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Research Facilities Synchrotron Ultraviolet Radiation Facility III High-Resolution Uv and Optical Spectroscopy Facility Low-Background Infrared Radiation Facility Controlled Background Radiometric Facility Spectral Irradiance and Radiance Responsivity Calibrations Using Uniform Sources (Sircus) Facility Medical-Industrial Radiation Facility Electron Paramagnetic Resonance Facility Radiopharmaceutical Standardization Laboratory |
Research Facilities Synchrotron Ultraviolet Radiation Facility III The NIST Synchrotron Ultraviolet Radiation Facility is used as a national standard of spectral irradiance for radiometric applications and a spectrometer calibration facility. The facility also serves a variety of research and applications needs in the ultraviolet and extreme ultraviolet spectral regions: detector development, characterization, and calibration; optical properties of materials; extreme ultraviolet optics; and damage and exposure studies. We welcome proposals for collaborative research in these areas. Contact: Charles
Clark The NIST Beowulf System (NBS) is a 128-processor parallel computing cluster. Its nodes consist of industry-standard personal computers, which were originally purchased by the Bureau of the Census for processing the 2000 Census and transferred to NIST in the autumn of 2000. The nodes are linked in groups of 16, communicate via fast Ethernet, and implement the Beowulf clustering system originally developed at NASA. The NBS cluster is used for computational simulation of Bose-Einstein condensation and coherent matter-wave systems, quantum information processing devices, electronic and optical properties of materials, and electromagnetic wave propagation. We welcome proposals for collaborative research that explore the use of parallel computing in such problems. Contact: Charles
Clark High-Resolution UV and Optical Spectroscopy Facility Accurate atomic data for neutral atoms and ions are required in support of high-technology products and manufacturing processes as well as advanced scientific applications. The primary source of such data is high-resolution optical spectroscopy. Spectrometers in NIST's High-Resolution Ultraviolet and Optical Spectroscopy Facility are the most powerful in the world for observations of emission and absorption spectra in the soft X-ray to near infrared regions. The 10.7-meter grazing-incidence and normal-incidence vacuum spectrographs permit observations from 3 nm to 600 nm with resolving powers of 70,000 to 400,000 and wavelength uncertainties as low as 0.0002 nanometer. In the visible and near-infrared region, an echelle spectrograph provides resolving powers exceeding 1,000,000. NIST's new high-resolution Fourier transform spectrometer will be capable of observations from 300 nm to 6 mm with unmatched resolution and wavelength accuracy. A variety of discharge sources are used to excite spectra of neutral atoms and ions stripped of up to 20 electrons. Species up to 40 times ionized are observed in plasmas created by ablating samples with a high-power laser. Our current research includes observations of transitions in highly ionized atoms for diagnostics of plasma conditions in tokamaks and stars, precision measurements of rare gas spectra in the infrared, laser spectroscopy of Rydberg states in alkali atoms, and Fourier transform spectroscopy of rare earth elements for application to development of more efficient commercial lighting. Contact: Joseph
Reader Low-Background Infrared Radiation Facility In the NIST Low-Background Infrared Radiation Facility, radiant background noise levels less than a few nanowatts are attained in two large (60 cm diameter × 152 cm long) vacuum chambers by cooling internal cryoshields to temperatures less than 20 kelvin using a closed-cycle helium refrigerator system. These chambers, the broadband chamber and the spectral chamber, are equipped with absolute cryogenic radiometers (ACR) of the electrical substitution type that operate at 2 K to 4 K . Capabilities: The ACR is a broadband detector with a flat response from the visible to the long wavelength infrared spectral region. The ACR in the broadband chamber can measure power levels of 20 nW to 100 W at its 3 cm diameter aperture within an uncertainty of less than 1 percent. The spectral chamber is equipped with a prism grating infrared spectrometer that covers the spectral range of 2 micrometers to 30 micrometers with a spectral resolution of 2 percent. The spectral chamber ACR is more sensitive and can measure power levels of few nanowatts at its 2-cm aperture within an uncertainty of less than 1 percent. Both radiometers have a resolution of 1 nW, and their time constants are about 20 seconds. Applications: This unique facility can be used to measure total radiant power from sources such as cryogenic blackbodies to deduce their radiant temperatures. The spectral chamber allows the measurement of the spectral distribution of radiation from sources and characterization of infrared detectors and optical components. Availability: The facility is operated by NIST staff in support of user infrared calibrations. It is available for collaborative research by NIST and outside scientists in areas of mutual interest. Contact: Steven
Lorentz Controlled Background Radiometric Facility Infrared radiometry has an important role in space-based civilian, defense, and industrial applications. A facility to maintain an infrared scale for specialized applications was developed with funding from NIST, the National Aeronautics and Space Administration, and the Department of Defense. In particular, the capability for measurements on large-area, vacuum-operational, blackbody sources operated from 200 K to about 400 K is being established. These measurements will be traceable to NIST via infrared radiometry through the radiance temperature of the source. An alternative scheme that is directly traceable to an absolute cryogenic radiometer using laser-illuminated sphere sources and transfer detectors is also under development. An example of the type of scientific activity that this facility supports is the use of satellites for the determination of temperature, based on radiance measurements, for the Earth's surface and atmosphere. These measurements are the basis for the study of global warming. A goal of the facility will be the development of infrared radiometers, which will be used for intercomparisons of large-area blackbody sources used by contractors for NASA's Earth Science Enterprise Project.
Spectral Irradiance and Radiance Responsivity Calibrations Using Uniform Sources (Sircus) Facility We have developed a laser-based facility for spectral irradiance and radiance responsivity calibrations using uniform sources (SIRCUS) for the calibration of radiance meters, irradiance meters, and digital imaging systems such as CCD cameras. In this facility, powerful, continuous-wave single-frequency, tunable lasers are directed into an integrating sphere, producing a uniform, monochromatic, Lambertian source. High-level transfer standard irradiance meters-directly traceable to national standards maintained at NIST-are used to determine the radiance of the integrating sphere with an uncertainty of 0.1 percent or less. The integrating sphere then is used to calibrate other instruments for spectral irradiance and radiance responsivity. Capabilities: With this facility, we have calibrated both narrow-band and broad-band radiometers. We have demonstrated 10 orders-of-magnitude dynamic range in the calibration of a narrow-band radiometer (~ 1 nm), along with extremely accurate spectral measurements (~ 0.001 nm). Most of the measurements to date have used the UV-Vis-NIR facility (spectral coverage from 200 nm to 1100 nm), but we have started construction of the IR facility (for calibrations in the 1 µm to 20 µm spectral range). Applications: Instruments that have been calibrated include NASA radiometers, DoD radiometers, and NIST high-level radiometers. Imaging systems calibrated include a CCD-based camera, microscope, and spectrograph. Availability: The facility is operated by NIST staff to support a variety of radiance and irradiance responsivity calibrations. It is available for collaborative research by NIST and outside scientists in areas of mutual interest. Contact: Steve
Brown Medical-Industrial Radiation Facility NIST operates an electron accelerator as the heart of a new user facility for the medical and industrial radiation communities. The Medical-Industrial Radiation Facility (MIRF) is based on an rf-powered, traveling-wave electron linac donated by the Radiation Therapy Center of the Yale University New Haven Hospital. This reconfigured accelerator provides electron energies from 7 MeV to 32 MeV at average beam currents of up to 0.1 mA. In addition to the original beam-steering system and medical-therapy scanner/collimator head, three additional beam ports and a switching magnet have been added at NIST. The flexibility afforded by access to these four beam lines allows NIST to address issues in radiation metrology, radiation effects, and the uses of electron and high-energy photon beams. Capabilities: The medical beam line can provide electron doses of up to 5 Gy/min at the patient location and is equipped with a target to produce a 25 MeV bremsstrahlung beam as used in high-energy photon therapy. On other beam lines, dose rates in excess of 1 kGy/s over a small area have been achieved with electrons, and exposure rates of about 2,500 R/min can be attained with suitable bremsstrahlung convertors to produce high-energy photon beams used in industrial radiography. Applications: MIRF offers unique opportunities for medical and industrial research. At the facility, a number of organizations are collaborating on a variety of projects: Medical dosimetry. Medical linacs are used for treating approximately 500,000 cancer patients annually at some 1,300 treatment facilities in the United States. Among the medical dosimetry applications of MIRF are the development and testing of instruments and dosimetry systems for use in clinical facilities as well as investigations into shielding requirements for the radiation scattered from the patient. Radionuclide production. Through photonuclear reactions, radioisotopes can be produced with high-energy electron accelerators as an alternative to the use of nuclear reactors. Applications on MIRF include production tests of radionuclides for use in nuclear medicine. Radiography. The facility provides for studies pertinent to industrial radiography and computed tomography. In addition, ongoing development on one of the beam lines is aimed at producing quasi-monoenergetic photon beams of channeling radiation and coherent bremsstrahlung suitable for use in digital-subtraction angiography. Radiation effects and processing. Current applications include electron-beam treatment of waste water, curing of polymer composites, and radiation effects on electronics. Availability: MIRF is available for collaborative research by researchers from industry, academia, and other government agencies under the supervision of NIST staff. Contact: Stephen
M. Seltzer Electron Paramagnetic Resonance Facility NIST is leading a national and international effort in electron paramagnetic resonance (EPR) dosimetry for measuring ionizing radiation. Paramagnetic centers (molecules or atoms with unpaired electrons) are produced by the action of radiation on materials. In the EPR measurement, irradiated materials are placed in a magnetic field and electron spin transitions are induced by an electromagnetic field of the appropriate frequency, typically in the gigahertz range. EPR is used as a non-destructive probe of the structure and concentration of paramagnetic centers. The centers created by ionizing radiation are proportional to the absorbed dose and provide a sensitive and versatile measurement method. Capabilities: The EPR dosimetry facility is supported by three state-of-the-art X-band EPR spectrometers capable of measuring radiation effects on a wide range of materials from inorganic semiconductors to biological tissues. The data acquisition system provides full computer control of all spectrometer functions, including real-time spectral display and rapid acquisition scan to analyze rapidly decaying signals. The data acquisition system is interfaced with an advanced data analysis station for data manipulation and is capable of simulating and deconvoluting multicomponent spectra. Applications: EPR dosimetry is operable over many orders of magnitude in absorbed dose (10-2 Gy to 105 Gy) and impacts many facets of society and industry: Radiation accident dosimetry. Using biological tissues (bone, tooth enamel) or inanimate materials (clothing), retrospective dose assessment and mapping can be accomplished. Clinical radiology. Ionizing radiation doses administered in cancer therapy can be measured for external beam therapy using dosimeters of crystalline alanine (an amino acid) or validated for internally delivered bone-seeking radiopharmaceuticals using bone biopsies. Industrial radiation processing. Routine and transfer dosimetry for industrial radiation facilities can be performed using alanine dosimeters as well as post-irradiation monitoring of radiation-processed meats, shellfish, and fruits using bone, shell, or seed. The EPR facility also serves as a fully functional materials research facility for analyzing radiation effects on semiconductors, optical fibers, functional polymers, and composites. Availability: The EPR facility is available for collaborative research by researchers from industry, academia, and other government agencies under the supervision of NIST staff. Contact: Marc
F. Desrosiers Radiopharmaceutical Standardization Laboratory Radioactivity measurements for diagnostic and therapeutic nuclear medicine in the United States are based on measurements at NIST. Activity measurements for the gamma ray-emitting radionuclides are made using 4πβ liquid scintillation spectrometry and 4πγ ionization chamber. The calibration process also includes identification of radionuclidic impurities by germanium spectrometry. Recent development work has focused on therapeutic nuclides for nuclear medicine, radioimmunotherapy, and bone palliation. Capabilities: The radiopharmaceutical standardization laboratory provides calibration services for radionuclides and is available for technical users who must make measurements consistent with national standards or who require higher accuracy calibrations than are available with commercial standards. NIST also undertakes basic research to develop new methods of standardizing radionuclides for diagnostic and therapeutic applications. These studies include measurements of decay-scheme parameters, such as half lives and gamma ray emission probabilities, and identification of radionuclidic impurities. Availability: The customer has no direct use of the facility. NIST staff can provide calibration services for any previously standardized radionuclide. As part of the same program, research associates of the Nuclear Energy Institute produce standards that are certified by NIST as Standard Reference Materials for distribution to the radiopharmaceutical user communities. Contact: Brian
E. Zimmerman Neutron Interferometer and Optics Facility The Neutron Interferometry and Optics Facility (NIOF) located at the NIST Center for Neutron Research is one of the world's premier user facilities for neutron interferometry and related neutron optical measurements. A neutron interferometer splits and then recombines neutron waves. This gives the interferometer its unique ability to access experimentally the phase of neutron waves. Phase measurements are used to study the magnetic, nuclear, and structural properties of materials as well as fundamental questions in quantum physics. Related, innovative neutron optical techniques for use in condensed matter and materials science research are being developed. Capabilities: Neutrons are extracted from a dual-crystal parallel-tracking monochromator system, providing neutron energies in a range of 4 meV to 20 meV. Neutrons are counted with integrating 3He detectors or by high-resolution position-sensitive detectors with a resolution better than 50 µm. The sensitivity of the apparatus is enhanced greatly by state-of-the-art thermal, acoustical, and vibration isolation systems. To reduce vibration, the NIOF is built on its own foundation, separate from the rest of the building. The position of the interferometer is maintained to high precision by a computer-controlled servo system. The result is a neutron interferometer facility with exceptional phase stability (5 × 10-3 rad/day)and fringe visibility (70 percent). The vibration isolation is -7 g; the positional stability, 2 µm in translation and 1 µrad in rotation; and the temperature stability, 0.1 K/day. Applications: NIOF applications include neutron phase contrast imaging, neutron tomography, neutron Fourier spectroscopy for surface studies, determination of hydrogen content in materials, measurement of bound coherent scattering lengths, small-angle neutron scattering studies with perfect crystals, tests and demonstrations of quantum principles with matter waves, measurement of the neutron-electron scattering length, and phase transition studies. Availability: Beam time on the NIOF is available to qualified scientists from the United States and abroad, subject to approval and scheduling by the facility oversight committee. Contact: Muhammad
Arif
Date
created:
August 17, 2001 |