Bureau of Standards Instrument Shops Division are primarily used for the short-run or single-piece application. Computer-assisted programming speeds the preparation of tapes while providing capability for the generation of irregular, elliptic, and hyperbolic MECHANICAL curves. On the machining center, the generation of FACILITIES patterns and their rotation and/or translation are easily accomplished. Machining Center: This unit is a numerically controlled bed-type milling machine with an eight-station turret in which tools are mounted. Selection of these tools, as well as "on," "off," speeds, feeds, positioning, end and side milling, drilling, tapping, and boring cycles, are controlled through punched paper tape. Selection of inch/metric operation, mirror image, and EIA or ASCII(ISO) tape codes are accomplished by manual switches. Table travel of this machine is 20 inches by 40 inches. Vertical capacity of the machine is from 0 inch to 22 inches with 10 inches of this travel under tape control. The table offers linear and circular interpolation while the vertical travel is point-to-point. Instrument Shops Division at the Boulder Laboratories has a similar machining center and a single spindle machining center. Lathe: The lathe is of the slant-bed type with an eight-station turret in which tools are mounted. It is a two-axis machine offering linear and circular interpolation. It has capability for turning, drilling, boring, threading, grooving, and knurling. All above features, as well as speeds and feeds, are controlled by punched paper tape. Inch/metric operation and EIA or ASCII tape code formats are selected by manual switches. Capacity of this machine is 101⁄2 inches over the cross slide and longitudinal travel is 26 inches. Coordinate Measuring Machine: A three-axis machine interfaced with a digital readout system, computer, and a Teletype unit. Measuring range of the machine is 30 inches by 26 inches horizontal and 16 inches vertical. Accuracy within any horiozntal plane is ±0.0002 inch. Vertical axis accuracy is ±0.0002 inch. A right-angle probe holder permits measuring details of vertical planes. Optical viewing screens and microscopes are available for non-contacting measure ments. Contact: Robert E. Lach, Shops Building, Room 136, DEADWEIGHT FORCE These seven machines are the NBS standards for the calibration of precise force-measuring instruments such as proving rings, load cells, and other similar devices. The machines are not used for testing the strength of materials or for calibrating scales and other weighing equipment. Capability: The machines apply specific calibration loads of high accuracy in the engineering units of the pound-force and in some cases, as noted in the table below, in units of the kilogram-force. The accuracy is better than 0.002 percent of load. The characteristics of the machines are as follows: Maximum load Units of intermediate loads Minimum load 5 lbf 6100 lbf 200 lbf 100 lbf (3050 kgf) (100 kgf) (50 kgf) 25,300 lbf 400 lbf 100 lbf 1,000,000 lbf Note 1-Intermediate loads vary, 10,000 lbf, 20,000 lbf, and 30,000 lbf depending on range. Availability: The machines are not available for Literature: "Research and Testing Facilities of the En- Contact: Roscoe L. Bloss, Chief, Engineering Mechan- of the collection time and of pressure and temperature after the air is accumulated in the known volume. Smaller flows, from 50 cm3 min-1 up to 50 scfm, are measured with piston-type or bell-type provers. Flowrate of a liquid is measured by static or dynamic weighing the quantity accumulated during a known time interval. Rotation of the diverter valve controls fluid collection in a weigh tank, with a switching error less than 10 ms. Net weights are measured to within 0.01 percent on commercial lever balances or weighing scales. The countertimer is accurate to one part in 106. Calibration reports are based (usually) on ten separate observations taken in groups of five successive runs on each of two separate days. These reported values have an estimated overall uncertainty from 0.13 to 0.25 percent, depending on the sensitivity and repeatability of the system under test. Applications: Calibration of flowmeters of either fixed restriction or moving element types, at rates from 0.03 to 10,000 gallons per minute (1.9 X 10to 6.3 X 10-1m3/s) for water, and from 0.03 to 1000 gallons per minute for liquids such as aircraft fuels. Calibration of critical-flow nozzles and other types of meters for gaseous flow, over the range from 50 cm3 min-1 to 2700 scfm (1.5 kg/s). Availability: Calibration services for Federal agencies, and for industrial or commercial laboratories in USA or abroad. Literature: [1] F. W. Ruegg and M. R. Shafer, Flow Measure- Contact: F. W. Ruegg, Chief of Fluid Meters Section, Fluid Mechanics Building, Room 111, Phone 301-9213681. FLUID FLOW MEASUREMENT Laboratory techniques provide precise measurement of the flux of fluid in a closed system, to permit calibration of meters for fluid quantity and flowrate, using air, water, and certain liquid hydrocarbons. Capabilities: A liquid flowmeter calibrator is used for flow measurement of filtered and dried air supplied from a compressor at rates up to 2700 scfm (cu ft/min at 14.69 psia and 70°F). Air is fed through sonic nozzles in 2, 3, 4 or 6-inch meter runs at pressures up to 110 psig (758 kNm-2) through a special three-way ball valve to a tank of known volume. The mass rate of flow is computed from measurements THREE-DIMENSIONAL PRECISION In a numerically controlled machine tool, the cutters are positioned precisely by the digits on a punched paper tape, or often by direct computer control. The workpiece, instead of being removed from the machine for checking a single measurement, is inspected as a finished piece for the accuracy of all its dimensions and angles. This automated metrology facility is designed to meet the needs of such automated production. Capability: A 3-axis measuring machine built to stateof-the-art specifications will be housed in a stabilized environment, and can be operated either manually or under full control from a programmed computer. It has a working volume of 48 X 24 X 12 inches with a 16-inch clearance under the bridge, and can detect a difference in length of 0.250nm (10 micro-inches), using a non-contacting sensor. Bulk disc storage of computer programs is provided, and a line printer capable of graphic presentation is available. Reference to the SI metre will eventually be provided by a stabilized laser interferometer. Applications: Provides digital data on probe position in three dimensions, or two-dimensional graphic projection of complex three-dimensional shapes. Substitutes for the skilled handling of gage blocks, micrometer calipers, height gages, sine bars, straight edges, polygons, plug and ring gages, master gears, and thread wires. Availability: To any NBS worker after minimal training. In appropriate instances, individual workers from other Federal organizations may gain access to the facility. Literature: Simpson, J. A., Use of a microscope as a non-contacting microdisplacement device, Rev. Sci. Instr. 42, 1378 (1971). Contact: Dr. J. A. Simpson, Acting Chief, Mechanics Division, Metrology Building, Room B322, Phone 301-921-2171. UNIVERSAL TESTING MACHINE, TWELVE MILLION POUND-FORCE This hydraulically operated machine of 12-million pounds-force capacity, believed to be the largest in the world, was designed to test large structural components and to apply the forces needed to calibrate force measuring devices of large capacity. Capability: The machine can apply axial force of 12,000,000 lbf in compression 6,000,000 lbf in tension, and a transverse force of 4,000,000 lbf to a flexural member. Working space between the screw columns is 8 feet 4 inches, and the working surface of the main platen is 8 feet 4 inches by 15 feet. The reinforced concrete foundation includes a tie-down There are two hydraulic capsules in the sensitive crosshead, one providing the force measuring function and the other for preloading. Pressure transducers in a constant temperature oven on the crosshead provide signals to analog readout for force, strain, and displacement, and also to a digital readout calibrated to within± 0.5 percent of the applied load. Both coarse and fine adjustment of power cylinder motion (5 feet max.) are provided from the control console. Applications: Axial forces of 12,000,000 lbf can be applied to column sections or fabricated members with lengths up to 58 feet, or to elastic devices such as the load cells used to measure rocket thrust or rolling mill forces. To apply the full 6,000,000 lbf tension to eye bars, drill rod for undersea operations, large diameter wire rope, and the like, both threaded couplings and clevis fixtures are provided to take specimens up to 53 feet long. Transverse or flexural tests under 4,000,000 lbf load can be made on beams and similar structures with lengths up to 90 feet. Availability: To be negotiated, for prearranged schedule not interfering with the work of the Section or with Government priorities. Other requestors must attest no competition with non-Government agencies. Literature: A. F. Kirstein, Universal Testing Machine of 12-Million-lbf Capacity, Nat. Bur. Stand. (U.S.) Spec. Publ. 355 (Sept. 1971); NBS Tech. News Bull. 55, No. 11, p. 174-5 (Nov. 1971). Contact: Roscoe L. Bloss, Chief of Engineering Mechanics Section, Engineering Mechanics Building, Room 219, Phone 301-921-2621. WIND TUNNEL FOR UNSTEADY FLOWS This facility is designed for the study of unsteady conditions in low-speed aerodynamics. Capabilities: In two test sections, 4.5 feet square by 16 feet in length, each fitted with a set of continuously rotating shutters, oscillatory flows of air can be generated at mean speeds from nearly zero up to 45 feet per second. Provision is also made for simu lating gusts and lulls of adjustable amplitude and frontal duration and for varying the intensity and scale of the free-stream turbulence. One set of rotating shutters lags the other by a quarter-turn to give more uniform loading on the fan. The flow can be oscillated sinusoidally at frequencies from 0.1 Hz to 25 Hz. The amplitude is limited to about 5 fps at 10 Hz but can be increased to 45 fps at 0.1 Hz. The "time-constant" for the overall facility is approximately 0.2 seconds. Applications: Such important problems in unsteady aerodynamics as the dynamic response of various types of wind-speed instruments, the effect of wind loading on buildings and other structures under the action of a variable wind, unsteady heat transfer phenomena, and unsteady boundary layers may be investigated in this facility. Availability: The direct use of this facility is limited to staff members of the Aerodynamics Section or qualified guest scientists. However, it may be used indirectly through cooperative or contractual research arrangements with other Government agencies or with private industrial organizations. Contact: Philip S. Klebanoff, Chief of Aerodynamics Section, Fluid Mechanics Building, Room 105, Phone 301-921-3684. NUCLEAR REACTOR AND ASSOCIATED FACILITIES NUCLEAR REACTOR The NBS research reactor is a high-flux reactor designed for materials research and analysis. It operates around the clock at a power level of 10 MW, generating neutron fluxes averaging 1014 neutrons per square centimeter per second. Capability: The intense neutron flux makes possible a wide variety of experiments and investigations such as crystal structure determination, lattice dynamics measurements, phase transition studies, trace element analysis, radioisotope production, and radiation effects studies. The neutrons are made available through beam ports, pneumatic tubes, and in-core irradiation thimbles. The reactor facilities can be seen NUCLEAR REACTOR. Plan view of the NBS reactor showing beam ports, pneumatic tubes, and vertical thimbles. in the diagram and include: 9 radial beam ports 2 through beam ports 2 cold-source beam ports 1 thermal column 4 pneumatic tubes 7 vertical thimbles in the reflector 10 vertical thimbles in the core Availability: All but one of the beam ports and several of the vertical thimbles already have experimental equipments installed. These facilities and their availability are described in the following pages. The remaining facilities listed above are available for suitable programs. Literature: W. F. Sheely, The NBS Reactor: Its Description and a Guide to Use by Experimenters, NBS Rept. 9081 (1966). Contact: Dr. Robert S. Carter, Chief of the Reactor Radiation Division, Reactor Building, Room A106, Phone (301) 921-2421. FILTERED NEUTRON BEAMS Nearly monoenergetic nertrons with energies above ~100 keV can be readily produced with adequate yields in positive-ion accelerators, but there are no convenient accelerator sources of monoenergetic neutrons with energies below 100 keV. Much of the neutron dose, however, comes from neutrons in this energy range, and dosimetry development is severely hampered by the lack of test facilities. Capability: Thick scandium, iron, or silicon filters placed in a through tube of the NBS reactor result in monoenergetic neutron beams of 2 keV, 25 keV, or 144 keV, respectively. Calculated intensities are in the range of 10% n/cm2s, with very low gammaray background. ENERGY: 2, 25 and 144 keV ENERGY SPREAD: 10% INTENSITY: 106 n/cm2s (continuous beam) GAMMA RAY BACKGROUND: very small owing Applications: The NBS filtered beams will constitute a primary neutron source facility for neutrons of 2 keV, 25 keV, and 144 keV. This facility is to function as the point of reference for the development and maintenance of secondary source capabilities at satellite locations, as well as providing means for the evaluation and calibration of new types of dosimeters. The filtered beams will also be used for cross section measurements, and fission physics measurements, which require require a high-intensity, monoenergetic, "clean," continuous neutron beam. Availability: Beam time is available to NBS staff, other agency and university users, industrial users, and guest workers. Operation only by qualified Division personnel under the direction of Dr. A. R. Schwartz or Dr. I. Schroder. Literature: NBS Reactor: Summary of Activities, Oct. 1971Sept. 1972, Nat. Bur. Stand. (U.S.) Tech. Note 759 (Mar. 1973). Contact: Dr. Charles D. Bowman, Chief, Neutron Standards Section, Radiation Physics Building, Room B117, phone 301-921-2234. INTERMEDIATE-ENERGY STANDARD NEUTRON This facility provides a primary standard neutron field with a smoothly varying energy spectrum that may be accurately calculated. The energy range of the neutron spectrum-95% of the spectrum is between 2 keV and 5 MeV-is just that of core neutrons in presently conceived U.S. fast breeder reactors. The system, which is operated in the thermal column of the NBS rector, is one of several energy-distributed, fast-neutron fields developed by the NBS Neutron Standards Program. Capabilities: The ISNF arrangement is fundamentally simple: a spherical cavity in graphite, a thin shell of 10B mounted at the center, and fission source disks of 235U placed around the periphery of the cavity. Fission neutrons returning from the graphite give rise to the ISNF field at the center of the cavity: Total flux intensity ~109 n/cm2,s Total fluence for 24 hour irradiation ~1014n/cm2 Uniformity of the field <2% variation over 4 cm Initial accuracy of flux and spectrum ±5% Applications: Two general kinds of applications are planned for the ISNF: (1) measurement of absolute and relative integral reaction rates for breeder reactor development; (2) calibration of various types of neutron detectors important for nuclear technology. Availability: The ISNF facility will be operational late in 1974. Experiments by outside users will be an essential feature of the ISNF measurements program but they will require careful coordination and scheduling. Literature: NBS Reactor: Summary of activities, Oct. 1971Sept. 1972, Nat. Bur. Stand. (U.S.) Tech. Note 758 (Mar. 1973). Contact: Dr. James A. Grundl, Neutron Standards Section, Reactor Building, Room A-120, phone (301) 9212421. ISOTOPE SEPARATOR LABORATORY Isotopic separations are produced by the combined action of an electric and a magnetic field on a stream of ions, which is transmitted through an electrostatic lens system and a 90°-sector magnet to a dispersion and target chamber. Capability: Potentials up to 90 kilovolts produce ion beam currents up to 100 microamperes. Sector electromagnet of 150-centimeter radius. Mass dispersion sufficient to separate all known isotopes. Target with temperature control. Collimating aperture and lens system adjusts shape of beam. Applications: Preparation of isotopically pure substances, irradiation of materials, studies of nuclear structure, ion implantation in semiconductors, precise chemical sectioning of foils. Source material may vary from gaseous substance to metallic oxide, with |