[RASMB] XL/I absorbance problem

[Leech, AP]

Hello again,

Many thanks to Virgil, John, Borries and Tom for such timely and
informative replies.

I have now attached two plots showing actual data: the first
(IncidentIntensityComp.gif) shows the data from 00001.RN2 scan
280 nm velocity scan on an empty hole. The top trace is the
incident and the bottom the intensity as seen through the empty
hole. The second graph shows two incident (.RNx) plots. These
were both at 280 nm; the top one from an old scan long before
this problem arose and the bottom one from a recent scan. Note
the different scales.

I agree with Virgil that we may have a slit problem, but I think
this is causing the broad dip in the intensity profile. The marked
difference between the old and new incident light profiles makes
me think the problem is with the lamp and/or reference detector.

I've tried re-aligning the lamp (no difference) but I hadn't
thought of swapping between machines. I'm not sure we can do this
as the lamp housing is rather different on the old XL/A and I don't
think it would fit.

What I did wonder is whether it is permissible/advisable to try
the XL/A monochromator in the XL/I? It would appear to fit, though
it has less pins. But I don't know if this would do something
nasty e.g. short out the laser power supply at the socket!

Any further comments are appreciated - I will let you know the
resolution (if any) of the problem.

Best to all,

Andrew

-- 
Dr Andrew Leech                   *  Laboratory Manager
Technology Facility               *  Molecular Interactions Laboratory
Department of Biology (Area 15)   *  Tel   : +44 (0)1904 328723
University of York                *  Fax   : +44 (0)1904 328804
PO Box 373,  York  YO10 5YW       *  Email : apl3 at york.ac.uk
-------------- next part --------------
A non-text attachment was scrubbed...
Name: IncidentIntensityComp.gif
Type: image/gif
Size: 7015 bytes
Desc: not available
URL: <http://list.rasmb.org/pipermail/rasmb-rasmb.org/attachments/20070613/4768937d/attachment.gif>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: IncidentBeforeAfter.gif
Type: image/gif
Size: 8584 bytes
Desc: not available
URL: <http://list.rasmb.org/pipermail/rasmb-rasmb.org/attachments/20070613/4768937d/attachment-0001.gif>