The Interaction Point, September 2, 2005

September 2, 2005

GLAST Milestone: ACD Subsystem Delivered to SLAC

Team members from NASA’s Goddard Space Flight Center (GSFC) successfully delivered the ACD with the help of LAT I&T team members (pictured left to right).
Back row: Larry Wai (EK), Tom Nieland (REG), Tom Borden (REG), Steve Harper (GSFC), Al Lacks (GSFC), Name Unknown (Truck Driver), Jim Anderson (GSFC), Charles Coltharp (GSFC), Mike Lenz (GSFC), Richard Vermillion (GSFC), Dave Engesser (CEF) and Steve West (GSFC).
Front row: Paul Haney (GSFC), Tom Johnson (GSFC), Percy Clay (CEF), Name Unknown (Truck Driver), David Kiehl (REG), Ken Segal (GSFC) and Dick Horn (GSFC).
(Image courtesy of Sandy Pierson)

The Anti-Coincidence Detector Subsystem wrapped in protective foil.
(Photos by Tom Nieland)

By Elliott Bloom and Tom Borden

A significant milestone for the GLAST project took place in mid-August. The Anti-Coincidence Detector Subsystem (ACD) of the LAT was delivered to SLAC and installed in Bldg. 33. The activities started Saturday about 9:00 a.m. with the off loading from the truck and finished with the ACD in the clean tent. As of about 4:00 p.m. on Saturday, the ACD was secured in the clean tent that was designed for it. Checkout of the ACD began on Sunday morning and continued for a few days before final handoff to the LAT systems engineering and Integration and Test teams. The people responsible for this part of the project were here from NASA-Goddard throughout the week. All went well. It was an exciting day for everyone involved. For more information, see:
http://www-glast.stanford.edu

The Anti-Coincidence Detector is the first line of defense against the enormous charged particle background from cosmic ray primary and Earth albedo secondary electrons and nuclei. It consists of segmented plastic scintillator tiles, read out by wave-shifting fibers and photo-multiplier tubes. The segmentation is designed to avoid the self-veto problem of EGRET at high energies while still providing high cosmic-ray rejection.