Cary 100 UV region irregular spectra

Hi all,

I have a Cary 100. When I run a scan from 800nm to 200nm, the UV region always shows irregular, strong, sharp peaks. The peaks are not repeatable if scan the same samples multiple times. I have changed the UV lamp, and done the alignment. It does not help.  The visible region is normal. Does anyone have an idea what is going on? Thanks a lot.

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  • To align the lamps you can use these parameters to get ~40%T with the lowest gain possible (i.e. ~120 for UV lamp and ~105 for Vis).

    For UV lamp: In the Align application, click the Cary tab and set these parameters:
    • Single Beam Normal
    • Y-Mode = %T
    • Energy = 115 (adjust to achieve >40%T)
    • Ave. Time = 0.1sec
    • SBW = 1.0nm
    • Wavelength = 235nm

    To optimize the Visible lamp:
    In the Align application, click the Cary tab and set these parameters:
    • Single Beam Normal
    • Y-Mode = %T
    • Energy = 100 (adjust to achieve >40%T)
    • Ave. Time = 0.1sec
    • SBW = 1.0nm
    • Wavelength = 500nm

    When you use double beam normal/reversed, you will get a signal close to 100%T whatsoever. Using the single beam will give you an indication of the lighttroughput and thus alignment quality.

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