Spectrometer_PWS.pdf

Performance Work Statement Spectrometer for Air Force Institute of Technology

(a) PURPOSE AND BACKGROUND: The Air Force Institute of Technology, Department of Systems and Engineering Management (AFIT/ENV) will be performing research on light emitting diodes (LEDs) in the ultraviolet (UV) range.

This research requires measurements to be taken with a light measurement system (spectrometer) at small wavelength increments. This spectrometer system uses an integrating sphere coated with a highly reflective material to measure light from an LED and is calibrated using a deuterium lamp mounted directly to the sphere to provide NIST traceability. The UV source, which is an LED, mounts into the sphere. The spectrometer is connected to the sphere using a fiber optic bundle to permit UV energy to be measured in air and in water. This system must also include a second sphere that can be submerged in water and attached to a deuterium lamp with a fiber optic bundle to measure LED output when submerged in water.

(b) The spectrometer system must include the following characteristics and components:

(1) Capable of measuring total radiant flux (W) and spectral flux (W/nm) of light emitting diodes (LEDs) over the wavelength range of 210nm to 400nm.

(2) The system must accommodate LEDs with an optical flux of 10µW to 200 mW. The spectrum of the LEDs will be Gaussian with a full width half maximum (FWHM) value of 10nm at 220nm to 300 nm.

(3) The system must permit measurement of UV energy emissions from LEDs in air or immersed in water. At least the in-air measurements must be traceable to National Institute of Standards and Technology (NIST) standards. Further, standards and measurement tools must be provided to permit traceability to NIST standards to be established for in-water measurements. This may, for example be provided through the use of two integrating spheres with appropriate calibration sources.

(4) One or more NIST traceable deuterium lamps must be provided with power supply to permit calibration of UV light.

(5) Spheres must be lined with Spectralon or other material which will reflect UV energy between 210nm and 400nm with greater than 98% efficiency.

(6) At least the in air measurement system (sphere) must be equipped with a chiller having an LED socket which permits the temperature of the LED to be controlled while it emits UV energy to be measured. The chiller device must control LED temperature within a 30-100 degree Celsius range.

(7) Spheres must include a calibration port through with the deuterium lamp may be directly mounted for calibration.

(8) Each sphere must include a detector port with SMA adapter as well as appropriate baffling.

(9) System must include a socket (including anode, cathode and case lead) for LED installation.

(10) Chiller must include a controller to allow manual adjustment of the temperature.

(11) Spectrometer must include a cooled-back thinned spectrometer with angle designed for measurements.

(12) Spectrometer must include correction for stray light.

(13) Spectrometer must be connected to sphere using a solarization-resistant fiber.

(14) Spectrometer must include shutter assembly that is internal or at the entrance to enable use under water.

(15) System must include software for calibration and measurements that is compatible with the calibration lamps and will allow stray light correction.

(c) The system must be provided to AFIT/ENV within eight (8) weeks of contract award.