Following the installation of the flight build detectors in late
2000, a series of calibration activities were conducted at GSFC
in the Space Systems Development and Integration Facility
(SSDIF) in ambient environment from Mar-Aug 2001 (see the GSFC :
Mar-Aug 2001 calibration plan for details). The light stimulus
was delivered by the Calibration Delivery System (CDS) through
the Reflective Aberrated Simulator for Calibration (RAS/Cal).
ACS and RAS/Cal were covered with lumalloy and Kapton blankets
to minimize stray light from the clean room ceiling lights. Some
activities did not require RAS/Cal - the configuration of the
external stimulus was then tailored specifically for these
items. A diagram of the CDS is shown in Fig. 1. It directly
feeds RAS/Cal, located at the ACS aperture, through a series of
five flat and concave mirrors. The focal length of the first
concave mirror in the light path is ~1/4 m and of the second,
~1/8 m. ACS is in diamond configuration in the Thermal Balance
Fixture (TBF). A choice o