National Institute of Standards and Technology, Acquisition and Assistance Division, Building 301, Room B117, Gaithersburg, MD 20899

66 -- BUILD PHOTOMETRIC FLUX INTEGRATING SPHERE SOL 52SBNB6C9226 DUE 091696 POC Linda Shariati (301) 975-5053 The National Institute of Standards and Technology (NIST) intends to build a photometric flux integrating sphere. The Contractor shall be responsible for the mechanical design, optical design and fabrication of an integrating sphere, lamp mounting hardware and support assembly. The sphere will be used in the photometric calibration facility at NIST to calibrate lamps of various kinds in the UV and visible region. When the fabrication is complete, the integrating sphere shall perform as follows: The diffuse reflectance of the actual sphere coating are measured to be higher than 95% in the 250 to 1100 nm region and the variation of the reflectance in the 380 nm to 830 nm region are measured to be less than 1.0 percent (plus or minus 0.5 percent from the average). The coating does not exhibit fluorescence by UV radiation; The reflectance characteristics and the surface condition of the coating do not change after washing or sweeping the surface; If segmented interior coating are used, each segment shall be curved so that the entire inner surface is spherical, and the gaps of the front surfaces between tiles are less than 3 mm wide and less than 3 mm deep; All the ports, lamp holders and baffles are installed within plus or minus 1 cm from the specified positions; The lamp holders and sockets can be exchanged with no need of additional change of wire connections; All the screw base sockets are of 4-contact type, and an incandescent standard lamp is mounted and operated on the socket repeatedly, reproducing the lamp voltage to within 0.05 percent on the constant current operation; The photometric signal for a standard incandescent lamp (and for an auxiliary lamp) for repeated opening and closing of the sphere repeats within 0.05 percent; and When the sphere is closed, the difference of the photometric signals with the normal room lights on and off, with no lamp in the sphere turned on, should be less than 0.02 percent of the photometric signal for a 40 W incandescent standard lamp. A sketch of a possible configuration will be provided in the RFP. This should not be considered the only configuration since the Contractor shall be responsible for the photometric flux integrating sphere meeting the performance requirements listed above. Specifications include, but are not limited to: the sphere shall be 2.5 meters diameter and the entire structure shall fit within the height of the Photometry laboratory. Offerors will be furnished with a copy of the room drawing. The coating material shall be sufficiently hard to facilitate washing and sweeping of the surfaces, and have near Lambertian diffuse-reflection characteristics. The hemispherical reflectance of the interior coating material shall be no less than 95 percent in the 250 nm to 1100 nm region, and the variation of the reflectance in the 380 nm to 830 nm region shall be less than 1.0 percent (plus or minus 0.5 percent from the average). The coating shall not exhibit any fluorescence and not be degraded by age or by UV radiation. There shall be five ports on the sphere wall on the equator, and two ports at 45 degrees upwards and downwards from Port 1. All the ports except Port 5 shall be the same design equipped with a lid which covers the opening with the same material as used in the sphere wall and keeps light tight when the port is not used. On Port 2, an auxiliary lamp (supplied by NIST) and a small baffle shall be mounted on the lid. Port 5 shall be located at 45 degrees horizontal way from Port 1, and shall have a 10 cm diameter, and equipped with a similar flange and a lid which shall keep the sphere light tight when the port is not used. The inner surface of the lids shall be flush to the sphere coating surface, and gaps around the lid surface shall be less than 1 mm. Baffle 1 shall be supported by a pipe stretching from the sphere wall, and the location can be adjusted from 10 cm to 75 cm from the Port 1. Near the baffled surface, a temperature probe (supplied by NIST) shall be installed and its wires shall be carried inside the pipe. Baffle 2 shall be supported in a similar manner at 20-25 cm from the Port 5, and is easily removable. A lamp holder shall be mounted on top or from the bottom of the sphere, interchangeably. The lamp holder consists of a support rod and interchangeable lamp sockets equipped with an internal 4-pin electric connector. The lamp holder shall be rated for maximum weight of 5 kg. The lamp sockets for screw bases shall be rated for maximum current of 15 A and maximum voltage of 300V DC. The Contractor shall design the sphere in such a manner that the joints between the two halves remain light tight with repeated opening and closing of the sphere. The repeatability of the photometric signal for repeated opening and closing shall be within 0.05 percent. If segmented interior coatings are used, the Contractor shall design the tiles in such a manner as to minimize optical effects from the joints between the tiles. The tiles shall have interlocking construction so that any gaps still reflect light effectively. The gaps of the front surfaces between tiles are expected to be less than 3 mm wide and less than 3 mm deep. The Contractor shall provide lamp mounting facility within the sphere for operating incandescent lamps with screw bases and four-foot linear fluorescent lamps. The lamp mounting apparatus shall be designed in such a manner as to minimize its effect on the optical properties of the sphere. The Contractor shall provide key personnel for this acquisition. The Government requires one engineer with a degree in physics or engineering and at least five years of experience in the development of photometric integrating spheres and one chemist or chemical engineer having at least five years of experience in coating materials. Offerors will be required to submit a typical sample of the interior coating material with their proposal. Those offerors within the competitive range may be contacted for a site review of the Contractor's facility. The period of performance shall be a maximum of 5 months total. The initial meeting will take place within 14 days after the contract is signed. The final design review shall take place within 30 days of the initial meeting. Most of the fabrication will occur at the Contractor's facility and final assembly will occur at NIST. The photometric flux integrating sphere shall be delivered 150 days from contract award. The Request for Proposals (RFP) will be available approximately fifteen days after publication of this announcement and responses will be due approximately thirty days after issuance. All responsible sources may submit a proposal which will be considered by the agency. All requests for the RFP must be in writing to the above mentioned address. See Numbered Note 26. (0212)

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