Re: question on linearity of flow channels

Ray Hicks (hicks@icrf.icnet.uk)
Mon, 3 Jul 1995 12:24:03 +0100 (BST)

Hi Peter,
As you suspect, the gain of photomultipliers is not linear with respect
to applied voltage. It would be better for you to use linear electronic
amplification (if available on your machine), and to use the amount of
amplification applied as a "correction factor".

Ray

On Fri, 30 Jun 1995, Peter D Briggs wrote:

>
> Hi, just a small question that I hope someone can answer:
>
> I'm doing research on polyploidy in several plant species and
> have been using flow to determine ploidy level. In order to quantify and
> compare, I have been running CRBC's as an external standard. After every
> five samples run, I run the CRBC's and adjust the voltage to get the CRBC
> peak at approximately channel 100 on the P-MT3 screen. My question is,
> what sort of a relationship is there between voltage and channel
> shifting? If you adjust the voltage to bring the CRBC peak up 10 channels,
> is it a linear relationship with all channels being shifted 10 as well?
> Or is there some non-linear relationship?
> Some of our samples have been giving us consistently weird
> results, and if a non-linear shift is possible, that would explain what
> we're seeing.
> Thanks in advance for your input...
>
> Peter Briggs
> pbriggs@uoguelph.ca
>

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