GLAST LAT ACD: Outline of GLAST LAT ACD Photomultiplier Review

Outline of GLAST LAT ACD Photomultiplier Review

PURPOSE

The GLAST/LAT Project will be ready for Critical Design Review (CDR) in April 2003. The ACD subsystem will be ready for CDR at an earlier date, in summer/fall 2002, but needs to initiate a long-lead procurement of PMTs, valued at about $350K, in June 2002. The purpose of this review is to minimize the risks associated with committing to this purchase before the ACD is fully ready for CDR, ie, all designs and documentation are "frozen."

Note that the ACD subsystem went through a thorough joint DOE/NASA Preliminary Design Review in January 2002 (with internal pre-review in July 2001 and SLAC internal review in April 2002).

REVIEW CHARGE

The review committee should answer the following questions:

1. Has the ACD subsystem team addressed all the issues involving the PMT purchase, for example: are all relevant PMT parameters identified and appropriately specified; are mechanical and electrical interfaces to the PMT well-defined, documented and release to configuration management; are the electronics designed to handle specified variations in PMT characteristics?

2. Is the PMT specification complete (including both technical performance and quality assurance provisions)? Are the specified values appropriate and realistic?

3. Are there any other issues or questions related to this procurement which should be addressed by ACD subsystem management or LAT Project management?

Introduction

Overview of the ACD Design

Some trade and performance studies

Technical Discussion

Selection of a Photomultiplier Tube

Specifications/Characteristics/Testing

Specifications for ACD Photomultiplier Tubes

Drawing of ACD Photomultiplier Tube

Documentation for Qualification Photomultiplier Tubes

Temperature Characteristics of ACD Photomultiplier Tubes

Helium Sensitivity of ACD Photomultiplier Tubes

Magnetic Shielding for ACD Photomultiplier Tubes

Photos of ACD Photomultiplier Tubes

Assembly Procedure

Acceptance/Performance Verification Testing of ACD Photomultiplier Tubes Last Updated: May 20, 2004