View source for Test in d2n

[https://hallaweb.jlab.org/wiki/images/9/95/2008-033.pdf Studies of the Transmission of Gases for the Cerenkov Counters]

[https://hallaweb.jlab.org/wiki/index.php/File:Gastransmission.xls.tar.gz Transmission data measured at Syracuse]

Brad's note:

Here is a spreadsheet (gastransmission.xls) with transmission data
measured at Syracuse on behalf of BTeV years ago.  It shows essentially
100% transmission from 180--350nm.  Unfortunately, I don't know the
length of gas that was sampled, so a transmissability/absorption length
can not be computed, but absorption is basically zero over this range.

Hall B measured a sample of the C4F8O we used for transversity/d2n in
2009.  Their report is also attached (2008-033.pdf).  The relevant
figure is #22 (C4F8O).  The transmittance plots are over 1.5m of gas at
1 atm.  There is essentially no measured absorption from 200nm--500nm.
NOTE: please do not be fooled/misled by figures 12, 14, 15, etc.
The observed fall off in those plots is an artifact of the
UV-glass PMT used for those data.  Figure 22 has data taken after they
borrowed a quartz-face PMT and you see it is basically flat up to the
region where the PMT quantum efficiency starts to die (ie. 200nm for
this particular tube).  (See also: comment at bottom of p.6).

The Hall B data and the Syracuse data both support the conclusion that
C4F8O is essentially 100% transparent down to 180nm over a nominal 1.5m
of gas length.

I am not aware of measured transmittance/absorption data below for
wavelengths below 180nm.