Helium Atmosphere Research Articles

Blue- and white-emitting Dy3+-doped aluminum oxide prepared using precursor synthesis

Al2O3:Dy3+ phosphors have been successfully prepared using the precursor method utilizing Al1-xDyx(OH)(HCOO)2 as a precursor. The synthesis of the precursor was carried out according to the reaction of the metal nitrates with different concentrations of formic acid. A similar method was used to obtain dysprosium formate, Dy(HCOO)3, which is the most probable impurity phase formed during the preparation of Al1-xDyx(OH)(HCOO)2. The crystal structures of Al1-xDyx(OH)(HCOO)2 and Dy(HCOO)3 have been studied using X-ray powder diffraction and Raman spectroscopy. The phosphors in the form of their amorphous oxides (Al2О3:Dy3+) and solid solutions ((Al1-xDyx)2O3) with a spinel γ-Al2О3 structure were obtained via the thermolysis of Al1-xDyx(OH)(HCOO)2 under a helium atmosphere. The absorption, excitation, and luminescence spectra of the phosphors prepared with different dopant concentrations and upon annealing the Al1-xDyx(OH)(HCOO)2 precursor at various temperatures were analyzed in detail. For both amorphous Al2О3:Dy3+ and (Al1-xDyx)2O3 phosphors, the luminescence intensity associated with intrinsic internal defects in the aluminum host decreases upon increasing the dysprosium content. The energy transfer from the host to the activator (Dy3+) leads to a shift in the luminescence in the white color region, which is confirmed by the CIE chromaticity coordinates of the (Al1-xDyx)2O3 compounds. The Al2О3:0.005Dy3+ and γ-(Al0.995Dy0.005)2O3 aluminum oxides exhibit high thermal stability over a wide temperature range and are promising blue-white luminescence materials.

Cyclohexylammonium Hexaisothiocyanatonickelate(II) Dihydrate as a Single-Source Precursor for High Surface Area Nickel Oxide and Sulfide Nanocrystals

Cyclohexylammonium hexaisothiocyanatonickelate(II) dihydrate, (C6H11NH3)4[Ni(NCS)6]·2H2O, was synthesized, for the first time, by a four-step method in a yield of 95%. The compound was fully characterized by elemental microanalysis, Fourier transform infrared (FTIR), ultraviolet-visible-near infrared (UV-Vis-NIR), and nuclear magnetic resonance (NMR) spectroscopy and thermogravimetry. A single crystal X-ray diffraction (SXRD) gave the monoclinic space group P21/c with a = 15.8179 (5) Å, b = 10.6222 (3) Å, c = 13.8751 (4) Å, β = 109.362 (1)°, V = 2199.45 (11) Å3, Z = 2 (T = 293 K) for this novel hybrid organic–inorganic compound. The title compound was employed as a single-source precursor for the synthesis of mesoporous, high surface area nickel oxide (53 Å; 452 m2/g) and nickel sulfide (46 Å; 220 m2/g) via pyrolysis under air at 550 °C or helium atmosphere at 500 °C, respectively. X-ray powder diffraction (XRPD) demonstrated the nanocrystalline nature of both NiO and NiS with an average crystallite size of 16 and 54 nm, respectively. Scanning electron microscope (SEM) indicated the formation of agglomerated, quasi-spherical particles of nickel oxide and agglomerated flake-like structures of nickel sulfide. The high surface area, porosity, and nanocrystallinity of both NiO and NiS, obtained via this approach, are promising for a wide spectrum of applications.

Formation of Catalytically Active Nanoparticles under Thermolysis of Silver Chloroplatinate(II) and Chloroplatinate(IV).

The thermal behaviour of Ag2[PtCl4] and Ag2[PtCl6] complex salts in inert and reducing atmospheres has been studied. The thermolysis of compounds in a helium atmosphere is shown to occur in two stages. At the first stage, the complexes decompose in the temperature range of 350–500 °C with the formation of platinum and silver chloride and the release of chlorine gas. At the second stage, silver chloride is sublimated in the temperature range of 700–900 °C, while metallic platinum remains in the solid phase. In contrast to the thermolysis of Ag2[PtCl6], the thermal decomposition of Ag2[PtCl4] at 350 °C is accompanied by significant heat release, which is associated with disproportionation of the initial salt to Ag2[PtCl6], silver chloride, and platinum metal. It is confirmed by DSC measurements, DFT calculations of a suggested reaction, and XRD. The thermolysis of Ag2[PtCl4] and Ag2[PtCl6] compounds is shown to occur in a hydrogen atmosphere in two poorly separable steps. The compounds are decomposed within 170–350 °C, and silver and platinum are reduced to a metallic state, while a metastable single-phase solid solution of Ag0.67Pt0.33 is formed. The catalytic activity of the resulting nanoalloy Ag0.67Pt0.33 is studied in the reaction of CO total (TOX) and preferential (PROX) oxidation. Ag0.67Pt0.33 enhanced Pt nano-powder activity in CO TOX, but was not selective in CO PROX.

Microstructure and fatigue strength of A356 alloy castings refined on the surface by rapid crystallization

Abstract The effect of the microstructure on the fatigue strength of A356 alloy castings with a surface refined through rapid crystallization has been investigated. The refinement of the structure, in order to improve the fatigue strength of the alloy surface, was accomplished with an electric arc plasma. The surface fusions were made in helium atmosphere by changing the welding current intensity from 100 to 300 A and the arc advance speed from 200 to 600 mm/min. The rapid crystallization reduced the parameters 𝜆1 and 𝜆2 of the 𝜆 phase dendrites and 𝜆E of the eutectic, compared to the initial material. The parameter 𝜆E changed by a factor of nearly 3. The structural refinement was determined by the amount of heat input into the fusion area. The fatigue strength increased with decreasing values of the λ parameters of the structure.

Study of the Influence of Oxygen on the Hydrodynamic Behavior of Helium Atmospheric Pressure Plasma Jet by Shadowgraphy System

This work investigates the effect of oxygen (O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) as gas admixture on hydrodynamic characteristics of a coaxial double-ring electrode helium plasma jet by a “Z-type” shadowgraphy system. The shadowgraphy images and visual optical photographs show that the addition of O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> will slow down the transition of gas flow from the laminar region to the turbulent region regardless of the plasma is ignited or not. The hydrodynamic behaviors of the plasma jet at the impact region for epoxy resin (EP) and aluminum substrates are also researched. The addition of oxygen reduces the vortex on the surface of both EP and aluminum surface. As a result, with the increase of O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> , the decrease of gas temperature caused by reduction of electrons and the reduction of the density difference between the mixed gas and the ambient air weaken the gas velocity and results in a weaker collision between the gas and the substrate, which is the main factor for less vortex on the substrate surface.

Experimental investigation on effective thermal conductivity of powder-packed assembly gaps in heat pipe cooled reactor core

The heat pipe cooled reactor utilizes monolithic solid core inserted with fuel rods and heat pipes. There exist assembly gaps between fuel rods, heat pipes and the solid block to avoid contact stress resulted from heterogeneous thermal expansion. In order to reduce the additional thermal resistance caused by assembly gaps, thermal conductive powders can be filled into the gaps. For the sake of evaluation on the effects of powder packed gaps on the reactor safety margin of heat pipe cooled reactor, the effective thermal conductivity of stainless-steel powder packed beds with different particle sizes was measured using the one-dimensional steady-state hollow-cylinder method in both air and helium atmosphere under the heating temperature of 800–1000 K and the pressure of 1 bar. The Zehner-Schlünder model was calibrated by adjusting the particle deformation parameter and the flattened surface fraction based on the experimental data in air. The comparison of prediction results by the adjusted Zehner-Schlünder model with experimental results in helium and relevant experimental data from previous literature shows the relatively error within ± 20%. Finally, the performance of powder packed gaps on increasing the reactor safety margin was evaluated by analyzing the different heat transfer modes and initial assembly-gap sizes. Results show that the performance improves with the increase of initial assembly-gap size and the fuel temperature decreases by 19.19 K compared to the helium-filled gap even with a small initial assembly-gap size of 0.2 mm.

An Isolated White Dwarf with a 70 s Spin Period

Abstract We report the discovery of an isolated white dwarf with a spin period of 70 s. We obtained high-speed photometry of three ultramassive white dwarfs within 100 pc and discovered significant variability in one. SDSS J221141.80+113604.4 is a 1.27 M ⊙ (assuming a CO core) magnetic white dwarf that shows 2.9% brightness variations in the BG40 filter with a 70.32 ± 0.04 s period, becoming the fastest spinning isolated white dwarf currently known. A detailed model atmosphere analysis shows that it has a mixed hydrogen and helium atmosphere with a dipole field strength of B d = 15 MG. Given its large mass, fast rotation, strong magnetic field, unusual atmospheric composition, and relatively large tangential velocity for its cooling age, J2211+1136 displays all of the signatures of a double white dwarf merger remnant. Long-term monitoring of the spin evolution of J2211+1136 and other fast-spinning isolated white dwarfs opens a new discovery space for substellar and planetary mass companions around white dwarfs. In addition, the discovery of such fast rotators outside of the ZZ Ceti instability strip suggests that some should also exist within the strip. Hence, some of the monoperiodic variables found within the instability strip may be fast-spinning white dwarfs impersonating ZZ Ceti pulsators.

Synthesis of magneto-dielectric coatings in electron-beam produced plasma in medium vacuum

Using sequential electron-beam evaporation of high-temperature dielectric (alumina ceramic) and magnetic (iron) targets in various gas atmospheres (helium, air, and oxygen) in medium vacuum (5–8 Pa), magneto-dielectric coatings with thickness of around 2 μm were deposited from a multicomponent beam plasma at a deposition rate of 0.2–0.3 μm/min. The coating magnetic properties were explored by the ferromagnetic resonance technique, revealing that their effective magnetization depends on the type of operating gas and varied from 4.2 to 6.8 kGs (for deposition in helium) to 0.3 kGs (in oxygen), which is characteristic of oxide ferromagnetic materials and is considerably lower than the corresponding value (∼22 kGs) for thin iron films formed by vacuum arc deposition in high vacuum. X-ray structural analysis of coatings deposited in medium vacuum in helium showed that the magnetic layer has a magnetite (Fe3O4) structure. The alumina ceramic layer provides the dielectric properties of the magneto-dielectric coating; a relative dielectric constant of 6.0 and a conductivity of 8.4 mS/m were achieved.

Preliminary computational and experimental design studies of the ISHTAR thermostatic rig for the high-temperature reactors materials irradiation

Abstract The Irradiation System for High-Temperature Reactors (ISHTAR) thermostatic rig will be used to irradiate advanced core material samples in conditions corresponding to those prevailing in the high-temperature reactors (HTRs): these conditions include a stable temperature extending up to 1000°C in the helium atmosphere. Computational and experimental studies concerning the design have been conducted, proving the possibility of these conditions’ fulfillment inside the rig while maintaining the safety limits for MARIA research reactor. The outcome is the thermostatic rig design that will be implemented in the MARIA reactor. Appropriate irradiation temperature will be achieved by a combination of electric heating with the control system, gamma heating, and a helium insulation gap with precisely designed thickness. The ISHTAR rig will be placed inside the vertical irradiation channel, which is located in the reactor pool. The device is being developed from scratch at the Nuclear Facilities Operation Department of the National Centre for Nuclear Research as a part of the GOSPOSTRATEG programme.

Residual moisture in the sewage sludge feed significantly affects the pyrolysis process: Simulation of continuous process in a batch reactor

Residual moisture (0–10 wt%) in the pyrolyzed fuel has a significant effect on the distribution and properties of pyrolysis products. It is due to the concentration of steam in the primary pyrolysis gas which is estimated to as much as 80 vol%. This is normally not taken into account in case of fixed-bed reactor studies at laboratory scale, where inert carrier gas is used to secure the absence of oxidizing agent, because the moisture is released within the beginning of heating and carried over from the hot zone before the pyrolysis starts. Consequently, the application of the results to large-scale technologies (working in the continuous sludge feeding regime) is not entirely valid because in industrial large-scale systems the steam passes through the hot pyrolysis zone and takes part in high-temperature reactions. In the experiments presented within this manuscript, we allowed the residual moisture typical for industrially dried sludge (10 wt%) to react within the pyrolysis process by incorporating it into the carrier gas (consisting finally of 70 vol% steam and 30 vol% He). This steam reacted within the pyrolysis process at temperatures 400–800 °C in a fixed-bed reactor. The results were thoroughly compared with the results of a previous study with pure helium atmosphere, within the same experimental setup. When comparing the experiments with and without steam in the carrier gas, a significant difference in the distribution and properties of the products was observed especially at temperatures above 600 °C. The use of steam as a carrier gas (instead of inert gas) resulted in a remarkably higher pyrolysis gas yield. The pyrolysis gas constituted of almost double the content of hydrogen with a decrease in the yield of the sludge-char. Moreover, particular changes in sludge-char properties were observed. Not only the steam enhanced textural properties of the sludge-chars, especially the specific surface area and the total specific pore volume, but it also resulted in a significantly lower content of C, H, N and S and lower heating value of the sludge-char. These parameters can be decisive in case of sludge-char utilization ranging from agronomic through adsorbents to fuel use. Our approach provides a simplified way to better predict the distribution and properties of pyrolysis products in large-scale units. This can be time and money saving and is crucial to make decisions about the applicability of pyrolysis technology to specific sewage sludge products.

Helium tribology of Inconel 617 subjected to laser peening for high temperature nuclear reactor applications

Inconel 617 is among the best candidates for utilization in high temperature gas cooled reactor tribo-components. However, the combined effects of sliding contact, along with intermittent idle times and very high temperature material degradation, deteriorates the alloy tribological performance, especially under a helium atmosphere. Laser peening is a surface treatment technique which can enhance the properties at the surface and subsurface by generating deep residual stresses and enhanced microstructure. Herein, we report the tribological behavior of regular laser peened as well as thermally-engineered laser peened Inconel 617 under helium and air atmospheres at 800 °C. In addition to friction and wear studies, the specimens are characterized by different analytical techniques to further understand the mechanisms involved in the peening process and sliding contact. Regardless of the peening process and post-process treatment types, it is observed that laser peening improves the tribological characteristics of Inconel 617. Interestingly, laser peening followed by helium thermal aging shows highly enhanced tribological behavior. This is attributed to the strengthening effect of the laser peening on the surface oxides providing an excellent and lasting protective and lubricating film under helium exposure.

Design of the upstream decay pipe window of the long baseline neutrino facility

The beam windows of high-energy beam lines are important, and it is sometimes difficult to design because it is necessary to ensure particle propagation with minimum disturbance and fulfill mechanical requirements at the same time. The upstream decay pipe window of the long baseline neutrino facility at Fermilab has an extremely large diameter (1.8 m), with a thickness of only 1.5 mm to separate the helium atmosphere in the decay pipe and the nitrogen atmosphere on the other side. Furthermore, the center of this dish-shaped window is expected to be a 200-mm-diameter beryllium dish welded to the outside aluminum alloy A6061, and this welded combination must withstand extreme conditions of a 2.4-MW, high-energy proton beam without leakage. These severe conditions make the design of this window an unprecedented challenge. This paper describes the static thermal-structural analyses based on which the structure has been optimized, as well as dynamic analyses for understanding the shockwave effects originating in the beam. After optimization, the maximum von Mises stresses in the window decreased significantly in both normal operation and accident cases, making our design very reasonable.

Helium Atmospheric Pressure Plasma Jet Source Treatment of White Grapes Juice for Winemaking

In the last few years, new emerging technologies to develop novel winemaking methods were reported. Most of them pointed out the need to assess the barrel aging on the wine product, fermentation process, green technologies for wine treatment for long term storage. Among these, plasma technologies at atmospheric pressure are on the way of replacing old and expensive methods for must, wine and yeast treatment, the goal being the long-term storage, aging and even decontamination of such products, and seems to meet the requirements of the winemakers. Using the principles of dielectric barrier discharge, we power up an atmospheric pressure plasma jet in helium. This plasma is used for treatment of fresh must obtained from white grapes. Our research manuscript is focused on the correlation of plasma parameters (applied voltage, plasma power, reactive species, gas temperature) with the physico-chemical properties of white must and wine (1 and 2 years old), via ultraviolet–visible and infrared spectroscopy, and colorimetry. Two types of white must were plasma treated and studied over time. The 10 W plasma source did not exceed 40 °C during treatment, the must did not suffer during thermal treatment. A higher quantity of RONS was observed during plasma-must exposure, supporting further oxidation processes. The UV-Vis and FTIR spectroscopy revealed the presence of phenols, flavones and sugar in the wine samples. Simultaneous visualization of CIE L*a*b* and RGB in color space charts allows easier understanding of wine changing in color parameters. These experimental results supporting the possible usability of atmospheric pressure plasma for winemaking.

Structure and magnetic properties of Fe-Co alloy nanoparticles synthesized by pulsed-laser inert gas condensation

Fe-Co alloy nanoparticles of different compositions (Fe content of 76, 51, and 30 at%), along with pure Fe and Co nanoparticles, were prepared by pulsed-laser inert gas condensation, consisting in laser ablation of Fe-Co alloy targets under helium atmosphere. From the morphological point of view, the obtained nanoparticles have nearly spherical shape, follow a lognormal size distribution and exhibit little aggregation. X-ray diffraction and high-resolution electron microscopy coupled with electron energy loss spectroscopy show that the Fe-Co nanoparticles are single crystals with body-centered cubic structure. Furthermore, in the majority of nanoparticles the composition is highly uniform across the whole diameter and there is little variation in composition from one nanoparticle to another. Exposure to non-inert atmosphere leads to the formation of a core@shell metal@oxide morphology characterized by a spinel oxide shell of 2–3 nm around the metallic alloy core. All samples display a ferromagnetic behavior, characterized by a hysteretic magnetization loop. The saturation magnetization attains a maximum value of 2.43 Bohr magnetons per atom for Fe content of 76 at%, in agreement with the Slater-Pauling curve for alloys of 3d elements. Instead, the coercive field, ranging from 29 to 60 kA m−1, is much larger than the reported values for polycrystalline bulk Fe-Co compounds and monotonically increases from pure Fe to pure Co. These results demonstrate that pulsed-laser inert gas condensation allows to prepare high-quality nanoalloys with tailorable magnetic properties, overcoming the limitations of thermal evaporation methods with respect to compositional control.

Effect of a mesoporous catalyst on the flash pyrolysis of tobacco

Thermal and catalytic pyrolysis of a tobacco blend were studied by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The Py-GC/MS experiments were carried out in helium and air atmosphere at 300, 500 and 700 °C. SBA-15 mesoporous silica has been used as a catalyst blended with the tobacco at 5%, 15% and 50%. The results obtained show that under inert atmosphere and at high pyrolysis temperatures, the catalyst addition did not significantly modify the formation of pyrolysis products, while under oxidising atmosphere and at low temperatures, the formation of pyrolysis products decrease considerably. It was found that components linked to tobacco use responsible of the most severe health effects are generated from 500 °C on. Catalyst selectivity has been observed, maintaining nicotine release while decreasing the generation of other pyrolysis products. It was found that the concentration of the catalyst modifies the formation of the selected pyrolysis products significantly, although 5% of the catalyst is enough to obtain significant results.

On the expansion dynamics of plasma plume produced by laser ablation of LiYF4 crystal in a helium atmosphere

The effect of helium ambient gas on the expansion dynamics of plasma plume produced by ablating the LiYF4 crystal with 355 nm laser pulses is investigated. To study the expansion dynamics, the time-resolved optical signals from the plume constituents, either neutral or ionized, were recorded as a function of various experimental parameters, including laser fluency, at different distances, d, from the target along the expansion direction of the plume and at various angles with reference to the target normal. The analysis of the plume constituents at different distances from the target was used to derive the expansion velocities of the species. Depending on the species and on d, the shifted Maxwell–Boltzmann distribution component of the fit gave the values of the expansion velocities in the range 1.0 × 104 m s−1–4.0 × 104 m s−1. The effect of laser fluency on the expansion velocities of the plume species was also investigated. With the exception of Y and Y+, the expansion velocities of all the plume species, increased linearly with increasing laser fluency up to ∼8 J cm−2. Beyond this value, a saturation regime is observed. The angular distribution of the plume constituents in 1 Pa of He evidenced that all the plume species were focused along the target normal, and the FWHM of the angular distribution curve resulted reduced when compared with the vacuum.

Aging-resistant carbon molecular sieve membrane derived from pre-crosslinked Matrimid® for propylene/propane separation

Despite the well-recognized potential of carbon molecular sieve (CMS) membranes for olefin/paraffin separation, its gradual performance degradation has been the main bottleneck to reach commercialization. Particularly, the structural transformation of CMS membranes has recently been identified as an additional challenge to be resolved. Herein, we systematically studied the aging phenomenon under nitrogen and helium atmosphere, as well as the aging of CMS membranes during propylene separation under oxygen-free dry conditions. In order to minimize this structural transformation, the shift of carbon structure must be prevented by fastening the chains. We implemented a pre-crosslinking step on Matrimid® polymer precursors with various contents of crosslinking agent prior to pyrolysis to establish firm networks, resulting in a remarkable improvement of long-term stability nearly 18-fold when tested in long-term (500 h) at 7 barg and 50 °C. Moreover, it was found that there exists an optimal pre-crosslinking density of CMS membrane for aging suppression.

Pyrolysis of Porous Organic Polymers under a Chlorine Atmosphere to Produce Heteroatom-Doped Microporous Carbons.

Three types of cross-linked porous organic polymers (either oxygen-, nitrogen-, or sulfur-doped) were carbonized under a chlorine atmosphere to obtain chars in the form of microporous heteroatom-doped carbons. The studied organic polymers constitute thermosetting resins obtained via sol-gel polycondensation of resorcinol and five-membered heterocyclic aldehydes (either furan, pyrrole, or thiophene). Carbonization under highly oxidative chlorine (concentrated and diluted Cl2 atmosphere) was compared with pyrolysis under an inert helium atmosphere. All pyrolyzed samples were additionally annealed under NH3. The influence of pyrolysis and additional annealing conditions on the carbon materials’ porosity and chemical composition was elucidated.

Pyrolysis and oxidative decomposition mechanism of trifluoromethylated fused triazinones

The pyrolysis and oxidative decomposition courses of a novel class of trifluoromethylated fused triazinones by using a Simultaneous thermal analysis (STA) coupled online with the Fourier transform infrared spectroscopy (FTIR) and the Quadrupole mass spectrometry (QMS) were determined. It was found that the pyrolysis and oxidation processes of these compounds run through simultaneous, radical processes in one, main stage in both: helium and air atmospheres. The FTIR and QMS analyses allowed confirming the simultaneous cleavage of CCF3, CN, NN, and CCl bonds, formation of radical intermediates, reactions of radical intermediates with each other in a gaseous phase leading to the formation of final volatile products such as RNCO, CF3CN, CF3H, HCOCOH, alkenes, aromatic amine derivatives, CO2 and H2O in inert conditions as well as RNCO, CF3CN, CF3H, HCOCOH, alkenes, aromatic amine derivatives, CO2, CO and H2O in oxidative conditions. Moreover, the favourable thermal properties and high purity were highlighted in evaluating the suitability of trifluoromethylated compounds as potential candidates for pharmaceutical applications.

Experimental methods for laboratory measurements of helium spectral line broadening in white dwarf photospheres

White Dwarf (WD) stars are the most common stellar remnant in the universe. WDs usually have a hydrogen or helium atmosphere, and helium WD (called DB) spectra can be used to solve outstanding problems in stellar and galactic evolution. DB origins, which are still a mystery, must be known to solve these problems. DB masses are crucial for discriminating between different proposed DB evolutionary hypotheses. Current DB mass determination methods deliver conflicting results. The spectroscopic mass determination method relies on line broadening models that have not been validated at DB atmosphere conditions. We performed helium benchmark experiments using the White Dwarf Photosphere Experiment (WDPE) platform at Sandia National Laboratories' Z-machine that aims to study He line broadening at DB conditions. Using hydrogen/helium mixture plasmas allows investigating the importance of He Stark and van der Waals broadening simultaneously. Accurate experimental data reduction methods are essential to test these line-broadening theories. In this paper, we present data calibration methods for these benchmark He line shape experiments. We give a detailed account of data processing, spectral power calibrations, and instrument broadening measurements. Uncertainties for each data calibration step are also derived. We demonstrate that our experiments meet all benchmark experiment accuracy requirements: WDPE wavelength uncertainties are &amp;lt;1 Å, spectral powers can be determined to within 15%, densities are accurate at the 20% level, and instrumental broadening can be measured with 20% accuracy. Fulfilling these stringent requirements enables WDPE experimental data to provide physically meaningful conclusions about line broadening at DB conditions.