Welcome to the XRF Wiki. This Wiki is a repository of information contributed by members of [email protected]. Members can view and edit the pages. The pages are currently not viewable by the public. The pages below represent a rough overview of the technology and techniques associated with X-Ray Florescence Spectroscopy as well as serving as a place for members to organize the spectra that they have contributed to the forum.?
As a starting point, the pages will be populated by information taken from member posts from the past few years - with references/attribution. Perhaps in time, these pages can be edited by members to make them more complete and less choppy. Members can also edit this page, making the structure of the content more organized.?
Pages can contain information about a particular topic, links to relevant resources (such as manuals, research papers, etc.), links to relevant forum discussions on the topic, book titles, or anything that might be useful.
What follows is very much a work in progress.
?
Adding to the Wiki
For those unfamiliar with the Wiki phenomenon, it is basically a user editable encyclopedia. The idea is that there are pages with different articles, which the user can read and also choose to edit if desired. If a piece of information is incorrect, a link outdated, or the presentation choppy or unclear, the user can just click "Edit Page" at the bottom and then fix the mistake. There is also a "Page History," so if you a user were to make a mistake or maliciously destroy a page (which wouldn't happen here) an editor can come along and restore the page to a previous version.?
If you have used MediaWiki (the engine that runs behind the scene of Wikipedia.org) you will be familiar with a certain style of creating an article. There are tags that one uses to change the formatting of the parts of the article. The Wiki on Groups.io uses a different background engine and so the standard MediaWiki syntax does not apply here. Rather, the page is edited using the same tools as one would use to compose a message on the forums. If you are a programmer or someone who likes using the tagged syntax directly, you can access the underlying page source code, be activating the advanced editing toolbar (the icon with three lines on the far right of the basic toolbar) and then clicking on the source code icon <> on the far right of the Advance Editing Toolbar. You will immediately notice that the underlying source code is HTML. Most things can be done just by using the various icons, but advanced features like table can only be implemented by manually writing the source code. (Although there are website available that will generate the source code for you through a graphical interface.)
This section describes the hardware used for XRF. We will describe the basic theory of operation of each stage in the processing tool chain and then present different commercial systems that are available as these systems are often integrated together.
[Editor note: General theory needs to be in an independent page separate from specific manufacturer information.
[Editor note - question: Should this be arranged by category, e.g detectors, preamps, etc or by manufacturer with the manufacturers product line on one page. Perhaps it's best to put a list of products with theory but the details of the products on a manufacture page...]
Detectors?- what's available, theory of operation, tradeoffs
Detector Cooling?- keeping detectors cool to avoid thermal noise and keeping the TEC from overheating
Preamps?- theory of operation, brief summary of what out there (and what not to do - such as trying to use a PMT preamp for a SiPIN diode...)
Pulse Processing Theory - high level overview of the stages of going from detector pulse to channel peaks on the computer
Commercial Systems - many commercial systems are integrated so it seems to make sense to present, for example all Amptek products together. [question: are their other affordable integrated systems besides Amptek?]
The link does pretty much the same thing, a small box has the
picture and it fills only half the screen. ?I need to do a ctrl + to zoom it up
and with a lower resolution.
The .PNG¡¯s that were sent via the email were only 203KB
I just went to the
site and looked at the photos in this email.? They only look slightly
reduced in resolution compared to the originals but are certainly
legible.? Dud, are you sure it is not your mailer?
My photos are always attached at full resolution. Perhaps is reducing the
resolution to save space. Is anyone else having a problem reading my scans?
?
?
El El mi¨¦, ene. 8, 2020 a la(s) 2:09 p.?m., Dude <dfemer@...> escribi¨®:
Charles,
Your
.png screen grabs are not coming up to a full screen and the resolution makes
it hard to see detail. Is there some way to fix that.
We¡¯d
also like to see a photo of your Si ¨CPIN setup.
I
always try to identify the plots by color in the lower left?corner
box.? The one I was referring to is the tritium in blue.
?
Charles
?
On
Wed, Jan 8, 2020 at 12:15 PM Randall Buck <rbuck@...> wrote:
Hi Charles,
I would like to see a close up photo of your Si-PIN alone.
Randall
----- Original Message -----
From: Charles David Young <charlesdavidyoung@...>
To: [email protected], Mike
Loughlin <loughlin3@...>
Sent: Tue, 07 Jan 2020 10:42:31 -0800 (PST)
Subject: Re: [XRF] Tritium with Amptek Si-PIN vs NaI
And here is an XRF of a Nb disk that George provided me that is being
excited by a single Am241 button.? I have included a photo of the setup.
The Am241 is glued to a lead strip and is pressed up against the Nb disk in
a baggy.? The red Si-PIN protective cap is peeking out below just behind
the lead strip.? As you can see the Nb Ka and Kb peaks are very clear and
there is hardly a trace of the normal Np peaks from the Am241.? For
comparison I have included that same Nb scan alongside an Am241 scan that
is not shielded (blue)
It really is amazing how nice an exciter Am241 is when it is properly
shielded and placed in front of the target.
> I have been playing with the Si-PIN that I got from Geo and am getting
> some great results.? When measuring a tritium keychain with NaI I get
a
> strong peak down in the teens (dark blue) but I have never been sure where
> to place that peak given that this is a broad Bremsstrahlung region.?
I had
> been placing it at 11keV because this is supposed to be in the middle of
> that region.
>
> However, my Si-PIN results show how dominant the Zn sulphide peaks are so
> now I would place my NaI peak right between them at 9keV.? That makes
for a
> great calibration point at the extreme low end of my NaI setup.
>
> Charles
>
>
>
I just went to the site and looked at the photos in this email.? They only look slightly reduced in resolution compared to the originals but are certainly legible.? Dud, are you sure it is not your mailer?
My photos are always attached at full resolution. Perhaps is reducing the resolution to save space. Is anyone else having a problem reading my scans? ?
El El mi¨¦, ene. 8, 2020 a la(s) 2:09 p.?m., Dude <dfemer@...> escribi¨®:
Charles,
Your .png screen grabs are not coming up to a full screen and the resolution
makes it hard to see detail. Is there some way to fix that.
We¡¯d also like to see a photo of your Si ¨CPIN setup.
I always try to identify the plots by color in the lower
left?corner box.? The one I was referring to is the tritium in blue.
?
Charles
?
On Wed, Jan 8, 2020 at 12:15 PM Randall Buck <rbuck@...> wrote:
Hi Charles,
I would like to see a close up photo of your Si-PIN alone.
Randall
----- Original Message -----
From: Charles David Young <charlesdavidyoung@...>
To: [email protected], Mike
Loughlin <loughlin3@...>
Sent: Tue, 07 Jan 2020 10:42:31 -0800 (PST)
Subject: Re: [XRF] Tritium with Amptek Si-PIN vs NaI
And here is an XRF of a Nb disk that George provided me that is being
excited by a single Am241 button.? I have included a photo of the setup.
The Am241 is glued to a lead strip and is pressed up against the Nb disk in
a baggy.? The red Si-PIN protective cap is peeking out below just behind
the lead strip.? As you can see the Nb Ka and Kb peaks are very clear and
there is hardly a trace of the normal Np peaks from the Am241.? For
comparison I have included that same Nb scan alongside an Am241 scan that
is not shielded (blue)
It really is amazing how nice an exciter Am241 is when it is properly
shielded and placed in front of the target.
> I have been playing with the Si-PIN that I got from Geo and am getting
> some great results.? When measuring a tritium keychain with NaI I get
a
> strong peak down in the teens (dark blue) but I have never been sure where
> to place that peak given that this is a broad Bremsstrahlung region.?
I had
> been placing it at 11keV because this is supposed to be in the middle of
> that region.
>
> However, my Si-PIN results show how dominant the Zn sulphide peaks are so
> now I would place my NaI peak right between them at 9keV.? That makes
for a
> great calibration point at the extreme low end of my NaI setup.
>
> Charles
>
>
>
My photos are always attached at full resolution. Perhaps is reducing the resolution to save space. Is anyone else having a problem reading my scans? ?
I always try to identify the plots by color in the lower
left?corner box.? The one I was referring to is the tritium in blue.
?
Charles
?
On Wed, Jan 8, 2020 at 12:15 PM Randall Buck <rbuck@...> wrote:
Hi Charles,
I would like to see a close up photo of your Si-PIN alone.
Randall
----- Original Message -----
From: Charles David Young <charlesdavidyoung@...>
To: [email protected], Mike
Loughlin <loughlin3@...>
Sent: Tue, 07 Jan 2020 10:42:31 -0800 (PST)
Subject: Re: [XRF] Tritium with Amptek Si-PIN vs NaI
And here is an XRF of a Nb disk that George provided me that is being
excited by a single Am241 button.? I have included a photo of the setup.
The Am241 is glued to a lead strip and is pressed up against the Nb disk in
a baggy.? The red Si-PIN protective cap is peeking out below just behind
the lead strip.? As you can see the Nb Ka and Kb peaks are very clear and
there is hardly a trace of the normal Np peaks from the Am241.? For
comparison I have included that same Nb scan alongside an Am241 scan that
is not shielded (blue)
It really is amazing how nice an exciter Am241 is when it is properly
shielded and placed in front of the target.
> I have been playing with the Si-PIN that I got from Geo and am getting
> some great results.? When measuring a tritium keychain with NaI I get
a
> strong peak down in the teens (dark blue) but I have never been sure where
> to place that peak given that this is a broad Bremsstrahlung region.?
I had
> been placing it at 11keV because this is supposed to be in the middle of
> that region.
>
> However, my Si-PIN results show how dominant the Zn sulphide peaks are so
> now I would place my NaI peak right between them at 9keV.? That makes
for a
> great calibration point at the extreme low end of my NaI setup.
>
> Charles
>
>
>
I always try to identify the plots by color in the lower
left?corner box.? The one I was referring to is the tritium in blue.
?
Charles
?
On Wed, Jan 8, 2020 at 12:15 PM Randall Buck <rbuck@...> wrote:
Hi Charles,
I would like to see a close up photo of your Si-PIN alone.
Randall
----- Original Message -----
From: Charles David Young <charlesdavidyoung@...>
To: [email protected], Mike
Loughlin <loughlin3@...>
Sent: Tue, 07 Jan 2020 10:42:31 -0800 (PST)
Subject: Re: [XRF] Tritium with Amptek Si-PIN vs NaI
And here is an XRF of a Nb disk that George provided me that is being
excited by a single Am241 button.? I have included a photo of the setup.
The Am241 is glued to a lead strip and is pressed up against the Nb disk in
a baggy.? The red Si-PIN protective cap is peeking out below just behind
the lead strip.? As you can see the Nb Ka and Kb peaks are very clear and
there is hardly a trace of the normal Np peaks from the Am241.? For
comparison I have included that same Nb scan alongside an Am241 scan that
is not shielded (blue)
It really is amazing how nice an exciter Am241 is when it is properly
shielded and placed in front of the target.
> I have been playing with the Si-PIN that I got from Geo and am getting
> some great results.? When measuring a tritium keychain with NaI I get
a
> strong peak down in the teens (dark blue) but I have never been sure where
> to place that peak given that this is a broad Bremsstrahlung region.?
I had
> been placing it at 11keV because this is supposed to be in the middle of
> that region.
>
> However, my Si-PIN results show how dominant the Zn sulphide peaks are so
> now I would place my NaI peak right between them at 9keV.? That makes
for a
> great calibration point at the extreme low end of my NaI setup.
>
> Charles
>
>
>
On Wed, Jan 8, 2020 at 12:15 PM Randall Buck <rbuck@...> wrote:
Hi Charles,
I would like to see a close up photo of your Si-PIN alone.
Randall
----- Original Message -----
From: Charles David Young <charlesdavidyoung@...>
To: [email protected], Mike Loughlin <loughlin3@...>
Sent: Tue, 07 Jan 2020 10:42:31 -0800 (PST)
Subject: Re: [XRF] Tritium with Amptek Si-PIN vs NaI
And here is an XRF of a Nb disk that George provided me that is being
excited by a single Am241 button.? I have included a photo of the setup.
The Am241 is glued to a lead strip and is pressed up against the Nb disk in
a baggy.? The red Si-PIN protective cap is peeking out below just behind
the lead strip.? As you can see the Nb Ka and Kb peaks are very clear and
there is hardly a trace of the normal Np peaks from the Am241.? For
comparison I have included that same Nb scan alongside an Am241 scan that
is not shielded (blue)
It really is amazing how nice an exciter Am241 is when it is properly
shielded and placed in front of the target.
> I have been playing with the Si-PIN that I got from Geo and am getting
> some great results.? When measuring a tritium keychain with NaI I get a
> strong peak down in the teens (dark blue) but I have never been sure where
> to place that peak given that this is a broad Bremsstrahlung region.? I had
> been placing it at 11keV because this is supposed to be in the middle of
> that region.
>
> However, my Si-PIN results show how dominant the Zn sulphide peaks are so
> now I would place my NaI peak right between them at 9keV.? That makes for a
> great calibration point at the extreme low end of my NaI setup.
>
> Charles
>
>
>
----- Original Message ----- From: Charles David Young <charlesdavidyoung@...> To: [email protected], Mike Loughlin <loughlin3@...> Sent: Tue, 07 Jan 2020 10:42:31 -0800 (PST) Subject: Re: [XRF] Tritium with Amptek Si-PIN vs NaI
And here is an XRF of a Nb disk that George provided me that is being excited by a single Am241 button. I have included a photo of the setup.
The Am241 is glued to a lead strip and is pressed up against the Nb disk in a baggy. The red Si-PIN protective cap is peeking out below just behind the lead strip. As you can see the Nb Ka and Kb peaks are very clear and there is hardly a trace of the normal Np peaks from the Am241. For comparison I have included that same Nb scan alongside an Am241 scan that is not shielded (blue)
It really is amazing how nice an exciter Am241 is when it is properly shielded and placed in front of the target.
Charles
On Tue, Jan 7, 2020 at 10:59 AM Charles David Young < charlesdavidyoung@...> wrote:
I have been playing with the Si-PIN that I got from Geo and am getting some great results. When measuring a tritium keychain with NaI I get a strong peak down in the teens (dark blue) but I have never been sure where to place that peak given that this is a broad Bremsstrahlung region. I had been placing it at 11keV because this is supposed to be in the middle of that region.
However, my Si-PIN results show how dominant the Zn sulphide peaks are so now I would place my NaI peak right between them at 9keV. That makes for a great calibration point at the extreme low end of my NaI setup.
----- Original Message ----- From: Charles David Young <charlesdavidyoung@...> To: [email protected], Mike Loughlin <loughlin3@...> Sent: Tue, 07 Jan 2020 09:59:14 -0800 (PST) Subject: [XRF] Tritium with Amptek Si-PIN vs NaI
I have been playing with the Si-PIN that I got from Geo and am getting some great results. When measuring a tritium keychain with NaI I get a strong peak down in the teens (dark blue) but I have never been sure where to place that peak given that this is a broad Bremsstrahlung region. I had been placing it at 11keV because this is supposed to be in the middle of that region.
However, my Si-PIN results show how dominant the Zn sulphide peaks are so now I would place my NaI peak right between them at 9keV. That makes for a great calibration point at the extreme low end of my NaI setup.
----- Original Message ----- From: Dude <dfemer@...> To: [email protected] Sent: Wed, 08 Jan 2020 11:17:33 -0500 (EST) Subject: Re: [XRF] Tritium with Amptek Si-PIN vs NaI
Geo,
Which SSD and what is the hardware set up you are using with it? How about some pictures.
" A 316 Stainless Steel ?piece of metal works well."
?
That's one of the things on my bucket ;list too-
?
Charles, it's amazing that you took to the new Si-PIN so well and right away.
?
By the way the SDD detector is in an on line now. Looks nice.Have only the one, no spare yet, too expensive!
?
Also found some premade cables for the Amptek PX-2 power supply that is hopefully going ton power the 2nd CdTe head. Lemo cables are hard to find in the right configuration.... we're waiting to see what housing the other fellows are going to use with the Si-PIN OEM kits before we try to standardize connectors or cases. The DP5 stack would best be served in a Hammond cast aluminum box milled out to allow the connectors to protrude, maybe someone with a home made CNC mill will help out....
[mailto:[email protected]] On Behalf Of Charles David Young Sent: Tuesday, January 7, 2020 5:31 PM To:[email protected] Cc: Mike Loughlin Subject: Re: [XRF] Tritium with Amptek Si-PIN vs NaI
?
Attached is the same tritium scan with Cu and Au
characteristic x-rays bracketing the Zn peaks.? If any doubt remains that
those are Zn peaks here is a high resolution scan I have seen around the
internet. Also, I don't really care about the shape of the brem.? I am
convinced that what I am seeing with my NaI is actually the Zn peaks merged
together at about 9keV.? I think that is a better estimate than the 11keV I
was using before.
?
BTW, I have really not needed to calibrate this Si-PIN at
all.? Geo sent it to me fully calibrated.? So far everything I have
tried checks out.
Charles
?
?
On Tue, Jan 7, 2020 at 4:50 PM Dude <dfemer@...> wrote:
Charles,
You may
be close to what that cal peak will be but it isn¡¯t necessarily accurate. The
shape of the brem is going to be dependent on the filtering its undergone from
both the glass and the different detector¡¯s windows.? To do a proper cal
use a monochromatic source of the proper energy for each detector. Getting the
cal points right saves a lot of interpretation grief later, especially with
high resolution detectors.? Spend the money and do it right they say. Get
" A 316
Stainless Steel ?piece of metal works well."
?
That's
one of the things on my bucket ;list too-
?
Charles,
it's amazing that you took to the new Si-PIN so well and right away.
?
By
the way the SDD detector is in an on line now. Looks nice.Have only the one, no
spare yet, too expensive!
?
Also
found some premade cables for the Amptek PX-2 power supply that is hopefully
going ton power the 2nd CdTe head. Lemo cables are hard to find in the right
configuration.... we're waiting to see what housing the other fellows are going
to use with the Si-PIN OEM kits before we try to standardize connectors or
cases. The DP5 stack would best be served in a Hammond cast aluminum box milled
out to allow the connectors to protrude, maybe someone with a home made CNC
mill will help out....
?
?
Geo
?
-----
Original Message -----
From: Dude <dfemer@...>
To: [email protected]
Cc: 'Mike Loughlin' <loughlin3@...>
Sent: Tue, 07 Jan 2020 23:43:08 -0500 (EST)
Subject: Re: [XRF] Tritium with Amptek Si-PIN vs NaI
You
missed the point, there is no doubt the ?SI Pin spectra are Zn
characteristic x-rays based on a good calibration and are well in spec.?
The
NaI spectra aren¡¯t even calibrated in the composite spectra. It would be really
nice that when you are talking about a specific peak that you put the cursor on
it and leave out all the other spectra so we can actually determine energy and
what
the data mean.?
You are
convinced that its seeing the Zn and that¡¯s not saying it
isn¡¯t either. ?A scientific approach will prove the point not a personal
belief
that you¡¯re going to base the rest of you calibrations on.? You have a
hypothesis -prove it. You¡¯ve got two signals overlapping each other in a
detector with very poor resolution.? You need to separate out the
interferences
so you can determine definitively what you are looking at and determine the
best
calibration point. Using the NaI detector run a pure Zn target with a non brem
source (AM-241 would be a good source) then with the Tritium source. Take both
spectra sequentially to avoid E drift.? Overlay it over the Tritium
?Brem
spectra. ?Interpret that data and come to a conclusion independent of your
bias
A Fe-55
check source would be useful to bracket the Am-241 energy
cal in order to get a tight E-cal.? It ?would be even more useful for
the low energy
cal of the NaI detector rather than a weak tritium light.
You
always need to do a Energy Cal check every time you use the
instrument and even at the end of the day - or at some point it¡¯s going to bite
you.? A 316 Stainless Steel ?piece of metal works well.
Dud
?
From:[email protected]
[mailto:[email protected]] On Behalf Of Charles David Young Sent: Tuesday, January 7, 2020 5:31 PM To:[email protected] Cc: Mike Loughlin Subject: Re: [XRF] Tritium with Amptek Si-PIN vs NaI
?
Attached is the same tritium scan with Cu and Au
characteristic x-rays bracketing the Zn peaks.? If any doubt remains that
those are Zn peaks here is a high resolution scan I have seen around the
internet. Also, I don't really care about the shape of the brem.? I am
convinced that what I am seeing with my NaI is actually the Zn peaks merged
together at about 9keV.? I think that is a better estimate than the 11keV
I
was using before.
?
BTW, I have really not needed to calibrate this Si-PIN at
all.? Geo sent it to me fully calibrated.? So far everything I have
tried checks out.
Charles
?
?
On Tue, Jan 7, 2020 at 4:50 PM Dude <dfemer@...> wrote:
Charles,
You may
be close to what that cal peak will be but it isn¡¯t necessarily accurate. The
shape of the brem is going to be dependent on the filtering its undergone from
both the glass and the different detector¡¯s windows.? To do a proper cal
use a monochromatic source of the proper energy for each detector. Getting the
cal points right saves a lot of interpretation grief later, especially with
high resolution detectors.? Spend the money and do it right they say. Get
a Fe 55 disk or light up a characteristic x-ray
Dud
?
From:[email protected] [mailto:[email protected]] On Behalf Of Charles
David Young Sent: Tuesday, January 7, 2020 9:59 AM To:[email protected];
Mike Loughlin Subject: [XRF] Tritium with Amptek Si-PIN vs NaI
?
I
have been playing with the Si-PIN that I got from Geo and am getting some great
results.? When measuring a tritium keychain with NaI I get a strong peak
down in the teens (dark blue) but I have never been sure where to place that
peak given that this is a broad Bremsstrahlung region.? I had been placing
it at 11keV because this is supposed to be in the middle of that region.
?
However,
my Si-PIN results show how dominant the Zn sulphide peaks are so now I would
place my NaI peak right between them at 9keV.? That makes for a great
calibration point at the extreme low end of my NaI setup.
" A 316 Stainless Steel ?piece of metal works well."
That's one of the things on my bucket ;list too-
Charles, it's amazing that you took to the new Si-PIN so well and right away.
By the way the SDD detector is in an on line now. Looks nice.Have only the one, no spare yet, too expensive!
Also found some premade cables for the Amptek PX-2 power supply that is hopefully going ton power the 2nd CdTe head. Lemo cables are hard to find in the right configuration.... we're waiting to see what housing the other fellows are going to use with the Si-PIN OEM kits before we try to standardize connectors or cases. The DP5 stack would best be served in a Hammond cast aluminum box milled out to allow the connectors to protrude, maybe someone with a home made CNC mill will help out....
----- Original Message ----- From: Dude <dfemer@...> To: [email protected] Cc: 'Mike Loughlin' <loughlin3@...> Sent: Tue, 07 Jan 2020 23:43:08 -0500 (EST) Subject: Re: [XRF] Tritium with Amptek Si-PIN vs NaI
Charles,
You missed the point, there is no doubt the ?SI Pin spectra are Zn characteristic x-rays based on a good calibration and are well in spec.? The NaI spectra aren¡¯t even calibrated in the composite spectra. It would be really nice that when you are talking about a specific peak that you put the cursor on it and leave out all the other spectra so we can actually determine energy and what the data mean.?
You are convinced that its seeing the Zn and that¡¯s not saying it isn¡¯t either. ?A scientific approach will prove the point not a personal belief that you¡¯re going to base the rest of you calibrations on.? You have a hypothesis -prove it. You¡¯ve got two signals overlapping each other in a detector with very poor resolution.? You need to separate out the interferences so you can determine definitively what you are looking at and determine the best calibration point. Using the NaI detector run a pure Zn target with a non brem source (AM-241 would be a good source) then with the Tritium source. Take both spectra sequentially to avoid E drift.? Overlay it over the Tritium ?Brem spectra. ?Interpret that data and come to a conclusion independent of your bias
A Fe-55 check source would be useful to bracket the Am-241 energy cal in order to get a tight E-cal.? It ?would be even more useful for the low energy cal of the NaI detector rather than a weak tritium light.
You always need to do a Energy Cal check every time you use the instrument and even at the end of the day - or at some point it¡¯s going to bite you.? A 316 Stainless Steel ?piece of metal works well.
Dud
?
From:[email protected] [mailto:[email protected]] On Behalf Of Charles David Young Sent: Tuesday, January 7, 2020 5:31 PM To:[email protected] Cc: Mike Loughlin Subject: Re: [XRF] Tritium with Amptek Si-PIN vs NaI
?
Attached is the same tritium scan with Cu and Au characteristic x-rays bracketing the Zn peaks.? If any doubt remains that those are Zn peaks here is a high resolution scan I have seen around the internet. Also, I don't really care about the shape of the brem.? I am convinced that what I am seeing with my NaI is actually the Zn peaks merged together at about 9keV.? I think that is a better estimate than the 11keV I was using before.
?
BTW, I have really not needed to calibrate this Si-PIN at all.? Geo sent it to me fully calibrated.? So far everything I have tried checks out.
Charles
?
?
On Tue, Jan 7, 2020 at 4:50 PM Dude <dfemer@...> wrote:
Charles,
You may be close to what that cal peak will be but it isn¡¯t necessarily accurate. The shape of the brem is going to be dependent on the filtering its undergone from both the glass and the different detector¡¯s windows.? To do a proper cal use a monochromatic source of the proper energy for each detector. Getting the cal points right saves a lot of interpretation grief later, especially with high resolution detectors.? Spend the money and do it right they say. Get a Fe 55 disk or light up a characteristic x-ray
Dud
?
From:[email protected] [mailto:[email protected]] On Behalf Of Charles David Young Sent: Tuesday, January 7, 2020 9:59 AM To:[email protected]; Mike Loughlin Subject: [XRF] Tritium with Amptek Si-PIN vs NaI
?
I have been playing with the Si-PIN that I got from Geo and am getting some great results.? When measuring a tritium keychain with NaI I get a strong peak down in the teens (dark blue) but I have never been sure where to place that peak given that this is a broad Bremsstrahlung region.? I had been placing it at 11keV because this is supposed to be in the middle of that region.
?
However, my Si-PIN results show how dominant the Zn sulphide peaks are so now I would place my NaI peak right between them at 9keV.? That makes for a great calibration point at the extreme low end of my NaI setup.
You missed the point, there is no doubt the ?SI Pin spectra are Zn
characteristic x-rays based on a good calibration and are well in spec.? The
NaI spectra aren¡¯t even calibrated in the composite spectra. It would be really
nice that when you are talking about a specific peak that you put the cursor on
it and leave out all the other spectra so we can actually determine energy and what
the data mean.?
You are convinced that its seeing the Zn and that¡¯s not saying it
isn¡¯t either. ?A scientific approach will prove the point not a personal belief
that you¡¯re going to base the rest of you calibrations on.? You have a
hypothesis -prove it. You¡¯ve got two signals overlapping each other in a
detector with very poor resolution.? You need to separate out the interferences
so you can determine definitively what you are looking at and determine the best
calibration point. Using the NaI detector run a pure Zn target with a non brem
source (AM-241 would be a good source) then with the Tritium source. Take both
spectra sequentially to avoid E drift.? Overlay it over the Tritium ?Brem
spectra. ?Interpret that data and come to a conclusion independent of your bias
A Fe-55 check source would be useful to bracket the Am-241 energy
cal in order to get a tight E-cal.? It ?would be even more useful for the low energy
cal of the NaI detector rather than a weak tritium light.
You always need to do a Energy Cal check every time you use the
instrument and even at the end of the day - or at some point it¡¯s going to bite
you.? A 316 Stainless Steel ?piece of metal works well.
From:[email protected]
[mailto:[email protected]] On Behalf Of Charles David Young Sent: Tuesday, January 7, 2020 5:31 PM To:[email protected] Cc: Mike Loughlin Subject: Re: [XRF] Tritium with Amptek Si-PIN vs NaI
?
Attached is the same tritium scan with Cu and Au
characteristic x-rays bracketing the Zn peaks.? If any doubt remains that
those are Zn peaks here is a high resolution scan I have seen around the
internet. Also, I don't really care about the shape of the brem.? I am
convinced that what I am seeing with my NaI is actually the Zn peaks merged
together at about 9keV.? I think that is a better estimate than the 11keV I
was using before.
?
BTW, I have really not needed to calibrate this Si-PIN at
all.? Geo sent it to me fully calibrated.? So far everything I have
tried checks out.
Charles
?
?
On Tue, Jan 7, 2020 at 4:50 PM Dude <dfemer@...> wrote:
Charles,
You may
be close to what that cal peak will be but it isn¡¯t necessarily accurate. The
shape of the brem is going to be dependent on the filtering its undergone from
both the glass and the different detector¡¯s windows.? To do a proper cal
use a monochromatic source of the proper energy for each detector. Getting the
cal points right saves a lot of interpretation grief later, especially with
high resolution detectors.? Spend the money and do it right they say. Get
a Fe 55 disk or light up a characteristic x-ray
Dud
?
From:[email protected] [mailto:[email protected]] On Behalf Of Charles
David Young Sent: Tuesday, January 7, 2020 9:59 AM To:[email protected];
Mike Loughlin Subject: [XRF] Tritium with Amptek Si-PIN vs NaI
?
I
have been playing with the Si-PIN that I got from Geo and am getting some great
results.? When measuring a tritium keychain with NaI I get a strong peak
down in the teens (dark blue) but I have never been sure where to place that
peak given that this is a broad Bremsstrahlung region.? I had been placing
it at 11keV because this is supposed to be in the middle of that region.
?
However,
my Si-PIN results show how dominant the Zn sulphide peaks are so now I would
place my NaI peak right between them at 9keV.? That makes for a great
calibration point at the extreme low end of my NaI setup.
Attached is the same tritium scan with Cu and Au characteristic x-rays bracketing the Zn peaks.? If any doubt remains that those are Zn peaks here is a high resolution scan I have seen around the internet. Also, I don't really care about the shape of the brem.? I am convinced that what I am seeing with my NaI is actually the Zn peaks merged together at about 9keV.? I think that is a better estimate than the 11keV I was using before.
BTW, I have really not needed to calibrate this Si-PIN at all.? Geo sent it to me fully calibrated.? So far everything I have tried checks out.
On Tue, Jan 7, 2020 at 4:50 PM Dude <dfemer@...> wrote:
Charles,
You may be close to what that cal peak will be but it isn¡¯t necessarily
accurate. The shape of the brem is going to be dependent on the filtering its
undergone from both the glass and the different detector¡¯s windows.? To do a
proper cal use a monochromatic source of the proper energy for each detector. Getting
the cal points right saves a lot of interpretation grief later, especially with
high resolution detectors.? Spend the money and do it right they say. Get a Fe 55
disk or light up a characteristic x-ray
Dud
?
From:[email protected]
[mailto:[email protected]] On Behalf Of Charles David Young Sent: Tuesday, January 7, 2020 9:59 AM To:[email protected]; Mike Loughlin Subject: [XRF] Tritium with Amptek Si-PIN vs NaI
?
I have been playing with the Si-PIN that I got from Geo and
am getting some great results.? When measuring a tritium keychain with NaI
I get a strong peak down in the teens (dark blue) but I have never been sure
where to place that peak given that this is a broad Bremsstrahlung
region.? I had been placing it at 11keV because this is supposed to be in
the middle of that region.
?
However, my Si-PIN results show how dominant the Zn sulphide
peaks are so now I would place my NaI peak right between them at 9keV.?
That makes for a great calibration point at the extreme low end of my NaI
setup.
You may be close to what that cal peak will be but it isn¡¯t necessarily
accurate. The shape of the brem is going to be dependent on the filtering its
undergone from both the glass and the different detector¡¯s windows. ?To do a
proper cal use a monochromatic source of the proper energy for each detector. Getting
the cal points right saves a lot of interpretation grief later, especially with
high resolution detectors.? Spend the money and do it right they say. Get a Fe 55
disk or light up a characteristic x-ray
From:[email protected]
[mailto:[email protected]] On Behalf Of Charles David Young Sent: Tuesday, January 7, 2020 9:59 AM To:[email protected]; Mike Loughlin Subject: [XRF] Tritium with Amptek Si-PIN vs NaI
?
I have been playing with the Si-PIN that I got from Geo and
am getting some great results.? When measuring a tritium keychain with NaI
I get a strong peak down in the teens (dark blue) but I have never been sure
where to place that peak given that this is a broad Bremsstrahlung
region.? I had been placing it at 11keV because this is supposed to be in
the middle of that region.
?
However, my Si-PIN results show how dominant the Zn sulphide
peaks are so now I would place my NaI peak right between them at 9keV.?
That makes for a great calibration point at the extreme low end of my NaI
setup.
Here is a series of elements that I had previously done with NaI.? I added what I thought was a solid 14K gold medallion, which turned out to be gold plated copper!
Great results, we can't wait to see whyat yopu come up with next Charles/
With NaI(Tl), Cs-137 @ 662 is pretty much the standard where quality is tested, for these silicon nand cadmium detect5ors the benchmark is 5.9 keV, the Ka peak of Mn.
This can be had either by exciting Mn directly ( scrap a dead carbon-zinc cell for several? kinds of nearly pure elements!)
or by obtaining a Fe-55 source from SpecTech.
Cd-109 is a good source too, for its silver Ka peak,(22.16) but now my disks are old, I just use a silver "stamp" and excite it with the RAPCAP/
Geo
----- Original Message ----- From: Charles David Young <charlesdavidyoung@...> To: [email protected], Mike Loughlin <loughlin3@...> Sent: Tue, 07 Jan 2020 13:42:31 -0500 (EST) Subject: Re: [XRF] Tritium with Amptek Si-PIN vs NaI
And here is an XRF of a Nb disk that George provided me that is being excited by a single Am241 button.? I have included a photo of the setup.
The Am241 is glued to a lead strip and is pressed up against the Nb disk in a baggy.? The red Si-PIN protective cap is peeking out below just behind the lead strip.? As you can see the Nb Ka and Kb peaks are very clear and there is hardly a trace of the normal Np peaks from the Am241.? For comparison I have included that same Nb scan alongside an Am241 scan that is not shielded (blue)
It really is amazing how nice an exciter Am241 is when it is properly shielded and placed in front of the target.
I have been playing with the Si-PIN that I got from Geo and am getting some great results.? When measuring a tritium keychain
with NaI I get a strong peak down in the teens (dark blue) but I have never been sure where to place that peak given that this is a broad Bremsstrahlung region.? I had been placing it at 11keV because this is supposed to be in the middle of that region.
However, my Si-PIN results show how dominant the Zn sulphide peaks are so now I would place my NaI peak right between them at 9keV.? That makes for a great calibration point at the extreme low end of my NaI setup.
Great results, we can't wait to see whyat yopu come up with next Charles/
With NaI(Tl), Cs-137 @ 662 is pretty much the standard where quality is tested, for these silicon nand cadmium detect5ors the benchmark is 5.9 keV, the Ka peak of Mn.
This can be had either by exciting Mn directly ( scrap a dead carbon-zinc cell for several? kinds of nearly pure elements!)
or by obtaining a Fe-55 source from SpecTech.
Cd-109 is a good source too, for its silver Ka peak,(22.16) but now my disks are old, I just use a silver "stamp" and excite it with the RAPCAP/
Geo
----- Original Message ----- From: Charles David Young <charlesdavidyoung@...> To: [email protected], Mike Loughlin <loughlin3@...> Sent: Tue, 07 Jan 2020 13:42:31 -0500 (EST) Subject: Re: [XRF] Tritium with Amptek Si-PIN vs NaI
And here is an XRF of a Nb disk that George provided me that is being excited by a single Am241 button.? I have included a photo of the setup.
The Am241 is glued to a lead strip and is pressed up against the Nb disk in a baggy.? The red Si-PIN protective cap is peeking out below just behind the lead strip.? As you can see the Nb Ka and Kb peaks are very clear and there is hardly a trace of the normal Np peaks from the Am241.? For comparison I have included that same Nb scan alongside an Am241 scan that is not shielded (blue)
It really is amazing how nice an exciter Am241 is when it is properly shielded and placed in front of the target.
I have been playing with the Si-PIN that I got from Geo and am getting some great results.? When measuring a tritium keychain
with NaI I get a strong peak down in the teens (dark blue) but I have never been sure where to place that peak given that this is a broad Bremsstrahlung region.? I had been placing it at 11keV because this is supposed to be in the middle of that region.
However, my Si-PIN results show how dominant the Zn sulphide peaks are so now I would place my NaI peak right between them at 9keV.? That makes for a great calibration point at the extreme low end of my NaI setup.
Great results, we can't wait to see whyat yopu come up with next Charles/
With NaI(Tl), Cs-137 @ 662 is pretty much the standard where quality is tested, for these silicon nand cadmium detect5ors the benchmark is 5.9 keV, the Ka peak of Mn.
This can be had either by exciting Mn directly ( scrap a dead carbon-zinc cell for several? kinds of nearly pure elements!)
or by obtaining a Fe-55 source from SpecTech.
Cd-109 is a good source too, for its silver Ka peak,(22.16) but now my disks are old, I just use a silver "stamp" and excite it with the RAPCAP/
----- Original Message ----- From: Charles David Young <charlesdavidyoung@...> To: [email protected], Mike Loughlin <loughlin3@...> Sent: Tue, 07 Jan 2020 13:42:31 -0500 (EST) Subject: Re: [XRF] Tritium with Amptek Si-PIN vs NaI
And here is an XRF of a Nb disk that George provided me that is being excited by a single Am241 button.? I have included a photo of the setup.
The Am241 is glued to a lead strip and is pressed up against the Nb disk in a baggy.? The red Si-PIN protective cap is peeking out below just behind the lead strip.? As you can see the Nb Ka and Kb peaks are very clear and there is hardly a trace of the normal Np peaks from the Am241.? For comparison I have included that same Nb scan alongside an Am241 scan that is not shielded (blue)
It really is amazing how nice an exciter Am241 is when it is properly shielded and placed in front of the target.
I have been playing with the Si-PIN that I got from Geo and am getting some great results.? When measuring a tritium keychain
with NaI I get a strong peak down in the teens (dark blue) but I have never been sure where to place that peak given that this is a broad Bremsstrahlung region.? I had been placing it at 11keV because this is supposed to be in the middle of that region.
However, my Si-PIN results show how dominant the Zn sulphide peaks are so now I would place my NaI peak right between them at 9keV.? That makes for a great calibration point at the extreme low end of my NaI setup.
----- Original Message ----- From: Charles David Young <charlesdavidyoung@...> To: [email protected], Mike Loughlin <loughlin3@...> Sent: Tue, 07 Jan 2020 12:59:14 -0500 (EST) Subject: [XRF] Tritium with Amptek Si-PIN vs NaI
I have been playing with the Si-PIN that I got from Geo and am getting some great results.? When measuring a tritium keychain
with NaI I get a strong peak down in the teens (dark blue) but I have never been sure where to place that peak given that this is a broad Bremsstrahlung region.? I had been placing it at 11keV because this is supposed to be in the middle of that region.
However, my Si-PIN results show how dominant the Zn sulphide peaks are so now I would place my NaI peak right between them at 9keV.? That makes for a great calibration point at the extreme low end of my NaI setup.
And here is an XRF of a Nb disk that George provided me that is being excited by a single Am241 button.? I have included a photo of the setup.
The Am241 is glued to a lead strip and is pressed up against the Nb disk in a baggy.? The red Si-PIN protective cap is peeking out below just behind the lead strip.? As you can see the Nb Ka and Kb peaks are very clear and there is hardly a trace of the normal Np peaks from the Am241.? For comparison I have included that same Nb scan alongside an Am241 scan that is not shielded (blue)
It really is amazing how nice an exciter Am241 is when it is properly shielded and placed in front of the target.
I have been playing with the Si-PIN that I got from Geo and am getting some great results.? When measuring
a tritium keychain
with NaI I get a strong peak down in the teens (dark blue) but I have never been sure where to place that peak given that this is a broad Bremsstrahlung region.? I had been placing it at 11keV because this is supposed to be in the middle of that region.
However, my Si-PIN results show how dominant the Zn sulphide peaks are so now I would place my NaI peak right between them at 9keV.? That makes for a great calibration point at the extreme low end of my NaI setup.
I have been playing with the Si-PIN that I got from Geo and am getting some great results.? When measuring
a tritium keychain
with NaI I get a strong peak down in the teens (dark blue) but I have never been sure where to place that peak given that this is a broad Bremsstrahlung region.? I had been placing it at 11keV because this is supposed to be in the middle of that region.
However, my Si-PIN results show how dominant the Zn sulphide peaks are so now I would place my NaI peak right between them at 9keV.? That makes for a great calibration point at the extreme low end of my NaI setup.
The commonly used exciters for amateur XRF are 1-Internal Radiation from the radioactive mineral itself 2- Isotopes 3- X-Ray generators, usually but not limited to X-Ray Tubes.
X-Ray tube PRO- Strong flux makes for fast XRF survey. CON- Costly Usually AC powered/ benchtop Bremsstrahlung and Characteristic X-Ray interference. Difficult to background-subtract. LIMITED ENERGY PEAKS (usually 50 kVp)
Isotope- PRO- Portable Limited suitable isotopes available Half-Life can be an issue Very well know discreet energy interference can be used as a calibration source to double check accuracy even years later. Also known interference peaks can be background subtracted.
CON- Weak flux makes for long sample times (hours even)
All 3 major methods mentioned above work. There are many others, such as Particle Induced (PIXE), I favor the Beta Particle Exciter for higher energies than X-Ray tubes or Isotopes can reach.
Likewise all 3 methods have drawbacks.
Here I show in pictures the difference between a (Weak)? X-Ray Tube and a "Strong" isotope source. The Exciter and Time change but the sample is the same- a 1" X 1.5" "Stamp" made of a known metal alloy, 70% Cu and 30% Ni, 0.005" thick The sensor is an early version Amptek SDD 1-2-3, the hottest thing going in its day. First the classic RAPCAP ring with Am-X8 set to 45 degrees. The scan is good, readable and can be done in? around 15 minutes. More detailed scans can take an hour or even overnight.
Not bad at all if I do say so myself!
Now-on to the "Weak"? X-Ray Tube.
Ho-Hum right? Just more of the same? Now both together in the same scale, offset in energy for clarity.
One point of all this concerns the interference caused in the detector by natural radioisotopes in the sample (minerals, alloys). Nature provides Uranium Decay Chains (both U-238 and U-235), Thorium-232 Decay Chain and monochromatic K-40. Sometime weak, sometimes strong, often in secular equilibrium all the way down the decay chain, sometimes not. Some use this as an excitation source, which is fine, but has limitations. For most of us, it is a nuisance to be minimized. Especially as we have recently studied, the Niobium peaks being swamped by? Uranium's early? decay product's Ka peaks.
The answer of course and shown graphically in the last picture above is simply to overwhelm the natural radiation with stronger peaks from the desired atoms.
All those tools are available to the amateur scientist today, probably for the first time in history, at least to this technological level. Unfortunately the downside is the recent uptick in popularity has driven of prices of surplus apparatus, virtually anything to do with XRF- sky high.?
