Documents
Resources
Learning Center
Upload
Plans & pricing Sign in
Sign Out

SCT Barrel Thermal Enclosure_2_

VIEWS: 15 PAGES: 12

									SCT Barrel Thermal Enclosure
ATLAS Project Document No: Institute Document No. Created: 04/09/03 Modified: Page: 1 of 2 Rev. No.: Draft 2

ATL-IS-CS-0018

Supply of Thermal Enclosure for the ATLAS SCT Barrel Detector

Technical Specification

Abstract This specification details the technical requirements relating to the manufacture and supply of the Thermal Enclosure for the ATLAS SCT Barrel detector.

Prepared by: Anthony Jones (Tony) Peter Ford Stephen Haywood

Checked by: Andy Nichols ? Eric Perrin ? Debbie Greenfield ?

Approved by: Mike Tyndel ? Richard Nickerson ?

Distribution List The above, plus Steve McMahon

ATLAS Project Document No:

Page: 2 of 12 Rev. No.: Draft 1

ATL-IS-CS-0018 History of Changes
Rev. No. 1 2 Date 19/9/03 8/10/03 Pages Description of changes

Technical details supplied by Tony Jones. Creation of separate tender Form by Stephen Haywood.

ATLAS Project Document No:

Page: 3 of 12 Rev. No.: Draft 1

ATL-IS-CS-0018 Table of Contents
1

OVERVIEW............................................................................................................................................................................................... 4 1.1 The ATLAS Experiment ...................................................................................................................................................................... 4 1.2 The ATLAS Semiconductor Tracker ................................................................................................................................................... 4 1.3 The ATLAS SCT Barrel Thermal Enclosure ....................................................................................................................................... 4 1.4 RAL and CCLRC................................................................................................................................................................................. 4 2 Description of the Thermal Enclosure 4 2.1 Half Cylinders ...................................................................................................................................................................................... 5 2.2 Flat Side Panels.................................................................................................................................................................................... 5 2.3 Annular End Panels ............................................................................................................................................................................. 5 2.4 Inner Thermal Enclosure Cylinder ....................................................................................................................................................... 5 2.5 Bulkheads ............................................................................................................................................................................................ 5 2.6 Additions to Complete the Thermal Enclosure ....................................................................................................................................5 2.7 Test Sector Unit ................................................................................................................................................................................... 6 2.8 Operational Environment and Requirements ....................................................................................................................................... 6 2.8.1 Environment ................................................................................................................................................................................. 6 2.8.2 Requirements ............................................................................................................................................................................... 6

3 4

DRAWINGS ............................................................................................................................................................................................... 6 MATERIALS AND COMPONENTS ...................................................................................................................................................... 7 4.1 4.2 Suggested Sources of Materials ........................................................................................................................................................... 7 Customer Supplied Components .......................................................................................................................................................... 7

5 6

ALTERNATIVE BIDS .............................................................................................................................................................................. 7 METROLOGY AND TESTING .............................................................................................................................................................. 8 6.1 6.2 6.3 Metrology ............................................................................................................................................................................................ 8 Leak-testing for Panels ........................................................................................................................................................................ 8 Leak-testing for Assembled Thermal Enclosure ..................................................................................................................................8

7

PROGRAMME REQUIREMENTS ........................................................................................................................................................ 8 7.1 7.2 Schedule............................................................................................................................................................................................... 8 Documentation ..................................................................................................................................................................................... 8

8

PACKAGING AND SHIPPING ............................................................................................................................................................... 8

ATLAS Project Document No:

Page: 4 of 12 Rev. No.: Draft 1

ATL-IS-CS-0018

1
1.1

Overview
The ATLAS Experiment
The ATLAS Experiment is a very large and extremely complex particle physics detector which is being constructed at CERN in Geneva and is scheduled to start data-taking in 2007. ATLAS is a large international project involving many collaborators from institutes from around the world. ATLAS is a high energy particle physics experiment that is due to begin operation in 2006. The experiment consists of a number of separate detectors, one surrounding another. For a more details, refer to the ATLAS website at: http://atlas.web.cern.ch/ATLAS/Welcome.html

1.2

The ATLAS Semiconductor Tracker
At the heart of ATLAS is a very delicate silicon tracking detector – the Semiconductor Track (SCT). This will track charged particles with precisions of 10 m. The SCT consists of a cylindrical Barrel section (approximately 1.6 m long, with a radius of 0.55 m) and two End-caps.

1.3

The ATLAS SCT Barrel Thermal Enclosure
The silicon of the SCT is required to run at a temperature of –7oC in a dry N2 environment. For the SCT Barrel, this environment is maintained by the SCT Barrel Thermal Enclosure (TE). The Barrel SCT is surrounded by CO2, and the TE must ensure that there is no exchange of the two environmental gases. The TE consists of:  Two identical half cylinders,  Two identical flat side panels,  Two identical annular end panels,  One Inner Thermal Enclosure (ITE) cylinder.

1.4

RAL and CCLRC
The SCT Barrel TE is being designed and assembled at the Rutherford Appleton Laboratory (RAL), situated near Oxford, England. RAL is part of the Council of the Central Laboratory of the Research Councils (CCLRC), hereafter referred to as CLRC.

2

Description of the Thermal Enclosure
This section provides a simplified description of the components of the TE. The complete description is provided by the drawings – see Section 3.

ATLAS Project Document No:

Page: 5 of 12 Rev. No.: Draft 1

ATL-IS-CS-0018

Upper half cylinder

Flat side panels (2 off) 2 off Lower half cylinder Dummy bulkheads (2 off) ITE cylinder

Annular end panels (2 off)

2.1

Half Cylinders
Each half cylinder is constructed from five cylindrical panel sub-assemblies bonded together. Each panel has inner and outer walls of carbon fibre, separated by strips of Airex  foam, and is filled with dry carbon dioxide gas to improve thermal insulation characteristics.

2.2

Flat Side Panels
Each panel has inner and outer walls of carbon fibre with hollow carbon fibre inner rail sections at top and bottom edges and aluminium-alloy end-fixing brackets. The separation between the walls is filled with aerogel panels in evacuated mylar bags.

2.3

Annular End Panels
Each panel has inner and outer walls of carbon fibre, separated by strips of Airex  foam. The separation between the walls is filled with aerogel panels in evacuated mylar bags. Each outer wall contains six channels.

2.4

Inner Thermal Enclosure Cylinder
This is a carbon-fibre laminate cylinder. Didn‟t mention PEEK seals.

2.5

Bulkheads
The Outer TE cylinder will be connected to each annular end panel by a bulkhead which will electrical, optical-fibre and cooling services to leave the silicon tracking detector through the TE. For the trial assembly and leak-testing of the TE, CLRC will provide dummy bulkheads.

2.6

Additions to Complete the Thermal Enclosure
To give the TE its necessary functionality, it will have heater pads placed on the outer surface, and cooling circuits attached to the inner surface of the half cylinders. These will be attached to heat-

ATLAS Project Document No:

Page: 6 of 12 Rev. No.: Draft 1

ATL-IS-CS-0018

spreading foils which will act as a Faraday cage. The supply of these parts is not part of this tendering action. The heating/cooling power will be of the order of 300 W/m2.

2.7

Test Sector Unit
As a first step to verify the design of the TE, a Test Sector Unit (TSU) shall be manufactured. The TSU will consist of:  A representation of the cylindrical part of the TE, comprising two cylindrical panels, identical to those in the final TE, (one of which is narrower??)  Two side panels, identical to those in the final TE,  Two end panels which will be of a simpler design than those in the final TE.

2.8
2.8.1

Operational Environment and Requirements
Environment     Accesibility – once installed in the ATLAS Experiment, there will be very little chance for access. Radiation – materials are required to be radiation hard up to a fluence of 2  1015n/cm2 (1MeV neutrons) or 3  107 Gray, representing 10 years of operational life inside ATLAS. Activation – materials should not become significantly activated as a result of the irradiation. Magnetic field – the SCT will sit in a 2 T magnetic field, therefore magnetic materials should be avoided wherever possible. Internal temperature – 7oC. External temperature – +20oC. Pressure – tolerate internal pressures up to 4 mbar above local atmospheric pressure. Leak rate – must be less than 6 l/mbar/hour. Mass – should have a minimal mass (actually what is required is a minimum number of radiation lengths). Envelope – the space between the silicon tracking detector and the inside of the TE, and surrounding detectors and the outside of the TE is critical. Therefore it is essential that the tolerances specified on drawing are achieved. CTE – must be low to ensure TE remains within envelopes and avoid stresses.

2.8.2

Requirements      



3

Drawings
The design of the ATLAS SCT Barrel TE is detailed in the following drawings: correct titles? TD-1020-164 General Assembly TD-1020-120 Half Cylinders TD-1020-400 Flat Side Panels TD-1020-267 Annular End Panels TD-1020-270 ITE Cylinder TD-1034-170 Assembly of Test Sector Unit

Propose not to deliver anything other than printed or HPGL drawings – do not supply models.

ATLAS Project Document No:

Page: 7 of 12 Rev. No.: Draft 1

ATL-IS-CS-0018

4
4.1

Materials and Components
Suggested Sources of Materials
The CFRP material specified on the drawings type T300/CX-920-820-47.5% is manufactured in the UK by Hexcel Composites. It has been chosen because of its:  Stiffness – 105 Gpa perpendicular to weave direction.  Radiation resitance – <5% reduction in ngth after 2  105 Gy.  Low CTE – 5  106 K1. For further information on this material and the processing procedures etc., contact the supplier. The UK contact address is: Hexcel Composites, Duxford, Cambridge, CB2 4QD, UK Tel. No +44 (0)1223 833 141 Web site http://hexcelcomposites.com What about comment on “advice for obtaining min CTE and optimal layering configuation” ? The epoxy adhesive specified on the drawings type Araldite 2011 (AW106/HV953U), 100/80 pbw, is supplied in the UK by Vantico Ltd. For further information on this material and the processing procedures etc. contact the supplier. The UK contact address is: Vantico Ltd., Duxford, Cambridge, CB2 4QA, UK Tel. No +44 (0)1223 493 000 Web site http://www.adhesives.vantico.com What about Airex  ??

4.2

Customer Supplied Components
  Aerogel in evacuated mylar bags. Dummy bulkheads.

5

Alternative Bids
In addition to Conforming Bids, CLRC welcomes Alternative Bids which provide improvements with respect to cost, production schedule, manufacturing processes or performance. It is necessary that any alternative designs should satisfy the requirements set out in Section 2.8. Any proposal for the use of alternative materials must provide evidence that they are as least as good as those proposed by CLRC.

ATLAS Project Document No:

Page: 8 of 12 Rev. No.: Draft 1

ATL-IS-CS-0018

6
6.1

Metrology and Testing
Metrology
Before or after leak-testing ? What is required to be measured ?

6.2

Leak-testing for Panels
Each cylindrical panel (including those in the Test Sector Unit) shall be leak-tested. Requirements ?

6.3

Leak-testing for Assembled Thermal Enclosure
The fully assembled carbon-fibre TE, with the inclusion of the dummy bulkheads will be assembled by CLRC at RAL and leak-tested at RAL. Representatives from the manufacturers may attnd the tests. Requirements ?

7
7.1

Programme Requirements
Verification of Test Sector Unit
The purpose of the

7.2 7.3

Schedule Documentation
Materils certificants of conformability Fortinghtly reports, measuring progress with respect to milestones, highlighting difficulties

7.4

Notifiable events ?
Attend metrolgy

8

Packaging and Shipping
Address for delivery

9

Contacts
Futher information and clarification of the requirements in this document can be obtained from the RAL project team: Mr. A. Jones Tel. No (44) 01235 446331 Fax. No (44) 01235 446863 E-mail A.Jones@rl.ac.uk Mr. A. Nichols Tel. No (44) 01235 445251 Fax. No (44) 01235 446863 E-mail A.Nichols@rl.ac.uk Mr. P. Ford

ATLAS Project Document No:

Page: 9 of 12 Rev. No.: Draft 1

ATL-IS-CS-0018
Tel. No (44) 01235 445626 Fax. No (44) 01235 446863 E-mail P.Ford@rl.ac.uk

10

Appendix: Additional Questions for All Bidders
Brief answers to the following questions will enable the RAL to make a fully informed overall judgement of the quotation. Important note : All information given will be treated in strict confidence between the tenderer and the RAL and will not be given to any other person or organisation. Questions specific to the current design. Have you had previous experience of producing components with thin CFRP skins ?. Do you anticipate having any serious problems producing these particular thin CRFP skin components ?. Are distortions beyond the dimensional and geometrical tolerances likely to be present when the thin CFRP skins are released from the moulding tools ?. Do you expect further distortions to occur as a consequence of component to component bonding ?. Are you confident that you can achieve the required dimensional and geometrical tolerances stated on the drawings and thus achieve the envelope requirements as specified in section 2.3 ?. What are the best dimensional and geometrical tolerances that you would consider to be achievable for this demanding requirement ?. Do you have or have ready access to specialised technical expertise in producing components of this nature including the CTE and modulus issues referred to in section 2.10 of this document ?. Have you identified any seriously risky areas in the current design ?. Do you consider that alternative features would guarantee a more satisfactory result ?. Have you had previous experience regarding the selective metalisation of CFRP components for electrical conductivity purposes ?. Can you obtain sub-contract specialised selective metalisation services of a guaranteed high quality ?. The maximum working temperature for the barrier film of the vacuum insulated silica aerogel panels fitted inside the side panels shown in Fig 3. and the OTE annular shaped end panels shown in Fig 4. together with the Test Sector Unit end panels shown in Fig 8 is 120 o C. Do you anticipate any processing problems implementing this requirement ?. Questions related to the facilities that are offered by the tenderer. In such a case it is necessary to inform the RAL at the tendering stage of any sub-contracting intentions, and to provide information regarding the sub-contractors QA/ISO accreditation and a statement of how the tenderer intends to monitor the progress of sub-contracted work and provide the required metrology reports etc.. (from previou sect 3.1) Where is your proposed CFRP structure manufacturing plant located ?. Does the manufacturing plant have in-house CNC facilities capable of producing the tooling required for this work in one machine setting ?. Does the CNC facility have full CAD/CAM capability ?. Do you intend to use the solid models for CAD/CAM machining ?. Do you intend to sub-contract the CNC machining of the tooling ?. (See also note 3.1 above). If yes will you identify the sub-contractor ?. Is the sub-contracting company ISO or similarly accredited and are their metrology instruments regularly calibrated etc. ?. What formal arrangements will you make with them to closely monitor the progress and the accuracy of their work and do they operate within an accredited QA system ?.

ATLAS Project Document No:

Page: 10 of 12 Rev. No.: Draft 1

ATL-IS-CS-0018

Do you intend to sub-contract the machining of any of the non CFRP component parts ?. (see also note 3.1 above). Also the same identification, ISO, progress, accuracy and QA questions apply to this subcontractor. Does your proposed CFRP manufacturing plant have in-house metrology, inspection, trial assembly and low pressure leak testing facilities suitable for this work ?. Does your proposed manufacturing plant have ISO or similar accreditation and are your metrology instruments regularly calibrated ?. Does you proposed manufacturing plant operate within an accredited QA system ?. Do you anticipate any delays in procurement of the materials required and also will there be any storage / storage timescale problems ?. Do you have a back-up supplier ?.

11

Appendix B: Alignment, envelope size verification, and low pressure testing jig
The jig will be supplied by the RAL, and is shown schematically below. The floor level footprint size of the jig will be 1.4 metres wide x 1.7 metres long (approximately). The schematic diagram is not to scale and is only intended to show the basic principles. Two accurately located stiff side plates of the jig will have dummy bearings attached and will be used to accurately locate the flat side panels of the Thermal Enclosure and establish the geometrical accuracy of the composite structure. The dummy bearings will have „o‟ ring type seals fitted inside the Thermal Enclosure. The seals will take a „D‟ shape over the bearings and be retained in position by simple flanges. The upper and lower half cylinders will be held in aligned positions as shown by a simple jacking screw arrangement. This arrangement will allow representatives of the RAL to position the longitudinal seals along the joints between the upper and lower half cylinders and the flat side panels. The schematic diagram below shows stage 1 of the trial assembly, envelope size verification and low pressure testing process.

The schematic diagram below shows the attachment of the upper and lower half cylinders at stage 2 of the process, after which the jacking screw arrangement will be removed.

ATLAS Project Document No:

Page: 11 of 12 Rev. No.: Draft 1

ATL-IS-CS-0018

The schematic diagram below shows the attachment of the dummy bulkheads (which will be supplied by the RAL) complete with the dummy bulkhead to composite structure seals in place. The schematic shows that the jacking screws have been removed for the fitting of the dummy bulkhead.

The schematic digram below shows the insertion (from the far side of the diagram) of the inner thermal enclosure ( ITE ) attached two one of the annular end panels, complete with the required seals. The annular end panel is fixed to the far side dummy bulkhead and the near side end of the inner thermal enclosure is temporarily supported whilst the near side annular end panel complete with seals is fitted.

The schematic diagram below shows that the near side annular end plate has been fitted and that the composite structure is now in its fully assembled state. The alignment envelope verification can now be done using an accurately machined template which locates on both side plates of the jig and can be traversed along the length of the upper and lower half cylinders of the Thermal Enclosure.

ATLAS Project Document No:

Page: 12 of 12 Rev. No.: Draft 1

ATL-IS-CS-0018
Low pressure leak testing of the complete Thermal Enclosure can now be done.

12

Appendix C: Low pressure leak testing set-ups.
The low pressure leak testing requirements of the initial Thermal Enclosure Test Sector Unit, only requires the testing of the separation volume between the walls of the representative cylindrical region. This test at a low pressure of 10 mbar above atmospheric pressure should preferably be done using dry nitrogen gas. The test set-up for this will only require flexible rubber tubing and a simple water manometer to measure the pressure. The dry nitrogen gas inside the separation volume will need to be isolated from the gas supply so that any leak rate present can be established. Initial leak finding will only require a simple soap bubble or similar test method. The same routine will be followed for the leak testing requirements of the components for the final SCT Barrel Thermal Enclosure. This includes the low pressure leak testing of the separation volume between the walls of the upper and lower half cylinders, and the low pressure leak testing of the complete Thermal Enclosure assembly.


								
To top