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 ran
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 th
Amazing idea. I thunk you were the only one who succeeded to use third harmonic
of Si for taking EXAFS at high atomic number elements. But that does not
explain the peaks and dips.
Anatoly
> On Jun 15, 2023, at 12:22 AM, matthew marcus wrote:
>
> Suppose the mono is being used at the 333 re
Suppose the mono is being used at the 333 reflection (for Si),
intentionally working at the 3rd harmonic. In that case, if the
fundamental isn't filtered out, you could get just what we see, with the
sample doing the filtering before the beam gets to the transmission chamber.
mam
On 6
Thank you, Matthew and Robert, but I think the explanation is more simplle. The
fact that there are peaks in I0 and dips in transmission is a clue that
explains why transmission is almost linear while I0 curves up.
Anatoly
> On Jun 14, 2023, at 11:34 PM, matthew marcus wrote:
>
> One thing
One thing that's pretty odd is that the glitches are peaks in I0, and
dips in It. It would be much easier to explain if It was the one that
increased steeply and I0 was more linear, but the presence of the edge
in It shows that you didn't switch them. Red = It. What's that sudden
drop at the
Hi Anatoly,
reflectivity of Pt over that energy range does not vary that much:
[image: image.png]
I guessed what angle you were set for, assuming Pd K-edge...
So something wrong with I0?
-R.
On Wed, Jun 14, 2023 at 5:28 PM Anatoly Frenkel <
anatoly.fren...@stonybrook.edu> wrote:
> Hello, all
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 reflectiv
