Volume 98, Number 1, January-February 1993 Journal of Research of the National Institute of Standards and Technology Contents Articles The NIST Cold Neutron Research Facility H. J. Prask, J. M. Rowe,J. J. 1 Rush, and I. G. Schroder 15 Outline of Neutron Scattering Formalism N. F. Berk 31 Small Angle Neutron Scattering at the National B. Hammouda, S. Krueger, and Institute of Standards and Technology C. J. Glinka 47 Neutron Reflectivity and Grazing J. F. Ankner, C. F. Majkrzak, Angle Diffraction and S. K. Satija 59 The Triple Axis and SPINS Spectrometers S. F. Trevino 71 Neutron Time-of-Flight Spectroscopy John R. D. Copley and Terrence J. Udovic Ultra-High Resolution Inelastic D. A. Neumann and 89 Neutron Scattering B. Hammouda Neutron Depth Profiling: Overview and R. G. Downing, G. P. Lamaze, 109 Description of NIST Facilities and J. K. Langland 127 Prompt-Gamma Activation Analysis Richard M. Lindstrom 135 Facilities for Fundamental Neutron Physics Research M. Arif, M. S. Dewey, at the NIST Cold Neutron Research Facility G. L. Greene, and W. M. Snow News Briefs GENERAL DEVELOPMENTS 145 President Honors Baldrige Winners FAA Asks NIST to Measure High-Flying EMFs Certification Plan Assesses Antenna Performance Microwave Users: New Noise Standards Available 146 NIST/Industry to Work on Superconducting Materials ISDN Demo Dubbed a "Milestone" Assessors Wanted for Fastener Accreditation Award to Advance Diamond Film Technology NVLAP Test Program Adds Wood-Based Products 147 Field Strength Comparison Status Updated Eleven Inventions Ready for Licensing Volume 98, Number 1, January-February 1993 Journal of Research of the National Institute of Standards and Technology Twenty-one Grants Announced for ATP's Third Year 148 Weights and Measures Handbooks Updated for 1993 Futuristic Waveguides Detect Chemicals with Light Export Workshop Announced on Advanced Materials 149 U.S. Joins Japan's Real World Computing Program ILAC 92 Meeting NASA Praises NIST Work Supporting Advanced Communications Technology Satellite NIST Carries Out First Demonstration of Integrated-Optic 150 Waveguide Laser Fabricated in Lithium Tantalate Sensor to Detect and Classify Sub-Micrometer Particles Now Available for Licensing from NIST NIST Develops Method for Producing Micromachined Gas Sensor Array by CMOS Post-Fabrication Process Method Developed for Electrical Characterization of 151 Multicarrier Semiconductors Product Data Hypermedia Overview ASME Y14.5.1 Standard Nears Completion NIST Researchers Establish Environmental Properties of MTBE, Popular Oxygenate Fuel Additive Molecular Beams and Diode Lasers Probe Atmospheric 152 Dimer Molecules Measurements with NIST Gamma-Ray Spectrometer Featured in International Workshop NIST Dedicates New High-Dose Cobalt-60 Facility for 153 Radiation Processing Applications NIST Provides Radon Standards to United Kingdom and Italy Council on Ionizing Radiation Measurements and Standards (CIRMS) Meets at NIST NIST Quantifies Oxides on Intermetallics Compounds Formed at Electronic Interconnects Calculations Suggest Strain Reduces Steric Hindrance in 154 Environmentally Enhanced Fracture of Silica and Silicon NIST-ACC Collaboration on Environmental Degradation in Glass-Fiber-Based Composites NIST Works to Improve U.S. Passport Security NIST Completes Study on Fundamental Boiling Mechanisms of Ozone-Safe Refrigerant/Lubricant Mixtures Acoustic Emission of Structural Materials Exposed to 155 Open Flames First Text Retrieval Conference (TREC) Held NIST Publishes Results of First Optical Character Recognition Systems Conference NIST Collaborates with the Department of the Army on Threats to Computer Systems Programs for Neural Network Calculations 156 Volume 98, Number 1, January-February 1993 Journal of Research of the National Institute of Standards and Technology STANDARD REFERENCE MATERIALS 156 Standard Reference Materials 2709-2711 Soil Samples Standard Reference Materials 458-460 Beryllium-Copper Alloys STANDARD REFERENCE DATA 157 Data on Chemical Reactions in Solutions Available New PC Database Calibrates Infrared Spectrometers Volume 98, Number 1, January-February 1993 Journal of Research of the National Institute of Standards and Technology Foreword Since 1967 when the National Institute of Standards and Technology Reactor (NBSR) achieved criticality, reactor-based research programs have increased enormously both in scope and in number of research participants (over 600 in FY 91). Currently operating at 20 MW power and a peak thermal core flux of 4 x 10'4n/(cm 2 s), the NBSR is one of the top three research reactors in the country, with a broad range of research programs which utilize thermal beams. In recent years, there has been an increasing interest in the use of "cold" neutrons (energy <0.005 eV) for a variety of studies. As a result of their longer wavelengths, total reflection at interfaces makes it possible to build neutron guides, which can be used to transport intense beams over many tens of meters, and to focus beams down onto smaller spots. This, in turn, has opened up many new instrumentation possibilities and research opportunities, which are best characterized in terms of increased resolution in energy (by up to five orders of magnitude) and in the size of structures which can be determined. Western Europe has not only been the site of the initial development of neutron guides and cold sources, it has been the unquestioned leader in the utilization of these devices in advanced neutron scattering facilities employing new instrumentation. In 1984 the United States had one operating cold source at Brookhaven National Laboratory, one under development [at the then National Bureau of Standards (now NIST)], and no guide halls. In contrast, at the Institut Laue- Langevin (ILL) - the most extensively used research reactor in the world -16 of 27 instruments were on cold neutron guides. Since then a second cold source and second guide hall have been added to the ILL complex. The growing impact of cold neutrons in chemistry, physics, materials science, and biology was recognized in 1984 by the Seitz-Eastman Committee, commissioned by the National Academy of Sciences at the request of the President's science advisor. This study was instrumental in focusing attention on the need for cold neutron capabilities in this country. In 1987, NBS and the Depart- ment of Commerce responded to the national need for cold neutron capability by initiating the development of the Cold Neutron Research Facility (CNRF). As of December 1992, nine experi- mental stations had been developed and installed, two more were ready for installation and commis- sioning, and the balance (for 15 total) were at various stages of design and construction. A second generation cold source that will greatly increase the intensity of all stations has been designed and is being built for installation in 1993. The external user program has been initiated, with excellent response from the community, both inside and outside NIST. This therefore is an appropriate time to produce a detailed, technical description of the facility and of the research that it will enable. For this special issue of the Journal of Research a number of review papers have been prepared which describe research activities which employ cold neutrons, and the NIST instruments with which such activities can be pursued. J. Michael Rowe Chief, Reactor Radiation Division, National Institute of Standards and Technology Volume 98, Number 1, January-February 1993 Journal of Research of the National Institute of Standards and Technology [J. Res. NatI. Inst. Stand. Technol. 98, 1 (1993)] The NIST Cold Neutron Research Facility Volume 98 Number 1 January-February 1993 H. J. Prask, J. M. Rowe, J. J. The Cold Neutron Research Facility more details on some of the research Rush, and I. G. Schroder (CNRF) at the National Institute of opportunities that the facility will bring Standards and Technology (NIST) Re- to NIST. National Institute of Standards search Reactor (NBSR) is now coming on line, with the first seven experimen- Key words: cold neutrons; guide hall; and Technology, tal stations operational, and more sta- neutron facilities; neutron guides; neu- Gaithersburg, MD 20899 tions scheduled to be installed during tron instrumentation; neutron proper- 1992. The present article provides an ties; neutrons; research reactors. introduction to the facility, and to other articles in the current issue that give Accepted: July 8, 1992 1. Introduction Since the advent of nuclear reactors with reason- * the nondestructive nature of low energy neutrons ably high fluence rates (fluxes) in the 1950s, the * the fact that neutrons with wavelengths compara- use of the thermal neutrons produced by these ble to interatomic spacings in condensed matter sources to study a wide range of problems has have energies comparable to the energies of grown rapidly. This growth has resulted from the atomic vibrations. properties of neutrons as probes, which include: The potential of this research was realized early, * absorption with subsequent radioactive decay and the Atomic Energy Commission built a succes- (used as an analytical tool) sion of research reactors with increasing fluence * high penetration as a result of the lack of an elec- rates throughout the 1950s and 1960s. trical charge This potential was also perceived by three physi- * scattering by nuclear interactions (which leads to cists at the National Bureau of Standards (NBS, a non monotonic variation of scattering with now NIST)-R. S. Carter, H. Landon,