[RASMB] Lamp intensity fluctuations

[Titus M. Franzmann]

Hi everyone. 

We are experiencing a phenomenon with our ProteomLab XL/I that I we do not
understand and unfortunately Beckman is not able to address at this point. 
Over the time-course of our experiments the lamp intensity increase
significantly and then decreases again (please see attached files). This
pattern is present in all runs and most pronounced in intensity mode.
However, absorbance data seem to be compromised as well. 
I sat down and monitored the photomultiplier Voltage in the hardware monitor
menu in the Beckman software and noticed that the voltage settings varied
between scans. The voltage varied by more than 100 V. My understanding is
that the voltage setting should not change between scans of the same cell as
this will affect the dynamics of the photomultiplier. However, I am not sure
if that assumption is correct, or if there is some room to do minor
adjustments during scans.
Any comment is greatly appreciated. 
Best
Titus M. Franzmann

 
Dr. Titus M. Franzmann
S. G. Walter Lab
Mol., Cell. and Develop. Biol. Dept. 
University of Michigan
4140C Nat. Sci. Bldg
830 N. University Ave.
Ann Arbor, MI 48109-1048
titusfranzmann.spaces.live.com




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