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Vat photopolymerization (VP) is a rapidly growing category of additive manufacturing. As VP methods mature the expectation is that the quality of printed parts will be highly reproducible. At present, detailed characterization of the light engines used in liquid crystal display (LCD)-based VP systems is lacking and so it is unclear if they are built to sufficiently tight tolerances to meet the current and/or future needs of additive manufacturing. Herein, we map the irradiance, spectral characteristics, and optical divergence of a nominally 405 nm LCD-based VP light engine. We find that there is notable variation in all of these properties as a function of position on the light engine that cause changes in extent of polymerization and surface texture. We further demonstrate through a derived photon absorption figure of merit and through printed test parts that the spatial heterogeneity observed in the light engine is significant enough to affect part fidelity. These findings help to explain several possible causes of variable part quality and also highlight the need for improved optical performance on LCD-based VP printers.

After we replaced the argon mini-arc with a laser-driven light source in the Ultraviolet Spectral Comparator Facility at the National Institute of Standards and Technology (NIST), we realized that the optical power should be sufficient to use the comparator system for absolute-cryogenic radiometry. Calibrating working standard detectors directly against an absolute-cryogenic radiometer in the system used for calibrations would eliminate all uncertainties resulting from the use of transfer standards, which were calibrated in a separate system using a different light source and optics. The transfer standards are the middlemen we refer to in the title. Any uncertainty caused by differences in bandpass, out-off-band radiation, spectral purity, collimation, or data interpolation would be removed. In the end, we successfully set up a twin system resembling the Ultraviolet Spectral Comparator Facility and used this system to perform a primary calibration of several photodiodes, based on an absolute-cryogenic radiometer. Using this system, we were able to reduce relative standard uncertainties at wavelengths below 220 nm from above 1 % ( k = 1 ) to below 0.5%. We refer to this system as the Ultraviolet Scale Realization Facility or UV-SRF.

We have developed a new method for the exact calculation of synchrotron radiation for the National Institute of Standards and Technology Synchrotron Ultraviolet Radiation Facility, SURF III. Instead of using the Schwinger formula, which is only an approximation, we develop formulae based on Graf’s addition theorem for Bessel functions and accurate asymptotic expansions for Hankel functions and Bessel functions. By measuring the radiation intensity profile at two distances from the storage ring, we also confirm an apparent vertical emittance that is consistent with the vertical betatron oscillations that are intentionally introduced to extend beam lifetime by spreading the electron beam spatially. Finally, we determine how much diffraction by beamline apertures enhances the spectral irradiance at an integrating sphere entrance port at the end station. This should eliminate small but treatable components of the uncertainty budget that one should consider when using SURF III or similar synchrotrons as standard, calculable sources of ultraviolet and other radiation. https://doi.org/10.1063/1.5018412

IR-enhanced Si photodiodes have improved radiometric and electronic characteristics as compared to other widely used Si photodiodes and can be used as responsivity standards in the wavelength range from 300 nm to 1000 nm. Their low predicted uncertainty for radiant power responsivity measurements can result in improvements in the existing monochromator-based Si responsivity scales. They have several advantages over traditionally used Si-trap detectors, such as wider acceptance angle, higher shunt resistance, and higher responsivity in the NIR region. Radiometric and electronic measurement results are discussed to illustrate these characteristics. The spectral power responsivity scales can be improved using a set of the IR-enhanced Si photodiodes not only to transfer the calibration from the cryogenic radiometer, but for use in the monochromator facility as working standards. This improvement will reduce the length of the calibration chain and create a one-step scale transfer between the cryogenic radiometer- and the monochromator-based facility.

Interest in the use of synchrotron radiation (SR) as a source of continuum in the extreme ultraviolet (EUV) spectral region was stimulated by the 1956 Physical Review article by Diran Tomboulian and Paul Hartman [1] of Cornell University. In their all-too-brief access to the Cornell 320 MeV electron synchrotron, they showed that SR should be an extremely useful intensity standard in the EUV. They also showed the continuum nature of SR by observing structure at the K-edge of Be at 112 eV.

The Seventeenth Pan-American Synchrotron Radiation Instrumentation Conference (SRI-2013) was held at NIST (Gaithersburg, MD, USA) from June 17–21, 2013, and was co-chaired by Cornell/CHESS and Jefferson Lab. The two and one-half day meeting, preceded by two days of workshops, was attended by some 150 delegates and was considered a big success, despite new US governmental travel restrictions that limited attendance. All the major Pan-American institutions as well as several European and Asian ones were represented. The meeting focused much more on instrumentation than last year's larger international meeting, SRI-2012, in Lyons, France, and was characterized by sessions and posters that provided a good overview of the field and its frontiers. The smaller meeting also afforded many opportunities for lively discussions and networking, and thus generally fulfilled the initial intent of this meeting series that was initiated at NIST, then the National Bureau of Standards (NBS), in 1979.

At present, broadband radiometric measurements of LEDs with uniform and low-uncertainty results are not available. Currently, either complicated and expensive spectral radiometric measurements or broadband photometric LED measurements are used. The broadband photometric measurements are based on the CIE standardized V(λ) function, which cannot be used in the UV range and leads to large errors when blue or red LEDs are measured in its wings, where the realization is always poor. Reference irradiance meters with spectrally constant response and high-intensity LED irradiance sources were developed here to implement the previously suggested broadband radiometric LED measurement procedure [1, 2]. Using a detector with spectrally constant response, the broadband radiometric quantities of any LEDs or LED groups can be simply measured with low uncertainty without using any source standard. The spectral flatness of filtered-Si detectors and low-noise pyroelectric radiometers are compared. Examples are given for integrated irradiance measurement of UV and blue LED sources using the here introduced reference (standard) pyroelectric irradiance meters. For validation, the broadband measured integrated irradiance of several LED-365 sources were compared with the spectrally determined integrated irradiance derived from an FEL spectral irradiance lamp-standard. Integrated responsivity transfer from the reference irradiance meter to transfer standard and field UV irradiance meters is discussed.

We report on a successful bilateral intercomparison between the Physikalisch-Technische Bundesanstalt (PTB) and the National Institute of Standards and Technology (NIST). In both laboratories deuterium lamps were calibrated using the calculability of synchrotron radiation. However, the methods applied in the two laboratories differed significantly. Whereas the calibrations at PTB were performed in vacuum and led to spectral radiant intensities, the measurements at NIST were done in air and resulted in spectral irradiances. Therefore, for this bilateral comparison we not only proved the equivalence of the two measurement procedures, but also the validity of the conversion between the different spectro-radiometric quantities. This successful comparison re-establishes the usefulness of deuterium lamps as transfer standards in the ultraviolet spectral range.

In 2004, the National Institute of Standards and Technology established the ultraviolet spectral irradiance scale from 200 nm to 400 nm using the calculable irradiance of the Synchrotron Ultraviolet Radiation Facility (SURF). Since the establishment of the scale, spectral irradiance calibrations of many customer lamps have been performed in direct comparison with synchrotron radiation. However, to ensure long-term stability of the scale, three check-standard deuterium lamps were calibrated using SURF III at the same time as customer lamps were being calibrated. Here, we present the results of the long-term monitoring of the scale using these check-standard lamps to ensure customer lamps are calibrated within the expanded calibration uncertainty (k = 2) of 1.2%.

We report theory and measurements of a simple and absolute technique for the determination of the total emitted spectral fluorescence yield inside an integrating sphere from the sphere coating under irradiation with a monochromatic beam. This technique measures the spectral response of a monochromator–detector system to the radiation exiting from an integrating sphere. The total spectral fluorescence yield can be calculated from the response measurement and an overall responsivity function that is obtained by calibrating the system with a standard source. This technique provides quantitative fluorescence analysis of the coating of an integrating sphere wall.

Synchrotron radiation was recognized as an important tool for radiometry shortly after the advent of dedicated storage rings as radiation sources more than four decades ago. [1] Initially, synchrotron radiation was conceived as a calculable primary standard for absolute calibration of radiation sources. With the explosion of synchrotron radiation facilities around the globe during the last several decades, synchrotron-radiation-based radiometry has been actively pursued among many national standard laboratories in countries including the U.S., Germany, the U.K., Japan, and Russia because of increasing demands from semiconductor photolithography, UV curing industry, medical diagnostics and treatments, and solar radiation monitoring. To date, the use of synchrotron radiation for radiometry is no longer limited to a primary radiation standard. Dispersed synchrotron radiation, although usually not calculable, provides radiation from IR to X-rays for radiometric characterization of detector response and materi...

We report experimental results on the stability of photodiodes obtained at three different wavelengths in the vacuum ultraviolet spectral region. Two of these experiments were based on radiation damage inflicted with excimer lasers at 193 and 157 nm and one of them used 135 nm synchrotron radiation. It was found that the detector degradation rate increased considerably with the photon energy and depended on the structure of the photodiodes. Detectors based on the Si/SiO 2 interface were damaged much faster than Schottky-type diodes or Si diodes with metal passivating layers. Possible damage mechanisms to the Si/SiO 2 interface and its electronic structure are reviewed. In the end, a model to quantify the dependence of the damage on the photon energy is introduced.

We have measured the response of chromium-doped alumina screens to soft x-ray radiation and derived quantum efficiency curves for the energy range from 2.5 to 4.5 keV. Persistent luminescence (or afterglow) from this material is observed for several minutes following the removal of the x-ray source. It is also observed that the luminescence output rises gradually for several minutes before maximizing during x-ray irradiation. In the article we discuss possible sources of this delayed luminescence and its consequences for application of these screens as soft x-ray detectors. Such screens have found application as narrow-band radiation detectors for a hot fusion plasma diagnostic.

A new source-based radiometry beamline was recently constructed at the Synchrotron Ultraviolet Radiation Facility (SURF III). The goal of this beamline is to establish a national source standard with a wide spectral range from the far ultraviolet to the infrared by using the calculability of SURF III. The new beamline is a straight-through white-light beamline with few, if any, optical components involved in delivering the radiation to the user end-station for applications such as source and irradiance intercomparisons. Due to the low tunable operating electron energy of SURF III (from 380 MeV to less than 100 MeV), the beamline is uniquely suited to work in the ultraviolet to infrared spectral range. In this paper we discuss the design of the beamline and present first results on the vertical angular distribution of the radiation determined with filtered radiometers in the ultraviolet, visible and near-infrared spectral ranges.

We have measured the response of chromium-doped alumina screens to vacuum ultraviolet radiation and derived quantum efficiency curves for the energy range from 30 to 300 eV. A model is presented to explain the structure in this curve. In addition, the radiation hardness of such screens, which have found application as narrow-band radiation detectors for a hot fusion plasma diagnostic, is reported here for MeV electrons. Finally, a simple model is constructed to obtain the carrier diffusion length and the bulk efficiency of this material.

The Synchrotron Ultraviolet Radiation Facility (SURF III) at the National Institute of Standards and Technology provides a unique opportunity for high-accuracy ultraviolet (UV) to infrared radiometry due to the 70-fold improvement in the uniformity of the magnetic field from the previous generation of SURF. This improvement enables the properties of the output radiation, such as spectral power, angular spread, and polarization, to be more accurately predicted based on the use of the Schwinger’s equation. The radiation from SURF III is completely characterized by only three parameters, the magnetic field, the radius of the electron beam trajectory, and the electron beam current. For radiometry, the calculability of SURF III provides an important standard light source for source intercomparison. In contrast to the widely used blackbody source where the thermal radiation is completely characterized by the temperature and the emissivity of the blackbody walls, synchrotron radiation extends the wavelength range to UV and x ray which is impractical for blackbody sources. At SURF III, a new beamline, beamline 3, is constructed as a white light beamline for source-based radiometry. We describe the design of the new beamline 3 and its front-end high accuracy electron beam current monitor. This monitor not only measures one of the three fundamental parameters, the electron beam current, it also serves as an electron beam diagnostic tool. We also discuss ways to verify the calculability of SURF III using filter radiometers.

Imaging an electron beam with visible light is a common method of diagnostics applied to electron accelerators. It is a straightforward way to deduce the transverse electron distribution as well as its changes over time. The electrons stored in the Synchrotron Ultraviolet Radiation Facility (SURF) III at the National Institute of Standards and Technology (NIST) were studied over an extended period of time to characterize the upgraded accelerator. There is good agreement between experimental and theoretical horizontal beam sizes at three different electron energies.

The National Institute of Standards and Technology (NIST) operates the newly upgraded Synchrotron Ultraviolet Radiation Facility (SURF III) mainly as a light source for radiometry. SURF III provides continuum radiation from the far-infrared to the soft X-ray spectral range and has its peak output in the extreme ultraviolet. SURF III is a circular-orbit, weak-focusing (single dipole magnet) storage ring, a feature which is advantageous if the synchrotron radiation output is calculated. We report the improvements achieved during a recent upgrade from SURF II to SURF III and our strategy to accurately determine the magnetic flux density, radio frequency (RF), beam current, and beam size, which are the parameters necessary to characterize the source completely.

The completion of the upgrade of the synchrotron facilities at the National Institute of Standards and Technology (NIST) has yielded a better characterized broadband source of ultraviolet (UV) radiation at the Synchrotron Ultraviolet Radiation Facility (SURF III). A cryogenic-radiometer-based facility that uses the monochromatized radiation from SURF III has been established on beamline 4 (BL-4) to characterize detectors and optical materials in the wavelength range 125 nm to 325 nm. This upgraded cryogenic radiometry facility will be used to measure the spectral responsivity of detectors in the UV with a relative standard uncertainty of less than 10 ±2 . To demonstrate the capability of BL-4, we have performed a transmittance measurement of calciumuoride (CaF2 ). Accurate transmittance measurements of optical materials in the UV are urgently needed to evaluate which materials are the best choices for use in making lenses for UV lithography. A study of CaF2 in spectral transmittance, surface scattering, and surface absorption is presented.

Total photoion yield spectra in the vicinity of the 3d thresholds of Xe, Cs and Ba are presented. These spectra were recorded with higher photon energy resolution than previously reported. For xenon the new experimental data reveal additional structures. Employing Hartree-Fock calculations, the origin of the prominent resonances is explained: for Xe and Cs the main absorption features are caused by shape resonances above threshold, whereas for Ba it is revealed that the 4f orbital has finally collapsed and the sharp resonances are caused by discrete excitations into bound states.

We have constructed a new ultraviolet (UV) radiometry facility at the Synchrotron Ultraviolet Radiation Facility (SURF II) at the National Institute of Standards and Technology (NIST). The facility combines a high-throughput normal-incidence monochromator with an absolute cryogenic radiometer (ACR) optimized for UV measurements to provide absolute detector-based radiometric calibrations in the spectral range 125 nm to approximately 320 nm. The system can be configured for spectroradiometric calibration of photodetectors with completely automated mapping of detector spatial and angular responsivity. The facility can easily be adapted for other spectroradiometric measurements including transmittance and reflectance and the spectral range can be extended to about 50 nm.

Sulfur K{beta} x-ray-emission spectra from carbonyl sulfide have been measured with resonant excitation at the sulfur K absorption threshold and compared with results of self-consistent field and singles-doubles configuration-interaction calculations. For excitation to the strong 4{pi} absorption resonance, a splitting of the main emission peak is interpreted in terms of influence of the 4{pi} electron on the final valence-hole states. The polarization selectivity of the emission spectrometer was used to distinguish emission polarized parallel versus perpendicular with respect to the polarization of the excitation radiation. The observed polarization dependence is consistent with the molecular symmetries of the calculated intermediate and final states. {copyright} {ital 1998} {ital The American Physical Society}

This paper reports novel measurements of x-ray optical radiation on an absolute scale from the intense and ultra-short radiation generated in the soft x-ray regime of a free electron laser. We give a brief description of the detection principle for radiation measurements which was specifically adapted for this photon energy range. We present data characterizing the soft x-ray instrument at the Linac Coherent Light Source (LCLS) with respect to the radiant power output and transmission by using an absolute detector temporarily placed at the downstream end of the instrument. This provides an estimation of the reflectivity of all x-ray optical elements in the beamline and provides the absolute photon number per bandwidth per pulse. This parameter is important for many experiments that need to understand the trade-offs between high energy resolution and high flux, such as experiments focused on studying materials via resonant processes. Furthermore, the results are compared with the LCLS diagnostic gas detectors to test the limits of linearity, and observations are reported on radiation contamination from spontaneous undulator radiation and higher harmonic content.

Calculations based on the theory of radiationless resonant Raman scattering are employed in the interpretation of new $\mathrm{Xe}{L}_{3}{\ensuremath{-}M}_{4,5}{M}_{4,5}$ Auger spectra recorded using synchrotron radiation tuned to energies across the ${L}_{3}$ edge. Fits of theoretical line shapes to the spectra are employed in separating intensities due to $\mathrm{nd}$ spectator (resonant) and diagram Auger processes. Near-threshold Auger intensity, previously attributed to diagram decay, is found to be due to the large$\ensuremath{-}n$ spectator lines that result from postcollision-interaction--induced ``recapture'' of threshold photoelectrons to $\mathrm{nd}$ orbitals.

Argon L{sub 2,3}-M{sub 2,3}M{sub 2,3} Auger-electron spectra were measured in coincidence with K{alpha} fluorescent x rays in studies of K-shell vacancy decays at several photon energies above the K threshold and on the 1s{r_arrow}4p resonance. The complex spectra recorded by conventional electron spectroscopy are greatly simplified when recorded in coincidence with fluorescent x rays, allowing a more detailed analysis of the vacancy cascade process. The resulting coincidence spectra are compared with Hartree-Fock calculations, which include shake-up transitions in the resonant case. Small energy shifts of the coincident electron spectra are attributed to postcollision interaction with 1s photoelectrons. {copyright} {ital 1997} {ital The American Physical Society}

A technique has been developed for coating commercial off the shelf (COTS) detector arrays with a thin, uniform layer of quantum dots. The quantum deposition is accomplished using an Optomec Aerosol Jet rapid prototyping system. When illuminated by UV andvacuumUV (VUV) the quantum dots will fluoresce and those emitted photons will be detected by the underlying detector array. The size of the quantum dots used determines the fluorescence wavelength and that would be matched to the peak sensitivity of the underlying detector array. The devices have been tested at the NIST synchrotron facility in Gaithersburg and have shown sensitivity down to 150nm. Performance at wavelengths below 150nm is limited by absorption by solvent residues from deposition process.

An analysis is presented of the angular correlation between fluorescence photons and subsequently emitted Auger electrons following K-shell ionization. The relative intensities of the Auger lines change in the coincidence experiment compared to the normal Auger lines measured after direct 2p photoionization. A theoretical model is introduced to account for angular correlation effects and applied to reproduce experimental findings.

In theories of photoelectron angular distributions at soft-x-ray energies from 1 to 10 keV, first-order corrections to the dipole approximation give rise to two nondipolar asymmetry parameters in addition to the well-known dipolar asymmetry parameter \ensuremath{\beta}. The nondipolar parameters characterize the forward-backward asymmetry with respect to the propagation vector of the photon beam. Experimentally, the measurement of the nondipolar effect has been hampered because of the complications resulting from the three-parameter angular distribution. In this paper, we suggest various experimental approaches to the measurement of the three asymmetry parameters using partially linearly polarized x rays, corresponding to measurements on synchrotron radiation beamlines. We describe methods to extract the asymmetry parameters using such approaches. \textcopyright{} 1996 The American Physical Society.

The total photoion yield spectrum of atomic chromium has been determined in the range of the 2p thresholds. The experimental data are compared to Hartree-Fock calculations, which include the interaction between three configurations, and to a previously published electron energy loss spectrum of solid chromium.

The soft X-ray photoabsorption and total photoion yield spectra of atomic Cu have been determined in the range of the L-edges. At the L2 and L3 thresholds there are clearly visible jumps in the absorption cross section. Superimposed on this step-like increase are weak but in part surprisingly sharp structures. The atomic data are compared both to Hartree-Fock calculations and the soft X-ray absorption of copper metal.

The National Institute of Standards and Technology (NIST) has operated the Synchrotron Ultraviolet Radiation Facility (SURF) continuously since the early 1960s. The original accelerator was converted into a storage ring, called SURF II, in 1974. Then in 1998, motivated mainly by limitations in the accuracy of radiometric calibrations and the wish to extend the spectrum of the emitted synchrotron radiation to shorter wavelengths, a second major upgrade was performed. This time the whole magnet system was replaced to improve the calculability and allow for higher magnetic fields. Since the recommissioning of SURF III we have been working to improve the stability of the stored electron beam through modifications of the radio-frequency system, leading to operations with unprecedented stability and new record injection currents topping 700 mA.

Suppression of beam instabilities has become an important goal at synchrotron radiation light sources, where highly sensitive applications like metrology, Fourier transform spectroscopy, and microscopy are now in use. We describe measurements connecting beam size and position changes to the onset of the saw-tooth instability and an instability generated by attempts to enlarge the vertical beam size for lifetime improvements.

The 1s X-ray absorption spectra of atomic calcium, chromium, manganese and copper were determined experimentally and calculated theoretically. The spectra are dominated by a prominent line at threshold which precedes a smooth continuum extending to higher energies. Hartree-Fock calculations taking relativistic effects, relaxation and term dependence into account describe the discrete atomic resonance at threshold very well. The resonances at threshold have no counterpart in the spectra of the metals. The experimental atom to metal core level binding energy shifts agree well with the predictions of the thermodynamical model by Johansson and Martensson (1980).

The soft X-ray absorption spectrum of atomic manganese (Z=25) at the L threshold is presented. The experimental spectrum is compared to Hartree-Fock (HF) calculations of the 2p to 3d dipole excitations, to previously published spectra of solid Mn and of manganese impurities in Cu and Ag obtained by electron energy loss spectroscopy (EELS) and to the soft X-ray absorption spectrum (XAS) of MnF2. It is shown that the atomic 2p absorption spectrum can be well described by a single configuration HF calculation in intermediate coupling and that the main features at the 2p absorption threshold of solid Mn, the manganese impurity systems and MnF2 are of atomic origin.

The X-ray absorption spectra of the atomic rare earth cerium, samarium, gadolinium, erbium and ytterbium were measured for photon energies close to the 2p threshold. Correcting for the instrumental broadening, the widths of the white lines were determined. Except for cerium, these experimental widths fall below the theoretical total L level widths. Combining the available experimental data for the elements between Xe (Z=54) and Hg (Z=80) and new data on Xe it is demonstrated that theory and experiment agree for atomic numbers Z>or=70 but differ for the low-Z elements.

In this study, the field emission characterization of carbon nanosheet thin film was conducted using a diode configuration with an anode-cathode distance of 254 mum. Photoelectron emission microscopy (PEEM) was used to investigate the field emission uniformity over the surfaces of carbon nanosheet thin films.

Currently we are commissioning a second multilayer‐based beamline to study the radiation hardness of multilayers under extreme‐ultraviolet (EUV) irradiation in an oxidizing atmosphere. Multilayer lifetime is one of the most important issues for the commercialization of extreme‐ultraviolet lithography. The beamline employs a spherical multilayer mirror and a beryllium filter. The mirror demagnifies the source and reflects 13.4 nm radiation as well as visible light. The beryllium filter suppresses the visible light reflected by the mirror and provides also a barrier between the extremely clean storage ring vacuum and the water atmosphere of the test chamber.

A new facility for measuring irradiance in the UV was commissioned recently at the National Institute of Standards and Technology (NIST). The facility uses the calculable radiation from the Synchrotron Ultraviolet Radiation Facility as the primary standard. To measure the irradiance from a source under test, an integrating sphere spectrometer-detector system measures both the source under test and the synchrotron radiation sequentially, and the irradiance from the source under test can be determined. In particular, we discuss the calibration of deuterium lamps using this facility from 200 to 400 nm. This facility improves the current NIST UV irradiance scale to a relative measurement uncertainty of 1.2% (k=2).

Recent improvements to the synchrotron ultraviolet radiation facility led to unprecedented performance. High injection currents and beam stability, as well as tunable electron energies over a wide range make this storage ring a prime source for synchrotron radiation from the extreme‐ultraviolet to far‐infrared spectral regions. We will discuss plans to capitalize on this unprecedented performance through implementation of new experimental stations and extension of existing ones. It also will be shown that for applications using extreme‐ultraviolet to infrared synchrotron radiation a low electron energy storage ring has distinct advantages.

These proceedings are a collection of the articles presented at the seventeenth Pan-American Synchrotron Radiation Instrumentation Conference SRI2013, held on the campus of the National Institute of Standards and Technology (NIST), located in Gaithersburg, Maryland, United States of America, 19–21 June, 2013. SRI2013 was jointly hosted by the Cornell University Cornell High Energy Synchrotron Source (CHESS), the Thomas Jefferson National Accelerator Facility (Jefferson Lab), and the Synchrotron Ultraviolet Radiation Facility (SURF III) at NIST. This meeting's focus was clearly on instrumentation, thus fulfilling the intent of this SRI meeting series, which was initiated at NIST, then the National Bureau of Standards (NBS), in 1979. SRI2013 hosted more than 150 delegates, despite the new US governmental travel restrictions. This proceedings series aims to be an essential reference work for practitioners in the field. It primarily documents the evolution and development of techniques, but also recent scientific advances, that were presented during the two and a half days of the conference. We are extremely thankful to all the authors who contributed to making these proceedings a volume of reference as well as to the reviewers for their careful reading and constructive recommendations for improving the articles. Great thanks go to Robert Dragoset at NIST, for creating and maintaining the conference website and generating the conference logo. We are also thankful for the excellent support we received from the Conference Program at NIST, especially Kathy Kilmer and Angela Ellis. And we would like to dedicate these proceedings to the memory of Kathy Kilmer, who passed away on 15 October, 2013. NIST will not be the same without her. The Co-Editors: Uwe Arp (SURF/NIST) Peter Reversz (CHESS) Gwyn P Williams (Jefferson Lab)

We have recently installed a new sample chamber at the NIST/DARPA EUV Reflectometry Facility at the National Institute of Standards and Technology. The chamber replaces a much smaller system on Beamline 7 at the Synchrotron Ultraviolet Radiation Facility that was commissioned almost ten years ago as a dedicated facility for the measurement of normal-incidence extreme ultraviolet optics used in lithography development, astronomy, and plasma physics. The previous measurement chamber was limited to optics less than 10 cm in diameter, and, thus, we were not able to measure many of the optics used in modern telescopes and extreme ultraviolet lithography steppers. The new chamber was designed to accommodate optics up to 36 cm in diameter and weighing up to 40 kg, and with modifications will be able to measure optics up to 50 cm in diameter. It has three translation and three rotation axes for the sample and two rotation axes for the detector, with an accuracy of better than 0.5 mm in translation and 0.04o in rotation. We will describe design considerations, performance of the positioning mechanisms, and initial reflectivity measurements of both curved and flat surfaces.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Strong evidence for self-excited emission of coherent synchrotron radiation in the microwave spectral region was observed at the Synchrotron Ultraviolet Radiation Facility (SURF III) electron storage ring at the NIST. The microwave emission between 25 and 35 mm was dominated by intense bursts of radiation. The intensity enhancement during these bursts was on the order of 10 000 to 50 000 over the incoherent value. The shape, width, and period of the bursts depend strongly on the operational parameters of the storage ring. Coherent microwave emission was observed only when the beam was unstable, namely, during bunch-length relaxation oscillations. We report on the measurements of the microwave bursts, and correlate the data with signals from a beam monitor electrode and photodiode detector. The coherent enhancement of the radiation intensity is ascribed to spontaneous self-induced microbunching of the electrons within the bunch.

The conversion of the electron storage ring at NIST (the National Institute of Standards and Technology) to SURF III (the Synchrotron Ultraviolet Radiation Facility) has resulted in a significant improvement to the azimuthal uniformity of the magnetic field as well as the capability for operating at higher beam energies. Measurements of magnetic field strength revealed azimuthal uniformity of better than ±0.05% at field strengths equivalent to operating energies of 52 MeV to 417 MeV. Initial operation is restricted to energies up to 331 MeV due to temporary limitations in the rf transmission system. Even at 331 MeV there is already a significant extension of the usable short wavelength range of the synchrotron radiation as compared to the range available at the 284 MeV operating energy of SURF II. These and other improvements have a major impact on SURF programs including: the Nanodetector, a conversion microscope which is a prototype real-time imaging system for EUV (extreme ultraviolet) lithography; the Spectrometer Calibration Beamline, used for high-accuracy absolute calibration of spectrometers; and the National EUV Reflectometry Facility, used to measure optical constants of thin-film multilayer optics.

The Synchrotron Ultraviolet Radiation Facility (SURF III) at the National Institute of Standards and Technology (NIST) provides a unique opportunity for high-accuracy vacuum ultraviolet (VUV) to visible radiometry with the completion of a recent upgrade to improve the uniformity of the magnetic field along the electron trajectory. In response to the rapid development from the semiconductor industry to astrophysics instrumentation, the major goal for UV radiometry at SURF III includes improving the UV radiometric standard of the nation for detector calibration and a national standard UV light source for source intercomparison. To further enhance the existing radiometric program at SURF III, two more beamlines (beamlines 3 and 4) are now dedicated for radiometry from the VUV to the visible range. The major component of beamline 4 is an Absolute Cryogenic Radiometer, which measures the incident radiation by an electrical substitution method. The beamline provides a facility for UV detector calibration and re...

The National Institute of Standards and Technology operates two spectral comparator facilities, both of which are used to provide detector calibrations from the ultraviolet to the near-infrared spectral range. One, the Ultraviolet Spectral Comparator Facility (UV SCF), has been in operation for more than two decades, providing one of the core calibration services. Recently, the illumination source used in the UV SCF has been changed from an argon mini-arc source to a laser-driven plasma light source. This new source has higher brightness, a smaller source size, better temporal stability, and much better conversion efficiency than the previous source. The improvements in the capabilities are summarized.

The success of the infrared program at the National Synchrotron Light Source has motivated the establishment of an infrared beamline at the Synchrotron Ultraviolet RAdiation Facility (SURF II) of the National Institute of Standards and Technology. Here, we describe the design of the infrared beamline and its associated infrared microscope instrumentation and show preliminary Fourier-transform infrared spectra. In addition, we present measurements of the long wavelength (> 1 cm) synchrotron emission and the noise spectrum of the infrared synchrotron radiation. The microwave measurements were undertaken to help assess the utility of SURF II as a submillimeter and far-infrared source.