We have a partial winner. My colleague Greg Elin has tracked down, on Recovery.gov, this announcement:
Obligated ~$47 million for EBSP equipment and ~$3 million for PSP equipment
That seems to correspond to this announcement from the 100 Days report:
2. Advanced Technology: Reveal Imaging Technologies of Massachusetts recently received a $47.5 million contract to develop, build, and install 123 reduced-size explosive-detection system units and their ancillary equipment at approximately 50 airports across the country, as part of the Electronic Baggage Screening Program.
Reveal Imaging has this release about the contract on their site:
U.S. Department of Homeland Security (DHS) Secretary Janet Napolitano announced today initial awards of $50 million in American Recovery and Reinvestment Act (ARRA) funds for explosive detection systems and advanced technology X-ray units that will streamline baggage screening and enhance security capabilities at airports nationwide. … DHS will purchase 123 reduced-size explosives detection systems from Reveal Imaging Technologies for approximately $47 million under an existing competitively awarded contract.