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 If a piece of information is incorrect, a link outdated, or the presentation choppy or unclear, the user can just click "Edit Page" at the bottom and then fix the mistake.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?]
I picked this up yesterday.? It was interesting because Brannerite UTi2O6 is supposed to be high in Ti and less so in Ta and Nb like betafites (Ca,Na,U)2(Ti, Nb,Ta)2O6Z(OH).? However, this specimen has much more Nb than anything else.? It is going back to the dealer
today with this scan so he can label it correctly.
Charles run a gamma spec on this. Note the low energy tail on the
U is it possible there is some Th in there? I can¡¯t pick out energies off the
jpg post the MCA file.
I picked this up yesterday.? It was interesting because
Brannerite UTi2O6
is supposed to be high in Ti and less so in Ta and Nb like betafites
(Ca,Na,U)2(Ti, Nb,Ta)2O6Z(OH).? However, this specimen has much more Nb
than anything else.? It is going back to the dealer today with this scan
so he can label it correctly.
I agree Geo its busy, confusing and adds nothing. It would be nice
to ?turn off any elements that are not ID¡¯d as It messes up the energy grid
lines, and is confusing about what¡¯s actually there. Moreover, using a pre-conceived
list of elements is a very poor way to interpret data as there are other interferences
that could also fit that data that will be missed.
On Sun, Feb 9, 2020 at 03:11 PM, Charles David Young wrote:
?
Only 3 elements really stand out: Fe U Ba.?
Nice display, the Fe Kb1 line is well placed. Have you
expanded the? X-axis to include 59.5 yet?
I'm interpreting the vertical black dotted lines are pretty certain and the
lighter, smaller lines are under consideration still.
Are you doing smoothing at all? If so in the DPP or the Theremino program? If
you do it in DPP, does it change the stored data or is it only temporary when
invoked?
----- Original Message ----- From: Charles David Young <charlesdavidyoung@...> To: [email protected], Mike Loughlin <loughlin3@...> Sent: Mon, 10 Feb 2020 07:33:50 -0500 (EST) Subject: [XRF] Brannerite! (or is it?)
I picked this up yesterday.? It was interesting because Brannerite UTi2O6 is supposed to be high in Ti and less so in Ta and Nb like betafites (Ca,Na,U)2(Ti, Nb,Ta)2O6Z(OH).? However, this specimen has much more Nb than anything else.? It is going back to the dealer today with this scan so he can label it correctly.
Good, thanks and it looks fine, keep it up. I did my first 24 hour run with Si-PIN in Gamma Scan mode (no XRF exciting from internal or external) on one a weakly radioactive target over the weekend with critical calibration before and after- good news, no drift noticed at all. Sweet.
If anyone is tempted to buy the Amptek CdTe on eBay from Bulgaria, a little warning the ad picture is cut right out of he Amptek catalog...¡.caveat emptor.
----- Original Message ----- From: Charles David Young <charlesdavidyoung@...> To: [email protected] Sent: Mon, 10 Feb 2020 07:19:56 -0500 (EST) Subject: Re: [XRF] Trinitite
Yes, that is correct, George.? The heavy black lines are what I consider firmly identified.
I normally expand the lower region and leave off the Bremsstrahlung and 59.5 peak to the right.
I never intentionally use smoothing.? I have not seen such a DPP option and I seriously doubt it would affect the stored data in any case.? In Theremino I have removed all smoothing unless you consider drawing a line from one peak to neighboring peaks smoothing.
On Sun, Feb 9, 2020 at 03:11 PM, Charles David Young wrote:
?
Only 3 elements really stand out: Fe U Ba.?
Nice display, the Fe Kb1 line is well placed. Have you expanded the? X-axis to include 59.5 yet? I'm interpreting the vertical black dotted lines are pretty certain and the lighter, smaller lines are under consideration still.
Are you doing smoothing at all? If so in the DPP or the Theremino program? If you do it in DPP, does it change the stored data or is it only temporary when invoked?
OK, guys, I shall have to revisit my sample - gamma spec.? It never occured to me to try XRF with it, but likely need to configure more than one AM-241 pill for that.
Has anyone tried using the old power germanium transistors with reverse a biased junction as a detector??
On Mon, Feb 10, 2020 at 5:53 AM AnotherWally <anotherwally@...> wrote:
On 2/8/20 4:49 PM, David Eckhardt wrote:
> Are you still able to get a meaningful spectrum from the trinitite
> _with amateur probes_?? It's over 70 years old.
I think it depends on what you mean by "meaningful".? I have not tried
XRF of Trinitite, but I have done some Gamma spec on my specimens.? I
have used a Scionix 2x2NaI(Tl) probe with the UCS-20 MCA as well as a
22mmx25mm CsI(Tl) probe with Theremino adapter and software.
I almost hate to attach this example because it is very sloppy and not
properly calibrated.? This scan of a small 4.3 gram specimen was done in
open air; no lead castle, no supplemental shielding and no background
removal.? This was a 7 hour scan and room temperature went wherever it
wanted to go.? I have made no effort to identify any of the isotopes; it
was nothing more than a preliminary scan of a new-to-me specimen just to
see what I could see - ? Just a quick'n'dirty preliminary look.? It was
done with my Scionix 2x2 NaI(Tl) probe and the UCS-20 MCA.? I saved the
UCS-20 data file and plotted it with GnuPlot so I could play with
intervals and data ranges.
But even with with that said, I think it is apparent a careful setup,
properly calibrated and attention paid to temperature drift would reveal
the general nature of what radioactivity remains (within the limits of a
NaI(Tl) probe).? For sure the Cs137 is easy to find, as is the Am241.?
Other stuff is there, too, but accurate calibration is missing. For
reference, the Scionix 2x2 NaI(Tl) probe I obtained from Luuk yields an
honest 6.8% resolution at 662 keV, and that is about the best I will be
doing any time soon.
I have been intending to take a more serious look at my Trinitite
specimens but right now my "rad lab" is in a serious state of disarray.?
I need to get it cleaned up, organized and shielding back in place
before I can try to do much more.? I have been getting serious Probe
Envy looking at Charles' and Geo's results but truthfully, right now I
can't even effectively use what I already have.
I picked this up yesterday.? It was interesting because Brannerite UTi2O6 is supposed to be high in Ti and less so in Ta and Nb like betafites (Ca,Na,U)2(Ti, Nb,Ta)2O6Z(OH).? However, this specimen has much more Nb than anything else.? It is going back to the dealer today with this scan so he can label it correctly.
Yes, that is correct, George.? The heavy black lines are what I consider firmly identified.
I normally expand the lower region and leave off the Bremsstrahlung and 59.5 peak to the right.
I never intentionally use smoothing.? I have not seen such a DPP option and I seriously doubt it would affect the stored data in any case.? In Theremino I have removed all smoothing unless you consider drawing a line from one peak to neighboring peaks smoothing.
On Sun, Feb 9, 2020 at 03:11 PM, Charles David Young wrote:
?
Only 3 elements really stand out: Fe U Ba.?
Nice display, the Fe Kb1 line is well placed. Have you expanded the? X-axis to include 59.5 yet? I'm interpreting the vertical black dotted lines are pretty certain and the lighter, smaller lines are under consideration still.
Are you doing smoothing at all? If so in the DPP or the Theremino program? If you do it in DPP, does it change the stored data or is it only temporary when invoked?
What you have is exactly what I have when it comes to 662 etc. Anything over 100 keV and I'm right back on the UCS-20 with a 2X2 Scionix and feel darned lucky to have it.
When you do get back in the saddle with your Gamma Spec, I will be glad to backstop you on any tough samples, to the best of my ability. Right now I'm just duffing around and learning this new generation gear.
Yesterday started my first 24 hour scan (Gamma spec not XRF) of a very weak source and was really surprised how well it turned out.
----- Original Message ----- From: AnotherWally <anotherwally@...> To: [email protected] Sent: Mon, 10 Feb 2020 00:53:17 -0500 (EST) Subject: Re: [XRF] Trinitite
On 2/8/20 4:49 PM, David Eckhardt wrote:
Are you still able to get a meaningful spectrum from the trinitite _with amateur probes_?? It's over 70 years old.
I think it depends on what you mean by "meaningful".? I have not tried XRF of Trinitite, but I have done some Gamma spec on my specimens.? I have used a Scionix 2x2NaI(Tl) probe with the UCS-20 MCA as well as a 22mmx25mm CsI(Tl) probe with Theremino adapter and software.
I almost hate to attach this example because it is very sloppy and not properly calibrated.? This scan of a small 4.3 gram specimen was done in open air; no lead castle, no supplemental shielding and no background removal.? This was a 7 hour scan and room temperature went wherever it wanted to go.? I have made no effort to identify any of the isotopes; it was nothing more than a preliminary scan of a new-to-me specimen just to see what I could see - ? Just a quick'n'dirty preliminary look.? It was done with my Scionix 2x2 NaI(Tl) probe and the UCS-20 MCA.? I saved the UCS-20 data file and plotted it with GnuPlot so I could play with intervals and data ranges.
But even with with that said, I think it is apparent a careful setup, properly calibrated and attention paid to temperature drift would reveal the general nature of what radioactivity remains (within the limits of a NaI(Tl) probe).? For sure the Cs137 is easy to find, as is the Am241.? Other stuff is there, too, but accurate calibration is missing. For reference, the Scionix 2x2 NaI(Tl) probe I obtained from Luuk yields an honest 6.8% resolution at 662 keV, and that is about the best I will be doing any time soon.
I have been intending to take a more serious look at my Trinitite specimens but right now my "rad lab" is in a serious state of disarray.? I need to get it cleaned up, organized and shielding back in place before I can try to do much more.? I have been getting serious Probe Envy looking at Charles' and Geo's results but truthfully, right now I can't even effectively use what I already have.
----- Original Message ----- From: Dude <dfemer@...> To: [email protected] Sent: Mon, 10 Feb 2020 00:23:11 -0500 (EST) Subject: Re: [XRF] XRF hardware
Geo,
The gun is set up w 3 beams 50, 40 , and 15 kV and depending on the mode it can use 5 filters. Filters are in on the 40 and 15 kV shots. ?Everything can be changed but The ?current is usually 11 uA.
[mailto:[email protected]] On Behalf Of GEOelectronics@... Sent: Sunday, February 9, 2020 12:47 PM To:[email protected] Subject: Re: [XRF] Li battery shiny vs dull
?
Cool,
that's a beast compared to mine. Max is 0.1 mA (100 microamp) here.
?
It
does have its own shielded housing, and I suspect the narrow measured beam cone
angle is controlled by an mechanical iris inside the sealed tube. I'm assuming
yours is also a side exit not and end-fire, those use transmission targets, the
kind I use have "reflection" tungsten targets.? The excitation
HV is less than the W Ka, so all I work with are Bremsstrahlung X-Rays, thus
[mailto:[email protected]] On Behalf Of GEOelectronics@... Sent: Sunday, February 9, 2020 10:53 AM To:[email protected] Subject: Re: [XRF] Li battery shiny vs dull
?
That
sounds logical Dud, hey on your Kevex stand alone tube, do you know the spot
size and the cone angle? The one in my rig here in the counting room seems to
On Sun, Feb 9, 2020 at 03:11 PM, Charles David Young wrote:
?
Only 3 elements really stand out: Fe U Ba.?
Nice display, the Fe Kb1 line is well placed. Have you expanded the? X-axis to include 59.5 yet? I'm interpreting the vertical black dotted lines are pretty certain and the lighter, smaller lines are under consideration still.
Are you doing smoothing at all? If so in the DPP or the Theremino program? If you do it in DPP, does it change the stored data or is it only temporary when invoked?
Are you still able to get a meaningful spectrum from the trinitite _with amateur probes_?? It's over 70 years old.
I think it depends on what you mean by "meaningful".? I have not tried XRF of Trinitite, but I have done some Gamma spec on my specimens.? I have used a Scionix 2x2NaI(Tl) probe with the UCS-20 MCA as well as a 22mmx25mm CsI(Tl) probe with Theremino adapter and software.
I almost hate to attach this example because it is very sloppy and not properly calibrated.? This scan of a small 4.3 gram specimen was done in open air; no lead castle, no supplemental shielding and no background removal.? This was a 7 hour scan and room temperature went wherever it wanted to go.? I have made no effort to identify any of the isotopes; it was nothing more than a preliminary scan of a new-to-me specimen just to see what I could see - ? Just a quick'n'dirty preliminary look.? It was done with my Scionix 2x2 NaI(Tl) probe and the UCS-20 MCA.? I saved the UCS-20 data file and plotted it with GnuPlot so I could play with intervals and data ranges.
But even with with that said, I think it is apparent a careful setup, properly calibrated and attention paid to temperature drift would reveal the general nature of what radioactivity remains (within the limits of a NaI(Tl) probe).? For sure the Cs137 is easy to find, as is the Am241.? Other stuff is there, too, but accurate calibration is missing. For reference, the Scionix 2x2 NaI(Tl) probe I obtained from Luuk yields an honest 6.8% resolution at 662 keV, and that is about the best I will be doing any time soon.
I have been intending to take a more serious look at my Trinitite specimens but right now my "rad lab" is in a serious state of disarray.? I need to get it cleaned up, organized and shielding back in place before I can try to do much more.? I have been getting serious Probe Envy looking at Charles' and Geo's results but truthfully, right now I can't even effectively use what I already have.
The gun is set up w 3 beams 50, 40 , and 15 kV and depending on
the mode it can use 5 filters. Filters are in on the 40 and 15 kV shots. ?Everything
can be changed but The ?current is usually 11 uA.
For a
full power 50 kV beam shot don¡¯t use a filter. A filter is
used to reduce the Brem above an elements absorption edge in order to get a
better
peak to background signal increasing the limit of detection in this narrow
range. The filter material is tailored to that edge and the beam voltage. Don¡¯t
use a filter for a general assay you¡®re just reducing the xray flux where you
want it the most.
In the X-Ray tube
electrons
are accelerated by a HV field, then are slowed down by a target. Notice I
didn't mention the filament. Some designs don't use a filament, they are called
Field Emission Tubes and are cold-cathode. Those aren't continuous output tho
and not used for XRF. Rather they build up a charge, 150 kV or more and
"fire" a pulse at the tube, similar to a photo flash. It's all over
in a few nanoseconds, but for X-Ray film it's OK, they just fire a dozen or
hundred pulses, really quickly.
?
For XRF we need a much
weaker ray, but it needs to be left on from minutes to hours- those tubes
require hot cathodes= filament to boil off some electrons free of the cathode
(the filament usually is also the cathode), a steady HV DC accelerates them,
they are focused into a beam by deflection plates, irises and magnetic focus
coils in a microfocus tube to get a small spot-.
Broad band Bremsstrahlung
radiation is created,?and if the peak HV is sufficiently above the Ka
binding energy of the target material, a huge peak at the targets
characteristic X-Ray energy(s) superimposes over the top of the broad Brems
continuum.
?
?
So? X-Ray tubes are
not by their very nature monochromatic.?
isotopes on the other hand
are monochromatic, but of many discreet energies.
?
It would be nice to have a
knob that said 0-50 kVp and mean it. Set it for 35 and you've actually set it
to "not over 35kVp", below it is a huge spray of energies up to the
PEAK HV available. kVp= kiloVolt Peak. Nor is most of the wattage in the peak
value, it is considerably below that, like 1/3 of the peak is the bulk of it.
?
My filters are just
absorbers that remove the lower energies, the one that happen to be exactly on
the energy peak you are trying to measure. Next the aluminum collimator absorbs
much the off-axis rays which do nothing but try to create interference from
your shielding.
?
Fortunately only a tiny
amount of power is needed to do XRF. By the way, Amptek specifically states
their warranty does not cover radiation damage to sensors, not to mention the
thin beryllium window is as fragile as a pancake probe.
[mailto:[email protected]] On Behalf Of GEOelectronics@... Sent: Sunday, February 9, 2020 12:47 PM To:[email protected] Subject: Re: [XRF] Li battery shiny vs dull
?
Cool,
that's a beast compared to mine. Max is 0.1 mA (100 microamp) here.
?
It
does have its own shielded housing, and I suspect the narrow measured beam cone
angle is controlled by an mechanical iris inside the sealed tube. I'm assuming
yours is also a side exit not and end-fire, those use transmission targets, the
kind I use have "reflection" tungsten targets.? The excitation
HV is less than the W Ka, so all I work with are Bremsstrahlung X-Rays, thus
[mailto:[email protected]] On Behalf Of GEOelectronics@... Sent: Sunday, February 9, 2020 10:53 AM To:[email protected] Subject: Re: [XRF] Li battery shiny vs dull
?
That
sounds logical Dud, hey on your Kevex stand alone tube, do you know the spot
size and the cone angle? The one in my rig here in the counting room seems to
----- Original Message ----- From: Dude <dfemer@...> To: [email protected] Sent: Sun, 09 Feb 2020 23:03:21 -0500 (EST) Subject: Re: [XRF] XRF hardware
Geo,
For a full power 50 kV beam shot don¡¯t use a filter. A filter is used to reduce the Brem above an elements absorption edge in order to get a better peak to background signal increasing the limit of detection in this narrow range. The filter material is tailored to that edge and the beam voltage. Don¡¯t use a filter for a general assay you¡®re just reducing the xray flux where you want it the most.
In the X-Ray tube electrons are accelerated by a HV field, then are slowed down by a target. Notice I didn't mention the filament. Some designs don't use a filament, they are called Field Emission Tubes and are cold-cathode. Those aren't continuous output tho and not used for XRF. Rather they build up a charge, 150 kV or more and "fire" a pulse at the tube, similar to a photo flash. It's all over in a few nanoseconds, but for X-Ray film it's OK, they just fire a dozen or hundred pulses, really quickly.
?
For XRF we need a much weaker ray, but it needs to be left on from minutes to hours- those tubes require hot cathodes= filament to boil off some electrons free of the cathode (the filament usually is also the cathode), a steady HV DC accelerates them, they are focused into a beam by deflection plates, irises and magnetic focus coils in a microfocus tube to get a small spot-.
Broad band Bremsstrahlung radiation is created,?and if the peak HV is sufficiently above the Ka binding energy of the target material, a huge peak at the targets characteristic X-Ray energy(s) superimposes over the top of the broad Brems continuum.
?
?
So? X-Ray tubes are not by their very nature monochromatic.?
isotopes on the other hand are monochromatic, but of many discreet energies.
?
It would be nice to have a knob that said 0-50 kVp and mean it. Set it for 35 and you've actually set it to "not over 35kVp", below it is a huge spray of energies up to the PEAK HV available. kVp= kiloVolt Peak. Nor is most of the wattage in the peak value, it is considerably below that, like 1/3 of the peak is the bulk of it.
?
My filters are just absorbers that remove the lower energies, the one that happen to be exactly on the energy peak you are trying to measure. Next the aluminum collimator absorbs much the off-axis rays which do nothing but try to create interference from your shielding.
?
Fortunately only a tiny amount of power is needed to do XRF. By the way, Amptek specifically states their warranty does not cover radiation damage to sensors, not to mention the thin beryllium window is as fragile as a pancake probe.
[mailto:[email protected]] On Behalf Of GEOelectronics@... Sent: Sunday, February 9, 2020 12:47 PM To:[email protected] Subject: Re: [XRF] Li battery shiny vs dull
?
Cool,
that's a beast compared to mine. Max is 0.1 mA (100 microamp) here.
?
It
does have its own shielded housing, and I suspect the narrow measured beam cone
angle is controlled by an mechanical iris inside the sealed tube. I'm assuming
yours is also a side exit not and end-fire, those use transmission targets, the
kind I use have "reflection" tungsten targets.? The excitation
HV is less than the W Ka, so all I work with are Bremsstrahlung X-Rays, thus
[mailto:[email protected]] On Behalf Of GEOelectronics@... Sent: Sunday, February 9, 2020 10:53 AM To:[email protected] Subject: Re: [XRF] Li battery shiny vs dull
?
That
sounds logical Dud, hey on your Kevex stand alone tube, do you know the spot
size and the cone angle? The one in my rig here in the counting room seems to
For a full power 50 kV beam shot don¡¯t use a filter. A filter is
used to reduce the Brem above an elements absorption edge in order to get a better
peak to background signal increasing the limit of detection in this narrow
range. The filter material is tailored to that edge and the beam voltage. Don¡¯t
use a filter for a general assay you¡®re just reducing the xray flux where you
want it the most.
In the X-Ray tube electrons
are accelerated by a HV field, then are slowed down by a target. Notice I
didn't mention the filament. Some designs don't use a filament, they are called
Field Emission Tubes and are cold-cathode. Those aren't continuous output tho
and not used for XRF. Rather they build up a charge, 150 kV or more and
"fire" a pulse at the tube, similar to a photo flash. It's all over
in a few nanoseconds, but for X-Ray film it's OK, they just fire a dozen or
hundred pulses, really quickly.
?
For XRF we need a much
weaker ray, but it needs to be left on from minutes to hours- those tubes
require hot cathodes= filament to boil off some electrons free of the cathode
(the filament usually is also the cathode), a steady HV DC accelerates them,
they are focused into a beam by deflection plates, irises and magnetic focus
coils in a microfocus tube to get a small spot-.
Broad band Bremsstrahlung
radiation is created,?and if the peak HV is sufficiently above the Ka
binding energy of the target material, a huge peak at the targets
characteristic X-Ray energy(s) superimposes over the top of the broad Brems
continuum.
?
?
So? X-Ray tubes are
not by their very nature monochromatic.?
isotopes on the other hand
are monochromatic, but of many discreet energies.
?
It would be nice to have a
knob that said 0-50 kVp and mean it. Set it for 35 and you've actually set it
to "not over 35kVp", below it is a huge spray of energies up to the
PEAK HV available. kVp= kiloVolt Peak. Nor is most of the wattage in the peak
value, it is considerably below that, like 1/3 of the peak is the bulk of it.
?
My filters are just
absorbers that remove the lower energies, the one that happen to be exactly on
the energy peak you are trying to measure. Next the aluminum collimator absorbs
much the off-axis rays which do nothing but try to create interference from
your shielding.
?
Fortunately only a tiny
amount of power is needed to do XRF. By the way, Amptek specifically states
their warranty does not cover radiation damage to sensors, not to mention the
thin beryllium window is as fragile as a pancake probe.
?
Geo>K0FF
?
?
-----
Original Message -----
From: Dude <dfemer@...>
To: [email protected]
Sent: Sun, 09 Feb 2020 16:20:35 -0500 (EST)
Cool,
that's a beast compared to mine. Max is 0.1 mA (100 microamp) here.
?
It
does have its own shielded housing, and I suspect the narrow measured beam cone
angle is controlled by an mechanical iris inside the sealed tube. I'm assuming
yours is also a side exit not and end-fire, those use transmission targets, the
kind I use have "reflection" tungsten targets.? The excitation
HV is less than the W Ka, so all I work with are Bremsstrahlung X-Rays, thus
the external filtering etc.
[mailto:[email protected]] On Behalf Of GEOelectronics@... Sent: Sunday, February 9, 2020 10:53 AM To:[email protected] Subject: Re: [XRF] Li battery shiny vs dull
?
That
sounds logical Dud, hey on your Kevex stand alone tube, do you know the spot
size and the cone angle? The one in my rig here in the counting room seems to
On Sun, Feb 9, 2020 at 07:04 PM, <GEOelectronics@...> wrote: What tube and power supply are you running? Next up is the LIXI. This company pioneered portable industrial real-time radiography.
In one iteration their battery operated real-time viewer is excited by a radioisotope. Main use is pipe weld inspection.
Other uses are to inspect multilayer PCBs for internal layer connections. instead of looking at it by eye, there is a cabinet to protect the user and TV camera installed on the viewer. For more info on this part search "X-Ray Image Intensifier". A simple pizza-paddle manipulator allows the specimen to be moved around between the X-Ray tube and vi\ewer. In this type the X-Ray tube is mounted inside the cabinet facing down, while the viewer is below the table looking up. A heavy duty i8ndustrial- all metal version of this is the one I'm converting to SDD XRF now.
Another version uses just the X-Ray tube assembly and viewer bolted together, mounted horizontally so a person or camera can look into the viewer. All the X-Ray tube modules perform the same functions but some have the HV generator integral with the tube, controlled by a small box by LV wiring in a single cable, while others have the HV gen inside the (larger) control box itself in which case the HV is conveyed over to the tube via coaxial HV cable, while the other controls are on LV wires to a separate connector (2 cable).
The tube and viewer bolt together with one bolt, making it easy to get double duty like I'm doing with one of the one wire versions.
Pics attached show the components. Except for the size of the box, all the control boxes look nearly identical, HV Voltage and current are adjustable with knobs and everything is fully metered.
Last time I talked to the factory, they were updating to a new solid state X-Ray generator but instead I think they were gobbled up in the oil boom by giant corporations (Schlumbeger?) like so many other small companies were.
These are self-contained X-Ray experiment stations, college level trainers and instrument. It has a 20 kVp/30 kVp switch selectable HV power supply, a hard vacuum copper target X-Ray tube (80 uA Max), built in goniometer, experiment holder, timer, X-Ray and scatter shielding and like most X-Rays it is key-operated.
Uses include XRF, XRD, Bragg Diffraction,? X-Ray Radiography and the list goes on and on. Manuals attached. Made in England, now sold by 3B Scientific, I've serviced many of these and have several in the shop right now.
In the X-Ray tube electrons are accelerated by a HV field, then are slowed down by a target. Notice I didn't mention the filament. Some designs don't use a filament, they are called Field Emission Tubes and are cold-cathode. Those aren't continuous output tho and not used for XRF. Rather they build up a charge, 150 kV or more and "fire" a pulse at the tube, similar to a photo flash. It's all over in a few nanoseconds, but for X-Ray film it's OK, they just fire a dozen or hundred pulses, really quickly.
For XRF we need a much weaker ray, but it needs to be left on from minutes to hours- those tubes require hot cathodes= filament to boil off some electrons free of the cathode (the filament usually is also the cathode), a steady HV DC accelerates them, they are focused into a beam by deflection plates, irises and magnetic focus coils in a microfocus tube to get a small spot-.
Broad band Bremsstrahlung radiation is created,?and if the peak HV is sufficiently above the Ka binding energy of the target material, a huge peak at the targets characteristic X-Ray energy(s) superimposes over the top of the broad Brems continuum.
So? X-Ray tubes are not by their very nature monochromatic.?
isotopes on the other hand are monochromatic, but of many discreet energies.
It would be nice to have a knob that said 0-50 kVp and mean it. Set it for 35 and you've actually set it to "not over 35kVp", below it is a huge spray of energies up to the PEAK HV available. kVp= kiloVolt Peak. Nor is most of the wattage in the peak value, it is considerably below that, like 1/3 of the peak is the bulk of it.
My filters are just absorbers that remove the lower energies, the one that happen to be exactly on the energy peak you are trying to measure. Next the aluminum collimator absorbs much the off-axis rays which do nothing but try to create interference from your shielding.
Fortunately only a tiny amount of power is needed to do XRF. By the way, Amptek specifically states their warranty does not cover radiation damage to sensors, not to mention the thin beryllium window is as fragile as a pancake probe.
Cool, that's a beast compared to mine. Max is 0.1 mA (100 microamp) here.
?
It does have its own shielded housing, and I suspect the narrow measured beam cone angle is controlled by an mechanical iris inside the sealed tube. I'm assuming yours is also a side exit not and end-fire, those use transmission targets, the kind I use have "reflection" tungsten targets.? The excitation HV is less than the W Ka, so all I work with are Bremsstrahlung X-Rays, thus the external filtering etc.
[mailto:[email protected]] On Behalf Of GEOelectronics@... Sent: Sunday, February 9, 2020 10:53 AM To:[email protected] Subject: Re: [XRF] Li battery shiny vs dull
?
That
sounds logical Dud, hey on your Kevex stand alone tube, do you know the spot
size and the cone angle? The one in my rig here in the counting room seems to
Cool,
that's a beast compared to mine. Max is 0.1 mA (100 microamp) here.
?
It
does have its own shielded housing, and I suspect the narrow measured beam cone
angle is controlled by an mechanical iris inside the sealed tube. I'm assuming
yours is also a side exit not and end-fire, those use transmission targets, the
kind I use have "reflection" tungsten targets.? The excitation
HV is less than the W Ka, so all I work with are Bremsstrahlung X-Rays, thus
the external filtering etc.
?
Geo
?
-----
Original Message -----
From: Dude <dfemer@...>
To: [email protected]
Sent: Sun, 09 Feb 2020 15:30:33 -0500 (EST)
Subject: Re: [XRF] Li battery shiny vs dull
My
Kevex¡¯s are PXS4-613W and ?run with a CU015 60 kV power supply.
Target
Voltage:? 5.0 to 60.0 kV
Current:?
0.01 to 1.00 mA
X-ray
source spot size: 0.01¡± x 0.020¡± (0.25mm x 0.45 mm)
Approximately
X-ray
Output: 101R/min at 60 watts
X-ray
Window: 0.005¡± (0.13mm) Be
Angle
of illumination: 35 degrees inclusive (Approx)
?
When
you first fire it up or when it¡¯s been sitting for a long
while ramp up the voltage in 20% steps at 10 % of max current steps ?to
allow
the tube to outgas. Do this over a 10- to 15 min period (1 minute minimum at
each step) before going to full power. Watch out for arcing. ?Don¡¯t run
prolonged operation at 5kV or less at high beam current as that will run the
filament
hotter than normal and will decrease the filament life.
They
warn that the X-rays are dangerous and ?may be fatal. The
X-ray tube window must be placed in a shielded chamber. It¡¯s also clearly
stated
not to let anyone named Geo operate this machinery.
That
sounds logical Dud, hey on your Kevex stand alone tube, do you know the spot
size and the cone angle? The one in my rig here in the counting room seems to
have a 16 degree cone- does that sound right?
Here is my latest best effort with trinitite using Am241 as an exciter.
Only 3 elements really stand out: Fe U Ba.? There are other possibilities such as Sn and Cs but I can't say for sure without a much longer run.? Note that many of the peaks are to be ignored because they come from the Am241 and the Pb shield.
Hi Dave, yes I think so. That's not what I'm doing but just by coincidence the 32 keV from Cs-137 decay is still very evident. We can assume the 662 is there too, I'm just not looking that high.
Now that we finally have access to high resolution room temp sensors, we can delve a little deeper into the X-rays and maybe make some conclusions.
Is anyone presently here deep into Trinitite analysis? (Gamma or XRF either one)
Geo>K0FF
----- Original Message ----- From: David Eckhardt <davearea51a@...> To: [email protected] Sent: Sat, 08 Feb 2020 19:49:37 -0500 (EST) Subject: Re: [XRF] Trinitite
Are you still able to get a meaningful spectrum from the trinitite with amateur probes?? It's over 70 years old.
I had a piece which was given to dad in the mid 50's.? His boss collected it shortly after the 'event' at Trinity before everything was plowed under.? I remember at the time, the clicking from it would get your attention with a CK1026 glass GM tube (home brew GM detector).? Over the years, I tracked its diminishing activity (with better instruments).? Wish I still had it, but lost in the 2012 forest fire.
Red Trinitite. Some have said the red color in some Trinitite is there because it was stored in metal drums which rusted, then transferred the rust to the Trinitite.
Others claim it is copper, from the multitude of heavy copper wires carrying signals to and from the shot tower.
Red Trinitite is very interesting simply? because it is different from the far more common green variety.
