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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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14 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

The simplest possible design for a KB microfocus mirror system?

We report a design for a Kirkpatrick-Baez (KB) microfocussing mirror system. The main components are described, with emphasis on a ‘tripod’ manipulator, where we outline the required coordinate transformation calculations. The merit of this device lies in its simplicity of design, minimal degrees of freedom, and speed and ease of setup on a beamline. Test results and an example of the mirrors in use on Diamond Beamline I16, showing a high-resolution polar domain map of KTiOPO{sub 4} with a spot size of 1.25 µm × 1.5 µm, are presented.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

X-ray nanoprobe project at Taiwan Photon Source

The hard X-ray nanoprobe facility at Taiwan Photon Source (TPS) provides versatile X-ray analysis techniques, with tens of nanometer resolution, including XRF, XAS, XEOL, projection microscope, CDI, etc. Resulting from the large numerical aperture obtained by utilizing Montel KB mirrors, the beamline with a moderate length 75 meters can conduct similar performance with those beamlines longer than 100 meters. The two silica-made Montel mirrors are 45 degree cut and placed in a V-shape to eliminate the gap loss and the deformation caused by gravity. The slope error of the KB mirror pair is less than 0.04 µrad accomplished by elastic emission machining (EEM) method. For the beamline, a horizontal DCM and two-stage focusing in horizontal direction is applied. For the endstation, a combination of SEM for quickly positioning the sample, a fly scanning system with laser interferometers, a precise temperature control system, and a load lock transfer system will be implemented. In this presentation, the design and construction progress of the beamline and endstation is reported. The endstation is scheduled to be in commissioning phase in 2016.

43 PARTICLE ACCELERATORS↗
DOE OSTI2015

Optimizing X-ray mirror thermal performance using matched profile cooling

To cover a large photon energy range, the length of an X-ray mirror is often longer than the beam footprint length for much of the applicable energy range. To limit thermal deformation of such a water-cooled X-ray mirror, a technique using side cooling with a cooled length shorter than the beam footprint length is proposed. This cooling length can be optimized by using finite-element analysis. For the Kirkpatrick–Baez (KB) mirrors at LCLS-II, the thermal deformation can be reduced by a factor of up to 30, compared with full-length cooling. Furthermore, a second, alternative technique, based on a similar principle is presented: using a long, single-length cooling block on each side of the mirror and adding electric heaters between the cooling blocks and the mirror substrate. The electric heaters consist of a number of cells, located along the mirror length. The total effective length of the electric heater can then be adjusted by choosing which cells to energize, using electric power supplies. The residual height error can be minimized to 0.02 nm RMS by using optimal heater parameters (length and power density). Compared with a case without heaters, this residual height error is reduced by a factor of up to 45. The residual height error in the LCLS-II KB mirrors, due to free-electron laser beam heat load, can be reduced by a factor of ~11 below the requirement. The proposed techniques are also effective in reducing thermal slope errors and are, therefore, applicable to white beam mirrors in synchrotron radiation beamlines.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2023

Ion Beam Figuring System for Synchrotron X-Ray Mirrors Achieving Sub-0.2-µrad and Sub-0.5-nm Root Mean Square

Abstract Optics with high-precision height and slope are increasingly desired in numerous industrial fields. For instance, Kirkpatrick–Baez (KB) mirrors play an important role in synchrotron X-ray applications. A KB system is composed of two aspherical, grazing-incidence mirrors used to focus an X-ray beam. The fabrication of KB mirrors is challenging due to the aspherical departure of the mirror surfaces from base geometries and the high-quality requirements for slope and height residuals. In this paper, we present the process of manufacturing an elliptical cylinder KB mirror using our in-house-developed ion beam figuring (IBF) and metrology technologies. First, the key aspects of figuring and finishing processes with IBF are illustrated in detail. The effect of positioning error on the convergence of the residual slope error is highlighted and compensated. Finally, inspection and cross-validation using different metrology instruments are performed and used as the final validation of the mirror. Results confirm that relative to the requested off-axis ellipse, the mirror has achieved 0.15-µrad root mean square (RMS) and 0.36-nm RMS residual slope and height errors, respectively, while maintaining the initial 0.3-nm RMS microroughness.

36 MATERIALS SCIENCE↗
DOE OSTI2017

A framed, 16-image Kirkpatrick–Baez x-ray microscope

A 16-image Kirkpatrick–Baez (KB)–type x-ray microscope consisting of compact KB mirrors has been assembled for the first time with mirrors aligned to allow it to be coupled to a high-speed framing camera. The high-speed framing camera has four independently gated strips whose emission sampling interval is ~30 ps. Images are arranged four to a strip with ~60-ps temporal spacing between frames on a strip. By spacing the timing of the strips, a frame spacing of ~15 ps is achieved. A framed resolution of ~6-um is achieved with this combination in a 400-um region of laser–plasma x-ray emission in the 2- to 8-keV energy range. A principal use of the microscope is to measure the evolution of the implosion stagnation region of cryogenic DT target implosions on the University of Rochester’s OMEGA Laser System. The unprecedented time and spatial resolution achieved with this framed, multi-image KB microscope have made it possible to accurately determine the cryogenic implosion core emission size and shape at the peak of stagnation. In conclusion, these core size measurements, taken in combination with those of ion temperature, neutron-production temporal width, and neutron yield allow for inference of core pressures, currently exceeding 50 GBar in OMEGA cryogenic target implosions.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2016

On-axis microscopes for the inelastic x-ray scattering beamline at NSLS-II

A novel on-axis X-ray microscope with 3 µm resolution, 3x magnification, and a working distance of 600 mm for in-situ sample alignment and X-ray beam visualization for the Inelastic X-ray Scattering (IXS) beamline at NSLS-II is presented. The microscope uses reflective optics, which minimizes dispersion, and allows imaging from Ultraviolet (UV) to Infrared (IR) with specifically chosen objective components (coatings, etc.). Additionally, a portable high resolution X-ray microscope for KB mirror alignment and X-ray beam characterization was developed.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

Microfocusing at the PG1 beamline at FLASH

The Kirkpatrick–Baez (KB) refocusing mirror system installed at the PG1 branch of the plane-grating monochromator beamline at the soft X-ray/XUV free-electron laser in Hamburg (FLASH) is designed to provide tight aberration-free focusing down to 4 µm × 6 µm full width at half-maximum (FWHM) on the sample. Such a focal spot size is mandatory to achieve ultimate resolution and to guarantee best performance of the vacuum-ultraviolet (VUV) off-axis parabolic double-monochromator Raman spectrometer permanently installed at the PG1 beamline as an experimental end-station. The vertical beam size on the sample of the Raman spectrometer, which operates without entrance slit, defines and limits the energy resolution of the instrument which has an unprecedented design value of 2 meV for photon energies below 70 eV and about 15 meV for higher energies up to 200 eV. In order to reach the designed focal spot size of 4 µm FWHM (vertically) and to hold the highest spectrometer resolution, special fully motorized in-vacuum manipulators for the KB mirror holders have been developed and the optics have been aligned employing wavefront-sensing techniques as well as ablative imprints analysis. Lastly, aberrations like astigmatism were minimized. In this article the design and layout of the KB mirror manipulators, the alignment procedure as well as microfocus optimization results are presented.

43 PARTICLE ACCELERATORS↗
DOE OSTI2016

Toyota beamline (BL33XU) at SPring-8

The Toyota beamline (BL33XU) at SPring-8 is an undulator beamline developed to assist in the study of various automotive-related materials. The light source is a tapered in-vacuum undulator that provides a variable energy band width as well as a high brilliance X-ray beam. Two different optical arrangements are available: Optics 1 and Optics 2. Optics 1 is dedicated to time-resolved X-ray absorption spectroscopy (XAFS), and consists of two channel-cut crystal monochromators and four water-cooled flat Si mirrors. The Si(111) and Si(220) monochromator crystals cover an energy range of 4.0–46.0 keV and are driven by high-speed AC servo motors. These monochromators, in conjunction with the tapered undulator, enable high-quality XAFS data acquisition with a temporal resolution of 10 ms. Optics 2 is optimized for X-ray diffraction, scattering and imaging and includes a recently installed double crystal monochromator, two water-cooled flat Si mirrors and Kirkpatrick-Baez (KB) focusing mirrors. The monochromator incorporates parallel mounted Si(111) and Si(311) crystals and covers an energy range of 4.5–70 keV. The beamline provides two experimental stations: Exp. Hutch 2 and Exp. Hutch 3. The gas supply system and mass spectrometers installed in Exp. Hutch 2 allow in-operando measurements under various atmospheres. The scanning three-dimensional X-ray diffraction (scanning 3DXRD) microscopy instrumentation developed and installed in Exp. Hutch 3 enables non-destructive orientation and stress mapping of 1 mm-thick steel specimens using a high energy microbeam.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2018

Microscopy Instrumentation and Nanopositioning at NSLS-II: Current Status and Future Directions

The development of ultra-brilliant synchrotron facilities and recent advances in the fabrication of efficient nano-focusing optics have stimulated rapid development and applications of the focused beams used to elucidate nanoscale phenomena in many areas of science and technology. Various nano-focusing optics, including Kirkpatrick- Baez (KB) and elliptical mirrors, Fresnel zone plates (ZP), compound refractive and kinoform lenses, and multilayer Laue lenses (MLL), are routinely used to achieve nano-focusing. The latest experiments utilizing KB mirrors have demonstrated focal spot size of 13 nm with the ZPs and MLLs being able to focus hard X-rays to 10 nm and below. When the focused beam size is reduced to below 100 nm, there is a need to develop a dedicated system tailored for a specific application, which satisfies stringent mechanical, vibrational, and thermal characteristics to successfully enable nano-scale imaging. Multiple degrees of motion, including their positioning accuracy, resonance frequencies, and amount of heat being dissipated, have to be thoroughly considered in order to efficiently perform nano-focusing experiments.

47 OTHER INSTRUMENTATION↗
DOE OSTI2015

Profile etching for prefiguring X-ray mirrors

A method to pre-shape mirror substrates through etching with a broad-beam ion source and a contoured mask is presented. A 100 mm-long elliptical cylinder substrate was obtained from a super-polished flat Si substrate with a 48 nm root-mean-square (r.m.s.) figure error and a 1.5 Å r.m.s. roughness after one profile-etching process at a beam voltage of 600 V without iteration. A follow-up profile coating can be used to achieve a final mirror. Profile etching and profile coating combined provide an economic way to make X-ray optics, such as nested Kirkpatrick–Baez mirrors.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
NASA NTRS1993

A survey of low frequency waves at Jupiter: The Ulysses encounter

We report the results of a survey of low-frequency (LF) plasma waves detected during the Ulysses Jupiter flyby. In the Jovian foreshock, two predominant wave periods are detected: 10(exp 2)-s and 5-s, as measured in the spacecraft frame. The 10(exp 2)-s waves are highly nonlinear propagate at large angles to vector-B(sub 0) (typically 50 deg), are steepened, and sometimes have attached whistler packets. For the interval analyzed the 10(exp 2)-s waves had mixed right-and left-hand polarizations. We argue that these are all consistent with being right-hand magnetosonic waves in the solar wind frame. The 10(exp 2)-s waves with attached whistler are similar to cometary waves. The trailing portions are linearly polaraized and the whistler portions circularly polarized with amplitudes decreasing linearly with time. The emissions are generated by approximately 2-keV protons flowing from the Jovian bow shock/magnetosheath into the upstream region. The instability is the ion beam instability. Higher Z ions were considered as a source of the waves but have been ruled out because of the low sunward velocities needed for their resonance. The 5-s waves have delta vector-B/B(sub 0 approximately = 0.5, are compressive and are left-hand polarized in the spacecraft frame. Local generation by three different resonant interactions were considered and have been ruled out. One possibility is that these waves are whistler mode by-products of the steepened lower-frequency magnetosonic waves. Mirror mode structures were detected throughout the outbound magnetosheath passes. For these structures, the theta(sub kB) values were consistently in the range of 80 deg to 90 deg, exceptionally high values.

Tsurutani, Bruce T.↗
DOE OSTI2016

On the connection between microbursts and nonlinear electronic structures in planetary radiation belts

Using a dynamical-system approach, we have investigated the efficiency of large-amplitude whistler waves for causing microburst precipitation in planetary radiation belts by modeling the microburst energy and particle fluxes produced as a result of nonlinear wave–particle interactions. We show that wave parameters, consistent with large-amplitude oblique whistlers, can commonly generate microbursts of electrons with hundreds of keV-energies as a result of Landau trapping. Relativistic microbursts (>1 MeV) can also be generated by a similar mechanism, but require waves with large propagation angles θ{sub kB}>50{sup ∘} and phase-speeds v{sub Φ}⩾c/9. Using our result for precipitating density and energy fluxes, we argue that holes in the distribution function of electrons near the magnetic mirror point can result in the generation of double layers and electron solitary holes consistent in scales (of the order of Debye lengths) to nonlinear structures observed in the radiation belts by the Van Allen Probes. Our results indicate a relationship between nonlinear electrostatic and electromagnetic structures in the dynamics of planetary radiation belts and their role in the cyclical production of energetic electrons (E⩾100 keV) on kinetic timescales, which is much faster than previously inferred.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS2019

Electron Scattering by Low-frequency Whistler Waves at Earth’s Bow Shock

Electrons are accelerated to nonthermal energies at shocks in space and astrophysical environments. While shock drift acceleration (SDA) has been considered a key process of electron acceleration at Earth’s bow shock, it has also been recognized that SDA needs to be combined with an additional stochastic process to explain the observed power-law energy spectra. Here, we show mildly energetic (∼0.5 keV) electrons are locally scattered (and accelerated while being confined) by magnetosonic-whistler waves within the shock transition layer, especially when the shock angle is large (θ(sub Bn) approximately equal or greater than 70°). When measured by the Magnetospheric Multiscale mission at a high cadence, ∼0.5 keV electron flux increased exponentially in the shock transition layer. However, the flux profile was not entirely smooth and the fluctuation showed temporal/spectral association with large-amplitude (δB/B ~ 0.3), low-frequency (approximately equal or less than 0.1 Ω(sub ce) where Ω(sub ce) is the cyclotron frequency), obliquely propagating (θ(sub kB) ~ 30°–60°, where θ(sub kB) is the angle between the wave vector and background magnetic field) whistler waves, indicating that the particles were interacting with the waves. Particle simulations demonstrate that, although linear cyclotron resonances with ∼0.5 keV electrons are unlikely due to the obliquity and low frequencies of the waves, the electrons are still scattered beyond 90° pitch angle by (1) resonant mirroring (transit-time damping), (2) non-resonant mirroring, and (3) subharmonic cyclotron resonances. Such coupled nonlinear scattering processes are likely to provide the stochasticity needed to explain the power-law formation.

Oka, M.↗
DOE OSTI2019

Gamma mirrors Quarterly Progress Report Y1Q4 FY2019

During the fourth quarter of FY19, we completed task 1.2 of Phase 1, the data analysis of the experimental campaign conducted at the Irradiated Fuel Examination Laboratory (IFEL) at ORNL. The best part of the analysis was conducted during the third quarter and the relevant findings can be found in the FY19 Q3 report. Phase II of the project was started during the month of September, more specifically Task 2. All experiments so far were conducted with ultrasmooth flat optics with a periodic multilayer coating with reflectivity of >80% in the 100 keV range. We have been determining the best available simulation tools to model X-ray focusing optics, typically made of quadratic surfaces, in order to survey the relevant parameter space and conduct the design study. Candidate focusing optics designs are Wolter I optics, Kirkpatrick-Baez or KB optics and Schmidt optics. Informed by the IFEL results, we are also considering a single-reflection concentrator design to attempt to quantify possible trade-off between bandpass multilayers overall reflectivity, multiple reflections and energy selectivity.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗