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 If a piece of information is incorrect, a link outdated, or the presentation choppy or unclear, the user can just click "Edit Page" at the bottom and then fix the mistake.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?]
Here is an assortment of wrist plates of various sizes and color.
They are essentially made of titanium or stainless steel alloy
Taray
On Sunday, October 4, 2020, 12:23:37 AM GMT+8, <geoelectronics@...> wrote:
Very good work Taray, thank you.
When you want to explain a photo of a scan better by adding charts, lines, pictures
or text,? on the DPPMCA program bring up the file of the scan then go to FILE
and select "Capture Plot". When clicked on, the screen will be saved in your clipboard similar to "Ctrl+C" function.? Open your photo program (I use PAINT) and simply drop the screen into the edit box by "Ctrl+V" or there should be a "Paste" icon on the photo program controls.?
Now you can do the editing like label peaks, draw reference lines and add text.
If there is a popup on the scan, such as Peak Search, for some reason that won't go along with the plot, so try "Ctrl+PrtSc" for nearly the same effect.
Most excellent explanation of the concept of fluorescence as it relates to XRF, Geo.? Similar concepts apply to all methods of spectroscopy, whether in the RF, infrared, visible spectrum, UV, X-ray, and gamma photons.? It also plays a role in why red LEDs are red, green LEDs are green, etc.? It all boils down to “characteristic emissions” for different elements.
?
While the concept of using a higher-energy (i.e., higher frequency/shorter wavelength) “exciter” to elicit a lower-energy photon – the concept behind using a higher-energy beta-emitter or gamma emitter to produce a lower-energy X-ray – the process can work in reverse.? I’ve seen plastic cards used which glow in the visible spectrum to “detect” the presence of an infrared laser beam.? Initially I didn’t understand how a low energy/low frequency IR beam could produce a higher-energy ‘response’ in the visible spectrum.? Then I remembered my ham radio concepts of using diodes to double the frequency of an incident input wave.?? Using the same physics, an ‘invisible’ light source (at least to humans) of 1100 nanometers in the infrared spectrum doubles in frequency to correspond to a half-wavelength of 550 nm, which is in the green-portion of the human perception of the visible spectrum.? Many laser diodes use frequency doubling to get the desired wavelength, but it comes at a cost… when you double the frequency, the power drops proportionally.? There are numerous “hacks” out there to dissect a Blue-ray DVD player or DVD “burner” to extract the laser diode, remove the optical frequency-doubler, and get a higher-power infrared laser.
From: GEOelectronics@... Sent: Saturday, October 3, 2020 12:10 PM To: [email protected] Subject: [XRF] FAQ- Why the unique X-Ray peaks from atoms?
?
PART-1 Definitions. Some are specific to the XRF sub-discipline.
Practicing XRF is what we do and discuss on this chat board.? For those who are reading but aren't practicing XRF techniques yet, lets lay out some of the theory behind XRF-
First the initials stand for X-Ray Fluorescence.? A few definitions of the noun fluorescence in layman is "shine" another is "glow"..? For our our purposes the definition of General Science is a little more detailed:
1.??? The giving off of light by a substance when it is exposed to electromagnetic radiation, such as visible light or x-rays. As long as electromagnetic radiation continues to bombard the substance, electrons in the fluorescent material become excited but return very quickly to lower energy, giving off light, always of the same frequency. Fluorescent dyes are often used in microscopic imaging, where different dyes can penetrate and illuminate different parts of the sample being examined, helping to distinguish its structures.
Compare?
2.??? The light produced in this way
So in very basic terms, the "F" in XRF is to shine by means of energy transfer at an atomic level, and the XR part defines? the "light" we detect as being X-Rays. To make the atom fluoresce X-Rays can be done by a number of means, not always having to do with applying X-Rays to the sample. The external energy can come from an electromagnetic source of from charged particles like Alpha Particles and fast electrons. A lot of the XRF we look at are excited by the energy ejected from the nucleus of a newly created element a result of radioactive decay of its parent element. This latter X-Ray and Gamma Ray from the daughter is usually immediate, but can be delayed, sometime much longer. Such daughter elements are appended with the small letter "m" for metastable. Check out Cs-137/Ba-137m decay scheme. Ba-137m has a half-life (T/2) of 2.55 minutes.
Remember radio waves, microwaves, infrared, visible light, ultraviolet light, X-Rays and Gamm Rays are all "light"- simply electromagnetic radiation of different energy levels..
In this practice we consider X-Rays as being electromagnetic energy being formed from the electron shell of an individual atom, while Gamma Rays originate within an atom's nucleus. Things will be a simpler in the long run if we all consider "Radioactive Decay" the? process that changes parent element to a different element# by changing the proton# in an atoms nucleus. Beta and Alpha decay are the most common, but there are many others. Once the element has changed to it's new nucleus, there are secondary emissions from that element's nucleus- these include the Gamma Rays and the production of XRF from the daughter product's electron shells.
A very obvious example is the major radioactive check disc we use for calibrating XRF systems: Fe-55. It decays by Electron-Capture (EC) to Mn-55. If we apply an external energy to stable Fe, we get back the XRF energy of Iron Ka1= 6.40 keV (there are others too). If we turn off the external exciter and test radioactive Fe-55, on our instruments, we see X-Rays of the daughter which is 5.90keV. There's no mistaking the two with a Si-PIN or other high resolution detector.
Highlight- natural X-Rays from radioactive element are of the daughter, induced X-Rays of stable elements is of that element.
Important! Keep the above in mind as we discuss XRF.
Let's stop here for discussion, we can add more definitions later via the edit function.
When you want to explain a photo of a scan better by adding charts, lines, pictures
or text,? on the DPPMCA program bring up the file of the scan then go to FILE
and select "Capture Plot". When clicked on, the screen will be saved in your clipboard similar to "Ctrl+C" function.? Open your photo program (I use PAINT) and simply drop the screen into the edit box by "Ctrl+V" or there should be a "Paste" icon on the photo program controls.?
Now you can do the editing like label peaks, draw reference lines and add text.
If there is a popup on the scan, such as Peak Search, for some reason that won't go along with the plot, so try "Ctrl+PrtSc" for nearly the same effect.
PART-1 Definitions. Some are specific to the XRF sub-discipline.
Practicing XRF is what we do and discuss on this chat board.? For those who are reading but aren't practicing XRF techniques yet, lets lay out some of the theory behind XRF-
First the initials stand for X-Ray Fluorescence.? A few definitions of the noun fluorescence in layman is "shine" another is "glow"..? For our our purposes the definition of General Science is a little more detailed:
The giving off of light by a substance when it is exposed to electromagnetic radiation, such as visible light or x-rays. As long as electromagnetic radiation continues to bombard the substance, electrons in the fluorescent material become excited but return very quickly to lower energy, giving off light, always of the same frequency. Fluorescent dyes are often used in microscopic imaging, where different dyes can penetrate and illuminate different parts of the sample being examined, helping to distinguish its structures.
Compare?
The light produced in this way
So in very basic terms, the "F" in XRF is to shine by means of energy transfer at an atomic level, and the XR part defines? the "light" we detect as being X-Rays. To make the atom fluoresce X-Rays can be done by a number of means, not always having to do with applying X-Rays to the sample. The external energy can come from an electromagnetic source of from charged particles like Alpha Particles and fast electrons. A lot of the XRF we look at are excited by the energy ejected from the nucleus of a newly created element a result of radioactive decay of its parent element. This latter X-Ray and Gamma Ray from the daughter is usually immediate, but can be delayed, sometime much longer. Such daughter elements are appended with the small letter "m" for metastable. Check out Cs-137/Ba-137m decay scheme. Ba-137m has a half-life (T/2) of 2.55 minutes.
Remember radio waves, microwaves, infrared, visible light, ultraviolet light, X-Rays and Gamm Rays are all "light"- simply electromagnetic radiation of different energy levels..
In this practice we consider X-Rays as being electromagnetic energy being formed from the electron shell of an individual atom, while Gamma Rays originate within an atom's nucleus. Things will be a simpler in the long run if we all consider "Radioactive Decay" the? process that changes parent element to a different element# by changing the proton# in an atoms nucleus. Beta and Alpha decay are the most common, but there are many others. Once the element has changed to it's new nucleus, there are secondary emissions from that element's nucleus- these include the Gamma Rays and the production of XRF from the daughter product's electron shells.
A very obvious example is the major radioactive check disc we use for calibrating XRF systems: Fe-55. It decays by Electron-Capture (EC) to Mn-55. If we apply an external energy to stable Fe, we get back the XRF energy of Iron Ka1= 6.40 keV (there are others too). If we turn off the external exciter and test radioactive Fe-55, on our instruments, we see X-Rays of the daughter which is 5.90keV. There's no mistaking the two with a Si-PIN or other high resolution detector.
Highlight- natural X-Rays from radioactive element are of the daughter, induced X-Rays of stable elements is of that element.
Important! Keep the above in mind as we discuss XRF.
Let's stop here for discussion, we can add more definitions later via the edit function.
"On Fri, Oct 2, 2020 at 11:10 AM, Randall Buck wrote:
Yes, for the principal lines. Neutrons do not influence electrons directly but they do alter the statistical distribution of the protons. notice the red and yellow are not a perfect match at all energies.
Randall"
Well... this is looking at two different isotopes of the same element, the major lines are that elements XRF and are the same for any of it's isotopes. The minor lines can be accounted for by the mounting substrate of the sample and the different decay schemes of the particular isotope.??
The Ka, La etc lines of a particular element are listed only once, not by isotope.
On 2 Oct 2020, at 8:51 PM,
GEOelectronics@... wrote:
?
Thanks
for those pictures. The one on the right with the long shank looks more like
the one I am familiar with. The bearing plate can be changed with small
incision, like changing brake pads on a car.
?
Geo
?
?
From:
"taray
singh via groups.io" <sukhjez@...> To: [email protected] Sent: Friday, October 2, 2020 6:30:12 AM Subject: Re: [XRF] Si pin xrf ..1st go
?
?
Dude
Good advice.
With regard to 2048 gain,I will put on hold for now
Need to recalibrate to do so.
Need time to familiarize software first.
Thanks for the apron analysis
It's a composite rubberized lead apron.
Most likely homogenous
It will attenuate medical 120 kev x rays according to lead
equivalent values.
Since it is close to the skin,the xrf esp from Sn to tissue is a
concern.
Radiation is stochastic in nature.
Nuclear medicine departments apron are different.
?
Regarding my knee implant analysis above,my ortho colleague agrees
it is?
CoCrMb .He was probably testing me.
I have some new implants awaiting xrf
Welcome to Medical XrF
Taray
?
?
On Friday, October 2, 2020, 04:37:52 AM GMT+8, Dude
<dfemer@...> wrote:
?
Taray,
Attached is a look at the original
X-ray apron file you sent (Apron Dud.jpg). This is the same as Apron 1 and is a
Pb Sn construction. Apron 2 is also a Pb Sn apron.
The F7F27 .jpeg you sent is looks to be
Apron 2 which is of a Pb Sn construction not Bi Sn.
?
Pb La1 10.55 keV
Pb Lb1? 12.61
Pb Lg1? 14.76
?
Bi La1 10.83 keV
Bi Lb1? 13.02
Bi Lg1? 15.24
?
Close together lines can create
interpretation problems especially in noisy low resolution data. The use of a
computer pick and pre labeled lines for ID is a bad idea and even worse is a
preconceived notion of what you are expecting. The data tells you what it is
not the other way around. A hypothesis is great, but test and verify it.
Note that your using a 1024 channel
conversion gain over an energy range of 133 keV / 1024 channels or 0.13
keV/channel.
The energy separation between Pb and Bi
La1 is only 0.38 keV or 3 channels and a Si detector has a FWHM resolution of
about 0.250 keV at the Pb La1. The Si detector efficiency falls off very
rapidly above 30 keV or so it would make better sense to calibrate 0 to 66 keV
using a 2048 conversion gain. That would give you 0.03 keV/channel and allows
you to do a AM-241 cal check as well.
I’d also recommend doing longer count
times to better define the peaks and to see the confirming lower yield peaks.
Yes, for the principal lines. Neutrons do not influence electrons directly but they do alter the statistical distribution of the protons. notice the red and yellow are not a perfect match at all energies.
With
regard to 2048 gain,I will put on hold for now
Need
to recalibrate to do so.
Need
time to familiarize software first.
Thanks
for the apron analysis
It's
a composite rubberized lead apron.
Most
likely homogenous
It
will attenuate medical 120 kev x rays according to lead equivalent values.
Since
it is close to the skin,the xrf esp from Sn to tissue is a concern.
Radiation
is stochastic in nature.
Nuclear
medicine departments apron are different.
?
?
Regarding
my knee implant analysis above,my ortho colleague agrees it is?
CoCrMb
.He was probably testing me.
I
have some new implants awaiting xrf
Welcome
to Medical XrF
Taray
?
?
?
On Friday, October 2, 2020, 04:37:52 AM GMT+8, Dude
<dfemer@...> wrote:
?
?
Taray,
Attached is a look at the original
X-ray apron file you sent (Apron Dud.jpg). This is the same as Apron 1 and is a
Pb Sn construction. Apron 2 is also a Pb Sn apron.
The F7F27 .jpeg you sent is looks to be
Apron 2 which is of a Pb Sn construction not Bi Sn.
?
Pb La1 10.55 keV
Pb Lb1? 12.61
Pb Lg1? 14.76
?
Bi La1 10.83 keV
Bi Lb1? 13.02
Bi Lg1? 15.24
?
Close together lines can create
interpretation problems especially in noisy low resolution data. The use of a
computer pick and pre labeled lines for ID is a bad idea and even worse is a
preconceived notion of what you are expecting. The data tells you what it is
not the other way around. A hypothesis is great, but test and verify it.
Note that your using a 1024 channel
conversion gain over an energy range of 133 keV / 1024 channels or 0.13
keV/channel.
The energy separation between Pb and Bi
La1 is only 0.38 keV or 3 channels and a Si detector has a FWHM resolution of
about 0.250 keV at the Pb La1. The Si detector efficiency falls off very
rapidly above 30 keV or so it would make better sense to calibrate 0 to 66 keV
using a 2048 conversion gain. That would give you 0.03 keV/channel and allows
you to do a AM-241 cal check as well.
I’d also recommend doing longer count
times to better define the peaks and to see the confirming lower yield peaks.
A) Take reading of a calibrated sample. B) Take reading of unknown sample C) Compare the two readings, calculate the ratio. D) Apply that ratio to the certified quantity in calibrated sample E) Determine the size of the detector (5mm X 5mm) F)? Calculate the weight of the parent by? your measured activity (D) (below) G) Calculate the Molar content (below) H) Calculate the # of atoms from the Molar content (below) per surface area of the probe (E)
On 2 Oct 2020, at 8:51 PM, GEOelectronics@... wrote:
?
Thanks for those pictures. The one on the right with the long shank looks more like the one I am familiar with. The bearing plate can be changed with small incision, like changing brake pads on a car.
Geo
From: "taray singh via groups.io" <sukhjez@...> To: [email protected] Sent: Friday, October 2, 2020 6:30:12 AM Subject: Re: [XRF] Si pin xrf ..1st go
Dude
Good advice.
With regard to 2048 gain,I will put on hold for now
Need to recalibrate to do so.
Need time to familiarize software first.
Thanks for the apron analysis
It's a composite rubberized lead apron.
Most likely homogenous
It will attenuate medical 120 kev x rays according to lead equivalent values.
Since it is close to the skin,the xrf esp from Sn to tissue is a concern.
Radiation is stochastic in nature.
Nuclear medicine departments apron are different.
Regarding my knee implant analysis above,my ortho colleague agrees it is?
CoCrMb .He was probably testing me.
I have some new implants awaiting xrf
Welcome to Medical XrF
Taray
On Friday, October 2, 2020, 04:37:52 AM GMT+8, Dude <dfemer@...> wrote:
Taray,
Attached is a look at the original X-ray apron file you
sent (Apron Dud.jpg). This is the same as Apron 1 and is a Pb Sn construction.
Apron 2 is also a Pb Sn apron.
The F7F27 .jpeg you sent is looks to be Apron 2 which is
of a Pb Sn construction not Bi Sn.
?
Pb La1 10.55 keV
Pb Lb1? 12.61
Pb Lg1? 14.76
?
Bi La1 10.83 keV
Bi Lb1? 13.02
Bi Lg1? 15.24
?
Close together lines can create interpretation problems
especially in noisy low resolution data. The use of a computer pick and pre
labeled lines for ID is a bad idea and even worse is a preconceived notion of
what you are expecting. The data tells you what it is not the other way around.
A hypothesis is great, but test and verify it.
Note that your using a 1024 channel conversion gain over
an energy range of 133 keV / 1024 channels or 0.13 keV/channel.
The energy separation between Pb and Bi La1 is only 0.38
keV or 3 channels and a Si detector has a FWHM resolution of about 0.250 keV at
the Pb La1. The Si detector efficiency falls off very rapidly above 30 keV or
so it would make better sense to calibrate 0 to 66 keV using a 2048 conversion
gain. That would give you 0.03 keV/channel and allows you to do a AM-241 cal
check as well.
I’d also recommend doing longer count times to better
define the peaks and to see the confirming lower yield peaks.
Thanks for those pictures. The one on the right with the long shank looks more like the one I am familiar with. The bearing plate can be changed with small incision, like changing brake pads on a car.
From: "taray singh via groups.io" <sukhjez@...> To: [email protected] Sent: Friday, October 2, 2020 6:30:12 AM Subject: Re: [XRF] Si pin xrf ..1st go
Dude
Good advice.
With regard to 2048 gain,I will put on hold for now
Need to recalibrate to do so.
Need time to familiarize software first.
Thanks for the apron analysis
It's a composite rubberized lead apron.
Most likely homogenous
It will attenuate medical 120 kev x rays according to lead equivalent values.
Since it is close to the skin,the xrf esp from Sn to tissue is a concern.
Radiation is stochastic in nature.
Nuclear medicine departments apron are different.
Regarding my knee implant analysis above,my ortho colleague agrees it is?
CoCrMb .He was probably testing me.
I have some new implants awaiting xrf
Welcome to Medical XrF
Taray
On Friday, October 2, 2020, 04:37:52 AM GMT+8, Dude <dfemer@...> wrote:
Taray,
Attached is a look at the original X-ray apron file you
sent (Apron Dud.jpg). This is the same as Apron 1 and is a Pb Sn construction.
Apron 2 is also a Pb Sn apron.
The F7F27 .jpeg you sent is looks to be Apron 2 which is
of a Pb Sn construction not Bi Sn.
?
Pb La1 10.55 keV
Pb Lb1? 12.61
Pb Lg1? 14.76
?
Bi La1 10.83 keV
Bi Lb1? 13.02
Bi Lg1? 15.24
?
Close together lines can create interpretation problems
especially in noisy low resolution data. The use of a computer pick and pre
labeled lines for ID is a bad idea and even worse is a preconceived notion of
what you are expecting. The data tells you what it is not the other way around.
A hypothesis is great, but test and verify it.
Note that your using a 1024 channel conversion gain over
an energy range of 133 keV / 1024 channels or 0.13 keV/channel.
The energy separation between Pb and Bi La1 is only 0.38
keV or 3 channels and a Si detector has a FWHM resolution of about 0.250 keV at
the Pb La1. The Si detector efficiency falls off very rapidly above 30 keV or
so it would make better sense to calibrate 0 to 66 keV using a 2048 conversion
gain. That would give you 0.03 keV/channel and allows you to do a AM-241 cal
check as well.
I’d also recommend doing longer count times to better
define the peaks and to see the confirming lower yield peaks.
With regard to 2048 gain,I will put on hold for now
Need to recalibrate to do so.
Need time to familiarize software first.
Thanks for the apron analysis
It's a composite rubberized lead apron.
Most likely homogenous
It will attenuate medical 120 kev x rays according to lead equivalent values.
Since it is close to the skin,the xrf esp from Sn to tissue is a concern.
Radiation is stochastic in nature.
Nuclear medicine departments apron are different.
Regarding my knee implant analysis above,my ortho colleague agrees it is?
CoCrMb .He was probably testing me.
I have some new implants awaiting xrf
Welcome to Medical XrF
Taray
On Friday, October 2, 2020, 04:37:52 AM GMT+8, Dude <dfemer@...> wrote:
Taray,
Attached is a look at the original X-ray apron file you
sent (Apron Dud.jpg). This is the same as Apron 1 and is a Pb Sn construction.
Apron 2 is also a Pb Sn apron.
The F7F27 .jpeg you sent is looks to be Apron 2 which is
of a Pb Sn construction not Bi Sn.
?
Pb La1 10.55 keV
Pb Lb1? 12.61
Pb Lg1? 14.76
?
Bi La1 10.83 keV
Bi Lb1? 13.02
Bi Lg1? 15.24
?
Close together lines can create interpretation problems
especially in noisy low resolution data. The use of a computer pick and pre
labeled lines for ID is a bad idea and even worse is a preconceived notion of
what you are expecting. The data tells you what it is not the other way around.
A hypothesis is great, but test and verify it.
Note that your using a 1024 channel conversion gain over
an energy range of 133 keV / 1024 channels or 0.13 keV/channel.
The energy separation between Pb and Bi La1 is only 0.38
keV or 3 channels and a Si detector has a FWHM resolution of about 0.250 keV at
the Pb La1. The Si detector efficiency falls off very rapidly above 30 keV or
so it would make better sense to calibrate 0 to 66 keV using a 2048 conversion
gain. That would give you 0.03 keV/channel and allows you to do a AM-241 cal
check as well.
I’d also recommend doing longer count times to better
define the peaks and to see the confirming lower yield peaks.
The
Be was used as a neutron reflector which increased the neutron flux during
detonation, it also prevented corrosion of the Pu. ?Al was used between the pit
and the Be coating to shield the Be from alpha particles which would generate neutrons.
I
just scanned the book, there are references to Be, but only that it makes lots
of neutrons when exposed to alpha decay (Pu-239). So it wouldn't have been
coated with Be. Aluminum foil would have been all that was needed.
?
Geo
?
-----
Original Message -----
From: WILLIAM S Dubyk <sdubyk@...>
To: [email protected]
Sent: Thu, 01 Oct 2020 19:30:26 -0400 (EDT)
Subject: Re: [XRF] Trinitite
?
margin-top: 0;
margin-bottom: 0;
}
/*]]>*/
?
That is pretty interesting, they considered either a RaBe or Po source to
ensure detonation.
The book was his autobiography (my copy is from May 1989) and he might have
included a picture of him holding it. I’ll try and run that down this
weekend.?
?
I
would do it now but I am at work.?
?
AlanJ?
?
On Oct 1, 2020, at 6:02 PM, Alan Jose <Alan.Jose@...> wrote:
?
No picture available but that information was gleaned from the biography on
Luis Alvarez entitled Alvarez from the late eighties. When time permits I’ll
look through the book to find the reference. I could be in error as that is
from my memory from a book I
read over thirty years ago. Some things stick and some things don’t.?
I just scanned the book, there are references to Be, but only that it makes lots of neutrons when exposed to alpha decay (Pu-239). So it wouldn't have been coated with Be. Aluminum foil would have been all that was needed.
Geo
----- Original Message ----- From: WILLIAM S Dubyk <sdubyk@...> To: [email protected] Sent: Thu, 01 Oct 2020 19:30:26 -0400 (EDT) Subject: Re: [XRF] Trinitite
That is pretty interesting, they considered either a RaBe or Po source to ensure detonation.
The book was his autobiography (my copy is from May 1989) and he might have included a picture of him holding it. I’ll try and run that down this weekend.?
I would do it now but I am at work.?
AlanJ?
On Oct 1, 2020, at 6:02 PM, Alan Jose <Alan.Jose@...> wrote:
No picture available but that information was gleaned from the biography on Luis Alvarez entitled Alvarez from the late eighties. When time permits I’ll look through the book to find the reference. I could be in error as that is from my memory from a book I read over thirty years ago. Some things stick and some things don’t.?
I just scanned the book, there are references to Be, but only that it makes lots of neutrons when exposed to alpha decay (Pu-239),? therefore? in the book he says they went to great lengths to keep Be contaminants out during the manufacture. So it wouldn't have been coated with Be. Aluminum foil would have been all that was needed.
----- Original Message ----- From: WILLIAM S Dubyk <sdubyk@...> To: [email protected] Sent: Thu, 01 Oct 2020 19:30:26 -0400 (EDT) Subject: Re: [XRF] Trinitite
?
?
?
That is pretty interesting, they considered either a RaBe or Po source to ensure detonation.
The book was his autobiography (my copy is from May 1989) and he might have included a picture of him holding it. I’ll try and run that down this weekend.?
?
I would do it now but I am at work.?
?
AlanJ?
?
On Oct 1, 2020, at 6:02 PM, Alan Jose <Alan.Jose@...> wrote:
?
No picture available but that information was gleaned from the biography on Luis Alvarez entitled Alvarez from the late eighties. When time permits I’ll look through the book to find the reference. I could be in error as that is from my memory from a book I read over thirty years ago. Some things stick and some things don’t.?
----- Original Message ----- From: Alan Jose <Alan.Jose@...> To: [email protected] Sent: Thu, 01 Oct 2020 19:11:20 -0400 (EDT) Subject: Re: [XRF] Trinitite
The book was his autobiography (my copy is from May 1989) and he might have included a picture of him holding it. I’ll try and run that down this weekend.?
I would do it now but I am at work.?
AlanJ?
On Oct 1, 2020, at 6:02 PM, Alan Jose <Alan.Jose@...> wrote:
No picture available but that information was gleaned from the biography on Luis Alvarez entitled Alvarez from the late eighties. When time permits I’ll look through the book to find the reference. I could be in error as that is from my memory from a book I read over thirty years ago. Some things stick and some things don’t.?
