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
This Message Is From an External SenderThis message came from outside your organization.ifeffit mailing list: https://millenia.cars.aps.anl.gov/mailman3/lists/ifeffit.millenia.cars.aps.anl.gov/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 > ZjQcmQRYFpfptBannerStart > This Message Is From an External Sender > This message came from outside your organization. > ZjQcmQRYFpfptBannerEnd > 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 > ZjQcmQRYFpfptBannerStart > This Message Is From an External Sender > This message came from outside your organization. > ZjQcmQRYFpfptBannerEnd > 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 > > > ifeffit mailing list: https://millenia.cars.aps.anl.gov/mailman3/lists/ifeffit.millenia.cars.aps.anl.gov/ > to unsubscribe, send mail to ifeffit-leave@millenia.cars.aps.anl.gov
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