Institute For Materials Research Research Articles

Mixed Ionic Electronic Conduction Caused by Phase Transformation and Interfacial Segregation in an Entropy Stabilized Oxide

Research on entropy-stabilized oxides (ESO) [1] has primarily focused on exploring new single-phase structures with diverse chemistries, or unique properties, such as high Li-ion conductivity, high dielectric constant, low thermal conductivity, good electrochemical cycling stability, and high storage capacity retention [2]. However, few studies discuss the impact of secondary phase formation on functionality such as electrical conductivity [3] despite the fact that annealing this single-phase ESO causes it to undergo a phase transformation leading to the formation of Cu-rich and Co-rich secondary phases [4]. To address this gap, this work [5] investigates the electrical transport mechanisms in the canonical entropy-stabilized oxide (Co,Cu,Mg,Ni,Zn)O as a function of secondary phase content. Here, the structure and composition of single-phase and multiphase ESOs, and their GBs and HIs are probed using atomic-resolution imaging by scanning transmission electron microscopy (STEM) coupled with nanoscale spectroscopy by electron energy-dispersive spectroscopy (EDS) and electron energy-loss spectroscopy (EELS). Our findings suggest that when single-phase, the oxide is an oxygen ion conductor. After 2 h of heat treatment, Cu-rich tenorite particles form at some grain boundaries, turning the grain interior rocksalt oxide into a mixed ionic-electronic conductor via oxygen ions and small hole polaron Co2+/Co3+ and Cu2+/Cu+ pairs. 24 h of heat treatment leads to the full coverage of Cu-rich tenorite particles at all grain boundaries and the formation of anisotropic Cu-rich tenorite and equiaxed Co-rich spinel particles in the grains. While the grain interiors exhibit similar mixed ionic-electronic conduction, Cu-rich tenorite grain boundary phases create a pathway for Cu2+/Cu3+ small hole polarons. The ability to selectively grow secondary phases nucleated at grain boundaries enables tuning of electrical properties in entropy-stabilized and complex concentrated oxides using microstructure design, nanoscale engineering, and heat treatment, paving the way to develop many novel materials.[1] C. M. Rost, J.-P. Maria, Nat Commun, 2015.[2] A. Salian, S. Mandal, Critical Reviews in Solid State and Materials Sciences, 2022.[3] M. Moździerz, K. Świerczek, Acta Materialia, 2021.[4] A. D. Dupuy, J. M. Schoenung, Journal of the European Ceramic Society, 2021.[5] H. Vahidi...W. J. Bowman (submitted). Acknowledgments This research was primarily supported by the National Science Foundation Materials Research Science and Engineering Center program through the UC Irvine Center for Complex and Active Materials (DMR-2011967). WJB and HV acknowledge partial support from the UCI new faculty startup funding. The authors acknowledge the use of facilities and instrumentation at the UC Irvine Materials Research Institute (IMRI) supported in part by the National Science Foundation Materials Research Science and Engineering Center program through the UC Irvine Center for Complex and Active Materials (DMR-2011967).

Direct Observation of Solid-Phase Crystallization of an Amorphous Complex Oxide in the Transmission Electron Microscope

Many complex metal oxides possess intricate structure-function relations, resulting in a wide range of tunable functional properties. The introduction of disorder through amorphization provides additional opportunities for tuning the properties, particularly in the area of electrochemical energy storage and conversion [1]. Consequently, amorphous and partly crystalline complex oxides have garnered growing interest in recent years, with two primary goals: to harness their unique functional properties or to employ them as a chemically-flexible, far-from-equilibrium, thin-film processing platform that offers novel synthesis opportunities [2] due to the minimal energy input required to initiate crystallization and other structural relaxation processes.Relevant to both these aims, the processing-structure-function relationship for amorphous complex oxides is examined by in situ solid-phase crystallization (SPC) in the (scanning) transmission electron microscope ((S)TEM), focusing on perovskite-like (ABO3) mixed ion-electron conducting (MIEC) amorphous complex oxides which make promising low-temperature solid-oxide cell (SOC) electrodes [3] due to the widely observed disorder-mediated oxygen surface-exchange [4]. Key aspects of MIEC amorphous complex oxide processing, such as the evolution of structure and chemistry with temperature and the corresponding effect on conductivity are detailed in the amorphous La0.8Sr0.2MnO3-δ (LSM) system. Further, approaches to direct amorphous complex oxide processing towards desirable synthesis products based on these insights are discussed.Here, we elucidate down to the atomic scale the development of structural characteristics such as porosity, crystallized fraction, crystallite tension, size, curvature, and surface termination, with the aim to establish approaches to tune surface functionality in partly crystalline MIECs by heating or electron beam irradiation [5]. In situ electrical measurements are used to correlate these changes with electrical behavior, revealing that the onset of crystallization is correlated with an increase in electronic conductivity by small polaron hopping, attributed to oxygen-metal-oxygen bond alignment. Further, in the absence of epitaxial constraints, an immiscibility-driven self-organization of amorphous heterointerfacial structures manifests by spinodal decomposition, that is likely to be broadly relevant in low-temperature processing of amorphous complex oxides [6]. Thus, processing from an amorphous complex oxide precursor could be a method to establish uniformly-dispersed nanoscale heterointerfaces of tunable characteristic length scale throughout a thin film volume, while also enabling direct tuning of the porous mesostructure by electron beam irradiation. Overall, case studies of amorphous complex oxide crystallization are limited to relatively few chemical systems and processing conditions. Thus, extending this body of work to explore a broader processing space, and extracting fundamental insights to establish process-structure-function relationships are prerequisites to realizing the full potential of partly crystallineMIEC systems, and provides guidance for processing amorphous complex oxides generally. Acknowledgments The authors acknowledge the UC Irvine School of Engineering new faculty setup funds, the National Science Foundation CAREER award (DMR-2042638) and the UC Irvine Materials Research Institute (IMRI). References S. Yan ... H. Xia, Small (2019)D. Prakash, ... F. Cavallo, Small (2022).J. Zhang ... Y. Chen, Advanced Functional Materials (2022)T. Chen ... N. Perry, ACS Applied Materials & Interfaces (2019)J. Wardini ... W. Bowman (submitted)J. MacManus-Driscoll, Advanced Functional Materials (2010)

Which Interfaces Matter Most? Variability in Grain Boundary Defect Chemistry and Conductivity in a Concentrated Solid Electrolyte

Inorganic solid electrolytes with fast ionic conductivity are critical components of fuel/electrolysis cells, all-solid-state batteries, membrane and separation reactors, sensors and other electrochemical devices. For example, solid oxygen ion (O2-) conductors are used in solid oxide fuel/electrolysis cells (SOFCs/SOECs) for high-efficiency conversion between chemical and electrical energy and chemical production from CO2. One major challenge in engineering such materials is the diminished grain boundary (GB) conductivity in polycrystalline oxide ceramics. This phenomenon, which was initially accredited to highly resistive silica-based glassy impurity phases, is attributed to the formation of intrinsic space charge layers (SCLs) directly adjacent to GB cores. The positive potential at the GB core (due to large concentrations of oxygen vacancies) results in a depletion of oxygen vacancies in the space charge layer as well as the segregation of charge-compensating acceptor solutes from grain interiors which ultimately reduces GB conductivity. Several strategies have been explored to improve GB conductivity by understanding and mitigating the SCL effects. While the standard Poisson–Boltzmann approach models the near-grain boundary defect behavior in dilute solid solutions and recent models by Mebane et al [1] and Virkant et al [2] incorporate the effects of defect-defect interactions (in concentrated solid solutions) and chemomechanical stress, respectively, there is yet to be a model developed that can predict individual GB conductivities in concentrated solid solutions based on direct experimental measurements of near-GB defect chemistry.Here, we present an experimental-computational framework that predicts which GBs in a polycrystalline electrolyte likely facilitate ionic conductivity. We developed a thermodynamic phase-field modeling framework and applied it to a model oxygen electrolyte Gd0.25Ce0.75O2-δ, wherein the GB-to-GB variability in defect concentrations (Gd3+ solutes, electrons localized at Ce3+, and oxygen vacancies) was measured microscopically using scanning transmission electron microscopy electron energy-loss spectroscopy (STEM EELS). These data were used to predict the GB-to-GB variability in cross-GB ionic conduction using a unique model, which prioritizes reproducing microscopically observed GB defect concentrations and considers defect-defect interactions in highly concentrated solid solutions, making the framework applicable to other technologically relevant solid electrolytes. Across the GBs studied, we revealed a non-monotonic relationship between depletion and GB conductivity, with the highest conductivity predicted for intermediate depletion amounts. This work lays the foundation for future experimental-computational research and advanced data-driven design of solid electrolytes needed for functional and energy storage/conversion devices.[1] D. S. Mebane, R. A. D. Souza, Energy & Environmental Science, 2015.[2] K. S. N. Vikrant, R. Edwin García, Energy & Environmental Science, 2018.[3] H. Vahidi, W.J. Bowman (Submitted). Acknowledgments HV and WJB acknowledge primary support from the UCI new faculty startup funding. This research was partially supported by the National Science Foundation Materials Research Science and Engineering Center program through the UC Irvine Center for Complex and Active Materials (DMR-2011967). We acknowledge the use of facilities and instrumentation at the UC Irvine Materials Research Institute (IMRI) supported in part by the same NSF MRSEC (DMR-2011967). AM, DM, and AC acknowledge funding from the NSF [WB1] [hv2] and the WVU MAE research department for the use of the Thorny Flat HPC Cluster for the numerical modeling work and computational resources.

Development of an automated 3D metallography system and some first application examples in microstructural analysis

Abstract Traditional metallography relies on the imaging of individual section planes. However, conclusions as to spatial shapes and microstructural arrangements can only be drawn to a limited extent. The idea to reconstruct three-dimensional microstructures from metallographic serial sections is therefore obvious and not at all new. However, the manual process of preparing a great number of individual sections and assembling them into image stacks is time-consuming and laborious and therefore constitutes an obstacle to frequent use. This is why the Federal Institute for Materials Research and Testing, or BAM for short (Bundesanstalt für Materialforschung und -prüfung), is developing a robot-assisted 3D metallography system performing the tasks of preparation and image acquisition on a metallographic section fully automatically and repeatedly. Preparation includes grinding, polishing and optional etching of the section surface. Image acquisition is performed using a light optical microscope with autofocus at several magnification levels. The obtained image stack is then pre-processed, segmented and converted to a 3D model resembling a microtomographic image, but with a higher lateral resolution at large volumes. As opposed to tomographic techniques, it is possible to perform traditional chemical etching for contrasting. The integration of a scanning electron microscope is in the planning stages. Studies conducted so far have demonstrated the possibility of visualizing hot gas corrosion layers, gray cast irons and ceramic-based microelectronic structures (vias).

Embedded sensors system to monitor cemented waste drums

Abstract. BAM (Federal Institute for Materials Research and Testing) is developing an electronic measurement system to be placed inside a waste drum, which will be filled with concrete. The goal of this measurement system is to monitor the process of hardening and the evolution of the concrete itself over time to indirectly identify potential defects such as corrosion or cracking. The measured parameters are humidity, temperature, and pressure. In this regard, particular attention was given to the design of the electronic board's enclosure, to allow the sensors to measure the state of the concrete without being in direct contact with it. In the scope of the European Commission's project of PREDIS, the supply of power to the battery-less sensors and the data acquired by such sensors are transmitted through the metallic waste drum by an innovative wireless technology developed by VTT (Technical Research Centre of Finland Ltd) in order to ensure long-term operation, while keeping the integrity of the sealed container. The sensing system is made of a chain of small units, called SensorNodes. Each SensorNode includes two off-the-shelf sensors, with one for relative humidity and temperature and one for pressure and temperature. A SensorNode is designed to have a unique identifier, in order to be connected to other units while being uniquely discoverable by a standard communication protocol. In this way, a distributed matrix of measurement points is created. One of the most challenging tasks in designing a measurement system to run in a harsh environment (such as hardening concrete) is to let the sensors sense the external environment without damaging the sensors themselves. In order to keep the external environment away from the electronic board while still letting the sensors measure the concrete behaviour, holes have been drilled through the lid and covered from the inside with a layer of porous membrane. The membrane's pores allow water and gas particles to pass through and let the enclosed air equilibrate with the external environment. With the help of the developed sensors, monitoring concrete in cemented waste drums will be possible. The derived data will also serve as the basis for ongoing modelling approaches for digital twins within the PREDIS project. Overall, the sensors provide a means of enabling safe nuclear waste management through advanced monitoring.

History of Steel Research in Institute for Materials Research (“KINKEN”) of Tohoku University

History of Steel Research in Institute for Materials Research (“KINKEN”) of Tohoku University

Automated Bonding Analysis with Crystal Orbital Hamilton Populations.

Invited for this month's cover are researchers from Bundesanstalt für Materialforschung und -prüfung (Federal Institute for Materials Research and Testing) in Germany, Friedrich Schiller University Jena, Université catholique de Louvain, University of Oregon, Science & Technology Facilities Council, RWTH Aachen University, Hoffmann Institute of Advanced Materials, and Dartmouth College. The cover picture shows a workflow for automatic bonding analysis with Python tools (green python). The bonding analysis itself is performed with the program LOBSTER (red lobster). The starting point is a crystal structure, and the results are automatic assessments of the bonding situation based on Crystal Orbital Hamilton Populations (COHP), including automatic plots and text outputs. Coordination environments and charges are also assessed. More information can be found in the Research Article by J. George, G. Hautier, and co-workers.

Effects of bending and torsion behavior on Ic degradation and microstructure of ReBCO coated conductors

The performance degradation caused by bending and torsion is crucial for the application of superconducting coated conductors. In this study, we investigated the critical current (Ic) degradation of four kinds of conductors under bending and torsion. With 1 mm resolution, the critical bending radius of STT236μm (Shanghai Superconductor Technology) conductors is 6–7 mm, and that of STT380μm conductors is 4–5 mm, and that of SAMRI (Suzhou Advanced Materials Research Institute) conductors is 4 mm. With better bending tolerance, SAMRI conductors also have a less critical twist pitch of 82–87 mm. Considering the residual thermal stress during fabrication, the longitudinal strain corresponding to 5 % Ic degradation is 0.484 %. Further, to figure out the failure mechanism of coated conductors, the micromorphology of the ReBCO layer was observed after chemical etching. The crack distribution not only verified the cause of Ic degradation under mechanical behaviors, but also helps to develop a crack-based Ic prediction method.

The Federal Institute of Materials Research and Testing (BAM) – 150 Years of Enabling Scientific and Technological Breakthrough

The Federal Institute of Materials Research and Testing (BAM) – 150 Years of Enabling Scientific and Technological Breakthrough

A Multiscale and Multimethod Approach to Assess and Mitigate Concrete Damage Due to Alkali–Silica Reaction

Alkali–silica reaction (ASR) is a chemical reaction within concrete which can lead over time to cracking and spalling. Due to the complexity of the problem, it still causes damage to concrete constructions worldwide. The study aims to illustrate the interdisciplinary research of the German Federal Institute for Materials Research and Testing (BAM) within the last 20 years, considering all aspects of ASR topics from the macro‐ to the micro‐level. First, methods for characterization and assessment of ASR risks and reaction products used at BAM are explained and classified in the international context. Subsequently, the added value of the research approach by combining different, preferably nondestructive, methods across all scales is explained using specific examples from a variety of research projects. Aspects covered range from the development of new test setups to assess aggregate reactivity, to analysis of microstructure and reaction products using microscopical, spectroscopical, and X‐ray methods, to the development of a testing methodology for existing concrete pavements including in‐depth analysis of the visual damage indicator and the deicing salt input using innovative testing techniques. Finally, research regarding a novel avoidance strategy that makes use of internal hydrophobization of the concrete mix is presented.

More Power in Series

More Power in Series

Distributed fiber optic radiation sensors

Abstract. The international research efforts focused on the development of radiation sensors based on optic fibers have their origins in the 1970s (Evans et al., 1978). Generally, the lightweight fiber optic sensors are immune to electromagnetic field interference and high voltages making them deployable in harsh environments at hard to reach areas where conventional sensors usually will not work at all. A further advantage of such radiation sensors is the possibility of remote and real-time monitoring (Huston et al., 2001). In this work, we present our results achieved in several research activities for development of fiber optic dosimeters. The findings show that both the measurement of the radiation-induced attenuation (RIA) along the entire sensing fiber and the accompanying change in the refractive index of the fiber core can be used for distributed radiation monitoring in the kGy and MGy range, respectively. Depending on the fiber type and material the RIA shows varying response to dose rates, environmental temperatures and the wavelength of the laser source used. Thereby, an operation with visible laser light provides most favorable performance in terms of high radiation sensitivity. Operating at these wavelengths, RIA monitoring could yield high-sensitivity dose measurement with sub-gray resolution and accuracy (Stajanca and Krebber, 2017b); however, conventional optical time-domain reflectometry (OTDR) systems for RIA measurements operating in the visible range suffer from low-spatial resolution, long measurement times and poor signal-to-noise (SNR) ratio. The limitations of the OTDR performance can be overcome by the incoherent optical frequency domain reflectometry (I-OFDR) developed by the Federal Institute of Materials Research and Testing (BAM, Liehr et al., 2009) with potential for dynamic real-time measurement. Over the years, several highly radiation sensitive fibers, such as perfluorinated polymer optical fibers (PF-POF, Stajanca and Krebber, 2017a), phosphorous-doped silica optical fibers (SOF, Paul et al., 2009), aluminium-doped SOF (Faustov et al., 2013) and erbium-doped SOF (Wosniok et al., 2016) have been identified and are commercially available. As mentioned before, the radiation-induced RIA increase is associated with an increase in the refractive index leading also to material compaction in the fiber core. The latter two effects can be used for measuring radiation distribution based on Brillouin scattering in the range of high radiation doses of several MGy (Phéron et al., 2012; Wosniok et al., 2016). When using fiber optic sensors for radiation monitoring, the existing post-irradiation annealing behavior of the optical fiber sensors must also be considered.

Development of High Performance Aerogel Concrete (HPAC) and statistical evaluation of compressive strength for practical use in construction

The Institute for Structural Concrete (ISC) at the University of Duisburg-Essen and the Institute of Materials Research of the German Aerospace Center (DLR) developed a new lightweight concrete, called “High Performance Aerogel Concrete” (HPAC). HPAC is made by embedding of silica aerogel granules in a high strength cement matrix. It exhibits a remarkable relation between compressive strength and thermal conductivity. HPAC for the load bearing layer of double-leaf external walls contains approx. 50 vol% aerogel and has a compressive strength in the range of normal concrete (20 MPa – 30 MPa). Up to now, the compressive strength of each mixture was determined on three to six cubes or cylinders. The scattering of the results has not been investigated yet. For this reason, 30 test specimens of a 50 vol%-mixture have been produced in two batches. The results of the compressive strength tests were then statistically evaluated. The underlying statistical distribution was determined by the Anderson-Darling-Test. Subsequently the 5 % fractile values of the mixtures, which represent the characteristic concrete compressive strength, were determined.

Modified lignin helps kill bacteria while avoiding antibiotic resistance

Bacteria are constantly mutating their DNA and developing new ways to evade once-useful antibiotics. A new study proposes an alternative to traditional antibiotics that could avoid promoting this resistance: tearing apart bacterial membranes with chemically modified lignin, a bountiful and cheap by-product of paper production ( ACS Biomater. Sci. Eng. 2021, DOI: 10.1021/acsbiomaterials.1c00856 ). Synthetic polymers have shown promise as antibacterials because they can compromise entire cell membranes rather than attack more specific targets that are easier for bacteria to evolve defense mechanisms against. But these polymers are often toxic or cause unwanted inflammatory and immune responses. By contrast, lignin—a highly branched, oxygen-containing plant biopolymer consisting chiefly of phenols—has been praised in previous studies for its potential biocompatibility . This is one reason that Rajamani Lakshminarayanan of the National University of Singapore and Dan Kai and Xian Jun Loh of the Institute of Materials Research and Engineering decided to try

Research on DC overcurrent characteristics and life prediction of YBCO tapes

The repeatability of superconducting DC limiters has not been introduced by other literature. Understanding the performance degradation characteristics of high-temperature superconducting (HTS) tapes under the overcurrent is of great significance for popularizing the application of a resistive-type DC superconducting fault current limiter. In this paper, the threshold experiment and repeated DC overcurrent experiment of HTS tape were carried out. With the critical current decay of the tapes under repeated DC overcurrent recorded, the current threshold under the DC overcurrent was obtained. And the performance degradation characteristics of the tapes under different repeated overcurrents were analysed, the resistance characteristics of the samples during different currents were compared. The results show that the DC overcurrent threshold of the copper-encapsulated second-generation (2G) YBCO tapes samples of Suzhou Advanced Materials Research Institute is 2.3/4 ms/3700 A. Under the repeated overcurrent, the performance degradation of the samples is abrupt, and the critical value is between 2.3/4 ms/3500 A and 2.3/4 ms/3550 A. The overcurrent has a limited influence on the magnitude of the resistance and will not affect the change trend of the resistance. The resistance at the falling edge of the current was greater than that at the rising edge of the current. The simulation was carried out by using COMSOL Multiphysics, and the simulation results matched the experimental results. The life prediction model of the samples was established and it was found that there is a custom equation relationship between the reliability of superconducting tapes and the number of the overcurrent, and the performance decline of this kind of samples is catastrophic.

Origin of lognormal distribution of wear coefficient values

Wear test results exhibit often large scattering and hence poor repeatability, reproducibility, and reliability. The study of spreading of tribological experimental results requires so called big datasets, allowing to understand the origin of scattering and to characterize statistical distributions.In various studies, wear coefficients were found to have lognormal distributions. Therefore, it was supposed that the wear coefficient is affected by two normally distributed variables, which combine through a product, namely the number of contacting asperities and the size of the produced wear particles.In the present study, taking advantage of large sets of measurements collected in the last decades in the Federal Institute for Materials Research and Testing, we demonstrate that a lognormal distribution may arise from a non-constant wear coefficient, too, i.e., when a system does not follow Archard’s law.

Ilich A. Ibarra.

"I chose chemistry as a career because I have always been interested in transformations … My favorite example of chemistry in everyday life is combustion …" Find out more about Ilich A. Ibarra in his Introducing … Profile.

Bending and uniaxial tensile strain effects on the critical current of REBCO coated conductor tapes

Bending tolerance is one of the most fundamental mechanical properties of REBCO coated conductors for application to a superconducting coil. In this study, we investigated critical current degradation of REBCO coated conductors under bending and uniaxial tensile strain at 77 K and self-field with three different kinds of production from SuperPower Inc, Suzhou Advanced Materials Research Institute (SAMRI) and Shanghai Superconductor Technology (STT), respectively. All the tapes showed better bending tolerance under compressive strain than tensile strain, particularly for STT tapes, which showed no Ic degradation in compressive bending strain even with bending radius of 4.5 mm, but a 5% Ic degradation in tensile strain with bending radius of 6–6.5 mm. A uniaxial tensile strain test was also carried out to verify the dependence of Ic under tensile bending strain, the test results showed a good agreement between them. The tensile strain tolerance was 0.28–0.29% for STT tapes, 0.4–0.43% for SAMRI tapes, and 0.5–0.55% for SuperPower tapes.

Inhalable SARS-CoV-2 Mimetic Particles Induce Pleiotropic Antigen Presentation

Covid-19 has caused over 4.5 million deaths worldwide and continues to ravage communities with limited access to injectable vaccines, or high rates of vaccine hesitancy. Inhalable vaccines have the potential to address these distribution and compliance issues as they are less likely to require cold storage, avoid the use of needles, and can elicit potent localized immune responses with only a single dose. Alveolar macrophages represent attractive targets for inhalable vaccines as they are abundant within lung mucosa (90-95% of all immune cells), are important mediators of mucosal immunity, and evidence suggests may be key cellular players in early Covid-19 pathogenesis. Here, we report inhalable coronavirus mimetic particles (CoMiP) designed to rapidly bind to, and be internalized by, alveolar macrophages to deliver nucleic acid encoded viral antigens. Inspired by the SARS-CoV-2 virion structure, CoMiPs package nucleic acid cargo within an endosomolytic peptide envelope that is wrapped in a macrophage-targeting glycosaminoglycan coating. Through this design, CoMiP carriers mimic several important features of the SARS-CoV-2 virion, particularly surface topography and macromolecular chemistry. As a result, CoMiPs effect pleiotropic transfection of macrophage and lung epithelial cells in vitro with multiple antigen-encoding plasmids. In vivo immunization yields increased mucosal IgA levels within the respiratory tract of CoMIP vaccinated mice.Funding: Funding for this work was provided by the COVID Research Seed Fund from the Huck Institutes of the Life Sciences and Materials Research Institute at the Pennsylvania State University.Declaration of Interests: None to declare. Ethics Approval Statement: Animal care committee is PSU IACUC, under protocol number 001552.

Performance Testing of a Large-Format X-ray Reflection Grating Prototype for a Suborbital Rocket Payload

The soft X-ray grating spectrometer on board the Off-plane Grating Rocket Experiment (OGRE) hopes to achieve the highest resolution soft X-ray spectrum of an astrophysical object when it is launched via suborbital rocket. Paramount to the success of the spectrometer are the performance of the [Formula: see text] reflection gratings populating its reflection grating assembly. To test current grating fabrication capabilities, a grating prototype for the payload was fabricated via electron-beam lithography at The Pennsylvania State University’s Materials Research Institute and was subsequently tested for performance at Max Planck Institute for Extraterrestrial Physics’ PANTER X-ray Test Facility. Bayesian modeling of the resulting data via Markov chain Monte Carlo (MCMC) sampling indicated that the grating achieved the OGRE single-grating resolution requirement of [Formula: see text] at the 94% confidence level. The resulting [Formula: see text] posterior probability distribution suggests that this confidence level is likely a conservative estimate though, since only a finite [Formula: see text] parameter space was sampled and the model could not constrain the upper bound of [Formula: see text] to less than infinity. Raytrace simulations of the tested system found that the observed data can be reproduced with a grating performing at [Formula: see text]. It is therefore postulated that the behavior of the obtained [Formula: see text] posterior probability distribution can be explained by a finite measurement limit of the system and not a finite limit on [Formula: see text]. Implications of these results and improvements to the test setup are discussed.