Re: [Ifeffit] Brain teaser

[Anatoly Frenkel]

HI Mike, it is dilute Pd in Au nanoparticles deposited on SiO2 with about
5% metal weight loading.
In my view, the lack of curvature in transmission (the original problem in
my post) is a simple consequence of two opposite trends, 1) the curving up
of the transmission signal by the same reason (yet to be identified, which
is something I will try to, after getting useful hints from many people
here) as the curving up of the incident beam and 2) the opposite trend due
to the greater removal of the photons at higher energy by I0 detector. The
two opposite trends tend to cancel each other.

Anatoly



On Thu, Jun 15, 2023 at 4:14 PM Mike Massey  wrote:

> A question because I'm not really super clear on how harmonics work:
>
> (I'll get to the question in a moment...) I note that I0 starts to go
> non-linear around 12200-12400 eV and stays that way. So an increase
> (proportional?) in the amount of signal in It might be happening at around
> the same point.
>
> Could Pd fluorescence into It be impacting the signal in It? I realize
> that the Pd emission lines are very low in energy but they are around 3k eV.
>
> I'm not super familiar with alloy systems but I did have an issue once
> upon a time with back fluorescence into an ion chamber and things went a
> bit wonky. This wouldn't exactly be "back" fluorescence, but if the system
> is mostly Pd with a little bit of Au, I guess...? And it might be easy
> enough to test, just put a high-pass filter in front of It?
>
> I got nothin' but it's kinda fun to take a shot. Cheers,
>
>
>
> Mike
>
>
>
>
> On Jun 16, 2023, at 03:26, Matt Newville 
> wrote:
>
> 
> Hi Anatoly,
>
> I think Robert or Matthew made this point, but if set up for Pd, the
> mirror angle may have been chosen to reject ~70 keV, but possibly not 36
> keV -- the harmonic at the Au edge.  Do you know what the mirror angle
> was?
>
> The Ar-filled I0 would be very efficient at absorbing 12 keV, and only
> pretty efficient at absorbing 36 keV.   That would leave a more
> harmonic-rich beam exiting I0 and hitting the sample than entering I0.  The
> good news is that the dense Pd/Au sample would be efficient at absorbing 36
> keV too (but it was ~1 absorption length at 24 keV?) too.
>
> Mono reflectivity of 36 keV vs 12 keV might also factor in.  If you were
> not deliberately detuning but the crystals were slightly misaligned,  the
> harmonic content may change significantly over the scan range.   I would
> not guess that to dominate, but maybe it factors in.
>
>
> On Thu, Jun 15, 2023 at 9:54 AM Anatoly Frenkel <
> anatoly.fren...@stonybrook.edu> wrote:
>
>> Thank you, Matt.
>> Ion chambers were filled with 90% Ar, and Pt coating was used, because we
>> were measuring Pd K edge for the project, but we decided to look at the Au
>> edge for testing purposes.
>>
>> Anatoly
>>
>> On Jun 15, 2023, at 10:45 AM, Matt Newville 
>> wrote:
>>
>> 
>> I'm not sure why the intensity would go up unless the ion chamber was
>> poorly set up.   But, as others have pointed out, the mirror reflectivity
>> for a Pt mirror should not change significantly over this energy range -
>> the energy range is not that close to the Pt L3 or L2 edges.Depending
>> on where it was located, fluorescence from the Pt mirror might pollute the
>> signal in the I0 ion chamber, but that would also likely be a fairly
>> constant background.
>>
>> But, why would you fill the I0 ion chamber with Argon?  A 10-cm ion
>> chamber filled with Ar would absorb about 50% of the beam at 12 keV.   Even
>> at 24 keV, that would absorb 8% of the beam - not necessarily a problem but
>> also probably generating at least a micro-Amp, so way more signal than you
>> would need.
>>
>> For mirror reflectivity curves, allow me to humbly remind everyone of
>>
>> https://xraydb.xrayabsorption.org/reflectivity/Pt/21.45/2.5/10/s/1000/51000/50/platinum/linear
>>
>> which is both interactive and works with X-ray energies above 30 keV.
>>
>>
>> On Wed, Jun 14, 2023 at 7:28 PM Anatoly Frenkel <
>> anatoly.fren...@stonybrook.edu> wrote:
>>
>>> Hello, all. It is a low- to medium- level brain teaser.
>>>
>>> Pt-coated collimating mirror was in place for Pd K-edge measurement, but
>>> Au L3-edge of Pd-Au alloy was measured (for testing purposes). I0 and It
>>> detectors were both Ar filled ionization chambers. Because of the energy
>>> dependence of reflectivity of the Pt mirror, I0 intensity was strongly
>>> nonlinear (blue curve). However, the transmission intensity in the It
>>> detector was almost linear (red curve). Why?
>>>
>>> Anatoly
>>>
>>> 
>>>
>>> ___
>>> Ifeffit mailing list
>>> Ifeffit@millenia.cars.aps.anl.gov
>>> http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
>>> Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit
>>>
>>
>>
>> --
>> --Matt Newville  630-327-7411
>> ___
>> Ifeffit mailing list
>> Ifeffit@millenia.cars.aps.anl.gov
>> 

Re: [Ifeffit] Brain teaser

[Mike Massey]

A question because I'm not really super clear on how harmonics work: (I'll get to the question in a moment...) I note that I0 starts to go non-linear around 12200-12400 eV and stays that way. So an increase (proportional?) in the amount of signal in It might be happening at around the same point.Could Pd fluorescence into It be impacting the signal in It? I realize that the Pd emission lines are very low in energy but they are around 3k eV.I'm not super familiar with alloy systems but I did have an issue once upon a time with back fluorescence into an ion chamber and things went a bit wonky. This wouldn't exactly be "back" fluorescence, but if the system is mostly Pd with a little bit of Au, I guess...? And it might be easy enough to test, just put a high-pass filter in front of It?I got nothin' but it's kinda fun to take a shot. Cheers,MikeOn Jun 16, 2023, at 03:26, Matt Newville  wrote:Hi Anatoly, I think Robert or Matthew made this point, but if set up for Pd, the mirror angle may have been chosen to reject ~70 keV, but possibly not 36 keV -- the harmonic at the Au edge.  Do you know what the mirror angle was?    The Ar-filled I0 would be very efficient at absorbing 12 keV, and only pretty efficient at absorbing 36 keV.   That would leave a more harmonic-rich beam exiting I0 and hitting the sample than entering I0.  The good news is that the dense Pd/Au sample would be efficient at absorbing 36 keV too (but it was ~1 absorption length at 24 keV?) too.Mono reflectivity of 36 keV vs 12 keV might also factor in.  If you were not deliberately detuning but the crystals were slightly misaligned,  the harmonic content may change significantly over the scan range.   I would not guess that to dominate, but maybe it factors in.On Thu, Jun 15, 2023 at 9:54 AM Anatoly Frenkel  wrote:Thank you, Matt. Ion chambers were filled with 90% Ar, and Pt coating was used, because we were measuring Pd K edge for the project, but we decided to look at the Au edge for testing purposes. AnatolyOn Jun 15, 2023, at 10:45 AM, Matt Newville  wrote:I'm not sure why the intensity would go up unless the ion chamber was poorly set up.   But, as others have pointed out, the mirror reflectivity for a Pt mirror should not change significantly over this energy range - the energy range is not that close to the Pt L3 or L2 edges.    Depending on where it was located, fluorescence from the Pt mirror might pollute the signal in the I0 ion chamber, but that would also likely be a fairly constant background. But, why would you fill the I0 ion chamber with Argon?  A 10-cm ion chamber filled with Ar would absorb about 50% of the beam at 12 keV.   Even at 24 keV, that would absorb 8% of the beam - not necessarily a problem but also probably generating at least a micro-Amp, so way more signal than you would need.For mirror reflectivity curves, allow me to humbly remind everyone of   https://xraydb.xrayabsorption.org/reflectivity/Pt/21.45/2.5/10/s/1000/51000/50/platinum/linearwhich is both interactive and works with X-ray energies above 30 keV.On Wed, Jun 14, 2023 at 7:28 PM Anatoly Frenkel  wrote:Hello, all. It is a low- to medium- level brain teaser.Pt-coated collimating mirror was in place for Pd K-edge measurement, but Au L3-edge of Pd-Au alloy was measured (for testing purposes). I0 and It detectors were both Ar filled ionization chambers. Because of the energy dependence of reflectivity of the Pt mirror, I0 intensity was strongly nonlinear (blue curve). However, the transmission intensity in the It detector was almost linear (red curve). Why? Anatoly
___
Ifeffit mailing list
Ifeffit@millenia.cars.aps.anl.gov
http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit
-- --Matt Newville cars.uchicago.edu> 630-327-7411
___Ifeffit mailing listIfeffit@millenia.cars.aps.anl.govhttp://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffitUnsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit___
Ifeffit mailing list
Ifeffit@millenia.cars.aps.anl.gov
http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit
-- --Matt Newville cars.uchicago.edu> 630-327-7411
___Ifeffit mailing listIfeffit@millenia.cars.aps.anl.govhttp://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffitUnsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit___
Ifeffit mailing list
Ifeffit@millenia.cars.aps.anl.gov
http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit

Re: [Ifeffit] Brain teaser

[Matt Newville]

Hi Anatoly,

I think Robert or Matthew made this point, but if set up for Pd, the mirror
angle may have been chosen to reject ~70 keV, but possibly not 36 keV --
the harmonic at the Au edge.  Do you know what the mirror angle was?

The Ar-filled I0 would be very efficient at absorbing 12 keV, and only
pretty efficient at absorbing 36 keV.   That would leave a more
harmonic-rich beam exiting I0 and hitting the sample than entering I0.  The
good news is that the dense Pd/Au sample would be efficient at absorbing 36
keV too (but it was ~1 absorption length at 24 keV?) too.

Mono reflectivity of 36 keV vs 12 keV might also factor in.  If you were
not deliberately detuning but the crystals were slightly misaligned,  the
harmonic content may change significantly over the scan range.   I would
not guess that to dominate, but maybe it factors in.


On Thu, Jun 15, 2023 at 9:54 AM Anatoly Frenkel <
anatoly.fren...@stonybrook.edu> wrote:

> Thank you, Matt.
> Ion chambers were filled with 90% Ar, and Pt coating was used, because we
> were measuring Pd K edge for the project, but we decided to look at the Au
> edge for testing purposes.
>
> Anatoly
>
> On Jun 15, 2023, at 10:45 AM, Matt Newville 
> wrote:
>
> 
> I'm not sure why the intensity would go up unless the ion chamber was
> poorly set up.   But, as others have pointed out, the mirror reflectivity
> for a Pt mirror should not change significantly over this energy range -
> the energy range is not that close to the Pt L3 or L2 edges.Depending
> on where it was located, fluorescence from the Pt mirror might pollute the
> signal in the I0 ion chamber, but that would also likely be a fairly
> constant background.
>
> But, why would you fill the I0 ion chamber with Argon?  A 10-cm ion
> chamber filled with Ar would absorb about 50% of the beam at 12 keV.   Even
> at 24 keV, that would absorb 8% of the beam - not necessarily a problem but
> also probably generating at least a micro-Amp, so way more signal than you
> would need.
>
> For mirror reflectivity curves, allow me to humbly remind everyone of
>
> https://xraydb.xrayabsorption.org/reflectivity/Pt/21.45/2.5/10/s/1000/51000/50/platinum/linear
>
> which is both interactive and works with X-ray energies above 30 keV.
>
>
> On Wed, Jun 14, 2023 at 7:28 PM Anatoly Frenkel <
> anatoly.fren...@stonybrook.edu> wrote:
>
>> Hello, all. It is a low- to medium- level brain teaser.
>>
>> Pt-coated collimating mirror was in place for Pd K-edge measurement, but
>> Au L3-edge of Pd-Au alloy was measured (for testing purposes). I0 and It
>> detectors were both Ar filled ionization chambers. Because of the energy
>> dependence of reflectivity of the Pt mirror, I0 intensity was strongly
>> nonlinear (blue curve). However, the transmission intensity in the It
>> detector was almost linear (red curve). Why?
>>
>> Anatoly
>>
>> 
>>
>> ___
>> Ifeffit mailing list
>> Ifeffit@millenia.cars.aps.anl.gov
>> http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
>> Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit
>>
>
>
> --
> --Matt Newville  630-327-7411
> ___
> Ifeffit mailing list
> Ifeffit@millenia.cars.aps.anl.gov
> http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
> Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit
>
> ___
> Ifeffit mailing list
> Ifeffit@millenia.cars.aps.anl.gov
> http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
> Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit
>


-- 
--Matt Newville  630-327-7411
___
Ifeffit mailing list
Ifeffit@millenia.cars.aps.anl.gov
http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit

Re: [Ifeffit] [Ext] Re: Brain teaser

[Anatoly Frenkel]

But collimating mirror is in the front end. AnatolyOn Jun 15, 2023, at 10:52 AM, Carlo Segre  wrote:I would have guessed that the increase in I0 is primarily due to Pt fluorescence.  The yield does increase as the energy rises.CarloOn Thu, Jun 15, 2023 at 9:45 AM Matt Newville  wrote:I'm not sure why the intensity would go up unless the ion chamber was poorly set up.   But, as others have pointed out, the mirror reflectivity for a Pt mirror should not change significantly over this energy range - the energy range is not that close to the Pt L3 or L2 edges.    Depending on where it was located, fluorescence from the Pt mirror might pollute the signal in the I0 ion chamber, but that would also likely be a fairly constant background. But, why would you fill the I0 ion chamber with Argon?  A 10-cm ion chamber filled with Ar would absorb about 50% of the beam at 12 keV.   Even at 24 keV, that would absorb 8% of the beam - not necessarily a problem but also probably generating at least a micro-Amp, so way more signal than you would need.For mirror reflectivity curves, allow me to humbly remind everyone of   https://xraydb.xrayabsorption.org/reflectivity/Pt/21.45/2.5/10/s/1000/51000/50/platinum/linearwhich is both interactive and works with X-ray energies above 30 keV.On Wed, Jun 14, 2023 at 7:28 PM Anatoly Frenkel  wrote:Hello, all. It is a low- to medium- level brain teaser.Pt-coated collimating mirror was in place for Pd K-edge measurement, but Au L3-edge of Pd-Au alloy was measured (for testing purposes). I0 and It detectors were both Ar filled ionization chambers. Because of the energy dependence of reflectivity of the Pt mirror, I0 intensity was strongly nonlinear (blue curve). However, the transmission intensity in the It detector was almost linear (red curve). Why? Anatoly
___
Ifeffit mailing list
Ifeffit@millenia.cars.aps.anl.gov
http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit
-- --Matt Newville cars.uchicago.edu> 630-327-7411
___
Ifeffit mailing list
Ifeffit@millenia.cars.aps.anl.gov
http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit
-- Carlo U. Segre (he/him) -- Duchossois Leadership Professor of PhysicsProfessor of Materials Science & EngineeringDirector, Center for Synchrotron Radiation Research and InstrumentationIllinois Institute of TechnologyVoice: 312.567.3498            Fax: 312.567.3494se...@iit.edu   http://phys.iit.edu/~segre   se...@debian.org
___Ifeffit mailing listIfeffit@millenia.cars.aps.anl.govhttp://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffitUnsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit___
Ifeffit mailing list
Ifeffit@millenia.cars.aps.anl.gov
http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit

Re: [Ifeffit] Brain teaser

[Anatoly Frenkel]

Thank you, Matt. Ion chambers were filled with 90% Ar, and Pt coating was used, because we were measuring Pd K edge for the project, but we decided to look at the Au edge for testing purposes. AnatolyOn Jun 15, 2023, at 10:45 AM, Matt Newville  wrote:I'm not sure why the intensity would go up unless the ion chamber was poorly set up.   But, as others have pointed out, the mirror reflectivity for a Pt mirror should not change significantly over this energy range - the energy range is not that close to the Pt L3 or L2 edges.    Depending on where it was located, fluorescence from the Pt mirror might pollute the signal in the I0 ion chamber, but that would also likely be a fairly constant background. But, why would you fill the I0 ion chamber with Argon?  A 10-cm ion chamber filled with Ar would absorb about 50% of the beam at 12 keV.   Even at 24 keV, that would absorb 8% of the beam - not necessarily a problem but also probably generating at least a micro-Amp, so way more signal than you would need.For mirror reflectivity curves, allow me to humbly remind everyone of   https://xraydb.xrayabsorption.org/reflectivity/Pt/21.45/2.5/10/s/1000/51000/50/platinum/linearwhich is both interactive and works with X-ray energies above 30 keV.On Wed, Jun 14, 2023 at 7:28 PM Anatoly Frenkel  wrote:Hello, all. It is a low- to medium- level brain teaser.Pt-coated collimating mirror was in place for Pd K-edge measurement, but Au L3-edge of Pd-Au alloy was measured (for testing purposes). I0 and It detectors were both Ar filled ionization chambers. Because of the energy dependence of reflectivity of the Pt mirror, I0 intensity was strongly nonlinear (blue curve). However, the transmission intensity in the It detector was almost linear (red curve). Why? Anatoly
___
Ifeffit mailing list
Ifeffit@millenia.cars.aps.anl.gov
http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit
-- --Matt Newville cars.uchicago.edu> 630-327-7411
___Ifeffit mailing listIfeffit@millenia.cars.aps.anl.govhttp://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffitUnsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit___
Ifeffit mailing list
Ifeffit@millenia.cars.aps.anl.gov
http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit

Re: [Ifeffit] [Ext] Re: Brain teaser

[Carlo Segre]

I would have guessed that the increase in I0 is primarily due to Pt
fluorescence.  The yield does increase as the energy rises.

Carlo

On Thu, Jun 15, 2023 at 9:45 AM Matt Newville 
wrote:

> I'm not sure why the intensity would go up unless the ion chamber was
> poorly set up.   But, as others have pointed out, the mirror reflectivity
> for a Pt mirror should not change significantly over this energy range -
> the energy range is not that close to the Pt L3 or L2 edges.Depending
> on where it was located, fluorescence from the Pt mirror might pollute the
> signal in the I0 ion chamber, but that would also likely be a fairly
> constant background.
>
> But, why would you fill the I0 ion chamber with Argon?  A 10-cm ion
> chamber filled with Ar would absorb about 50% of the beam at 12 keV.   Even
> at 24 keV, that would absorb 8% of the beam - not necessarily a problem but
> also probably generating at least a micro-Amp, so way more signal than you
> would need.
>
> For mirror reflectivity curves, allow me to humbly remind everyone of
>
> https://xraydb.xrayabsorption.org/reflectivity/Pt/21.45/2.5/10/s/1000/51000/50/platinum/linear
>
> which is both interactive and works with X-ray energies above 30 keV.
>
>
> On Wed, Jun 14, 2023 at 7:28 PM Anatoly Frenkel <
> anatoly.fren...@stonybrook.edu> wrote:
>
>> Hello, all. It is a low- to medium- level brain teaser.
>>
>> Pt-coated collimating mirror was in place for Pd K-edge measurement, but
>> Au L3-edge of Pd-Au alloy was measured (for testing purposes). I0 and It
>> detectors were both Ar filled ionization chambers. Because of the energy
>> dependence of reflectivity of the Pt mirror, I0 intensity was strongly
>> nonlinear (blue curve). However, the transmission intensity in the It
>> detector was almost linear (red curve). Why?
>>
>> Anatoly
>>
>> [image: image.png]
>> ___
>> Ifeffit mailing list
>> Ifeffit@millenia.cars.aps.anl.gov
>> http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
>> Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit
>>
>
>
> --
> --Matt Newville  630-327-7411
> ___
> Ifeffit mailing list
> Ifeffit@millenia.cars.aps.anl.gov
> http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
> Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit
>


-- 
Carlo U. Segre (he/him) -- Duchossois Leadership Professor of Physics
Professor of Materials Science & Engineering
Director, Center for Synchrotron Radiation Research and Instrumentation
Illinois Institute of Technology
Voice: 312.567.3498Fax: 312.567.3494
se...@iit.edu   http://phys.iit.edu/~segre   se...@debian.org
___
Ifeffit mailing list
Ifeffit@millenia.cars.aps.anl.gov
http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit

Re: [Ifeffit] Brain teaser

[Matt Newville]

I'm not sure why the intensity would go up unless the ion chamber was
poorly set up.   But, as others have pointed out, the mirror reflectivity
for a Pt mirror should not change significantly over this energy range -
the energy range is not that close to the Pt L3 or L2 edges.Depending
on where it was located, fluorescence from the Pt mirror might pollute the
signal in the I0 ion chamber, but that would also likely be a fairly
constant background.

But, why would you fill the I0 ion chamber with Argon?  A 10-cm ion chamber
filled with Ar would absorb about 50% of the beam at 12 keV.   Even at 24
keV, that would absorb 8% of the beam - not necessarily a problem but also
probably generating at least a micro-Amp, so way more signal than you would
need.

For mirror reflectivity curves, allow me to humbly remind everyone of

https://xraydb.xrayabsorption.org/reflectivity/Pt/21.45/2.5/10/s/1000/51000/50/platinum/linear

which is both interactive and works with X-ray energies above 30 keV.


On Wed, Jun 14, 2023 at 7:28 PM Anatoly Frenkel <
anatoly.fren...@stonybrook.edu> wrote:

> Hello, all. It is a low- to medium- level brain teaser.
>
> Pt-coated collimating mirror was in place for Pd K-edge measurement, but
> Au L3-edge of Pd-Au alloy was measured (for testing purposes). I0 and It
> detectors were both Ar filled ionization chambers. Because of the energy
> dependence of reflectivity of the Pt mirror, I0 intensity was strongly
> nonlinear (blue curve). However, the transmission intensity in the It
> detector was almost linear (red curve). Why?
>
> Anatoly
>
> [image: image.png]
> ___
> Ifeffit mailing list
> Ifeffit@millenia.cars.aps.anl.gov
> http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
> Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit
>


-- 
--Matt Newville  630-327-7411
___
Ifeffit mailing list
Ifeffit@millenia.cars.aps.anl.gov
http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit

Re: [Ifeffit] [Ext] Brain teaser

[Anatoly Frenkel]

Thank you, Robert, Matthew, Jeff, Kirill, Terry and Sirine for great 
suggestions. 

I initially thought that the explanation for the linearity or the transmission 
signal is a superposition of two opposite trends: 1) increase of flux with 
energy due to the mirror effect and 2) similar decrease with energy due to the 
photon removal by first effect in the I0 detector. But I did not look into the 
main reason for the curving up of the I0 signal and I agree it is not a result 
of the reflectivity. I fill follow up on all suggestions, and, if something 
more definitive transpires, will report back. 

Thanks again for your time and advice!

Anatoly

> On Jun 15, 2023, at 2:10 AM, matthew marcus  wrote:
> The mirror was set up for a run at the Pd K-edge, according to the problem 
> statement.  Therefore, its nominal angle must be such as to put the critical 
> energy >25keV.  An angle of 3mrad would do it. At that angle, the 
> reflectivity (assuming  no roughness) goes up with energy in the relevant 
> range, but only by a few percent.
> 
> We're not told what the ratio of gains of the current amps is, or whether the 
> ion chambers have the same path length, so we can't tell whether the signals 
> are comparable, as shown on the graph, or orders of magnitude different.
>mam
> 
> On 6/14/2023 10:17 PM, Jeffrey Terry wrote:
>> Well, I’ll take a shot. Looks like the mirror angle is totally fubared, you 
>> are getting Bragg peaks from the coating or substrate that are giving you 
>> the peaks in Io. Since you have no idea what angle those are going through 
>> Io, they are unlikely to make it into either the sample or It. Since those 
>> photons are removed from the beam hitting the sample, they would show up as 
>> intensity dips in It. I’d bet that most (all?) of the reflected beam is not 
>> going into the sample. I’m kind of surprised It signal is as clean as it is, 
>> but then I don’t know the gains on either measurement amplifiers. I couldn’t 
>> find a flat mirror angle that would cause the cutoff at 12870? eV but since 
>> it is a collimating mirror who knows what range of angles were actually 
>> being hit.
>> Jeff Terry
>> Interim Chair, Department of Biology
>> Interim Chair, Department of Social Sciences
>> Professor of Physics
>> Professor of Mechanical, Materials, and Aerospace Engineering
>> Editor, Applied Surface Science
>> Illinois Institute of Technology
>> 3101 S. Dearborn St.
>> Chicago IL 60616
>> 630-252-9708
>>> On Jun 14, 2023, at 7:27 PM, Anatoly Frenkel 
>>> mailto:anatoly.fren...@stonybrook.edu>> 
>>> wrote:
>>> Hello, all. It is a low- to medium- level brain teaser.
>>> Pt-coated collimating mirror was in place for Pd K-edge measurement, but Au 
>>> L3-edge of Pd-Au alloy was measured (for testing purposes). I0 and It 
>>> detectors were both Ar filled ionization chambers. Because of the energy 
>>> dependence of reflectivity of the Pt mirror, I0 intensity was strongly 
>>> nonlinear (blue curve). However, the transmission intensity in the It 
>>> detector was almost linear (red curve). Why?
>>> Anatoly
>>> 
>>> ___
>>> Ifeffit mailing list
>>> Ifeffit@millenia.cars.aps.anl.gov 
>>> http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
>>> Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit
>> ___
>> Ifeffit mailing list
>> Ifeffit@millenia.cars.aps.anl.gov
>> http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
>> Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit
> ___
> Ifeffit mailing list
> Ifeffit@millenia.cars.aps.anl.gov
> http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
> Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit

___
Ifeffit mailing list
Ifeffit@millenia.cars.aps.anl.gov
http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit

Re: [Ifeffit] Brain teaser

[Kirill LOMACHENKO]

rs. I couldn?t find a flat mirror 
angle that would cause the cutoff at 12870? eV but since it is a collimating 
mirror who knows what range of angles were actually being hit.

Jeff Terry
Interim Chair, Department of Biology
Interim Chair, Department of Social Sciences
Professor of Physics
Professor of Mechanical, Materials, and Aerospace Engineering
Editor, Applied Surface Science
Illinois Institute of Technology
3101 S. Dearborn St.
Chicago IL 60616
630-252-9708






On Jun 14, 2023, at 7:27 PM, Anatoly Frenkel  
wrote:

Hello, all. It is a low- to medium- level brain teaser.

Pt-coated collimating mirror was in place for Pd K-edge measurement, but Au 
L3-edge of Pd-Au alloy was measured (for testing purposes). I0 and It detectors 
were both Ar filled ionization chambers. Because of the energy dependence of 
reflectivity of the Pt mirror, I0 intensity was strongly nonlinear (blue 
curve). However, the transmission intensity in the It detector was almost 
linear (red curve). Why?

Anatoly


___
Ifeffit mailing list
Ifeffit@millenia.cars.aps.anl.gov
http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit

-- next part --
An HTML attachment was scrubbed...
URL: 
<http://millenia.cars.aps.anl.gov/pipermail/ifeffit/attachments/20230615/29a1e139/attachment-0001.htm>

--

Message: 3
Date: Wed, 14 Jun 2023 23:09:45 -0700
From: matthew marcus 
To: ifeffit@millenia.cars.aps.anl.gov
Subject: Re: [Ifeffit] [Ext] Brain teaser
Message-ID: <0df910ac-01ff-976d-dc34-19514d973...@lbl.gov>
Content-Type: text/plain; charset=UTF-8; format=flowed

The mirror was set up for a run at the Pd K-edge, according to the
problem statement.  Therefore, its nominal angle must be such as to put
the critical energy >25keV.  An angle of 3mrad would do it. At that
angle, the reflectivity (assuming  no roughness) goes up with energy in
the relevant range, but only by a few percent.

We're not told what the ratio of gains of the current amps is, or
whether the ion chambers have the same path length, so we can't tell
whether the signals are comparable, as shown on the graph, or orders of
magnitude different.
mam

On 6/14/2023 10:17 PM, Jeffrey Terry wrote:

Well, I?ll take a shot. Looks like the mirror angle is totally fubared,
you are getting Bragg peaks from the coating or substrate that are
giving you the peaks in Io. Since you have no idea what angle those are
going through Io, they are unlikely to make it into either the sample or
It. Since those photons are removed from the beam hitting the sample,
they would show up as intensity dips in It. I?d bet that most (all?) of
the reflected beam is not going into the sample. I?m kind of surprised
It signal is as clean as it is, but then I don?t know the gains on
either measurement amplifiers. I couldn?t find a flat mirror angle that
would cause the cutoff at 12870? eV but since it is a collimating mirror
who knows what range of angles were actually being hit.

Jeff Terry
Interim Chair, Department of Biology
Interim Chair, Department of Social?Sciences
Professor of Physics
Professor of Mechanical, Materials,?and Aerospace Engineering
Editor, Applied Surface Science
Illinois Institute of Technology
3101 S. Dearborn St.
Chicago IL 60616
630-252-9708






On Jun 14, 2023, at 7:27 PM, Anatoly Frenkel
mailto:anatoly.fren...@stonybrook.edu>> wrote:

Hello, all. It is a low- to medium- level brain teaser.

Pt-coated collimating mirror was in place for Pd K-edge measurement,
but Au L3-edge of Pd-Au alloy was measured (for testing purposes). I0
and It detectors were both Ar filled ionization chambers. Because of
the energy dependence of reflectivity of the Pt mirror, I0 intensity
was strongly nonlinear (blue curve). However, the transmission
intensity in the It detector was almost linear (red curve). Why?

Anatoly


___
Ifeffit mailing list
Ifeffit@millenia.cars.aps.anl.gov
<mailto:Ifeffit@millenia.cars.aps.anl.gov>
http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit


___
Ifeffit mailing list
Ifeffit@millenia.cars.aps.anl.gov
http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit


--

Subject: Digest Footer

___
Ifeffit mailing list
Ifeffit@millenia.cars.aps.anl.gov
http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit


--

End of Ifeffit Digest, Vol 244, Issue 8
***


___
Ifeffit mailing list
Ifeffit@millenia.cars

Re: [Ifeffit] [Ext] Brain teaser

[matthew marcus]

The mirror was set up for a run at the Pd K-edge, according to the 
problem statement.  Therefore, its nominal angle must be such as to put 
the critical energy >25keV.  An angle of 3mrad would do it. At that 
angle, the reflectivity (assuming  no roughness) goes up with energy in 
the relevant range, but only by a few percent.


We're not told what the ratio of gains of the current amps is, or 
whether the ion chambers have the same path length, so we can't tell 
whether the signals are comparable, as shown on the graph, or orders of 
magnitude different.

mam

On 6/14/2023 10:17 PM, Jeffrey Terry wrote:
Well, I’ll take a shot. Looks like the mirror angle is totally fubared, 
you are getting Bragg peaks from the coating or substrate that are 
giving you the peaks in Io. Since you have no idea what angle those are 
going through Io, they are unlikely to make it into either the sample or 
It. Since those photons are removed from the beam hitting the sample, 
they would show up as intensity dips in It. I’d bet that most (all?) of 
the reflected beam is not going into the sample. I’m kind of surprised 
It signal is as clean as it is, but then I don’t know the gains on 
either measurement amplifiers. I couldn’t find a flat mirror angle that 
would cause the cutoff at 12870? eV but since it is a collimating mirror 
who knows what range of angles were actually being hit.


Jeff Terry
Interim Chair, Department of Biology
Interim Chair, Department of Social Sciences
Professor of Physics
Professor of Mechanical, Materials, and Aerospace Engineering
Editor, Applied Surface Science
Illinois Institute of Technology
3101 S. Dearborn St.
Chicago IL 60616
630-252-9708





On Jun 14, 2023, at 7:27 PM, Anatoly Frenkel 
> wrote:


Hello, all. It is a low- to medium- level brain teaser.

Pt-coated collimating mirror was in place for Pd K-edge measurement, 
but Au L3-edge of Pd-Au alloy was measured (for testing purposes). I0 
and It detectors were both Ar filled ionization chambers. Because of 
the energy dependence of reflectivity of the Pt mirror, I0 intensity 
was strongly nonlinear (blue curve). However, the transmission 
intensity in the It detector was almost linear (red curve). Why?


Anatoly


___
Ifeffit mailing list
Ifeffit@millenia.cars.aps.anl.gov 


http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit



___
Ifeffit mailing list
Ifeffit@millenia.cars.aps.anl.gov
http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit

___
Ifeffit mailing list
Ifeffit@millenia.cars.aps.anl.gov
http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit