Hi Helen,



 +1 on using Aluminized Mylar and Aluminized Kapton (and we have some of
each at sector 13 if you want to borrow some).



The aluminum layer on Mylar is very thin (you can see visible light
through) but it holds helium.  In an undulator beam, Mylar might last 10
seconds. The thin aluminum layer helps a lot, but I would not guarantee
this by itself for multiple hours.



Kapton is leaky but holds up better in an undulator beam (but you can burn
a micro-hole in it over several hours with 10^13 photons/sec in a few
square microns: loving APS-U!)  The Aluminized version is a non-trivial
thickness (several microns) of aluminum, so not suitable for tender beams,
but should be OK above 5 keV (wait, which "V" in VTC -- Yb K or L3 edge?).




I'll say that we have had decent luck (with old APS undulator) with samples
in an otherwise regular Ziplock bag with a Kapton film window (held on with
carefully cut packing tape) for X-rays in and out and over-pressuring the
bag with blow-off N2 (which is free) or helium (which is not). But,
oxygen-sensitivity can vary a lot, so I’m not sure there is a single “best”
solution.



--Matt


On Sat, Mar 22, 2025 at 3:06 PM matthew marcus via Ifeffit <
ifeffit@millenia.cars.aps.anl.gov> wrote:

Aluminized mylar has a much lower permeability to oxygen than polyethylene
and still works with a heat-sealer. I'm assuming you're in the hard- or
tender X-ray range. mam On 3/22/2025 12: 16 PM, Carlo Segre via Ifeffit
wrote: > Hi Helen, We
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Aluminized mylar has a much lower permeability to oxygen than
polyethylene and still works with a heat-sealer.  I'm assuming you're in
the hard- or tender X-ray range.
	mam

On 3/22/2025 12:16 PM, Carlo Segre via Ifeffit wrote:

Hi Helen, We have had luck using a vacuum sealing system such as used
for food. However the Polyethylene is subject to degradation under the
beam so that wrapping with Kapton is helpful as well as double bagging
it. Finally, if you keep it under
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Hi Helen,

We have had luck using a vacuum sealing system such as used for food.
However the Polyethylene is subject to degradation under the beam so
that wrapping with Kapton is helpful as well as double bagging it.
Finally, if you keep it under Argon when transporting it to the beamline
and then in a helium filled chamber, you should avoid the oxidation.

Carlo


--
Carlo Segre, Duchossois Professor of Physics
Illinois Institute of Technology
------------------------------------------------------------------------
*From:* Helen Chen via Ifeffit <ifeffit@millenia.cars.aps.anl.gov>
*Sent:* Tuesday, March 18, 2025 8:05 PM
*To:* ifeffit@millenia.cars.aps.anl.gov <ifeffit@millenia.cars.aps.anl.gov>
*Cc:* Helen Chen <helen86@uw.edu>
*Subject:* [Ext][Ifeffit] Question about Air sensitive sample holder
Hello, Our group (Jerry Seidler) just started a project involving doing
VTC and HERFD on Yb doped CrX3 material. They are thin small crystal
sheets and are very air sensitive. We have tried encapsulated them
between a layer of laptop tape and
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Hello,
Our group (Jerry Seidler) just started a project involving doing VTC and
HERFD on Yb doped CrX3 material. They are thin small crystal sheets and
are very air sensitive. We have tried encapsulated them between a layer
of laptop tape and film, but after 12hr we see degradation due to air
leaks. I am looking for some advice on air sensitive sample holder. What
are some typical methods you use to deal with air sensitivity,
especially for samples in thin sheets geometry?
Thank you


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