Monitored Drift Tube _MDT_ Chamber Production

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					Monitored Drift Tube (MDT) Chamber Production
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Michigan is nearing completion of 80 MDT chambers Comprising 31000 drift tubes. Highlights: 1998-1999 Set up production facilities MDT Drift Tube
July 2000 Build “Module 0” prototype chamber Oct 2000 Begin normal MDT production July 15, 2003 Complete drift tube production! Sept 15, 2003 Complete series chamber production (projected) Oct 2003 – Begin chamber integration (electronics installation & final checkout) July 2004 – Begin Big Wheel Sector installation Oct 2006 – ATLAS detector commisioning

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Apr 2007 – First LHC beam run Edward Diehl University of Michigan DOE Site Review

July 21, 2003

MDT Production
Tube Construction Rates very stable over time!
Chamber Construction

Edward Diehl

University of Michigan DOE Site Review

July 21, 2003

Tube Production Facilities
Tube wiring table
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Adjustable for tube length High precision setup to meet strict mechanical tolerances

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Computer controlled with data written to production DB

Edward Diehl

University of Michigan DOE Site Review

July 21, 2003

Tube Quality Control
Tubes undergo several strict quality tests: 1) Wire Tension (350 ± 15 g) 2) Tube length (± 100 m) 3) Tube leak rate (< 10-8 bar-liter/sec) 4) Wire position (< 25 m) 5) Dark current under HV (< 2 nA/m @ 3400V) 6) Wire tension re-check after 10 days

Tubes data are tracked by bar code and stored in an extensive DB (with convenient web interface)
Edward Diehl University of Michigan DOE Site Review July 21, 2003

Tube Quality Data

Arrows show QA limits

Edward Diehl

University of Michigan DOE Site Review

July 21, 2003

Tube Failure Rates

Edward Diehl

University of Michigan DOE Site Review

July 21, 2003

Chamber Production
Chamber gluing is done with precision tooling mounted on a granite table

After gluing a tube layer a lifting frame is lowered to pick up the tube layer

Edward Diehl

University of Michigan DOE Site Review

July 21, 2003

Chamber Quality Control
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Chamber quality (mechanical precision) is ensured in several ways:
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Tooling alignment on granite is checked by both stretched wire and laser techniques before construction begins. Each tube layer is checked during gluing with the Optical Position System (OPS) [CCD camera viewing coded mask on chamber lifting frame] - accurate to 1 um. Check wire positions in CERN 3D x-ray tomograph – 6 UM chambers measured, all meet specs (wire position known to 25 m)

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Example of laser measurement of comb lateral alignment for current chamber (EML5)

Edward Diehl

University of Michigan DOE Site Review

July 21, 2003

Chamber QA - OPS Data

OPS cameras looking at coded mask (not visible) in lifting frame

Edward Diehl

University of Michigan DOE Site Review

July 21, 2003

Chamber Integration
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Initially only “base” chambers were constructed – i.e. no services installed As additional parts became available these were added to the chamber production cycle (without slowing production):
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Sept 2001 gas system Jan 2002 temperature sensors & survey targets Feb 2003 HV hedgehog cards & alignment system cabling July 2003 Signal hedgehog cards

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Michigan typically led the collaboration in services installation & consequently developed many of the installation techniques and discovered problems; e.g.
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Gas system: developed leak testing techniques and discovered (and fixed) problem with gas tubelets. Signal hedgehogs: found problems with bent connectors.

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Starting October 2003 we will start chamber integration – install all chamber services and certify chambersDOE Site Review July 21, 2003 Edward Diehl University of Michigan for installation - Zhenguo Zhao

Summary
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Michigan will shortly finish constructing 80 MDT chamber for ATLAS on time and on budget (in fact, somewhat ahead on both counts). Both individual MDT tubes and MDT chambers meet or exceed the strict ATLAS quality specifications. Following chamber construction we will immediately embark on the task of chamber integration: 14 chambers to be done at Michigan in Fall 2003 and rest at CERN in 2004. Michigan will keep its tube and chamber building facillities intact for 1 more year to permit building 25 EEL chambers starting mid-2004 if money is available. We anticipate no difficulties to produce these chambers.

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Edward Diehl

University of Michigan DOE Site Review

July 21, 2003


				
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