ATLAS

1
Summary of Survey Measurements of 180 Modules on
30 Pixel Sectors (9006-9035)
Ronald J. Madaras Lawrence Berkeley National
Laboratory June 14, 2005
2
Modules-on-Sector Measurements
3 modules on front side. 3 modules on back
side. 3 mounting buttons glued in holes in
carbon sector. X0,Y0 is always left
button, looking down on sector, for each side.
3
Modules-on-Sector Measurements
For each sector side we measure (using a
SmartScope)

• 1) X,Y of survey targets at the 4 corners of each
  module. Then calculate
• Delta X Xmeaured - Xnominal, Delta Y
  Ymeaured - Ynominal
• 32 X,Y,Z points on the top side of each module
  (16 along one long edge, 16 along the other long
  edge) in the vicinity of the first and last chip
  ID pads of each front-end chip.
• Calculate Bow Twist of module, Height of
  module above sector plane.
• 3) 12 X,Y,Z points on the sector surface. Fit 12
  points to a 3D sector plane.
• Save fit parameters, chi-square, residuals mean
  and residuals RMS.
• (This is done 3 times for each side, each time a
  module is measured.)
• 4) 4 X,Y,Z points on the button surface, for each
  of 3 mounting buttons. Fit 12
• points to a 3D button plane.
• Save fit parameters, chi-square, residuals mean
  and residuals RMS.
• (This is done 3 times for each side, each time a
  module is measured.)
• Compare sector plane and button plane.

4
Delta X, Delta Y of Module Survey Targets
Delta X and Delta Y of Survey Targets of Modules
on Sectors (for 180 modules on 30 sectors,
9006-9035)
From fits
Mean -2.6 microns Sigma 3.0 microns
Mean -0.2 microns Sigma 2.6 microns
5
Module Bow and Twist Measurements
Bow and Twist Measurements of Modules on
Sectors (for 180 modules on 30 sectors, 9006-9035)
Average Bow 3 microns RMS Bow 9 microns
Average Twist 0.1 mr RMS Twist 1.0 mr
Average Bow 7 microns RMS Bow 6
microns
Average Twist 0.8 mr RMS Twist 0.6 mr
6
Module Height Above Sector Surface
For each of the 180 modules on the 30 sectors,
calculate the height of the top side of the
module above the sector plane at the 32 measured
points. Then a) Calculate the Tilt of each
module with respect to the sector plane Tilt
Module height at top of module - Module height at
bottom b) Calculate the Mean of the 32 heights
and the RMS of the 32 heights for each
Module. Compare Mean Height to Nominal Value (270
microns).
Average Tilt 14 microns RMS Tilt 11
microns
Average 52 microns RMS 11 microns
Average 12 microns RMS 4 microns
7
Comparison of Sector and Button Planes

• At X0,Y0, calculate the Z difference between
  the sector and button planes
• Zdiff (Zsector-Zbutton) - Nominal Value
• For the front sector plane Zdiff sector
  thickness button thickness - 4018 (µm)
• For the back sector plane Zdiff -button
  thickness - (-700) (µm)

Average 22 microns RMS 12 microns
Average -12 microns RMS 21 microns
Results indicate actual button thickness is 17
microns greater than nominal.
8
Comparison of Sector and Button Planes
Non-parallelism of the sector and button
planes Non-parallelism (Zsector-Zbutton)X,Y -
(Zsector-Zbutton)0,0 Non-parallelism 0 if the
sector and button planes are parallel. Measure
non-parallelism for X0,Y-70 (along length of
sector) X70,Y0 (along width of
sector) Since the buttons are distributed mainly
in X, and not very much in Y, expect
non-parallelism along the length (Y) of the
sector to be measured less precisely than along
the width (X) of the sector. Non-parallelism
(NP) is measured 3 times for the front of the
sector and 3 times for the back of the sector,
once every time a module is measured. For a given
non-parallelism of the sector and button planes,
sign conventions are such that if we measure it
exactly, the front and back non-parallelisms have
opposite signs for X0,Y-70 and the same signs
for X70,Y0. Thus For X0,Y-70 Average NP
(of a sector) (Front NP - Back
NP)/2 Front/Back NP difference (Front NP
Back NP)/2 would be zero For X70,Y0 Average
NP (of a sector) (Front NP Back
NP)/2 Front/Back NP difference (Front NP -
Back NP)/2 would be zero A deviation from zero
of (Front NP /- Back NP)/2 indicates how well or
poorly we measure the non-parallelism.
9
Comparison of Sector and Button Planes
Non-parallelism (NP) of the sector and button
planes (continued)
30 Sectors
30 Sectors
Average 11 microns, RMS 25 microns
Average -1 microns, RMS 7 microns
30 Sectors
30 Sectors
Average -2 microns, RMS 14 microns
Average 1 microns, RMS 5 microns
10
Conclusions for 180 Modules on 30 Sectors
Modules are glued to sectors with a position
accuracy of 3 microns in X Y! For other
measured quantities
Average RMS Bow 7 6 microns Twist 0.8 0.6
mr Tilt 14 11 microns (Mean height above
sector plane) - Nominal 52 11 microns RMS
(Heights above sector plane) 12 4 microns Zd
iff (Zsector-Zbutton) - Nom Front 22 12 micro
ns Back -12 21 microns Non-parallelism X0,Y
-70 Average 11 25 microns (FrontBack)/2 -2 14
microns X70,Y0 Average -1 7 microns (Fr
ont-Back)/2 1 5 microns