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33rd International Physics Congress of the Turkish-Physical-Society (TPS) -- SEP 06-10, 2017 -- Bodrum, TURKEY WOS: 000445956100064 In this study, attenuation coefficients of two different stainless steel alloys (AISI 304 and AISI 310), which have a wide range of applications from home appliances to the automotive sector, and two different aluminum alloys (6013 and 5083), which have a high mechanical strength and a light weight structure and are used in many fields from aviation to military vehicles, has been determined. For this purpose, we used gamma spectrometer system with NaI(Tl) detector. In our measurements, we used Eu-152, Ra-226 and Co-60 as gamma ray sources. To narrow the beam of gamma rays, we designed the new steel based collimator. We also investigated the effect of using collimator. Obtained results were compared with the NIST XCOM values. Turkish Phys Soc

The ab initio calculations were performed using Cowan’s computer code for ground configuration5d46s incorporating other interacting even parity configurations 5d36s2 and 5d5, also for the three lowest excited configurations5d46p, 5d36s6p and 5d36s5f of odd parity matrix. The initial energy parameter scaling applied for Eav and ζ at 100% of the HFR values and Fk at 85%, Gk and Rk at 75% of the HFR values. The reported values of levels were taken from NIST ASD levels list. The levels were used to run least square fitted (LSF). This allowed adjusting the energy to the real values and hence a better prediction was achieved.The ab initio calculations were performed using Cowan’s computer code for ground configuration5d46s incorporating other interacting even parity configurations 5d36s2 and 5d5, also for the three lowest excited configurations5d46p, 5d36s6p and 5d36s5f of odd parity matrix. The initial energy parameter scaling applied for Eav and ζ at 100% of the HFR values and Fk at 85%, Gk and Rk at 75% of the HFR values. The reported values of levels were taken from NIST ASD levels list. The levels were used to run least square fitted (LSF). This allowed adjusting the energy to the real values and hence a better prediction was achieved.

The photon mass attenuation coefficients of LiF, BaSO4, CaCO3 and CaSO4 thermoluminescent dosimetric compounds at 100; 300; 500; 600; 800; 1,000; 1,500; 2,000; 3,000 and 5,000 keV gamma-ray energies were calculated. For this purpose, FLUKA Monte Carlo (MC) program which is one of the well-known MC codes was used in this study. Furthermore, obtained results were analyzed by means of ROOT program. National Institute of Standards and Technology (NIST) values were also used to compare the obtained theoretical values because the mass attenuation values of the used compounds could not found in the literature. Calculated mass attenuation coefficients were highly in accordance with the NIST values. As a consequence, FLUKA was successful in calculating the mass attenuation coefficients of the most used thermoluminescent compound.The photon mass attenuation coefficients of LiF, BaSO4, CaCO3 and CaSO4 thermoluminescent dosimetric compounds at 100; 300; 500; 600; 800; 1,000; 1,500; 2,000; 3,000 and 5,000 keV gamma-ray energies were calculated. For this purpose, FLUKA Monte Carlo (MC) program which is one of the well-known MC codes was used in this study. Furthermore, obtained results were analyzed by means of ROOT program. National Institute of Standards and Technology (NIST) values were also used to compare the obtained theoretical values because the mass attenuation values of the used compounds could not found in the literature. Calculated mass attenuation coefficients were highly in accordance with the NIST values. As a consequence, FLUKA was successful in calculating the mass attenuation coefficients of the most used thermoluminescent compound.

The most common radionucide used in High-dose rate (HDR) brachytherapy is 192Ir and has been used clinically for over 25 years. The first calibration of this source was performed at the University of Wisconsin - Madison. Other HDR sources are beginning to be introduced into the market, each of which requires a unique calibration. One of these sources is electronic brachytherapy (eBT). The calibration of these sources involves the use of different standards, namely a calibrated ion chamber traceable to a primary standards dosimetry laboratory such as NIST or a free-air chamber. The traceability of the ion chambers and the details of the free-air chamber will be described in detail. An uncertainty estimate for HDR sources (other source types are described elsewhere) will also be provided. [1] The University of Wisconsin has measured most HDR 192Ir source models and found that the calibration coefficients for well-type ionization chambers agree to within ± 1 %, with a total uncertainty of 2.4%. For eBT sourc...

We propose a novel Circle map based pseudorandom bit generation scheme. We evaluated the output streams by the NIST, DIEHARD and ENT statistical packages. The results of the tests show that the new generator provides an exclusive level of randomness of the bit sequences.

Detecting the early corrosion of steel that is embedded in reinforced concrete (rebar) is a goal that would greatly facilitate the inspection and measurement of corrosion in the US physical infrastructure. Since 2010, the National Institute of Standards and Technology (NIST) has been working on a large project to develop an electromagnetic (EM) probe that detects the specific corrosion products via spectroscopic means. Several principal iron corrosion products, such as hematite and goethite, are antiferromagnetic at field temperatures. At a given applied EM frequency, which depends on temperature, these compounds undergo a unique absorption resonance that identifies the presence of these particular iron corrosion products. The frequency of the resonances tends to be on the order of 100 GHz or higher, so transmitting EM waves through the cover concrete and back out again at a detectable level has been challenging. NIST has successfully detected these two iron corrosion products, and is developing equipment and methodologies that will be capable of penetrating the typical 50 mm of cover concrete in the field. The novel part of this project is the detection of specific compounds, rather than only geometrical changes in rebar cross-section. This method has the potential of providing an early-corrosion probe for steel in reinforced concrete, and for other applications where steel is covered by various layers and coatings.

In this paper we use Chebyshev polynomials of the first kind to generate pseudo-random binary sequences. The modified generator use a new scheme of bit extraction applied to four Chebyshev maps. The properties of the generated sequence is analysed by speed test and statistical NIST, ENT and DIEHARD packages.

Systematic studies have been carried out on two different powder materials used for additive manufacturing: stainless steel and cobalt-chrome. The characterization of these powders is important in NIST efforts to develop appropriate measurements and standards for additive materials and to document the property of powders used in a NIST-led additive manufacturing material round robin. An extensive array of characterization techniques was applied to these two powders, in both virgin and recycled states. The physical techniques included laser diffraction particle size analysis, X-ray computed tomography for size and shape analysis, and optical and scanning electron microscopy. Techniques sensitive to chemistry, including X-ray diffraction and energy dispersive analytical X-ray analysis using the X-rays generated during scanning electron microscopy, were also employed. Results of these analyses will be used to shed light on the question: how does virgin powder change after being exposed to and recycled from one or more additive manufacturing build cycles? In addition, these findings can give insight into the actual additive manufacturing process.

The joint project between NIST and Imperial College London to measure spectra of singly-ionized iron-group elements using Fourier transform and high-resolution grating spectroscopy is described.

Over the past two decades, the Sensor Science Division at the National Institute of Standards and Technology (NIST) has developed extensive capabilities for the characterization of the infrared optical properties of materials and components. These include the more recent development of infrared spectral emittance (emissivity) measurements by the direct method of radiance comparison to blackbody reference sources over a temperature range of 200 °C to 900 °C over a wavelength range of 2 μm to 20 μm. This paper reports on the recent progress. Initial validation of the measurement methodology was made through comparisons with the indirect method of reflectance measurement on the NIST infrared reference integrating sphere at a limited temperature range up to 200 °C. Subsequently, NIST piloted and participated in an international intercomparison of infrared spectral emittance with the national measurement institutes of France, Germany, Italy and Japan. The overall agreement of the results provides a strong validation of NIST's methodologies and uncertainty budgets. Most recently, to address the current lack of standards for total emittance, measurements are being extended to wavelengths up to 100 μm. Finally, angle-dependent emittance measurements are being implemented, which will also provide sufficient data for the calculation of hemispherical emittance.

Johnson Noise Thermometry is an electronic approach to measuring temperature. For several years, NIST has been developing a switching-correlator-type Johnson-noise thermometer that uses a quantized voltage noise source as an accurate voltage reference. When this method is used to measure resistors at the triple-point of water, the system creates a direct electronic method for determining the ratio of the Boltzmann constant k to the Planck constant h. In 2010, NIST optimized the JNT system for use with 100 Ω sense resistors and produced a determination for k with a relative standard uncertainty of 12×10−6. In order to further validate and improve the measurement method, we modified the system to operate with a 200 Ω resistor source instead of the 100 Ω source. In this paper, we summarize the technical challenges and achievements to date and project what is achievable in the near future.

In this work, the randomness analysis of Grain-128 stream cipher algorithm by using NIST Statistical Test Suite is introduced. The NIST Statistical Test Suite is applied to determine the randomness of this algorithm. The Grain - 128 is based on LFSR, NLFSR and Boolean function with suitable for limited resources like gate count, power consumption and area chip. It uses 128-bit key and 96-bit initial value (IV). Based on our result of conducting the analysis, we obtained that this algorithm is not random at the 1% significance level.

Measurement results from the calibration performed at NIST of ten new type S thermocouples have been analyzed to estimate the extrapolation error. Thermocouples have been calibrated at the fixed points of Zn, Al, Ag and Au and calibration curves were calculated using different numbers of FPs. It was found for these thermocouples that the absolute value of the extrapolation error, evaluated by measurement at the Au freezing-point temperature, is at most 0.10 °C and 0.27 °C when the fixed-points of Zn, Al and Ag, or the fixed-points of Zn and Al, are respectively used to calculate the calibration curve. It is also shown that absolute value of the extrapolation error, evaluated by measurement at the Ag freezing-point temperature is at most 0.25 °C when the fixed-points of Zn and Al, are used to calculate the calibration curve. This study is oriented to help those labs that lack a direct mechanism to achieve a high temperature calibration. It supports, up to 1064 °C, the application of a similar procedure to that used by Burns and Scroger in NIST SP-250-35 for calibrating a new type S thermocouple. The uncertainty amounts a few tenths of a degree Celsius.

We propose a modified encryption scheme based on 256 bit bent Boolean function and Feedback with Carry Shift Register. We estimated the output bits properties by the NIST, DIEHARD and ENT test packages. The results of the cryptanalysis show that the new cryptographic scheme provides an exclusive level of data security.

The world-wide ageing and deteriorating civil infrastructure network has necessitated the development of new Structural Health Monitoring (SHM) approaches that are capable of producing quantitative feedback on fracture mechanisms in critical civil structures such as bridges in real-time. In this paper, we present a methodology that combines techniques applied in quantitative seismological analyses with the enabling capabilities of the Acoustic Emission (AE) technique in order to gain insight into ongoing fracture processes in concrete structures. The proposed methodology employs the technique of Moment Tensor Inversion (MTI), a key analysis tool in seismology, in order to develop a full understanding of the physics of the source of fracture and infer its properties. The MTI technique is simple in concept but solution accuracy is highly dependent on the sampling of the wavefield in 3-D, especially in the case where the sensors are all uniaxial. For accuracy purposes, all our experiments were performed using high-fidelity Glaser/NIST point-contact sensors that show a flat response for frequencies between 20 kHz and 1 MHz. In this paper, we provide a general description of the proposed methodology with emphasis on the so-called hybrid MTI technique. Finally, we present a set of initial experiments conducted in the laboratory using repeatable artificial AE sources and we discuss the results.

We have recently updated the uncertainty budgets for calibrations in the NIST Thermocouple Calibration Laboratory. The purpose for the updates has been to 1) revise the estimated values of the relevant uncertainty elements to reflect the current calibration facilities and methods, 2) provide uncertainty budgets for every standard calibration service offered, and 3) make the uncertainty budgets more understandable to customers by expressing all uncertainties in units of temperature (°C) rather than emf. We have updated the uncertainty budgets for fixed-point calibrations of type S, R, and B thermocouples and comparison calibrations of type R and S thermocouples using a type S reference standard. In addition, we have constructed new uncertainty budgets for comparison calibrations of type B thermocouples using a type B reference standard as well as using both a type S and type B reference standard (for calibration over a larger range). We have updated the uncertainty budgets for comparison calibrations of base-metal thermocouples using a type S reference standard and alternately using a standard platinum resistance thermometer reference standard. Finally, we have constructed new uncertainty budgets for comparison tests of noble-metal and base-metal thermoelements using a type S reference standard. A description of these updates is presented in this paper.

Eight papers published by the National Institute of Standards and Technology (NIST) EBIT spectroscopy team and collaborators from mid-2009 to mid-2011 are summarized. Previous discussions of the D-lines in Na-like ions and the Lyman-alpha lines in H-like ions are updated with new information. Nine issues related to the accurate use of Fe XVII x-ray lines for plasma diagnostics are enumerated. Work by ourselves and others to combine an EBIT and a synchrotron in the hard and soft x-ray regimes is compared and contrasted.

We propose a new cryptographic scheme based on the Lorenz chaos attractor and 32 bit bent Boolean function. We evaluated the keystream generated by the scheme with batteries of the NIST statistical tests. We also applied a number of statistical analysis techniques, such as calculating histograms, correlations between two adjacent pixels, information entropy, and differential resistance, all refer to images encrypted by the proposed system. The results of the analysis show that the new cryptographic scheme ensures a secure way for sending digital data with potential applications in real-time image encryption.

Piezoelectric shakers are well suited to generate motion suitable for use with laser interferometric methods at frequencies of 3 kHz and above. One advantage of piezoelectric shakers is the higher achievable accelerations and displacement amplitudes as compared to electrodynamic (ED) shakers. Another advantage is the use of a solid ceramic construction rather than a compliant suspension system which results in much lower mechanical noise. Piezoelectric shakers have been developed and used at NIST for many years for high frequency calibration of accelerometers. Previous papers have documented the performance of these shakers for the calibration of accelerometers over the range of 3 kHz to 25 kHz using interferometric calibration methods. Piezoelectric shakers with solid ceramic construction coupled with new high resolution data acquisition systems have made it possible to extend the calibration of accelerometers to smaller amplitudes and a broader range of frequencies. These factors have also allowed calib...

The semiconductor manufacturing industry is now facing serious challenges in achieving defect detection rates with acceptable throughput and accuracy. With conventional bright‐field and dark‐field inspection methods now at their limits, it has become essential to explore alternative optical methods such as angle‐resolved scatterfield microscopy, 193 nm short wavelength solutions, and coherent illumination. In this paper we evaluate new optical technologies capable of extending high throughput defect inspection beyond the 22 nm node. We investigate source optimization for angle and polarization resolved illumination, measurement wavelengths down to 193 nm and interference microscopy using electromagnetic simulations and laboratory apparatus. Illumination engineering techniques recently developed at the National Institute of Standards and Technology (NIST), based on a bright‐field optical platform, are applied to signal‐based defect analysis of features with dimensions well below the measurement wavelength. A key to this approach is tailoring the illumination as a function of angle and polarization to targets of interest.

NBS‐1 is the US national neutron reference source. It has a neutron emission rate (June 1961) of 1.257×106 n/s1,2,3 with an uncertainty of 0.85% (k = 1). Neutron emission‐rate calibrations performed at the National Institute of Standards and Technology (NIST) are made in comparison to this source, either directly or indirectly. To calibrate a commercial 14 MeV neutron generator, NIST performed a set of comparison measurements to evaluate the neutron output relative to NBS‐1. The neutron output of the generator was determined with an uncertainty of about 7% (k = 1). The 15‐hour half‐life of one of the reactions used also makes possible off‐site measurements. Consideration is given to similar calibrations for a 2.5 MeV neutron generator.

New versions of the NIST Atomic Spectra Database (ASD, v. 4.0) and three bibliographic databases (Atomic Energy Levels and Spectra, v. 2.0, Atomic Transition Probabilities, v. 9.0, and Atomic Line Broadening and Shapes, v. 3.0) have recently been released. In this contribution I will describe the main changes in the way users get the data through the Web. The contents of ASD have been significantly extended. In particular, the data on highly ionized tungsten (W III–LXXIV) have been added from a recently published NIST compilation. The tables for Fe I and Fe II have been replaced with newer, much more extensive lists (10000 lines for Fe I). The other updated or new spectra include H, D, T, He I–II, Li I–III, Be I–IV, B I–V, C I–II, N I–II, O I–II, Na I–X, K I–XIX, and Hg I. The new version of ASD now incorporates data on isotopes of several elements. I will describe some of the issues the NIST ASD Team faces when updating the data.

Piezoelectric shakers have been developed and used at the National Institute of Standards and Technology (NIST) for decades for high‐frequency calibration of accelerometers. Recently, NIST researchers built new piezoelectric shakers in the hopes of reducing the uncertainties in the calibrations of accelerometers while extending the calibration frequency range beyond 20 kHz. The ability to build and measure piezoelectric shakers invites modeling of these systems in order to improve their design for increased performance, which includes a sinusoidal motion with lower distortion, lower cross‐axial motion, and an increased frequency range. In this paper, we present a model of piezoelectric shakers and match it to experimental data. The equations of motion for all masses are solved along with the coupled state equations for the piezoelectric actuator. Finally, additional electrical elements like inductors, capacitors, and resistors are added to the piezoelectric actuator for matching of experimental and theore...

Calibration of vibration transducers requires sinusoidal motion over a wide frequency range with low distortion and low cross‐axial motion. Piezoelectric shakers are well suited to generate such motion and are suitable for use with laser interferometric methods at frequencies of 3 kHz and above. An advantage of piezoelectric shakers is the higher achievable accelerations and displacement amplitudes as compared to electro‐dynamic (ED) shakers. Typical commercial ED calibration shakers produce maximum accelerations from 100 m/s2 to 500 m/s2. Very large ED shakers may produce somewhat higher accelerations but require large amplifiers and expensive cooling systems to dissipate heat. Due to the limitations in maximum accelerations by ED shakers at frequencies above 5 kHz, the amplitudes of the generated sinusoidal displacement are frequently below the resolution of laser interferometers used in primary calibration methods. This limits the usefulness of ED shakers in interferometric based calibrations at higher frequencies.Small piezoelectric shakers provide much higher acceleration and displacement amplitudes for frequencies above 5 kHz, making these shakers very useful for accelerometer calibrations employing laser interferometric measurements, as will be shown in this paper. These piezoelectric shakers have been developed and used at NIST for many years for high frequency calibration of accelerometers. This paper documents the construction and performance of a new version of these shakers developed at NIST for the calibration of accelerometers over the range of 3 kHz to 30 kHz and possibly higher. Examples of typical calibration results are also given.

NIST recently released a standard reference material (SRM) for the calibration of high resolution X‐ray diffraction (HRXRD) instruments. HRXRD is extensively used in the characterization of lattice distortion in thin single, epitaxial crystal layers on single‐crystal wafer substrates. Currently, there is a great need for improved accuracy and transferability for the measurement of strain fields in these epitaxial thin films. This implies an essential need for the calibration of HRXRD instruments to allow measurement intercomparison for both research and manufacturing communities. This first HRXRD SRM release provides certified measurements of diffraction features for a silicon reference substrate, Si (220) in transmission and Si (004) in reflection, allowing for calibration of either monochromator wavelength or goniometer angles. The SRM also provides information on the surface‐to‐crystal‐plane misalignment, which allows calibration of sample holders and sample alignment hardware. This calibration should reduce the uncertainties when comparing, for instance, reciprocal space maps. Here we present a detailed description of these measured values and provide methods for using these to calibrate HRXRD instrumentation. SRM 2000 provides the semiconductor and the larger nanoscience community with the first nanometer length‐scale reference standard with femtometer accuracy; the Si (220) transmission‐feature‐derived silicon lattice spacing, dSRM, has a value of 0.1920161 nm with an expanded uncertainty, U (dSRM), of 0.87 fm.

SPTpol will consist of an 850 element polarization sensitive bolometric camera deployed to the South Pole Telescope in late 2011. This camera is optimized for measurement of the polarization of the cosmic microwave background with arcminute resolution. These measurements will be used to constrain neutrino masses and to constrain the amplitude of gravitational waves from inflation. The camera includes two detector architectures that observe in two different frequency bands. At 150 GHz, SPTpol will use 650 feedhorn‐coupled TES polarimeters fabricated at NIST. At 90 GHz, it will use 200 absorber‐coupled polarimeters developed at Argonne National Lab. The NIST pixels will be coupled to the telescope using a monolithic array of corrugated feeds and the Argonne devices will be coupled with individually machined contoured feeds. The entire focal plane will be readout using a digital frequency‐domain multiplexer system. We provide an overview of the project, describe the detectors and discuss the design of this system.

A decade has elapsed since the design, development and realization of a SQUID‐based time‐division multiplexer at NIST. During this time the system has been used extensively for low‐temperature‐detector‐array measurements. Concurrently, there have been substantial advancements both in detector array and commercial electronic component technology. The relevance and applicability of the technology has blossomed as well, often accompanied by more demanding measurement requirements. These factors have motivated a complete redesign of the NIST room‐temperature read‐out electronics. The redesign has leveraged advancements in component technology to achieve new capabilities better suited to the SQUID multiplexers and detector arrays being realized today. As examples of specific performance enhancements, the overall system bandwidth has been increased by a factor of four (a row switching rate of 6.24 MHz), the compactness has been increased by over a factor of two (a higher number of detector columns and rows per circuit board), and there are two high speed outputs per column (allowing fast switching of SQUID offsets in addition to digital feedback). The system architecture, design implementations, and performance advantages of the new system will be discussed. As an application example, the science chain flight electronics for the Micro‐X High Resolution Microcalorimeter X‐ray Imaging Rocket will be described as both a motivation for, and a direct implementation of the new system.

Photon activation analysis detected elements in two NIST standards that did not have reported concentration values. A method is currently being developed to infer these concentrations by using scaling parameters and the appropriate known quantities within the NIST standard itself. Scaling parameters include: threshold, peak and endpoint energies; photo-nuclear cross sections for specific isotopes; Bremstrahlung spectrum; target thickness; and photon flux. Photo-nuclear cross sections and energies from the unknown elements must also be known. With these quantities, the same integral was performed for both the known and unknown elements resulting in an inference of the concentration of the un-reported element based on the reported value. Since Rb and Mn were elements that were reported in the standards, and because they had well-identified peaks, they were used as the standards of inference to determine concentrations of the unreported elements of As, I, Nb, Y, and Zr. This method was tested by choosing other known elements within the standards and inferring a value based on the stated procedure. The reported value of Mn in the first NIST standard was 403{+-}15 ppm and the reported value of Ca in the second NIST standard was 87000 ppm (no reported uncertainty). The inferred concentrations weremore » 370{+-}23 ppm and 80200{+-}8700 ppm respectively.« less

This work provides a method for determining when X‐ray reflectometry (XRR) data provides useful information about structural model parameters. State‐of‐the‐art analysis approaches for XRR data emphasize fitting measured data to a single structural model using fast optimization methods, such as genetic algorithms (GA). Though such optimization may find the best solution for a given model, it does not adequately map the parameter space to provide uncertainty estimates or test structural model validity. We present here two approaches for determining which structural parameters convey accurate information about the physical reality. First, using GA refinement, we repeatedly fit the data to several structural models. By comparing the maximum‐likelihood estimates of the parameters in each model, we identify model‐independent information. Second, we perform a Monte Carlo Markov Chain (MCMC) analysis using the most self‐consistent structural model to provide uncertainty estimates for structural parameters. This t...

Dr. Kim made internationally recognized contributions in many areas of atomic physics research and applications, and was still very active when he was killed in an automobile accident. He joined NIST in 1983 after 17 years at the Argonne National Laboratory following his Ph.D. work at the University of Chicago. Much of his early work at Argonne and especially at NIST was the elucidation and detailed analysis of the structure of highly charged ions. He developed a sophisticated, fully relativistic atomic structure theory that accurately predicts atomic energy levels, transition wavelengths, lifetimes, and transition probabilities for a large number of ions. This information has been vital to model the properties of the hot interior of fusion research plasmas, where atomic ions must be described with relativistic atomic structure calculations. In recent years, Dr. Kim worked on the precise calculation of ionization and excitation cross sections of numerous atoms, ions, and molecules that are important in fusion research and in plasma processing for manufacturing semiconductor chips. Dr. Kim greatly advanced the state‐of‐the‐art of calculations for these cross sections through development and implementation of highly innovative methods, including his Binary‐Encounter‐Bethe (BEB) theory and a scaled plane wave Born (scaled PWB) theory. His methods, using closed quantum mechanical formulas and no adjustable parameters, avoid tedious large‐scale computations with main‐frame computers. His calculations closely reproduce the results of benchmark experiments as well as large‐scale calculations requiring hours of computer time. This recent work on BEB and scaled PWB is reviewed and examples of its capabilities are shown.

Extreme‐ultraviolet (EUV) lithography is slated for introduction in the 2012 time frame for volume production of chips with 32‐nm design rules. NIST has a program to perform metrology on the multilayer mirrors used to focus the 13.5 nm EUV radiation employed in the stepper. This program includes accurate mirror reflectivity measurements and accelerated lifetime testing. One of the major obstacles to attaining high volume manufacturing is lifetime of the mirrors comprising the projection system. Ongoing endurance testing of Ru‐capped multilayer mirrors at the National Institute of Standards and Technology synchrotron facility has revealed that the damage resulting from EUV irradiation does not in general depend on the exposure conditions in an intuitive way. Previous exposures of Ru‐capped multilayers to EUV radiation in the presence of water vapor demonstrated that the mirror damage rate actually decreases with increasing water pressure. We will present results of recent exposures showing that the reducti...

Small Signal Surface Photo Voltage (SPV) measurement has become a widely accepted metrology for measuring resistivity of epitaxial and Czochralski wafers. For this metrology technique there are currently no Standard Reference Matertials (SRMs®) as defined by the National Institute of Standards and Technology (NIST). This paper will present a method for creating a NIST traceable standard for SPV measurement by further processing NIST 100 mm diameter silicon resistivity, SRM 2543 wafers.

The National Institute of Standards and Technology (NIST) is developing two interferometric methods for measuring the thickness, thickness variation, and flatness of free‐standing and chucked silicon wafers with diameters up to 300 mm. The “eXtremely accurate CALIBration InterferometeR” (XCALIBIR) is a precision phase measuring interferometer with an operating wavelength of 633 nm and a test beam of 300 mm diameter. XCALIBIR is used to evaluate the flatness of chucked wafers. NIST’s Infrared Interferometer (IR2) is a phase measuring interferometer that operates at 1.55 μm and is used to measure the thickness variation of free‐standing 300 mm silicon wafers.

We have developed an ab initio multi‐configuration Dirac‐Fock‐Sturm method for the precise calculation of X‐ray emission spectra, including energies, transition wavelengths and transition probabilities. The calculations are based on non‐orthogonal basis sets, generated by solving the Dirac‐Fock and Dirac‐Fock‐Sturm equations. Inclusion of Sturm functions into the basis set provides an efficient description of correlation effects in highly charged ions and fast convergence of the configuration interaction procedure.A second part of our study is devoted to developing a theoretical procedure and creating an interactive database to generate energies and transition frequencies for hydrogen‐like ions. This procedure is highly accurate and based on current knowledge of the relevant theory, which includes relativistic, quantum electrodynamic, recoil, and nuclear size effects.

Three atomic spectroscopic databases of the U.S. National Institute of Standards and Technology are reviewed. First, our principal spectroscopic database, the Atomic Spectra Database (ASD), is discussed, which will soon be put on the internet in a new, entirely redesigned and expanded version 3.0. This new edition will include several additional critical compilations that were recently completed at NIST. Furthermore, two new smaller specialized databases will be reviewed, — a handbook of basic atomic spectroscopic data and a tabulation of data for soft x‐ray lines, tailored to the needs of x‐ray space observatories. Finally, an overview of our plans for new critical data compilations during the next two‐to‐three years will be presented.

Two facilities have been constructed at NIST for realizing and maintaining the ITS‐90 below 84 K. The first facility is an integrated low temperature realization system that realizes the ITS‐90 below 84 K in its entirety and which we refer to as the Low Temperature ITS‐90 Realization Facility (LTRF). The second facility, known as the Low Temperature Calibration Facility (LTCF) is a multi‐purpose low temperature facility for scale dissemination and maintenance and for realization of certain ITS‐90 triple points in sealed cells. We present a description of the refrigeration, temperature‐control, and resistance‐measurement systems of the NIST LTRF and LTCF. For the LTRF, we also describe the realization cells and the copper block which contains them, the gas control system, and the pressure measurement system. The comparison and triple‐point realization systems of the LTCF are likewise described. The design parameters of NIST fixed point cells as used in both facilities are given. The origin and purity of the NIST fixed‐point materials as used in both facilities are given along with the isotopic content in the case of hydrogen.

The National Institute of Standards and Technology (NIST) Industrial Thermometer Calibration Laboratory (ITCL) is responsible for calibrating several different types of industrial thermometers. One of those types is the liquid‐in‐glass (LiG) thermometer, which includes both mercury (partial and total immersion) and organic (total immersion) filled models. Over the past two years, improvements in both calibration equipment and software used in the ITCL has led to a new assessment of the uncertainties assigned to the calibration of LiG thermometers covering the temperature range from −20 °C to 400 °C. In total, eighteen thermometers from three different manufacturers, six of which are mercury‐filled partial immersion, twelve of which are mercury‐filled total immersion, and two of which are organic‐filled total immersion models, were used for the determination of LiG thermometer calibration uncertainties over the range from −20 °C to 400 °C in the NIST ITCL.

The program in fundamental neutron physics at the National Institute of Standards and Technology (NIST) began nearly two decades ago. The Neutron Interactions and Dosimetry Group currently maintains four neutron beam lines dedicated to studies of fundamental neutron interactions. The neutrons are provided by the NIST Center for Neutron Research, a national user facility for studies that include condensed matter physics, materials science, nuclear chemistry, and biological science. The beam lines for fundamental physics experiments include a high-intensity polychromatic beam, a 0.496 nm monochromatic beam, a 0.89 nm monochromatic beam, and a neutron interferometer and optics facility. This paper discusses some of the parameters of the beam lines along with brief presentations of some of the experiments performed at the facilities.

A calibration facility has been developed to measure the peak diameter of particles suspended in liquid using differential mobility analysis (DMA). A description of the facility and the features that contribute to measurements with low uncertainties is included. Analysis of the DMA convolution integral allows correcting for the effects of charging probability, size distribution, and transfer function on the measured peak particle size. Current research using electrospray to aerosolize the particles is aimed at expanding the measurement size interval.

A system for monitoring the dynamic temperature profile during the deep UV (DUV) post‐exposure bake (PEB) is described. Platinum resistance temperature detectors (RTDs) are embedded into silicon wafers. Hardware and software convert the resistances to temperatures. The RTD calibration is National Institute of Standards and Technology (NIST) traceable. The wafers are tested on both a thermally uniform and stable hot plate and a production PEB hot plate. The temperature profiles for the PEB are fitted to a heat transfer model allowing heating and cooling time constants to be determined. High accuracy and precision are demonstrated. Reliability through 2000 thermal cycles is shown.

The argon triple point is a required reference point for calibration of standard platinum resistance thermometers (SPRTs) on the International Temperature Scale of 1990 (ITS‐90) for use in all four subranges extending below the triple point of mercury. Availability of affordable, commercially produced apparatus to realize the triple point of argon has been very limited. A portable apparatus, integrated with an interactive microprocessor control, liquid‐nitrogen cooling and a sealed argon cell containing approximately 1.8 mol of high purity argon is described. Operating procedures for use of the apparatus, developed with input from personnel at the National Institute for Standards and Technology (NIST), are presented. Following these procedures, measurements of multiple plateaus realized by the apparatus (made using the NIST argon reference SPRT and measurement system) show agreement with the NIST apparatus realization within ±0.1 mK.

Lightpipe radiation thermometers (LPRTs) are the sensor of choice for temperature measurements in Rapid Thermal Processing (RTP) applications. At the National Institute of Standards and Technology (NIST), we have developed protocols for calibrating and characterizing LPRTs for use in RTP and other applications. In this paper, the LPRTs and the sodium heat pipe blackbody (Na‐HPBB) used in the calibration process at NIST will be introduced. The calibration and characterization methods (spatial response, spectral response, temporal response, and optical inspection) of the LPRTs will be described also. Finally, a discussion of the application of LPRTs in an environment outside of the calibration laboratory, along with a list of recommendations for proper use of LPRTs, will be presented.

NIST's Ionizing Radiation Division maintains and operates three electron accelerators used in a number of applications including waste treatment and sterilization, radiation hardness testing, detector calibrations and materials modification studies. These facilities serve a large number of governmental, academic and industrial users as well as an active intramural research program. They include a 500 kV cascaded-rectifier accelerator, a 2.5 MV electron Van de Graaff accelerator and a 7 to 32 MeV electron linac, supplying beams ranging in energy from a few keV up to 32 MeV. In response to the recent anthrax incident, NIST along with the US Postal Service and the Armed Forces Radiobiology Research Institute (AFRRI) are working to develop protocols and testing procedures for the USPS mail sanitization program. NIST facilities and personnel are being employed in a series of quality-assurance measurements for both electron- and photon-beam sanitization. These include computational modeling, dose verification and VOC (volatile organic compounds) testing using megavoltage electron and photon sources.

NIST and International SEMATECH are developing single‐crystal reference materials for use in evaluating and calibrating critical dimension (CD) metrology tools. Primary calibration of these reference materials uses a high‐resolution transmission electron microscopy (HRTEM) image of the cross section of the feature at sufficient magnification to resolve and count the individual lattice planes; the transfer calibration is provided by complementary metrology techniques. In previous work, electrical test structure metrology served as the transfer metrology. Recent work has centered on evaluating the performance of these CD reference materials in the metrology tools which we expect will comprise the bulk of their usage: the critical dimension scanning electron microscope (CD‐SEM) and atomic force microscope (AFM). In particular, a critical dimension AFM (CD‐AFM) is particularly useful. This technique uses flared tips and two‐dimensional feedback to allow scanning of near‐vertical sidewalls. It is currently expected that CD‐AFM will serve as an additional transfer calibration technique. Additionally, since earlier samples showed a high variability in the appearance of the samples, additional screening using the CD‐SEM and AFM will provide significant improvement to verify that each device meets minimal uniformity characteristics.

The first phase of the EU collaborative project on sub‐kelvin thermometry, ‘ULT Dissemination’, is nearing completion, leading to the development of several thermometers and devices, and the instrumentation needed to disseminate the new Provisional Low Temperature Scale, PLTS‐2000, to users. Principal among these are a current‐sensing noise thermometer (CSNT), a CMN thermometer adapted for industrial use, a Coulomb blockade thermometer, a second‐sound acoustic thermometer and a superconductive reference device SRD‐1000. Several partners have set up 3He melting‐pressure thermometers to realise the PLTS‐2000, and will check it using Pt‐NMR, CMN and other thermometers. The scale, which was formally adopted by the Comite International des Poids et Mesures in October 2000, covers the range of temperature from 1 K down to 0.9 mK, and is defined by an equation for the melting pressure of 3He. The SRD employs novel fabrication and detection techniques with up to 10 samples, and is expected to meet the requirement for fixed points below 1 K, formerly filled by the NIST SRM 767 and 768. Other devices included in the project are ruthenium oxide sensors and a self‐contained 3He melting pressure thermometer. This paper reviews the project progress to date and indicates the potential for research, metrological and industrial application of the devices developed.

The National Institute of Standards and Technology (NIST) is responsible for realizing, maintaining, and disseminating the International Temperature Scale of 1990 (ITS‐90) to the United States of America. The ITS‐90 fixed‐point cells necessary to calibrate standard platinum resistance thermometers (SPRTs) require an extensive internal measurement assurance program to insure that the assigned fixed‐point cell uncertainties are achieved. There are six interactive elements for the realization of an ITS‐90 fixed‐point cell that contribute to the uncertainty of an SPRT calibration. These six elements are the fixed‐point cells, furnace/maintenance systems, SPRT, measurement system, realization techniques, and measurement assurance. Within these six elements, there are twenty‐eight parameters that are used to quantify and maintain the NIST‐assigned fixed‐point cell and SPRT calibration uncertainties.

The results at NIST of realizations and comparisons of the ITS‐90 below 84 K are presented. The 3He and 4He vapor pressure scales (0.65 K to 5.0 K), and the interpolating constant volume gas thermometer (ICVGT) scale (5.0 K to 24.556 K) as realized from 1994 to 1996 are carried on a series of five check rhodium‐iron resistance thermometers (RIRTs) which are periodically compared. The triple points of e‐H2, Ne, O2, and Ar have been realized using a variety of cells and gas sources over the last six years. The resistance ratios of seven check capsule‐type Standard Platinum Resistance Thermometers (SPRTs) at these triple points as well as the e‐H2 vapor pressure points realized since 1994 are summarized. These check SPRTs are periodically compared with each other and with the check RIRTs. Comparisons of the NIST realizations as recorded on these RIRTs and SPRTs are presented. Comparison results compiled since 1997 are presented relative to those RIRT resistances and SPRT resistance ratios that were submitted by NIST for the Consultative Committee on Thermometry (CCT) Key Comparisons (KC‐1 and KC‐2). Data from some NIST triple‐point realizations are compared to those from sealed triple‐point cells (STPCs) which were submitted by NIST to the PTB International Comparison of STPCs.

Two primary standard calorimeters have been developed for accurate measurements of 157 nm (F2) excimer laser power and energy. The calorimeter specifications and design are discussed. Results from the construction and testing of the calorimeters, control electronics, data acquisition, and N2 purge system are presented. These calorimeters have demonstrated a two‐fold improvement in sensitivity over existing NIST excimer laser calorimeters. The measurement uncertainty from electrical calibrations is a five‐fold improvement over the NIST 193 nm primary standard.

The National Institute of Standards and Technology metrology development for the semiconductor industry and its supporting infrastructure is a broad set of programs directed at many of the critical metrology needs. This paper will give examples of specific projects addressing needs in lithography, critical dimension and overlay, gate dielectric characterization, interconnect materials, and manufacturing support. The paper will emphasize the role collaboration with industry plays in project selection, project success, and transfer to industry.