|
Charles,
Looks good. Note that the Au “peak” is really just noise(4 counts).
?Its good to have the Am and Np tags turned on to save time when doing energy
ID’s.
You don’t need to scale up the graph to see small peaks just switch
to the Log Y plot. It will show all the peaks and enhances the low count peaks.
Ok it’s not as pretty and doesn’t have all those tall sharp peaks everyone seems
to like, but it has much more information in it and is the only way to
look at spectra ?when interpreting what you got.
Look at the Silver dollar raw spectra plotted in linear space. The
low energy instrument noise dominates the spectra with over 4500 counts and all
you can see is the Ag peak with 227 counts. Switch to Log space and everything
is seen.? I might point out the MCA was spending most of its time counting the
low energy noise below 1 keV. The lower limit discriminator (LLD %) should have
been set to cut out this noise to improve the count real time it takes to get a
peak defined.
?
Look at the terra cotta spectra ?in log space then you’ll see the
weaker high energy peaks displayed much better.
Dud
?
?
?
Mike, you might scale up the graphs and let the large peaks
go off the top.? Then we might be able to see the 2.6 peak better.
Dud, here is the scan of a silver dollar that has both Ag
and Cu.? I scaled it up to allow the Am241 reference peaks to be more
clearly visible.
?
toggle quoted message
Show quoted text
On Tue, Apr 14, 2020 at 3:54 AM Mike L. < loughlin3@...> wrote:
On Mon, Apr 13, 2020 at 08:16 PM, Mike L. wrote:
On Mon, Apr 13, 2020 at 08:46 AM, <charlesdavidyoung@...>
wrote:
And here are my preliminary NaI results.
Charles,
You should extend your energy out to at least K40 or to Tl208 at 2.62 MeV (as
Dud keeps suggesting).? I discovered something kind of interesting out
there.? My spectrum is not good enough to post yet, but it shows a honking
big K40 peak.? If you look at my earlier spectrum that overlays the
mantle, there is a peak a little north of 500 KeV (I labeled it Tl208) that is
not duplicated in the mantle spectrum.? I believe it might be an
annihilation peak from all those powerful K40 photons flying around.? So,
go look for antimatter reactions in your Mexican Frog ceramic flower pot.
Mike L.
My Spectrum out to 2.6 MeV.? My probe is not very
efficient on the high energy end, but it shows a slight peak at 2.62 and
the? K40 peak at 1.46 MeV.? The exposure time with the shard was
about 19 hours and just a few minutes with the mantle.? I had to use a
different PMT adapter to achieve linearity.? I need to understand what
causes HV pileup and poor linearity with my other amplifier to try and improve
the hardware.
Mike L.?
|
Charles,
Interesting Am Au interference, I didn’t know they had gold in there.
I missed your log space in the png as I was looking at your .mca file
after looking at Mike’s and Taray’s with your comment to scale it up off the
screen. I assumed it was in linear.? I was referring ?to mike’s plot on the
scaling to use a log scale which would do the job much better pulling the Tl-208
2.6 and the Bi 1764 out.
You’re weird, sir. Can’t say I’ve ever seen anyone use a log other
than a base 10, 2, or e with an odd ball exponent grid interval other than base
10 and why are you using a log interval for energy?
Dud
?
?
Note that I did not identify Au as an element.? It is
just one of the reference peaks because it shows up due to the Au in the Am241
button.
I always plot in log space.? See the Xlog and Ylog
buttons on the bottom?? The exponent for Ylog was set to 1.2 so I redid it
with an exponent of 2.
Mike, if you want more squishing in the Y scale you can go
in the INI file and change it.? Of course, you have to activate the Ylog
button as well.
?Scale options
===========================================
XlogExponent= ? ? ? ? ?1.5
YlogExponent= ? ? ? ? ?2.0
ThickLines= ? ? ? ? ? ?False
?
toggle quoted message
Show quoted text
On Tue, Apr 14, 2020 at 11:16 AM Dude < dfemer@...> wrote:
Charles,
Looks
good. Note that the Au “peak” is really just noise(4 counts). ?Its good to
have the Am and Np tags turned on to save time when doing energy ID’s.
You
don’t need to scale up the graph to see small peaks just switch to the Log Y
plot. It will show all the peaks and enhances the low count peaks. Ok it’s not
as pretty and doesn’t have all those tall sharp peaks everyone seems to like,
but it has much more information in it and is the only way to look at
spectra ?when interpreting what you got.
Look
at the Silver dollar raw spectra plotted in linear space. The low energy
instrument noise dominates the spectra with over 4500 counts and all you can
see is the Ag peak with 227 counts. Switch to Log space and everything is
seen.? I might point out the MCA was spending most of its time counting
the low energy noise below 1 keV. The lower limit discriminator (LLD %) should
have been set to cut out this noise to improve the count real time it takes to
get a peak defined.
?
Look
at the terra cotta spectra ?in log space then you’ll see the weaker high
energy peaks displayed much better.
Dud
?
?
?
Mike,
you might scale up the graphs and let the large peaks go off the top.?
Then we might be able to see the 2.6 peak better.
Dud,
here is the scan of a silver dollar that has both Ag and Cu.? I scaled it
up to allow the Am241 reference peaks to be more clearly visible.
?
On
Mon, Apr 13, 2020 at 08:16 PM, Mike L. wrote:
On
Mon, Apr 13, 2020 at 08:46 AM, <charlesdavidyoung@...> wrote:
And
here are my preliminary NaI results.
Charles,
You should extend your energy out to at least K40 or to Tl208 at 2.62 MeV (as
Dud keeps suggesting).? I discovered something kind of interesting out
there.? My spectrum is not good enough to post yet, but it shows a honking
big K40 peak.? If you look at my earlier spectrum that overlays the
mantle, there is a peak a little north of 500 KeV (I labeled it Tl208) that is
not duplicated in the mantle spectrum.? I believe it might be an
annihilation peak from all those powerful K40 photons flying around.? So,
go look for antimatter reactions in your Mexican Frog ceramic flower pot.
Mike L.
My
Spectrum out to 2.6 MeV.? My probe is not very efficient on the high
energy end, but it shows a slight peak at 2.62 and the? K40 peak at 1.46
MeV.? The exposure time with the shard was about 19 hours and just a few
minutes with the mantle.? I had to use a different PMT adapter to achieve
linearity.? I need to understand what causes HV pileup and poor linearity
with my other amplifier to try and improve the hardware.
Mike L.?
|
The log base is just one of the many options that Theremino offers.? I had not paid much attention to it until you brought it up.? The log scale for energy is nice for me because I tend to be more interested in the low energies.? As you know the spectral lines can get crowded down there.
So I did a 24 hour scan of the roof tile.? I agree that the Th is questionable but the Rb, Sr, and Ba are much stronger.? It turns out that Sr and Ba are commonly used in glazing:
However, this appears to be unglazed tile. I found another reference where Ba is used in roof tiles to reduce
efflorescence.
I am speculating that the company (US Tile) uses a compound containing both Ba and Sr for both their glazes and for mixing with the clay to give the unglazed tile a uniform appearance.
I don't yet know where the Rb comes from.
Charles
On Tue, Apr 14, 2020 at 8:49 PM Dude < dfemer@...> wrote:
Charles,
Interesting Am Au interference, I didn’t know they had gold in there.
I missed your log space in the png as I was looking at your .mca file
after looking at Mike’s and Taray’s with your comment to scale it up off the
screen. I assumed it was in linear.? I was referring ?to mike’s plot on the
scaling to use a log scale which would do the job much better pulling the Tl-208
2.6 and the Bi 1764 out.
You’re weird, sir. Can’t say I’ve ever seen anyone use a log other
than a base 10, 2, or e with an odd ball exponent grid interval other than base
10 and why are you using a log interval for energy?
Dud
?
?
Note that I did not identify Au as an element.? It is
just one of the reference peaks because it shows up due to the Au in the Am241
button.
I always plot in log space.? See the Xlog and Ylog
buttons on the bottom?? The exponent for Ylog was set to 1.2 so I redid it
with an exponent of 2.
Mike, if you want more squishing in the Y scale you can go
in the INI file and change it.? Of course, you have to activate the Ylog
button as well.
?Scale options
===========================================
XlogExponent= ? ? ? ? ?1.5
YlogExponent= ? ? ? ? ?2.0
ThickLines= ? ? ? ? ? ?False
?
On Tue, Apr 14, 2020 at 11:16 AM Dude <dfemer@...> wrote:
Charles,
Looks
good. Note that the Au “peak” is really just noise(4 counts).? Its good to
have the Am and Np tags turned on to save time when doing energy ID’s.
You
don’t need to scale up the graph to see small peaks just switch to the Log Y
plot. It will show all the peaks and enhances the low count peaks. Ok it’s not
as pretty and doesn’t have all those tall sharp peaks everyone seems to like,
but it has much more information in it and is the only way to look at
spectra ?when interpreting what you got.
Look
at the Silver dollar raw spectra plotted in linear space. The low energy
instrument noise dominates the spectra with over 4500 counts and all you can
see is the Ag peak with 227 counts. Switch to Log space and everything is
seen.? I might point out the MCA was spending most of its time counting
the low energy noise below 1 keV. The lower limit discriminator (LLD %) should
have been set to cut out this noise to improve the count real time it takes to
get a peak defined.
?
Look
at the terra cotta spectra ?in log space then you’ll see the weaker high
energy peaks displayed much better.
Dud
?
?
?
Mike,
you might scale up the graphs and let the large peaks go off the top.?
Then we might be able to see the 2.6 peak better.
Dud,
here is the scan of a silver dollar that has both Ag and Cu.? I scaled it
up to allow the Am241 reference peaks to be more clearly visible.
?
On
Mon, Apr 13, 2020 at 08:16 PM, Mike L. wrote:
On
Mon, Apr 13, 2020 at 08:46 AM, <charlesdavidyoung@...> wrote:
And
here are my preliminary NaI results.
Charles,
You should extend your energy out to at least K40 or to Tl208 at 2.62 MeV (as
Dud keeps suggesting).? I discovered something kind of interesting out
there.? My spectrum is not good enough to post yet, but it shows a honking
big K40 peak.? If you look at my earlier spectrum that overlays the
mantle, there is a peak a little north of 500 KeV (I labeled it Tl208) that is
not duplicated in the mantle spectrum.? I believe it might be an
annihilation peak from all those powerful K40 photons flying around.? So,
go look for antimatter reactions in your Mexican Frog ceramic flower pot.
Mike L.
My
Spectrum out to 2.6 MeV.? My probe is not very efficient on the high
energy end, but it shows a slight peak at 2.62 and the? K40 peak at 1.46
MeV.? The exposure time with the shard was about 19 hours and just a few
minutes with the mantle.? I had to use a different PMT adapter to achieve
linearity.? I need to understand what causes HV pileup and poor linearity
with my other amplifier to try and improve the hardware.
Mike L.?
|
Charles,
Attached are ?some shots of a piece of Indian pottery I had here
and a clay pot showing the full energy range and then the zoomed lower end
detail.
I see pretty much the same elements except for In and the Pt which
is actually some Zn and the Au from your Am source. ?There is also Ti in there.?
Most of these elements are pretty ubiquitous in nature.
?
Look at your potshard Theremino spectra and compare it to the Amptek
spectra and note the terrible resolution in the Theremino. That’s due to 3
things
1, You have Log energy selected which is crunching up 4096
channels and over writing channels trying to fit it into a display with a
limited pixel resolution of maybe 1080 pixels and then further converting it to
log space making it even worse. Turn off log Energy it should be linear to avoid
missing important detail.
2. You are using 4096 channels which gains you nothing but piling
up more channels in the Theremino display that it can’t display. It’s also wasting
count time for no benefit. Use a 2048 channel conversion gain it will get more
counts into where they belong and shorten your count time to resolve things and
get rid of some of the noise.?
3. A professional program will allow you to select an ?energy
range and expand it to allow the screen to show all bins and not have them
either decimated or piled up for display due to the screen resolution limits. Does
Theremino have an energy zoom function? Theremino was designed for NaI where
the resolution and screen limitations are compatible with that detectors resolution
but it’s not for a high res Si-Pin detector.
Dud
?
?
Here are the final scans of both sides of the
potsherd.? I was hoping that there would be a difference that could be
attributed to the paint but they look identical.
That being said, there seems to be a lot going on
here.? Here are the elements I could easily identify:
Mn Fe Zn Pt Pb Rb Sr Zr In Sn Sb Te Ba
Of course, there are our old clay friends Fe Rb Sr.? I
am guessing that a lot of the other elements are also due to water bringing
them in and their finding a welcome home in the mineral structure.
?
toggle quoted message
Show quoted text
On Thu, Apr 16, 2020 at 2:52 PM Charles David Young < charlesdavidyoung@...>
wrote:
Dud, that is great information about Rb and Sr in
clay.? It explains a lot.
It just so happens that I am scanning a potsherd that may be
about 1000 years old.? I collected it in Prescott while visiting a
cousin.? It was from a site that was surveyed for a housing
development.? I collected several hundred pieces.? I took them to the
local museum and they said they could be anywhere from 700 AD to 1400 AD.
This one has what appears to be paint markings.? I am
doing the painted side first and will do the other side afterwards.
?
On Thu, Apr 16, 2020 at 10:16 AM Dude <dfemer@...> wrote:
Charles,
Terra
Cotta is a clay which is derived from the weathering of iron rich igneous rock
which contain both potassium feldspars and biotite and muscovite micas. These
phyllosilicates ?commonly show a high Rb content as well as the K
feldspars.? Rb exchanges with potassium being of nearly the same ionic
radius and it is strongly absorbed by clay minerals so I would expect you’ll
see an natural component of Rb in the terra Cotta. Strontium is also absorbed
in clays. ??Run an XRF on some mica when you get a chance.
I
don’t know the reason why they would add it though.?
Dud
?
?
From
my terracotta roof tiles I now turn to my Gres De Valls saltillo floor
tiles.? Traditionally this style is unglazed and made in Saltillo, Mexico
but mine is glazed and comes from Spain.
I
ran the XRF on both sides and the results show the following elements:
Fe
is in the tile.? I am guessing it comes from the original clay.
As
in the roof tiles the Sr and Ba may be used to reduce efflorescence to make the
color more uniform.
Zr
is added to make the tile harder:
Zn
is used for a wide variety of reasons in ceramics and in this case is in the
glaze:
Rb
is widely used in ceramics but it is not clear why:
It
is hard to know how much of the Pb is actually in this tile since it is also
what my shield is made of, but it would not be surprising if it were there:
When
used in a glaze, lead gives a smooth, glasslike finish that allows bright
colours and decorative patterns to show through. It is often associated with
rich or intense colours.
Charles
?
Sometimes
I use the log x feature to expand the lower end more just to get a better look
at it.? As my daddy would say, a log ain't nothing but an exponent.
Attached is a new Terracotta spectrum using log y scale.? Yes, this very
much improves the display of those low count peaks.
I did this one a little differently, I did the Mantle first and let it fully
develop, then did the Terracotta shard (16 hours).? In this case, the y
scale only applies to the Terracotta spectrum.
The mantle spectrum is very much improved this way.? It shows the 2.614
MeV much better, but also shows the annihilation peak and the single Pair
Production escape peak (2.1 MeV).
There was a little drift on the high energy end.? A cold front blew in
last night.
This look at the higher energy side has been very instructive for me, I usually
just fish on the shallow end.? It was interesting (to me, at least) to see
that the annihilation peak with the Shard is so enhanced by the K40
component.? I had no idea of the extent of the energy/mass/energy
conversions occurring in my wife's flower pots.
Charles xrf work with the glazes is pretty interesting also.? I did not
know it would work with such small amounts of source material.? ?He
should try to match colors with metals using other glazed ceramics.
Mike L.
|
