FPD Calibration Studies

1
FPD Calibration Studies

• Michael Strang
• University of Texas at Arlington

2
First Appearance of Problem

• This is a recent calibration with 0x400 gain on
  board. Notice the dropping of the mean at the
  edge of SIFT chips happening on two boards in
  different cassettes

3
Old data looking for problem

• This is an old calibration (around April) with
  0x400 gain on board. The evidence of this
  structure is not as clear if it is present at all.

4
Trying to isolate problem

• During recent access last week, we unplugged the
  bayonet, unplugged the cables from the tunnel
  going to the TPP and isolated the TPP from
  contact with anything else (flex cables still
  connected) and structure is very clear.

5
Looked at CFT boards as well

• For comparison, looked at a random board from a
  different crate (53). Surprisingly, this same
  structure is present in parts of the board so
  while this problem seems enhanced in the FPD
  boards, it appears to be present in other boards
  as well.