[Halld-tagger] first results on fiber light yields

[Alexander Somov]

Hello Richard,

Actually fadc spectra for 1) and 3) agree reasonably well

Why 2) is about 20% wider (was it a different readout channel)?

(there could be some sampling effects due to the different pulse
shape around the peak. I would also compare amps without the
splitter).

Cheers,
       Alex





On Wed, 12 Feb 2014, Richard Jones wrote:

> Dear colleagues,
>
> We are working to obtain light yields for the first article fiber bundle
> that was produced for the tagger microscope some time back.  We have run
> into a problem trying to interpret what we see coming from the FADC250
> module that is installed in the data acquisition crate we are using for
> fiber QA tests.  Please see the plots on the wiki page linked below that
> illustrate the problem we are seeing.
>
> https://halldweb1.jlab.org/wiki/index.php/Tagger_Microscope#Light_yield_tests
>
> When we look at the signals on the scope, we see one set of amplitude
> ratios that clearly reveal the differences in light yield resulting from
> different lengths of the fibers that are covered in reflective paint.  The
> results from the FADC are much less distinguished, and disagree in the
> ratios of pulse heights.  Comments or suggestions as to what we are doing
> wrong would be appreciated.
>
> -Richard Jones
>