GLAST LAT Project Gamma-ray Large Area Space Telescope

GLAST LAT Project Gamma-ray Large Area Space Telescope Pitch Adapter Review, 20 January 2005 GLAST Large Area Telescope: Pitch Adapter PWB Metrology Bill Craig, Charlie Young Stanford Linear Accelerator Center bcraig@slac. stanford. edu 650 -926 -2983 1

GLAST LAT Project Pitch Adapter Review, 20 January 2005 CMM Surface Scan Overview q q q 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 1 mm steps in Z, 3 mm of Y travel in 115 steps, 1. 5 mm 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 2

GLAST LAT Project Pitch Adapter Review, 20 January 2005 Coordinate system for CMM scans Y Z X=355 X=0 Serial Number Boards were held flat by custom fixturing. IE 176 CMM 3

GLAST LAT Project Pitch Adapter Review, 20 January 2005 Board 2100 Surface 4

GLAST LAT Project Pitch Adapter Review, 20 January 2005 Board 2146 Surface 5

GLAST LAT Project Pitch Adapter Review, 20 January 2005 Board 11312 Surface 6

GLAST LAT Project Pitch Adapter Review, 20 January 2005 Board 11314 Surface 7

GLAST LAT Project Pitch Adapter Review, 20 January 2005 CMM residuals For each of the 4 boards, subtract a typical Y-Z plane trace from the surface. q Plot residuals to look for correlation length scales q On 3 of 4 evidence for ~10 cm length scale for variations, amplitude of 50 to 100 microns. q No apparent difference between -05 and -10 series q 8

GLAST LAT Project Pitch Adapter Review, 20 January 2005 Board 2100 Residuals Subtracted X scan [10] and smoothed with 2 D 11 pixel width boxcar 9

GLAST LAT Project Pitch Adapter Review, 20 January 2005 Board 2146 Residuals 10

GLAST LAT Project Pitch Adapter Review, 20 January 2005 Board 11312 Residuals 11

GLAST LAT Project Pitch Adapter Review, 20 January 2005 Board 11314 Residuals 12

GLAST LAT Project Pitch Adapter Review, 20 January 2005 Radial profiles q 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 13

GLAST LAT Project Pitch Adapter Review, 20 January 2005 Board 2100 Radial Profile 14

GLAST LAT Project Pitch Adapter Review, 20 January 2005 Board 2146 Radial Profile 15

GLAST LAT Project Pitch Adapter Review, 20 January 2005 Board 11312 Radial Profile 16

GLAST LAT Project Pitch Adapter Review, 20 January 2005 Board 11314 Radial Profile 17

GLAST LAT Project Pitch Adapter Review, 20 January 2005 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 q 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. q 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. q 18

GLAST LAT Project Pitch Adapter Review, 20 January 2005 Sectioning instructions Diane Kolos at GSFC has boards and will do sectioning and SEM analysis. q Instructions written by C. Young and sent to her on 13 January. q Status? q 19

GLAST LAT Project Pitch Adapter Review, 20 January 2005 Pitch Adapter Geometry 20

GLAST LAT Project Pitch Adapter Review, 20 January 2005 Board to be sectioned at a broken trace as shown. 21

GLAST LAT Project Pitch Adapter Review, 20 January 2005 45 degree sectioning of 1” lengths 22

GLAST LAT Project Pitch Adapter Review, 20 January 2005 Italian side CMM profile 23

GLAST LAT Project Pitch Adapter Review, 20 January 2005 Teledyne side CMM profilometery 24

GLAST LAT Project Pitch Adapter Review, 20 January 2005 Taylor-Hobson profilometery Done on two ‘rough’ sections of the 2 k series board q Worst Peak to Peak 30 microns, mean is 10 microns q Definitely periodic on few mm length scales (corresponds to tools marks visible on part under microscope) q 25

GLAST LAT Project Pitch Adapter Review, 20 January 2005 Visual Inspection Scanned ~5 boards of the 11 k series that had been rejected for breaks. q Verified that breaks occurred in clumps – Few single breaks – Typical number of breaks ~>5 – Several boards had many clumps of failures, these seemed to also have other hairline cracks or other signs of onset of failure – Most boards had only one or two clumps of failure, only 1 ASIC site affected. q Given the spatial distribution of irregularities in the radius may be worth doing detailed correlation between failure sites and surface features. q 26

GLAST LAT Project Pitch Adapter Review, 20 January 2005 Summary No obvious visual clues from most of the profilometry q Some indication of differences in radial profile between the small number of -05 and -10 series boards profiled – More radial variation in the -05 series boards but generally flat radial profile as function of ‘X’ – Indication of a significant radial variation as function of ‘X’ in -10 series boards. q No smoking guns but should correlate these findings against the spatial distribution of failures on the most recent Teledyne attempts. q 27

GLAST LAT Project Pitch Adapter Review, 20 January 2005 Board 2257 Radial Profile SLAC profilometer data. -10 series board 28

GLAST LAT Project Pitch Adapter Review, 20 January 2005 Board 2057 Radial Profile SLAC profilometer data. -10 series board 29

GLAST LAT Project Pitch Adapter Review, 20 January 2005 Board 2108 Radial Profile SLAC profilometer data. -10 series board 30

GLAST LAT Project Pitch Adapter Review, 20 January 2005 Board 2123 Radial Profile SLAC profilometer data. -10 series board 31

GLAST LAT Project Pitch Adapter Review, 20 January 2005 Board 11127 Radial Profile SLAC profilometer data. -05 series board 32

GLAST LAT Project Pitch Adapter Review, 20 January 2005 Board 11313 Radial Profile SLAC profilometer data. -05 series board 33

GLAST LAT Project Pitch Adapter Review, 20 January 2005 Board 11317 Radial Profile SLAC profilometer data. -05 series board 34

GLAST LAT Project Pitch Adapter Review, 20 January 2005 CMM profilometry Board 2132 35

GLAST LAT Project Pitch Adapter Review, 20 January 2005 CMM profilometry Board 2108 36

GLAST LAT Project Pitch Adapter Review, 20 January 2005 CMM profilometry Board 11127 37

GLAST LAT Project Pitch Adapter Review, 20 January 2005 CMM profilometry Board 11313 38