GLAST LAT project pitch adapter review

GLAST LAT Project
Pitch Adapter Review, 20 January 2005
1
GLAST Large Area Telescope:
GLAST Large Area Telescope:
Pitch Adapter PWB Metrology
Bill Craig, Charlie Young
Stanford Linear Accelerator Center

650-926-2983
Gamma-ray Large
Gamma-ray Large
Area Space
Area Space
Telescope
Telescope
GLAST LAT Project
Pitch Adapter Review, 20 January 2005
2
CMM Surface Scan Overview
CMM Surface Scan Overview

6 parts were taken to LLNL for metrology
–
4 parts, 2 of the -05 series, 2 of the -10 series.

Several non-contact methods attempted, none were successful
at getting a good view of the whole radius

Performed dense CMM scan at 1mm steps in Z, 3mm of Y
travel in 115 steps, 1.5mm probe radius.


Surface data shows features on few cm length scales with
amplitude of 50 to 100 microns.

No apparent difference on surface plots between the older -05
series and the newer -010 series for the few parts tested
GLAST LAT Project
Pitch Adapter Review, 20 January 2005
3
Coordinate system for CMM scans
Coordinate system for CMM scans
Serial Number
X=0
X=355
Y
Z
Boards were held flat by custom fixturing.
IE 176 CMM
GLAST LAT Project
Pitch Adapter Review, 20 January 2005
4
Board 2100 Surface
Board 2100 Surface
GLAST LAT Project
Pitch Adapter Review, 20 January 2005
5
Board 2146 Surface
Board 2146 Surface
GLAST LAT Project
Pitch Adapter Review, 20 January 2005

6
Board 11312 Surface
Board 11312 Surface
GLAST LAT Project
Pitch Adapter Review, 20 January 2005
7
Board 11314 Surface
Board 11314 Surface
GLAST LAT Project
Pitch Adapter Review, 20 January 2005
8
CMM residuals
CMM residuals

For each of the 4 boards, subtract a typical Y-Z plane trace
from the surface.

Plot residuals to look for correlation length scales

On 3 of 4 evidence for ~10 cm length scale for variations,
amplitude of 50 to 100 microns.

No apparent difference between -05 and -10 series
GLAST LAT Project
Pitch Adapter Review, 20 January 2005
9
Board 2100 Residuals
Board 2100 Residuals
Subtracted X scan [10] and smoothed with 2D 11
pixel width boxcar

GLAST LAT Project
Pitch Adapter Review, 20 January 2005
10
Board 2146 Residuals
Board 2146 Residuals
GLAST LAT Project
Pitch Adapter Review, 20 January 2005
11
Board 11312 Residuals
Board 11312 Residuals
GLAST LAT Project
Pitch Adapter Review, 20 January 2005
12
Board 11314 Residuals
Board 11314 Residuals
GLAST LAT Project
Pitch Adapter Review, 20 January 2005
13
Radial profiles
Radial profiles

For each of 355 X scans, perform four 3 point radius
determination
–
1) Upper part of board (Teledyne side about 1/3 of the way
along the arc)
–
2) Middle part of arc
–
3) Lower part of board (Italian side about 2/3 of the way

along the arc)
–
4) Full arc
GLAST LAT Project
Pitch Adapter Review, 20 January 2005
14
Board 2100 Radial Profile
Board 2100 Radial Profile
GLAST LAT Project
Pitch Adapter Review, 20 January 2005
15
Board 2146 Radial Profile
Board 2146 Radial Profile
GLAST LAT Project
Pitch Adapter Review, 20 January 2005
16
Board 11312 Radial Profile
Board 11312 Radial Profile
GLAST LAT Project
Pitch Adapter Review, 20 January 2005
17
Board 11314 Radial Profile
Board 11314 Radial Profile
GLAST LAT Project
Pitch Adapter Review, 20 January 2005
18
Radial results
Radial results

The two -10 series boards look different from the -05 series boards.

–
The dispersion in radial measurements is lower
•
SLAC profilometer data seems to corroborate this
–
There is a decided trend in X on the lower radial measurement on
the -10 series boards that is not seen on the -05 series

Limited board sample, unclear whether this has meaning but there
does seem to be a significant difference.
–
If this were a blind study, might predict that the -05 boards would
perform worse.

The very small radius toward the Italian side of the arc is worrisome
but, since it seems to have been there for some time, is probably not
the culprit for the sudden failure.
GLAST LAT Project
Pitch Adapter Review, 20 January 2005
19
Sectioning instructions
Sectioning instructions

Diane Kolos at GSFC has boards and will do sectioning and
SEM analysis.

Instructions written by C. Young and sent to her on 13
January.

Status?

GLAST LAT Project
Pitch Adapter Review, 20 January 2005
20
Pitch Adapter Geometry
Pitch Adapter Geometry
GLAST LAT Project
Pitch Adapter Review, 20 January 2005
21
Board to be sectioned at a broken trace as
Board to be sectioned at a broken trace as
shown.
shown.
GLAST LAT Project
Pitch Adapter Review, 20 January 2005
22
45 degree sectioning of 1” lengths
45 degree sectioning of 1” lengths
GLAST LAT Project
Pitch Adapter Review, 20 January 2005
23
Italian side CMM profile
Italian side CMM profile
GLAST LAT Project
Pitch Adapter Review, 20 January 2005
24
Teledyne side CMM profilometery
Teledyne side CMM profilometery
GLAST LAT Project
Pitch Adapter Review, 20 January 2005
25

Taylor-Hobson profilometery
Taylor-Hobson profilometery

Done on two ‘rough’ sections of the 2k series board

Worst Peak to Peak 30 microns, mean is 10 microns

Definitely periodic on few mm length scales (corresponds to
tools marks visible on part under microscope)