Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Mirrors”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 883 records · Page 49
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Two mirror X-ray pulse split and delay instrument for femtosecond time resolved investigations at the LCLS free electron laser facility

We built a two-mirror based X-ray split and delay (XRSD) device for soft X-rays at the Linac Coherent Light Source free electron laser facility. The instrument is based on an edge-polished mirror design covering an energy range of 250 eV-1800 eV and producing a delay between the two split pulses variable up to 400 femtoseconds with a sub-100 attosecond resolution. We present experimental and simulation results regarding molecular dissociation dynamics in CH3I and CO probed by the XRSD device. In conclusion, we observed ion kinetic energy and branching ratio dependence on the delay times which were reliably produced by the XRSD instrument.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2021

RISE: robust iterative surface extension for sub-nanometer X-ray mirror fabrication

Precision optics have been widely required in many advanced technological applications. X-ray mirrors, as an example, serve as the key optical components at synchrotron radiation and free electron laser facilities. They are rectangular silicon or glass substrates where a rectangular Clear Aperture (CA) needs to be polished to sub-nanometer Root Mean Squared (RMS) to keep the imaging capability of the incoming X-ray wavefront at the diffraction limit. The convolutional polishing model requires a CA to be extended with extra data, from which the dwell time is calculated via deconvolution. However, since deconvolution is very sensitive to boundary errors and noise, the existing surface extension methods can hardly fulfill the sub-nanometer requirement. On one hand, the figure errors in a CA were improperly modeled during the extension, leading to continuity issues along the boundary. On the other hand, uncorrectable high-frequency errors and noise were also extended. In this study, we propose a novel Robust Iterative Surface Extension (RISE) method that resolves these problems with a data fitting strategy. RISE models the figure errors in a CA with orthogonal polynomials and ensures that only correctable errors are fit and extended. Combined with boundary conditions, an iterative refinement of dwell time is then proposed to compensate the errors brought by the extension and deconvolution, which drastically reduces the estimated figure error residuals in a CA while the increase of total dwell time is negligible. To our best knowledge, RISE is the first data fitting-based surface extension method and is the first to optimize dwell time based on iterative extension. An experimental verification of RISE is given by fabricating two elliptic cylinders (10 mm × 80 mm CAs) starting from a sphere with a radius of curvature around 173 m using ion beam figuring. The figure errors in the two CAs greatly improved from 204.96 nm RMS and 190.28 nm RMS to 0.62 nm RMS and 0.71 nm RMS, respectively, which proves that RISE is an effective method for sub-nanometer level X-ray mirror fabrication.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Design of monolithic piezoelectric bimorph mirrors made from lithium niobate

Recent advances in deformable mirrors based on monolithic piezoelectric substrates, such as lithium niobate, have the potential to improve the image quality of X-ray optical systems on synchrotron and free-electron laser beamlines and microscopes. However, the quantitative relationship between design parameters and the deformed shape has not been readily available in the literature. We present an analytical model, validated through finite element analysis, enabling calculation of tangential and sagittal curvatures based on mirror dimensions, crystallographic orientation, and applied voltage. We demonstrate that through the selection of material orientation, it is possible to achieve different deformed shapes (sphere, cylinder, or hyperbolic paraboloid). This methodology can be generalized to other piezoelectric materials and substrate-integrated actuator systems.

Marzari, Francesco [University of Trento (Italy); ↗
DOE OSTI2025

Tandem neural network-based controller for x-ray bimorph mirrors

Nanometer-scale shape control of x-ray mirrors is crucial for coherent x-ray beam experiments at low-emittance synchrotron beamline instruments. Piezoelectric bimorph mirrors offer adaptive control but are hindered by nonlinearities such as cross talk, creep, and hysteresis. To overcome these limitations, we present a novel feedback-free control solution, inspired by the proportional–integral–derivative (PID) scheme, driven by tandem neural networks (TNNs). Using task-specific datasets, the TNN-based system predicts actuator voltages with greater speed, accuracy, and stability than a single NN-based model. This approach is ideal for real-time applications, such as adapting beam focus to dynamic sample sizes while maintaining precise wavefront quality. Our findings highlight the potential of artificial intelligence in rapidly optimizing adaptive optics and managing nonlinear control systems.

Zhang, Runyu↗
DOE OSTI2025

Investigation of a gallium alloy liquid metal mirror for application in inertial fusion energy systems

The final optic in future inertial fusion energy plants must maintain high performance and survivability under gigashot laser irradiation while exposed to fusion byproducts. Although no practical solution has been demonstrated, a self-healing final turning mirror based on a grazing-incidence liquid metal mirror has been theoretically explored. This work investigates the suitability of a gallium alloy. The experimental system simulates key conditions, including vacuum exposure and 10-Hz, 355-nm, and 6-ns laser pulses. Experiments address reflectivity, damage, and response as a function of pressure. Results highlight the potential of liquid metal gallium alloys for robust final optics in laser-based fusion power plants and inform non-traditional optics for intense laser systems.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2016

Perfect single-sided radiation and absorption without mirrors

Highly directional radiation from photonic structures is important for many applications, including high-power photonic crystal surface-emitting lasers, grating couplers, and light detection and ranging devices. However, previous dielectric, few-layer designs only achieved moderate asymmetry ratios, and a fundamental understanding of bounds on asymmetric radiation from arbitrary structures is still lacking. Here in this paper, we show that breaking the 180° rotational symmetry of the structure is crucial for achieving highly asymmetric radiation. We develop a general temporal coupled-mode theory formalism to derive bounds on the asymmetric decay rates to the top and bottom of a photonic crystal slab for a resonance with arbitrary in-plane wavevector. Guided by this formalism, we show that infinite asymmetry is still achievable even without the need for back-reflection mirrors, and we provide numerical examples of designs that achieve asymmetry ratios exceeding 10 4 . The emission direction can also be rapidly switched from top to bottom by tuning the wavevector or frequency. Furthermore, we show that with the addition of weak material absorption loss, such structures can be used to achieve perfect absorption with single-sided illumination, even for single-pass material absorption rates less than 0.5% and without back-reflection mirrors. Our work provides new design principles for achieving highly directional radiation and perfect absorption in photonics.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Fabrication and testing of high-performance all-metal neutron guides and axisymmetric mirrors by electrochemical replication

Neutron scattering is one of the most useful methods of studying the structure of matter, with applications to biomedical, structural, magnetic and energy-related materials. Neutron-scattering instruments are installed around research reactors or accelerator-based neutron sources, and neutron guides are critical components of these facilities. They are neutron-transport optical devices consisting of state-of-the-art mirrors often tens of meters long. Here we demonstrate a novel fabrication method of all-metallic neutron guides and axisymmetric mirrors by electroplating from precision mandrels. The process allows for the fabrication of single-piece all-metal guides of prismatic and axisymmetric shapes. We also demonstrate supermirror guides and axisymmetric focusing supermirrors produced with the same technology. We present the fabrication and tests of the multilayer-coated replicated guides and optic and show that the mandrel is reproduced with high fidelity and reliability. Furthermore, such supermirror optics will provide game-changing improvements in neutron techniques.

36 MATERIALS SCIENCE↗
DOE OSTI2013

Direct Measurement of U235 and Pu239 in Spent Fuel Rods with Gamma-Ray Mirrors

The amounts of fissile Pu and U in spent nuclear fuel are of primary concern to the safeguards community. In particular, there are issues when safeguards transitions from an item accountancy basis (such as fuel bundles) to a fissile material mass basis as occurs when spent fuel enters a reprocessing plant. Discrepancies occur because item accountancy requires estimating the content of fissile material using indirect techniques such as the fuel burn-up and item-level measurements of radiation emissions from fission by-products. Direct measurement of the fissile content by monitoring line emissions from fissile species themselves is impossible because the lines are much weaker than those emitted by shorter-lived isotopes in the fuel. The goal of this project is to develop a technique to directly measure these weaker lines despite the presence of overwhelming radiation from other isotopes. This is achieved by using gamma-ray mirrors as a narrow band-pass filter. The mirrors reflect only energies of interest toward a HPGe detector that is shielded from direct view of the spent fuel and its fierce emissions. This can significantly improve the reliability with which the mass of fissile material is tracked.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2017

Gamma-ray mirror technology for NDA of spent fuel

Direct measurements of gamma rays emitted by fissile material have been proposed as an alternative to measurements of the gamma rays from fission products. From a safeguards applications perspective, direct detection of uranium (U) and plutonium (Pu) K-shell fluorescence emission lines and specific lines from some of their isotopes could lead to improved shipper-receiver difference or input accountability at the start of Pu reprocessing. However, these measurements are difficult to implement when the spent fuel is in the line-of-sight of the detector, as the detector is exposed to high rates dominated by fission product emissions. To overcome the combination of high rates and high background, grazing incidence multilayer mirrors have been proposed as a solution to selectively reflect U and Pu hard X-ray and soft gamma rays in the 90 to 420 keV energy into a high-purity germanium (HPGe) detector shielded from the direct line-of-sight of spent fuel. Several groups demonstrated that K-shell fluorescence lines of U and Pu in spent fuel could be detected with Ge detectors. In the field of hard X-ray optics the performance of reflective multilayer coated reflective optics was demonstrated up to 645 keV at the European Synchrotron Radiation Facility. Initial measurements conducted at Oak Ridge National Laboratory with sealed sources and scoping experiments conducted at the ORNL Irradiated Fuels Examination Laboratory (IFEL) with spent nuclear fuel further demonstrated the pass-band properties of multilayer mirrors for reflecting specific emission lines into 1D and 2D HPGe detectors, respectively.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2018

Development of achromatic paraboloidal mirror lenses with 100 nm focus

The Fast-Track project goals are to ultimately develop an axially symmetric, achromatic paraboloidal mirror lens with a 100-nanometer focus. The optic will provide large numerical aperture, high efficiency, and high resolution, and will be a higher throughput, cost-effective alternative to conventional x-ray optics such as Kirkpatrick Baez mirrors for synchrotron beamline development and upgrades.

43 PARTICLE ACCELERATORS↗
DOE OSTI2018

Non-contact Mirror Measurements by a Laser Tracker

In my previous experience, beam line optics measurement is directly or semi-directly done by moving SMR along its surface. The fact there is that the touchable part is not critical to the mirror’s future use. But now for NSLSII project, we have to deal with the no-touch-at- all-to-the-surface situation. The following is a general idea of how to measure a mirror without contact its precision surface, further test need to be done to verify it.

36 MATERIALS SCIENCE↗
DOE OSTI2013

Non-contact Mirror Measurement by a Laser Tracker

In my previous experience, beam line optics measurement is directly or semi-directly done by moving SMR along its surface. The fact there is that the touchable part is not critical to the mirror’s future use. But now for NSLSII project, we have to deal with the no-touch-at-all-to-the-surface situation. The following is a general idea of how to measure a mirror without contact its precision surface, further test need to be done to verify it.

36 MATERIALS SCIENCE↗
DOE OSTI2020

“Mirror” magnet experiment for quench studies, quench analysis techniques development and in support of superconducting magnet modeling

In order to progress on various research points related to superconducting magnets, we suggest performing series of tests with induced and natural quenches on a mirror magnet, probably using a “11 T” coil. The “mirror” is to have voltage taps instrumented on half the strands, on both coil ends. It is to be instrumented with multiple spot-heaters, of the order of ten, in designated pole-turn areas. Instrumentation is to include quench antenna array facing the inner coil surface, as well as acoustic sensors on the inner layer pole. Further, acoustic sensors at the magnet ends and an acoustic calibration transducer are to be installed. Thus, we are to test sensitivity and precision of acoustic and quench antenna (QA) array sensors, both at close proximity to the coil, and we are to test and commission acoustic on-magnet real-time “calibration”. New or extended DAQ will be tested as well. In addition to diagnostic development, the purpose of the magnet experiment is to investigate current redistribution in the coil, both during quenching and in operating conditions; to assess voltage build up across strands and in the coil segments during quenching, to explore voltage signature differentiation between different type of quenches; to improve modeling of processes during quenching and for magnet design purposes. In this experiment, we expect to be able to characterize the processes during a quench in unprecedented details.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

A study of sacrificial mirrors for use prior to a laser wakefield accelerator driven by the Z-Petawatt laser

Many experiments at Sandia’s Z Pulsed Power Facility require x-ray backlighting diagnostics to understand experiment performance. Due to limitations in present-day source/detection modalities, most x-ray diagnostics at Z are restricted to photon energies <20 keV, ultimately limiting the density, amount, and atomic number of targets diagnosable in experiments. These limitations force the use of low-Z materials like Beryllium, and they prevent acquisition of important backlighting data for materials/densities that are opaque to soft x-rays and where background emission from the Z load and transmission lines overwhelm diagnostics. In this LDRD project, we have investigated the design and development of a laser wakefield acceleration platform driven by the Z-Petawatt laser – a platform that would enable the generation of a pulsed, collimated beam of high energy x-rays up to 100 keV. Geometrical considerations for implementation on the Z Machine require the use of sacrificial mirrors, which have been tested in offline experiments in the Chama target chamber in building 983. Our results suggest the use of sacrificial mirrors would not necessarily inhibit the laser wakefield x-ray process, particularly with the benefits stemming from planned laser upgrades. These conclusions support the continuation of laser wakefield source research and the development of the necessary infrastructure to deliver the Z-Petawatt laser to the Z center section along the appropriate lines of sight. Ultimately, this new capability will provide unprecedented views through dense states of matter, enabling the use of previously incompatible target materials/designs, and uncovering a new set of observables accessible through diffraction and spectroscopy in the hard x-ray regime. These will amplify the data return on precious Z shots and enhance Sandia’s ability to investigate fundamental physics in support of national security.

43 PARTICLE ACCELERATORS↗
DOE OSTI2025

Black Holes and de Sitter Space as Time Mirrors

It is usually assumed that matter disappears together with the spacetime at the center of a Schwarzschild black hole (BH). Here, we find that if we impose a boundary condition that the field does not disappear at the BH center (that is, field flux into the singularity vanishes), the BH acts as a time mirror that totally reflects the infalling light and matter outside the BH. Namely, the reflected field propagates backward in time, passes the event horizon and moves away from the BH. In this case, a BH can be used as a time machine that allows us to send a signal into the past. We also show that de Sitter spacetime acts as a time mirror provided particles do not disappear from the spacetime at r=∞.

Svidzinsky, Anatoly (ORCID:0000000247756767)↗
DOE OSTI2016

Multi-species measurements of the firehose and mirror instability thresholds in the solar wind

The firehose and mirror instabilities are thought to arise in a variety of space and astrophysical plasmas, constraining the pressure anisotropies and drifts between particle species. The plasma stability depends on all species simultaneously, meaning that a combined analysis is required. Here, we present the first such analysis in the solar wind, using the long-wavelength stability parameters to combine the anisotropies and drifts of all major species (core and beam protons, alphas, and electrons). At the threshold, the firehose parameter was found to be dominated by protons (67%), but also to have significant contributions from electrons (18%) and alphas (15%). Drifts were also found to be important, contributing 57% in the presence of a proton beam. A similar situation was found for the mirror, with contributions of 61%, 28%, and 11% for protons, electrons, and alphas, respectively. The parallel electric field contribution, however, was found to be small at 9%. Overall, the long-wavelength thresholds constrain the data well (<1% unstable), and the implications of this are discussed.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1967

Gimbaled-mirror scanning system capable of spiral pattern

Gimbaled-mirror infrared radiation scanner, with a lightweight torque motor direct coupled to each axis, is capable of scanning in a highly efficient spiral pattern. The scanner is lightweight and can be remotely positioned in previously inaccessible areas because the radiometer head and the gimbaled-mirror scanner can be separated.

Haertsch, O. C.↗
NASA NTRS1969

A new method for producing optical mirrors

Pure silicon improves optical mirrors for use in telescopes and high resolution optical systems. Pure silicon is used in both mirror and substrate in environments where large thermal changes occur. It has applicability in astronomical devices.

Markle, D. A.↗