Secondary electron mfp in PMMA

I have tried to find the mean free path for low energy electrons (e.g. secondaries with < 100 eV energy) in PMMA or other polymers in the
literature, but the results seem to scattered across different studies using different radiation (e.g., X-rays, electrons) or are concentrated mainly in higher electron energies or different substances, primarily metals. I can only make an indirect inference, but would prefer a direct confirmation. It seems there has to be a study of this done somewhere. Can anyone point me to a reference? Many thanks in advance.
Regards,
FC
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There really aren't too many people out there taking these measurements, and most of those are in elemental materials, so if you've found anything on PMMA, and the density and material properties are the same, take it.
Another option is empirical correlations. See http://www.nist.gov/srd /. They have an electron attenuation length database that they will mail you the software for free (at least if you are in the US, not sure about foreign). EALs are essentially IMFPs with elastic collisions taken into account, so they're actually a better approximation to what's happening to electrons in the material. They also have an IMFP database. The programs ask you to input an elemental composition and density and output EAL or IMFP as a function of electron kinetic energy between 50 eV to 2000 eV (range of AES and XPS measurements).
Don't expect to get a very good number, measurement or correlation regardless.
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snipped-for-privacy@gmail.com wrote:

Thanks, a free database is always handy. I was hoping to get data down to 1 eV, and was particularly interested in the 3-5 eV region which corresponds to bond scission. A number of independent references I have already looked at (which I would be happy to discuss with anyone interested) indicate a number around 20 nm for this energy range.
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