Key words: lasers, calibrations, laser measurements
OST continued to provide support to the laser field compliance program through consultations on optical radiation measurements, training of FDA Electro-Optics Specialists (EOS's), and calibration of radiation-measuring instruments maintained in the EOS kits. The activities of OST's laser calibration laboratory provide validity to the measurements made in compliance testing programs nationwide.
The OST Laser Calibration Laboratory maintains equipment for conducting high precision optical measurements. The laboratory measurement standard is a C-series calorimeter built by NIST. To assure the validity of measurements made by OST, periodic intercomparisons are conducted with NIST, and in-house quality assurance procedures are followed. As a continuation of work begun in FY 94, there were 55 optical radiation-measuring instruments calibrated in the OST laboratory. For each instrument calibrated, laser wavelengths and power levels were chosen to add to the historical data that has been maintained for the life of each instrument. This data was also used to confirm the stability of each instrument's response.
However, due to the advancing age of the instruments, the unavailability of replacement batteries, and the termination of repair support by the manufacturer, a set of amplifiers could not be calibrated and had to be removed from the EOS kits. It is anticipated that a power/energy meter will need to be removed from the EOS kits within the coming year for the same reasons. Also, a replacement for the oscilloscope currently maintained in the EOS kits is being evaluated in the OST laboratory.
In addtion, OST conducted a 2-day laboratory training session for the EOS's, reserve EOS's, and staff of the Office of Compliance (OC). During this training session, questions on the use of the instruments in the EOS kits were answered and measurement techniques were demonstrated. [Enf, Stds, PostMS]
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Key words: laser products, laser measurements, night vision aids
OST continued to assist OC in evaluating illuminators used with night vision equipment imported from the former Soviet Union. The testing was performed in order to determine whether the source of radiation in the equipment was an infrared light-emitting diode (LED) or a laser diode. Equipment containing a laser diode as the illuminator is subject to the Federal performance standard for laser products. OST evaluated 26 instruments in the laboratory. Measurements were performed with a spectroradiometer system to determine if each instrument incorporated a laser diode or a light-emitting diode. Those instruments incorporating laser diodes were found to have a spectral bandwidth of between 5 nm and 6 nm. Instruments with light-emitting diodes had a spectral bandwidth greater than 30 nm.
The majority of instruments were found to incorporate infrared LEDs as the source of illumination and are not therefore subject to the Federal performance standard for laser products. Five units were found to incorporate infrared laser diodes. OST testing showed that emissions from these units could pose an optical hazard if viewed directly. Calculations indicate that they all exceed Class I of the laser performance standard. FDA District Offices have been requested to detain further shipments of these products at the port of entry (Import Alert #95-02) until their compliance status with respect to the laser performance standard is documented.
In addition, OST continued to provide support to OC through the laboratory evaluation of the radiation output levels of laser products. The testing was performed in order to confirm the manufacturer's classification of the product. Products evaluated include a laser pointer, a mine-use alignment instrument, a truck tire alignment product, a diode-pumped frequency-doubled YAG laser, and two laser gun-sights. [Enf, PostMS]
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Key words: optical measurements, optical calibrations, sunlamps
The Electro-Optics Branch (EOB) Non-Coherent Calibration Laboratory in OST maintains equipment for conducting high precision optical measurements. The laboratory maintains spectroradiometer systems and optical measurement standards furnished by NIST. To assure the validity of measurements made by EOB, periodic intercomparisons are conducted with NIST, and in-house quality assurance procedures are followed.
OST continued to provide support to the sunlamp product compliance program through consultation on optical radiation measurements and an intercomparison with WEAC. WEAC conducts routine surveillance of replacement lamps used in suntanning facilities. Upon reviewing the intercomparison data, WEAC measurements at first did not agree with those of OST. Technical problems with the WEAC measurement system were identified and corrected by OST engineers, resulting in much better measurements agreement. [PostMS, Stds, Enf]
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Key words: microwave, oven
The microwave oven survey instrument calibration program has gradually seen less activity in the past few years. However, there is still a need for the program to provide calibration for the instruments used by OC and the FDA field offices. OST presently calibrates approximately 120 instruments per year for the field and for the OC inspectors.
The FDA-owned survey instruments range in age from 3 to more than 20 years
old. OST has been replacing one to four instruments per year, either with
new instruments or with units returned from the field. OST engineers repaired
10 instruments during the last calibration cycle. OST has also been supplying
the calibration standards for Holaday Industries. These calibrations are
performed in order to maintain a direct link to the instrument used by the
oven manufacturers, and thus for enforcement of the FDA Microwave Performance
Standard. [Enf]
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