# ATLAS DISK SECTOR FABRICATION AND SPECIFICATIONS

# Introduction

This note describes the fabrication sequence of the ATLAS Pixel Disk
Sector. This sequence is still under development and not all steps are
specified here. The fabrication of both aluminum-tube and
sealed-carbon-carbon-tube sectors are described. QC measurements for the
aluminum-tube sector are summarized in a Table as the last section of
this note. Key materials specifications are provided in Appendices. A
drawing package for the aluminum-tube disk sector is also included as an
Appendix.

# Aluminum-tube Sector

## Aluminum Tube

Cut tube to length

Measure tube length(record)

Weigh tube(record)

Anneal 3003 aluminum tubes to \"O\" condition (record)

Fill with wax

Bend-flatten-rebend as required (bending fixture) (flattening fixture)

Inspect\_ go no-go gage & visual

Remove filler wax

Clean thoroughly

Weigh tube again (should be same as first) (record)

Plug both ends

Weigh (record)

Mount in anodize fixture

Anodize (need to spec. procedure)

Weigh (record)

Cut the tube to length (fixture)

Weigh cut tube (record)

Weigh tube end transition pieces (record)

Weigh PEEK tube strain relief pieces (record)

Bond tube end transition and strain relief pieces to cut tube (fixture)

Weigh assembly (record)

Leak/pressure test (record)

Inspect\_ go no-go gage & visual (record)

Pack away in individual boxes with documentation (flat file)

## Carbon-carbon Facesheets

Inspect raw materials flatness thickness weight @ ºC and %RH (record)

Cut profile and alignment holes on mill (vacuum fixture)

Inspect (Go, No-Go gage) (record)

Ultrasonic clean then bake dry

Weight @ ºC and %RH (record)

## RVC Foam

Inspect raw materials flatness thickness weight @ ºC and %RH (record)

Rough-cut outer perimeter of foam using a scalpel to trace a pattern
around a template

Face 2 sides using tape on foam held on mill table by a vacuum chuck

Ultrasonic clean then bake dry

## Bond 1^st^ Facesheet to Foam

Apply cyanate ester just prior to bonding with reticulated vitreous
carbon foam. (position with alignment holes) chill, remove paper
backing, protect and set aside to allow condensed moisture to evaporate
from facesheet/cyanate ester

Weigh @ ºC and %RH with cyanate ester (record)

Rough position foam on facesheet w/cyanate ester

Place assemblly between flat plates w/spacers

Bake @ 250ºC for 3 hrs

Mount assembly onto same vacuum fixture in NC mill face to thickness,
cut tube slot and clear foam from mounting holes.

Ultrasonic clean then bake dry

Weigh @ ºC and %RH (record)

Inspect\_ go no-go gage & visual (record)

## Apply CGL & Glass Beads to Tube

Fixture to hold tube assembly during CGL application

Weigh tube and fixture (record)

Apply CGL to 1st side of tube (mask or CNC stage)

Weigh tube and fixture (record)

Apply glass beads to 1st side of tube

Weigh tube and fixture (record)

Apply CGL to 2nd side of tube (mask or CNC stage)

Weigh tube and fixture (record)

Apply glass beads to 2nd side of tube

Weigh tube and fixture (record)

## Bond 2^nd^ Facesheet and Hard Points

Prepare 2nd Facesheet for bonding

Apply cyanate ester just prior to bonding with reticulated vitreous
carbon foam. (position with alignment holes) (different cutting
template) chill, remove paper backing, protect and set aside to allow
condensed moisture to evaporate from facesheet/cyanate ester

Record weight @ ºC and %RH with cyanate ester

Add adhesive to strain relief positions Add hard points to 1st facesheet
with cyanate ester (hand place in position)

Inspect and weigh washers that go on face of sector (6 ea) @ ºC and %RH

Apply cyanate ester to carbon carbon spacer washers. Record weight of
spacers @ ºC and %RH with cyanate ester

Position 3 spacer washers on bonding fixture cyanate ester side up.
Position 1st facesheet on bonding fixture. Position tube on 1st
facesheet (pins through strain relief tabs?) Position 2nd facesheet on
bonding fixture. Position 3 spacer washers on top of 2nd facesheet

Clamp both sides of bonding fixture together

Inspect for proper fit

Bake @ 80 ºC for 16 hrs then 250 ºC for 3 hrs

Remove from bonding fixture

Record weight @ ºC and %RH

Inspect for flatness thickness and parallel sides

Place sector on milling fixture to take skim cut on spacer washers

Final inspection

## Final Assembly

Mount targets for survey

Seal foam

Clean

Inspect, weigh and record

Survey via optical CMM and record locations of targets relative to
mounting buttons

## Quality Control 

A preliminary summary of quality control items is given in the table
below. All length units are mm. All weights are in grams.

+-----------------------------------+-----------------------------------+
| ##### Item                        | **Measurement/Inspection**        |
+-----------------------------------+-----------------------------------+
| ###                               |                                   |
| ## Aluminum Tubes and Connections |                                   |
+-----------------------------------+-----------------------------------+
| Length after initial cutting      |                                   |
+-----------------------------------+-----------------------------------+
| Weight after initial cutting      |                                   |
+-----------------------------------+-----------------------------------+
| Inspect after annealing           |                                   |
+-----------------------------------+-----------------------------------+
| Go/no-go and inspect after        |                                   |
| bend/flatten                      |                                   |
+-----------------------------------+-----------------------------------+
| Weight after bending              |                                   |
+-----------------------------------+-----------------------------------+
| Weight with plugged ends for      |                                   |
| anodizing                         |                                   |
+-----------------------------------+-----------------------------------+
| Weigh after anodizing             |                                   |
+-----------------------------------+-----------------------------------+
| Weight after cutting to length    |                                   |
+-----------------------------------+-----------------------------------+
| Weigh square-to-round pieces      |                                   |
+-----------------------------------+-----------------------------------+
| Weigh PEEK strain relief pieces   |                                   |
+-----------------------------------+-----------------------------------+
| Weigh tube/connection assembly    |                                   |
+-----------------------------------+-----------------------------------+
| Leak/pressure test                |                                   |
+-----------------------------------+-----------------------------------+
| Visual inspection/label           |                                   |
+-----------------------------------+-----------------------------------+
| ##### Carbon-carbon Faceplates    |                                   |
+-----------------------------------+-----------------------------------+
| ##### Inspect raw plates          |                                   |
+-----------------------------------+-----------------------------------+
| Go/no go after cutting faceplates |                                   |
+-----------------------------------+-----------------------------------+
| Weigh faceplates                  |                                   |
+-----------------------------------+-----------------------------------+
| ##### RVC Foam                    |                                   |
+-----------------------------------+-----------------------------------+
| Inspect raw materials             |                                   |
+-----------------------------------+-----------------------------------+
| Determine density                 |                                   |
+-----------------------------------+-----------------------------------+
| Bond 1^st^ Faceplates to Foam     |                                   |
+-----------------------------------+-----------------------------------+
| Weigh faceplate with cyanate      |                                   |
| ester                             |                                   |
+-----------------------------------+-----------------------------------+
| Inspect after cutting foam        |                                   |
+-----------------------------------+-----------------------------------+
| Weigh after cutting foam          |                                   |
+-----------------------------------+-----------------------------------+
| ##### CGL+Glass Beads             |                                   |
+-----------------------------------+-----------------------------------+
| Weigh tube in fixture             |                                   |
+-----------------------------------+-----------------------------------+
| Weigh tube and fixture after CGL  |                                   |
| applied side 1                    |                                   |
+-----------------------------------+-----------------------------------+
| Weigh tube and fixture after CGL  |                                   |
| applied side 2                    |                                   |
+-----------------------------------+-----------------------------------+
| ##### Bond                        |                                   |
|  2^nd^ Faceplates and Hard Points |                                   |
+-----------------------------------+-----------------------------------+
| Weigh 2^nd^ faceplate with        |                                   |
| cyanate ester                     |                                   |
+-----------------------------------+-----------------------------------+
| Weigh hard points, spacers and    |                                   |
| washers                           |                                   |
+-----------------------------------+-----------------------------------+
| Weigh after heat cure             |                                   |
+-----------------------------------+-----------------------------------+
| Inspect for thickness             |                                   |
+-----------------------------------+-----------------------------------+
| Inspect for planarity             |                                   |
+-----------------------------------+-----------------------------------+
| Visual inspection after face cut  |                                   |
| mounting buttons                  |                                   |
+-----------------------------------+-----------------------------------+
| Final Assembly                    |                                   |
+-----------------------------------+-----------------------------------+
| Inspect after mounting targets    |                                   |
| and sealing foam                  |                                   |
+-----------------------------------+-----------------------------------+
| Weigh after final cleaning        |                                   |
+-----------------------------------+-----------------------------------+
| Survey targets/reference mounting |                                   |
| buttons                           |                                   |
+-----------------------------------+-----------------------------------+

# Appendix A: Carbon-Carbon Sheet Specification

![](media/image1.wmf){width="6.156944444444444in"
height="5.748611111111111in"}

# Appendix B - Reticulated Vitreous Carbon Foam Specification

# Appendix C - Aluminum Tube Specification

# Appendix D - Drawings of Aluminum-Tube Sector