. | . |
New NIST Method Improves Accuracy Of Spectrometers
Measurements of the intensity of light at different wavelengths can be made more accurately now, thanks to a new, simple method for correcting common instrument errors. The new method, developed by researchers at the National Institute of Standards and Technology (NIST), will benefit fields such as color measurement, lighting development, remote sensing, biotechnology and astronomy. The NIST method improves the measurement accuracy of spectrometers, devices that measure optical radiation at different wavelengths. Spectrometers are used widely in industrial settings and academic research to analyze the emissions from lamps or other light sources, as well as to analyze optical properties of materials. The NIST method corrects errors arising from the presence of stray light, unwanted scattered radiation within an instrument. Stray light is often the major source of measurement uncertainty for commonly used spectrometers. It can cause unexpectedly large systematic errors, even as much as 100 percent depending upon the application, when an instrument tries to measure a very low level of radiation at some wavelength while there are relatively high levels in other wavelength regions. The new NIST method nearly eliminates stray light errors, to a level less than 0.001 percent of the total signal, a desirable level for most industrial and scientific applications. This allows very accurate measurement of low-power components of radiation and accurate measurements across a large dynamic range of intensities. NIST researchers implemented and validated the method using a commercial CCD-array spectrograph, which measures light in the visible region instantly. They characterized the response to monochromatic emissions from tunable lasers that covered the instrument's full spectral range. Calculations were made using the measured data to produce a matrix that quantified the magnitude of the stray-light signal for every element (or pixel) of the detector array for every wavelength of light. The matrix then was used to correct the instrument's output signals for stray light. The method is simple and fast enough to be incorporated into an instrument's software to perform real-time stray-light corrections without much reduction in the instrument's speed. NIST recently began offering a special calibration service to characterize spectrometers for stray light using the new method. Plans are being made to transfer the technique to industry, and a technical paper is in preparation. For further information about the calibration service, contact Yuqin Zong at [email protected], or (301) 975-2332. Related Links SpaceDaily Search SpaceDaily Subscribe To SpaceDaily Express Observing The Solar System In Submillimeter Wavelengths Boston MA DC (SPX) Jun 17, 2005 The Submillimeter Array (SMA) will be ready and watching when NASA's Deep Impact probe strikes the nucleus of Comet Tempel 1 on July 4th. The impact is expected to excavate material from the comet's interior-material left over from the earliest days of our solar system.
|
|
The content herein, unless otherwise known to be public domain, are Copyright 1995-2016 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service. |