamma radiation. This is the reason why during the x-ray process, you will use a lead apron. Normally, you would need 3 meters of concrete to prevent gamma radiation from penetrating. Gamma radiations Gamma radiation in USA Side Effects of Gamma Radiation Some of the possible problems with heavy exposure to gamma radiations include radiation sickness. This is also known as radiation poisoning. Some of the gamma radiation signs can be nausea, vomiting, bleeding, mouth sores, nausea, diarrhea and loss of hair. Radiation sickness was very common after the bombs in Hiroshima as well as Nagasaki. This is also common after nuclear power plant disaster such as the one in Chernobyl. Radiation sickness can happen with fast exposure to high levels of radiation. Even if you are given gamma radiation for the treatment of an illness, you may still experience side effects from it even though it was meant to help you. Sometimes, you may see a change in your skin that can be mild to severe redness but sometimes it can be dark like a burn. Just like the symptoms of radiation sickness, you may have those with this treatment. This type of exposure can also damage the number of blood cells you have, causing a decrease. These effects are usually not long lasting but there are possibilities of having long term effects. Other effects include weak bones, difficulty with swallowing and dry mouth. It may also cause infertility problems in men or women. Chernobyl Tours ☢ Please support us with LIKE :) PLEASE ☢ Share On FacebookPinterestTwitterGoogle+ Previous Article What is Beta Radiation? Next Article Hiroshima and Nagasaki Related Posts A Definition of Alpha Decay VladyslavMarch 2, 2016 Effects of radiation on the body The Effects of Radiation on the Human Body VladyslavFebruary 23, 2016 One Response May 21, 2018 Hanan Khan Reply Great. Enjoyed reading it. I was looking for what types of medicines are Gamma rays used in. Maybe you could include that in another article. Thanks. Learned a thing or two. Leave a Reply Your email address will not be published. Comment Name* Email*

Read more at: https://chernobylguide.com/what_is_gamma_radiation/

whit3rd <whit3rd@gmail.com> wrote:

> On Sunday, July 17, 2022 at 1:00:00 PM UTC-7, a a wrote:
>
>> Gamma Radiation is never Low Level
>
> False, of course.
>> since
>> what matters is
>> long-term exposure to cancerogenic Gamma Radiation
>
> Not at all; for human health, what matters is the generation of ion pairs
> and gamma radiation includes energies that go right through a human
> body without much likelihood of interaction.
>
>> Long-term Low Level exposure
>> turns into
>> High Level Gamma Radiation
>
> That's just nonsense; word salad, plus some capitalizations.

Ignore him. I PLONKED him long ago as soon as he appeared.

--
MRM