[Halld-cal] Fwd: BCAL Light Guide Transmission

[Matthew Shepherd]

Begin forwarded message:

> From: Matthew Shepherd <mashephe at indiana.edu>
> Date: April 21, 2011 3:29:57 PM EDT
> To: Elton Smith <elton at jlab.org>
> Subject: BCAL Light Guide Transmission
> 
> 
> Hi Elton,
> 
> Attached is a scan of the transmission as a function of wavelength for the BCAL guides you sent to me.  The transmission is measured with air as the reference.  Positioning the light guide in the spectrophotometer is a challenge because of the shape and small aperture on one end.  I repositioned the light guide four different times for each guide to get an idea of the systematic error due to this. All four positions directed the light beam along the long axis of the guide, two in each direction.  You'll find four spectra for each light guide.
> 
> On the last page I've included, for reference, a scan of a production FCAL light guide that was fabricated here this week and also a lead glass bar.
> 
> You can see a more drastic low wavelength cutoff in your BCAL guides in addition to what seems to be consistently poorer performance in the blue part of the spectrum.  By eye, when compared with the FCAL guide against white background there is a very slight hint of yellow-brown color in the BCAL guide.
> 
> -Matt
> 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: BCAL_lg_spectra.pdf
Type: application/pdf
Size: 150462 bytes
Desc: not available
Url : https://mailman.jlab.org/pipermail/halld-cal/attachments/20110426/478c4284/attachment-0001.pdf 
-------------- next part --------------