High-temperature Blackbody Research Articles

A Multiwavelength Study of the Hard and Soft States of MAXI J1820+070 During Its 2018 Outburst

We present a comprehensive multiwavelength spectral analysis of the black hole (BH) X-ray binary MAXI J1820+070 during its 2018 outburst, utilizing AstroSat far-UV, soft X-ray, and hard X-ray data, along with (quasi-)simultaneous optical and X-ray data from the Las Cumbres Observatory and NICER, respectively. In the soft state, we detect soft X-ray and UV/optical excess components over and above the intrinsic accretion disk emission (kT in ∼ 0.58 keV) and a steep X-ray power-law component. The soft X-ray excess is consistent with a high-temperature blackbody (kT ∼ 0.79 keV), while the UV/optical excess is described by UV emission lines and two low-temperature blackbody components (kT ∼ 3.87 and ∼0.75 eV). Employing continuum spectral fitting, we determine the BH spin parameter (a = 0.77 ± 0.21), using the jet inclination angle of 64° ± 5° and a mass spanning 5–10 M ☉. In the hard state (HS), we observe a significantly enhanced optical/UV excess component, indicating a stronger reprocessed emission in the outer disk. Broadband X-ray spectroscopy in the HS reveals a two-component corona, each associated with its reflection component, in addition to the disk emission (kT in ∼ 0.19 keV). The softer coronal component dominates the bolometric X-ray luminosity and produces broader relativistic reflection features, while the harder component gets reflected far from the inner disk, yielding narrow reflection features. Furthermore, our analysis in the HS suggests a substantial truncation of the inner disk (≳51 gravitational radii) and a high disk density (∼1020 cm−3).

Spectral aerosol optical depth from SI-traceable spectral solar irradiance measurements

Abstract. Spectroradiometric measurements of direct solar irradiance traceable to the SI were performed by three spectroradiometer systems during a 3-week campaign in September 2022 at the Izaña Atmospheric Observatory (IZO) located on the island of Tenerife, Canary Islands, Spain. The spectroradiometers provided direct spectral irradiance measurements in the spectral ranges 300 to 550 nm (QASUME), 550 to 1700 nm (QASUME-IR), 300 to 2150 nm (BiTec Sensor, BTS), and 316 to 1030 nm (Precision Solar Spectroradiometer, PSR), with relative standard uncertainties of 0.7 %, 0.9 %, and 1 % for QASUME/QASUME-IR, the PSR, and the BTS respectively. The calibration of QASUME and QASUME-IR was validated prior to this campaign at Physikalisch-Technische Bundesanstalt (PTB) by measuring the spectral irradiance from two spectral irradiance sources, the high-temperature blackbody BB3200pg as a national primary standard and the tuneable laser facility TULIP. The top-of-atmosphere (ToA) solar irradiance spectra from the spectroradiometers were retrieved from direct solar irradiance measurements using zero-air-mass extrapolation during cloud-free conditions, which were then compared to the TSIS-1 Hybrid Solar Reference Spectrum (HSRS). These ToA solar spectra agreed to within 1 % for spectral ranges longer than 400 nm (for QASUME also at shorter wavelengths) in the spectral regions free of significant trace gas absorption and were well within the combined uncertainties over the full investigated spectral range. Using the results from the comparison with QASUME, the relative standard uncertainty of the TSIS-1 HSRS ToA solar spectrum in the spectral range 308 to 400 nm could be reduced from its nominal 1.3 % to 0.8 %, representing the relative standard uncertainty of the QASUME ToA solar spectrum in this spectral range. The spectral aerosol optical depth (AOD) retrieved from the solar irradiance measurements of these spectroradiometers using the TSIS-1 HSRS as the reference ToA solar spectrum agreed to within 0.01 in optical depth in nearly all common spectral channels of two narrowband filter radiometers belonging to the Global Atmosphere Watch Precision Filter Radiometer (GAW-PFR) network and Aerosol Robotic Network (AERONET). This study shows that it is now possible to retrieve spectral AOD over the extended spectral range from 300 to 1700 nm using solar irradiance measurements traceable to the SI using laboratory-calibrated spectroradiometers with similar quality to that from traditional Langley-based calibrated instruments. The main improvement to previous investigations is the recent availability of the high-spectral-resolution TSIS-1 HSRS with very low uncertainties, which provides the top-of-atmosphere reference for the spectral atmospheric transmission measurements obtained from ground-based solar irradiance measurements.

Performance Characterization of a Fully Transportable Mid-Infrared Laser Heterodyne Radiometer (LHR).

A fully transportable laser heterodyne radiometer (LHR), involving a flexible polycrystalline mid-infrared (PIR) fiber-coupling system and operating around 8 µm, was characterized and optimized with the help of a calibrated high temperature blackbody source to simulate solar radiation. Compared to a mid-IR free-space sunlight coupling system, usually used in a current LHR, such a fiber-coupling system configuration makes the mid-infrared (MIR) LHR fully transportable. The noise sources, heterodyne signal, and SNR of the MIR LHR were analyzed, and the optimum operating local oscillator (LO) photocurrent was experimentally obtained. The spectroscopic performance of the MIR LHR was finally evaluated. This work demonstrated that the developed fully transportable MIR LHR could be used for ground-based atmospheric sounding measurements of multiple trace gases in the atmospheric column. In addition, it also has high potential for applications on spacecraft or on an airborne platform.

Online in-situ monitoring of melt pool characteristic based on a single high-speed camera in laser powder bed fusion process

• A coaxial melt pool temperature measurement system with a single high-speed camera in the LPBF process is developed. • A dual-waveband image-matching method with sub-pixel accuracy, and an overall parameter calibration and optimization method are proposed. • The melt pool characteristics including the temperature distribution, profile, temperature gradient, and cooling rate are measured by the developed system, and the distribution of average temperature and peak temperature under different linear energy densities during single-line printing is compared and analyzed. In metal additive manufacturing (AM), the in-situ measurement of the melt pool characteristic plays a significant role in monitoring the quality of the printed components. In this work, based on dual-wavelength thermometry, a coaxial melt pool temperature measurement system with a single high-speed camera in the laser powder bed fusion (LPBF) process is developed, including the design of the relay and optical path amplification system, and the beam splitting and chromatic aberration correction system. Moreover, a dual-waveband image-matching method with sub-pixel accuracy, and an overall parameter calibration and optimization method are proposed to improve the accuracy of the coaxial temperature measurement system. Besides, the validation experiment measured by a high-temperature blackbody furnace and a standard photoelectric pyrometer indicates that the temperature measuring error of the developed system is less than 1%. The melt pool characteristics including the temperature distribution, profile, temperature gradient, and cooling rate were measured by the developed coaxial temperature measurement system, and the distribution of average temperature and peak temperature under different linear energy densities during single-line printing was also compared and analyzed. The single-line printing results of different parameters show that the higher the linear energy density, the higher the average temperature and peak temperature of the melt pool, and the optimized parameters minimize the fluctuation of melt pool temperature and are more favorable to the formation of high-quality parts. In multi-layer printing mode, the heat accumulation is strong, resulting in the slow cooling rate of the melt pool.

New traceability chain for spectral irradiance measurement at LNE-Cnam

LNE-Cnam has changed its traceability chain for measuring the spectral irradiance of a light source. This facility allows calibration of spectral irradiance of a standard lamp based on a comparison with a high temperature blackbody (HTBB). The reference spectral irradiance is determined by measuring the temperature of the HTBB with a filter radiometer calibrated against our radiant flux reference. This traceability scheme differs from the one used in our former setup, which was mainly based on the International Temperature Scale, ITS-90. Both principles are used in National Measurement Institutes. Our facility uses well known methods adapted to our best capabilities as well as a particular development in optical arrangement and filter radiometer calibration. Thanks to this new measurement setup, our spectral irradiance reference is now traceable to radiometric reference, i.e. our cryogenic radiometer. We have extended our measurement capability to cover the spectral range from 250 nm to 2500 nm. We have simplified the process by reducing the number of benches (three in one) and the number of operations, and we have designed a compact measuring setup through the use of a rotating integrative sphere. This allows us to reduce by at least a factor two our measurement uncertainties over almost the entire spectral range. With this new measurement facility, France participates in the ongoing CCPR k1.a key comparison. This is a key comparison of the Consultative Committee of Photometry and Radiometry for Spectral irradiance from 250 nm to 2500 nm of tungsten halogen lamps. This communication shows the method used, and its validation.

A new method to quantify particulate sodium and potassium salts (nitrate, chloride, and sulfate) by thermal desorption aerosol mass spectrometry

Abstract. The reaction of sea salt (or biomass burning) particles with sulfuric acid and nitric acid leads to the displacement of chloride relative to sodium (or potassium). We have developed a new particle mass spectrometer to quantify non-refractory and refractory sulfate aerosols (referred to as refractory aerosol thermal desorption mass spectrometer: rTDMS). The combination of a graphite particle collector and a carbon dioxide laser enables high desorption temperature (blackbody equivalent radiation temperature of up to 930 ∘C). Ion signals originating from evolved gas molecules are detected by a quadrupole mass spectrometer. Here we propose a new method to quantify the mass concentrations of sodium nitrate (NaNO3: SN), sodium chloride (NaCl: SC), sodium sulfate (Na2SO4: SS), potassium nitrate (KNO3: PN), potassium chloride (KCl: PC), and potassium sulfate (K2SO4: PS) particles by using the rTDMS. Laboratory experiments were performed to test the sensitivities of the rTDMS to various types of particles. We measured ion signals originating from single-component particles for each compound and found a good linearity (r2>0.8) between the major ion signals and mass loadings. We also measured ion signals originating from internally mixed SN + SC + SS (or PN + PC + PS) particles and found that the temporal profiles of ion signals at m/z 23 (Na+) (or 39; K+) were characterized by three sequential peaks associated with the evolution of the desorption temperature. We tested potential interferences in the quantification of sea salt particles under real-world conditions by artificially generating “modified” sea salt particles from a mixture of diluted seawater and SN (or SS) solution. The SS/SC ratios estimated from the ion signals at m/z 23, 36 (H35Cl+), and 48 (SO+) agreed well with those predicted from the solution concentrations to within ∼10 %. The SN/SC ratios estimated from the ion signals at m/z 30 (NO+) and 36 also agreed with those predicted from the solution concentrations to within ∼15 %, whereas the SN/SC ratios estimated from m/z 23 were significantly lower than the predicted values. Based on these experimental results, the applicability of the rTDMS to ambient measurements of sea salt particles is discussed.

Advancements in NRC’s Primary Spectral Irradiance Scale Realization

The National Research Council (NRC) of Canada has been working to establish new facilities and to improve measurement capabilities traceable to the International System of Units (SI units) in optical radiometry. The NRC primary spectral irradiance scale has transitioned from a detector-based approach in the range of 700 nm to 1600 nm to a detector and source-based realization from 250 nm to 2500 nm. A high temperature blackbody (HTBB) acts as the primary light source for the calibration of 1000 W FEL spectral irradiance standard lamps. The thermodynamic temperature of the HTBB is determined using an NRC-designed wide-band filter radiometer, with spectral responsivity SI-traceable to the NRC optical power scale. This new facility has significantly improved measurement uncertainties compared to the previous NRC spectral irradiance scale.

A Survey on Realization of Spectral Irradiation Standard by Using High Temperature Blackbody Radiation

A Survey on Realization of Spectral Irradiation Standard by Using High Temperature Blackbody Radiation

Design & simulation of high temperature blackbody source for calibration of Michelson interferometer ECE diagnostic

This paper presents the design, simulation and characterization of a high temperature black body source for a target temperature of 873 K and frequency range of 70 to 143 GHz. The high temperature black body source has been designed using CST Microwave Studio. Different solvers in CST have been used to determine various black body parameters such as scattering, emissivity, reflectivity, radiation intensity, temperature distribution etc. This work consists of two novel approaches. First, the emissivity values have been calculated from the simulation results. Second, the design and optimization of the emitter and heater surface has been carried out separately and finally integrated to form the black body source. After sufficient study & literature survey, silicon carbide was selected as a suitable material for emitter and molybdenum for heater. The design comprises of a pyramidal moth eye structure made up of silicon carbide. Design and simulations were carried out with different dimensions of pyramids by varying their slant angle and height. The thickness of the silicon carbide base plate has also been varied to achieve optimal performance. Selection of best design is done by comparing results of radiation intensity, emissivity and temperature gradient of various simulated models. The design aimed to obtain the emissivity values near to unity with uniform temperature distribution across the emitter surface. Significant improvement in emissivity values were obtained by multiple changes in the heater and emitter design. The designed source after fabrication will be used as a high temperature calibration source for Michelson interferometer system serving as an electron cyclotron emission (ECE) diagnostic at IPR.

On the uncertainties in the realization of the kelvin based on thermodynamic temperatures of high-temperature fixed-point cells

In July 2016 the Consultative Committee for Thermometry’s Non-Contact Thermometry Working Group formed a task group to compile a complete list of uncertainties for high-temperature fixed points, categorize them as well specified or not, and recommend areas of future research. We describe herein two paths to realizing T by indirect primary radiometry using high-temperature fixed-point blackbody cells: one in which published values for the metal–carbon eutectic material transition temperatures are used and the other where a set of cells has their transition temperatures determined directly. The uncertainty components that need to be considered for each path are given together with typically achievable values and how well those values are known. This work concentrates on Co–C, Pt–C and Re–C.

Approximation of a melting plateau of large area HTFP cells used for spectral irradiance realization.

This paper adopted an approximation of a melting plateau to solve the problem that temperature data cannot be monitored continuously when measuring the spectral irradiance of a large area tungsten carbide-carbon high-temperature fixed-point blackbody at each measured wavelength. Tests with fully measured curves showed that the method has a rather small deviation from the measured data of 0.017 K maximum, which corresponds to the spectral irradiance deviation of 0.005% at 500 nm. The maximum relative deviation between the Akima fitting method and the measured temperature in terms of spectral irradiance was 0.002%, which was better than -0.067% of a single temperature of 3020.11 K method and 0.026% of a linear interpolation method.

Detection of a High-Temperature Blackbody Hump in Black Hole Spectra. The strongly redshifted annihilation line

Abstract We detected a so called high-temperature blackbody (HBB) component, found in the 15 – 40 keV range, in the broad-band X-ray energy spectra of black hole (BH) candidate sources. A detailed study of this spectral feature is presented using data from five of the Galactic BH binaries, Cyg X–1, GX 339–4, GRS 1915+105, SS 433 and V4641 Sgr in the low/hard, intermediate, high/soft and very soft spectral states (LHS, IS, HSS and VSS, respectively) and spectral transitions between them using RXTE, INTEGRAL and BeppoSAX data. In order to fit the broad-band energy spectra of these sources we used an additive XSPEC model, composed of the Comptonization component and the Gaussian line component. In particular, we reveal that the IS spectra have the HBB component which color temperature, kTHBB is in the range of 4.5 – 5.9 keV. This HBB feature has been detected in some spectra of these five sources only in the IS (for the photon index Γ > 1.9) using different X-ray telescopes. We also demonstrate that a timescale of the HBB-feature is of orders of magnitude shorter than the timescale of the iron line and its edge. That leads us to conclude that these spectral features are formed in geometrically different parts of the source and which are not connected to each other. Laurent & Titarchuk (2018) demonstrated a presence of a gravitational redshifted annihilation line emission in a BH using the Monte-Carlo simulations and therefore the observed HBB hump leads us to suggest this feature is a gravitational redshifted annihilation line observed in these black holes.

Spectral irradiance primary scale realization and characterization of deuterium lamps from 200 to 400 nm.

To meet the increasing metrology demand of spectral irradiance in the short UV spectral range, a new spectral irradiance scale from 200 to 400 nm was realized at National Institute of Metrology (NIM) based on a high-temperature blackbody BB3500M, and a group of stable deuterium lamps are used as the transfer standards. Accurate real-time temperature of a blackbody is derived to reduce the temperature drift during the measurement period. A combination of an absolute and relative measurement system is designed to reduce repeatability uncertainty, and a selective optical filter method is used to remove fluorescence with a peak at 330 nm. A seven-point bandwidth novel correction method based on differential quadrature formula is put forward to correct the bandwidth error of the monochromator. The expanded uncertainties of the new spectral irradiance scale are 5.3% at 200 nm, 1.8% at 250 nm, 1.9% at 330 nm, and 3.6% at 400 nm, respectively. In the overlap wavelength from 250 to 400 nm, the average deviation between two types transfer standards, deuterium lamps and tungsten halogen lamps, is verified to be 0.39%, which are consistent with the associated measurement uncertainties.

Analysis of a blackbody irradiance method of measurement of solar blind UV cameras' sensitivity

This paper presents a critical analysis of a current typical method to measure sensitivity of solar blind ultraviolet cameras using a high temperature blackbody as a calibrated source of ultraviolet light. It has been shown that measurement of sensitivity of solar-blind ultraviolet (SBUV) cameras defined as minimal detectable blackbody irradiance at optics plane of the tested SBUV camera generates inflated, misleading and prone to measurement errors' results that should not be used for evaluation of SBUV cameras' performance.

Coupling efficiency of light intensity from the blackbody cavity into a cone-shaped optical fiber

High-temperature blackbody radiation can provide the light source for broadband fiber sensing systems. To improve coupling efficiency, a coupling model of light intensity from the blackbody cavity into a cone-shaped optical fiber was proposed. Influence of parameters of cone-shaped fiber and the blackbody cavity on coupling efficiency of light intensity were analyzed. Results show that coupling efficiency first decreases and then increases with the increase of the angle of cone-shaped fiber. When the angle of the cone is around 30°, coupling efficiency reaches the maximum. Cone-shaped fibers with angles around 8.8°, 19.4°, and 27.4° were fabricated by chemical etching. Experiments were carried out with cone-shaped fibers and a fiber with a flat end face. Results show that compared with the fiber with a flat end face, coupling efficiency of cone-shaped fiber with an angle around 8.8° is lower, cone-shaped fiber with an angle around 19.4° is almost the same, cone-shaped fiber with angle 27.4° is much stronger, and efficiency is improved by approximately 38%. The experimental results are consistent with the theoretical analysis.

Measurement of the Spectral Irradiance of Deuterium Lamps in the Range of Wavelengths 200–400 nm Using a High-Temperature Black Body Model

A procedure is presented for measurements of the spectral irradiance of deuterium lamps in the wavelength range 200–400 nm with unit reproduction using a high-temperature blackbody model. It is shown that the expanded measurement uncertainty varies between 1.6–6.9%. The measurement results were confirmed with calibrations between VNIIOFI (Russia) and PTB (Germany). The divergence of the results obtained by the two laboratories does not exceed 2%.

基于高温黑体的傅里叶光谱测量系统响应度分段线性标定

基于高温黑体的傅里叶光谱测量系统响应度分段线性标定

Heat radiation measurement method for high pressure oxy-fuel combustion

This paper describes a novel cost effective narrow-beam radiometer what was designed to measure incident heat flux at a specific location in high temperature and high pressure combustor. Beyond the radiometer the whole measurement assembly contains a water cooled plate for cold background, a high pressure window transparent for visible and IR radiation and a radiometer position/angle adjustment tool. The thermopile based radiometer measures the total heat radiation in a wavelength range of 0.6–8 µm. A special view tube was developed for decreasing the view angle to 0.35°, what angle was dictated by the dimensions of the combustor and the associated port sizes. Calibration curves were measured using a high temperature black body calibrator and the uncertainty of the measurement was evaluated. Although the presented radiant heat flux measurement method was developed for a specific combustor, it can be easily implemented for various combustion applications as well.

Development of large-area high-temperature fixed-point blackbodies for photometry and radiometry

Large-area high-temperature fixed-point (HTFP) blackbodies with working temperatures of approximately 2748 K and 3021 K, based on an Re–C eutectic and a WC–C peritectic respectively, have been developed and investigated. The blackbodies have an emissivity of 0.9997, show high-quality phase-transition plateaus and have high repeatability of the melting temperatures, but demonstrate temperature differences (from 0.2 K to 0.6 K) compared with small-cell blackbodies of the same HTFP. We associate these temperature differences with the temperature drop effect, which may differ from cell to cell. The large radiating cavity diameter of 14 mm allows developed HTFP blackbodies to be used for photometric and radiometric applications in irradiance mode with uncertainties as small as 0.12% (k = 1) in the visible. A photometer and an irradiance-mode filter radiometer (visible range), previously calibrated at VNIIOFI, were used to measure illuminance and irradiance of the HTFP blackbodies equipped with a precise outer aperture. The values measured by the detectors agreed with those based on the blackbody calculation to within 0.2%. The large-area HTFP blackbodies will be used in a joint PTB–VNIIOFI experiment on measuring thermodynamic temperature.

Methods of total spectral radiant flux realization at VNIIOFI

VNIIOFI carries out works on realization of independent methods for realization of the total spectral radiant flux (TSRF) of incoherent optical radiation sources - reference high-temperature blackbodies (BB), halogen lamps, and LED with quasi-Lambert spatial distribution of radiance. The paper describes three schemes for measuring facilities using photometers, spectroradiometers and computer-controlled high class goniometer. The paper describes different approaches for TSRF realization at the VNIIOFI National radiometric standard on the basis of high-temperature BB and LED sources, and gonio-spectroradiometer. Further, they are planned to be compared, and the use of fixed-point cells (in particular, based on the high-temperature δ(MoC)-C metal-carbon eutectic with a phase transition temperature of 2583 °C corresponding to the metrological optical “source-A”) as an option instead of the BB is considered in order to enhance calibration accuracy.