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| Division 844 > Division 844 Facilities > Spectrophotometry > Spectrophotometry Services | ||||||||
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Measurement services are available for dissemination of the scales of reflectance and transmittance maintained by the reference instruments. The primary purpose is to provide traceability to the scales, not for research on particular test items. These services are available as either calibrations or standard reference materials. In general, for a calibration service the customer supplies the test item, which is measured under the spectral and geometrical conditions specified by the customer. Standard reference materials are available for immediate purchase, and are calibrated under specific spectral and geometrical conditions. Calibrations Current fees can be found in the NIST Calibration Services User Guide Fee Schedule Optical Properties of Materials Measurements. Information on uncertainty, traceability, and other NIST Calibration Services can be found on the NIST Calibration Serivces web pages. For Special Tests, prices start at $2,100. The pricing is based on actual costs, based on labor and time, the number of test items, and the number of data points. For actual pricing, contact the NIST staff listed below. The uncertainties reported here follow, to the extent possible, the ISO Guide to the Expression of Uncertainty in Measurement (International Organization for Standardization, Geneva, Switzerland, 1993). Since 1994, the NIST policy has been to conform to the Guide in reporting its activities, using an expanded uncertainty coverage factor (as defined in the Guide) of k = 2. See Guidelines for Evaluating and Expressing the Uncertainty of NIST Measurement Results for a detailed explanation of the NIST policy. Unless otherwise noted all uncertainties will be stated as k = 2. Descriptions of each calibration service ID number are provided below. Spectral Transmittance Filters (38010C-38040C) Standards of spectral transmittance for checking the photometric scale of spectrophotometers are either 30 mm polished glass disks or 51 mm polished glass squares, 2 mm to 3 mm thick, designated as cobalt blue (38010C), copper green (38020C), carbon yellow (38030C), and selenium orange (38040C). The relative expanded uncertainty ranges from approximately 0.2 % to 0.3 % of the value. Information provided to the user includes values of transmittance at 25 °C at 10 nm intervals from 380 nm to 770 nm, the estimated uncertainty of each value, and data as to the effect of temperature change on transmittance at each wavelength. Limited supply of filters are available for nominal cost. Wavelength Standards (38050C-38051C) Based on the extensive experience that NIST has with this material and its long-term stability, NIST will no longer recommend the recertification of these standards. More information can be found in the paper "Holmium Oxide Glass Wavelength Standards." (90.0 kB) 
The transmittance and absorbance data from the paper can be download as an
Excel file. (404 kB)
Special Tests of Spectral Transmittance (38061S) Measurements of spectral transmittance can be made at wavelengths from 250 nm to 2500 nm for non-fluorescent submitted test items. In general, measurements are performed at room temperature with the incident beam normal to the front surface of the test item. Items with dimensions from 1 cm to 5.1 cm perpendicular to the incident beam are routinely accommodated. Other sizes and measurement conditions are possible in consultation with NIST staff. Uncertainty estimates will be given and will depend on the optical characteristics of the submitted test item and the instrument used to perform the measurement. Arrangements for these measurements on submitted test items must be made before shipment. The decision to perform the measurements and selection of the instruments to be used will rest with NIST. Test items not accepted for measurement will be returned. How to request calibration services The following criteria are used to determine acceptance of the calibration.
David Allen
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