Date: Fri, 07 Sep 2001 14:04:22 -0500
From: Andrew Brandt <brandta@fnal.gov>
Subject: pot motion runplan (fwd)

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For Saturday Sept 7, 2001

The plan is to insert 8 pots close to beam and determine closest
positions of all the pots which will allow us to 
map out the vertical location of beam. These studies have been
done at the end of the store without major impact to CDF or D0,
but not all the pots have been moved in far enough to determine
the beam axis accurately. 

We would like to start around beginning of shift 9 a.m. We estimate the
studies will take about 4 hours. The first 2 hours would not cause any
disruption to data taking at CDF and D0.  The last 1-2 hours would involve
tuning the pbar side pot positions, which is expected to cause a temporary
increase in the losses. The pots will be moved in very small steps 
(100 um) at low speed, and will be immediately retracted by 0.5-1mm when
the halo rates show an increase of 20%. In the past the halo rates have
always returned to the previous levels when this is done.

Details:

First we will insert all 8 vertical pots to the last known good
positions in pairs. This will take about 1 hour and should not
cause any noticeable change to CDF or D0.

P-side: Insert P1U and P2U to 20mm fast. Look at the rates, if the rates
begin to climb near ~50kHz, switch to slow. From this point on, if the
rates are near ~50kHz, insert slow rather than fast, don't move further
if the rates will go above 50kHz unless you are almost at the final
position. Insert to 22mm fast. Insert to 23.5 slow. Insert to 24mm slow
in 0.1mm steps. Repeat for P1D and P2D.  (24mm is standard operating
position)

A-side: Insert A1D and A2D to 20mm fast. Look at the rates, if the rates
begin to climb near ~50kHz, switch to slow. From this point on, if the
rates are near ~50kHz, insert slow rather than fast. Insert to 31mm
fast. Insert to 32.5mm slow. Insert to 33mm slow in 0.1mm steps. Repeat
for A1U and A2U. (33.5 mm is new standard operating position--was 34mm
before yesterday)

Once the pots are in position, we want to continue to insert them closer
to beam and find the positions for each location where the D0 halo
losses increase by 20% from the baseline values (if the CDF losses
are impacted significantly, we will move the pots back out a bit).

Start with P1U. Insert the pot in 0.1mm steps at slow speed. Let the pot
rest at each position for a few minutes and then verify the losses at
CDF and D0 (use the lumberjack plot for CDF and the visual scaler in the
SCR for D0). Record the pot position where we first start impacting D0
losses and where we impact CDF losses (if at all). After the position 
is established, then retract the pot to 24mm. Remeasure the halo losses
and verify that they have not changed from before the pot insertion.
Note that P-side insertions typically affect A-side halo rates which
are much lower than P-side halo rates. Repeat this for P1D, P2U and P2D. 

For the A side, start with A1U and perform a similar insertion to that
described above. Be especially careful on this side as we have 
occasionally seen impacts at CDF based on A-side pot insertion.