From: Marsh, Darren S. [marsh@SLAC.Stanford.EDU]

Sent: Wednesday, September 18, 2002 8:16 AM

To: Nick Virmani (E-mail); Borden, Thomas; Robert Johnson (E-mail);

Nordby, Martin E.; Klaisner, Lowell; Hartmut Sadrozinski (E-mail);

Alessandro Brez (E-mail)

Cc: Martin, Jim; Marcellini, Bob

Subject: Summary of Tracker Ladder Production Readiness Review


A Tracker Ladder Production Readiness Production Readiness Review (PRR) was held on September 16, 2002.  The purpose of the of PRR was to show that the Tracker Ladder production will meet the final performance and interface specification and the required design specification.


The following individuals were participants in the PRR.


Richard Horn, Systems Engineering - Committee Chair

Lowell Klaisner, Chief Engineer - Committee Member

Martin Nordby, Chief Mechanical Engineer - Committee Member

Nick Virmani, Mission Assurance - Committee Member

Harmut Sadrozinski, Tracker Scientist - Committee Member

Darren Marsh,  Mission Assurance - Committee Member


Robert Johnson, Tracker Subsystem Manager

Tom Borden, Tracker System Engineer

Alessandro Brez - INFN Development Engineer, Production Supervisor


Completion of the PRR and resolution of all resulting action items constitutes readiness for production.


The Tracker Ladder Production Readiness Review is for product manufactured at G&A Engineering located in Oricola, Italy.  A total of 1850 Tracker Ladders will be manufactured at G&A through January 2004.  An additional 850 Ladders will be manufactured at Mipot S.P.A. in Cormons, Italy through December 2003.  Manufacturing activities at Mipot will be subject to a separate PRR upon completion of pre-production activities there.  Fabrication activities at both subcontractors is under the direction of Alessandro Brez from INFN.


PRR presentation material and links for all relevant documentation and subcontractor information can be obtained at:


In preparation for the PRR, a Pre-PRR was held to review and discuss specific details relating to materials, critical operations and parameters and specific quality documentation for the ladders.  The action items resulting from the meeting are attached and label "Appendix A".  In addition, comments from Nick Virmani on LAT-PS-635 (8/13/02 draft), Tracker SSD Ladder Assembly Procedure, along with the Tracker responses to the comments are attached and label, "Appendix B". 


A Mechanical Parts Review Board Meeting was held on September 9, 2002 to accept materials utilized in ladder production.  The meeting minutes from the Mechanical Parts Review Board Meeting will be archived in the LAT Document Control System once they have been completed.


The following action items were generated from the Ladder PRR.


1.  LAT-DS-594, Ladder Assembly Drawing, needs to be revised in accordance with an existing action item to change the ladder overall length tolerance requirement.


2.  Robert Johnson will contact Nick Virmani and discuss the Tracker's responses to Nick's comments on the Ladder Assembly Procedure and obtain Nick's concurrence on the responses.


3.  The committee recommended the continued refinement and clarification of the Ladder Assembly Procedure to include details presently delineated in the internal G&A production traveler and to incorporate any agreed upon actions from previous ladder production review discussions.


4.  All "TBR's" are to be resolved.  The "TBR's" include:  1) determination of the number of ladders that may be wire bonded before electrical testing begins, 1) determination of "major nonconformance" definition to ensure a halt in production and prompt notification to Alessandro Brez, 3) review pull test data information and determine if mean value information should be added to ladder database.


5.  G&A is in the process of building 10 ladders to qualify the encapsulation process with encapsulation materials that are NASA flight approved.  A post-production review of these 10 ladders will take place at the G&A facility by Alessandro Brez, Tom Borden and Darren Marsh to evaluate the results of the encapsulation process and review process documentation.  Darren Marsh will also follow-up the supplier survey performed November 2001 to ensure quality procedure controls (equipment calibration, employee training and qualification, etc.) employed by G&A are adequate and complied with.   


A subset of the PRR committee will reconvene upon completion of the aforementioned actions to review production readiness status for flight quality ladders.



Darren S. Marsh

GLAST Large Area Telescope Project

Stanford Linear Accelerator Center

2575 Sand Hill Road, M/S 43A

Menlo Park, CA 94025

(650) 926-4577