NASA/George C. Marshall Space Flight Center, Procurement Office, Marshall Space Flight Center, AL 35812

B -- STUDIES OF AVALANCHE PHOTODIODES (APDS) AS READOUT DEVICES FOR SCINTILLATING FIBERS FOR HIGH ENERGY GAMMA-RAY ASTRONOMY TELESCOPES" SOL 8-W-7-ES-13672 POC Chrissa K. Hall, Contracting Officer, Phone (205) 544-5468, Fax (205) 544-9080, Email chrissa.hall@msfc.nasa.gov -- Michael R. Sosebee, Contracting Officer, Phone (205) 544-0415, Fax (205) 544-9080, Email mike.sosebee@msfc.nasa.gov WEB: Click here for the latest information about this notice, http://procurement.nasa.gov/EPS/MSFC/date.html#8-W-7-ES-13672. E-MAIL: Chrissa K. Hall, chrissa.hall@msfc.nasa.gov. THIS NOTICE CONSTITUTES AMENDMENT NO. 1 TO THE COMBINED SYNOPSIS/RFQ FOR Studies of Avalanche Photodiodes (APDs). Companies shall acknowledge all amendment(s) in their quote. This notice serves as the official amendment to subject synopsis/RFQ and a written amendment will not be issued. The purpose of this amendment is to delete the specifications under Task 1 and replace as follows: Task 1. Determine the feasibility and operating characteristics of arrays of APDs used in the Geiger mode for the readout of scintillation pulses from plastic fibers with these characteristics: Fiber diameter: ~250-500 micro-meters Signal level: 10-20 photons/pulse Signal pulse width (input): ~20 nano-seconds Recovery/shaping (output): <~ 1 micro-seconds Wavelength: ~450-650 nano-meters Signal event rate: <~100 counts per seconds The due date for receipt of offers is extended to December 11, 1997. Companies shall provide the information stated in the synopsis/RFQ posted on the NASA Acquisition Internet Service (NAIS)on November 7, 1997. The WWW address or URL of the NASA/MSFC Business Opportunities home page is http://procurement.nasa.gov/EPS/MSFC/class.html. (0328)

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