Correcting First Few Time Bins

1
Correcting First Few Time Bins
Problem

• First few time bins are dropped
• Does not allow us to use events with very short
  drift times.
• Dropped bins correlate to electronics reset time
  (which happens every event)

2
Correcting First Few Time Bins
Options

• Correct data (by fitting a function or
  bin-by-bin)
• Problem does not seem to be consistent effect
  (either from event to event, or channel to
  channel)
• Change the reset behaviour

3
Correcting First Few Time Bins
Electronics reset

• The preamplifiers in the star FEE cards have a
  reset switch which is closed until a trigger is
  received.
• This allows for a capacitor to discharge which
  should not otherwise
• It was hypothesized that the pre-amps will
  saturate without this reset
• We have been able to run with the reset disabled
  for many events over many hours
• The data, upon visual inspection looks to be the
  same as using the normal reset (but without
  dropped bins)

4
Modifications To Electronics Reset
So far
Reset removed from the system for one pad row
Normal reset
No reset
5
Modifications To Electronics Reset
So far
Reset removed from the system for one pad row
Normal reset
No reset
6
Whats next

• Data with cosmics has been taken over last two
  days
• Analyze those data to see if there is any
  difference in the data from the one row which is
  not being reset
• If data is unchanged design the modifications to
  the motherboard