Dear all,

I just took a silicon run with the TPOL. A file of plots from the
data is attached. My comments are:

Page 1: Pedestals look fine. RMS shows the beam profile in x and the
two peaks in y. This was why I doubted the pedestal algorithm Stefan
though I acknowledge that unless the rate of Brems is incredibly high
the algorithm should work since the Compton rate is low. What do you
think? This biases to some degree the cluster finding making it
harder to find clusters in the beamspot than outside.

Page 2: Scatter plot of page 1 quantities.

Page 3: No errors.

Page 4: Common modes look fine. In the tunnel with the LED these
looked a little odd but in normal conditions they seem fine.

Page 5: Error checking. All okay.

Pages 6, 7, 8 and 9: Okay I guess. See this second peak in y.
Remember the x values should be multiplied by 2 since we read out
every other strip. I will fix this sometime. Beam seems more off
centre in x than I remember.

Page 10: Okay the x-y plot looks fine, but I can't see the
correlation between eta and y! I tried this plot for different
numbers of events i.e. first 10k then 20k etc. and it doesn't seem
any better. I conclude from this that the end of run effect you were
talking about Stefan is not the reason and somehow the CALO and
silicon have mismatched events. Is this possible Stefan?

Anyway, go ahead and take more runs etc. Maybe there was just
something funny with this run. I have a plane to catch now.

Cheers,
Alex.