Temperature Calibration Procedure Research Articles

A sub-nanosecond pyrometer with broadband spectral channels for temperature measurement of dynamic compression experiments

Time-resolved temperature measurement of dynamic-compressed material is critical in the high-pressure research fields. For higher temporal resolution requirement of the dynamic experiments, a broadband optical pyrometer was developed, with a rise time of ∼70 ps and a measurable temperature range of 2500 K to higher than 10000 K. Expanding the detecting bandwidth to 100 nm∼300 nm for each channel, sensitivity of the detection system increases by nearly one order of magnitude compared to the conventional configuration. An improved temperature calibration procedure and data processing method was proposed, and temperature results of the shock compression experiments using a light gas gun were identical to the simultaneous measurements by a narrowband pyrometer. The dynamic radiation from the laser shocked matter also can be perfectly captured by the developed pyrometer, and the temporal profile of temperature agreed well with the shock velocity profile in both the shape and the duration time.

Development of a Temperature Calibration Device for Refrigerated Centrifuge

This article presents a novel design of a temperature calibration device and calibration procedure for refrigerated centrifuge. The temperature calibration results of 8 typical types of refrigerated centrifuges and the uncertainty analysis shows that the calibration device and calibration procedure presented in this article can meet the requirements of the temperature calibration for refrigerated centrifuge and ensure the temperature reliability of refrigerated centrifuge in its daily use.

A new internally heated diamond anvil cell system for time-resolved optical and x-ray measurements

We have developed a new internally heated diamond anvil cell (DAC) system for in situ high-pressure and high-temperature x-ray and optical experiments. We have adopted a self-heating W/Re gasket design allowing for both sample confinement and heating. This solution has been seldom used in the past but proved to be very efficient to reduce the size of the heating spot near the sample region, improving heating and cooling rates as compared to other resistive heating strategies. The system has been widely tested under high-temperature conditions by performing several thermal emission measurements. A robust relationship between electric power and average sample temperature inside the DAC has been established up to about 1500 K by a measurement campaign on different simple substances. A micro-Raman spectrometer was used for various in situ optical measurements and allowed us to map the temperature distribution of the sample. The distribution resulted to be uniform within the typical uncertainty of these measurements (5% at 1000 K). The high-temperature performances of the DAC were also verified in a series of XAS (x-ray absorption spectroscopy) experiments using both nano-polycrystalline and single-crystal diamond anvils. XAS measurements of germanium at 3.5 GPa were obtained in the 300 K-1300 K range, studying the melting transition and nucleation to the crystal phase. The achievable heating and cooling rates of the DAC were studied exploiting a XAS dispersive setup, collecting series of near-edge XAS spectra with sub-second time resolution. An original XAS-based dynamical temperature calibration procedure was developed and used to monitor the sample and diamond temperatures during the application of constant power cycles, indicating that heating and cooling rates in the 100 K/s range can be easily achieved using this device.

Novel high temperature vacuum nanoindentation system with active surface referencing and non-contact heating for measurements up to 800 °C.

High temperature nanoindentation is an emerging field with significant advances in instrumentation, calibration, and experimental protocols reported in the past couple of years. Performing stable and accurate measurements at elevated temperatures holds the key for small scale testing of materials at service temperatures. We report a novel high temperature vacuum nanoindentation system, High Temperature Ultra Nanoindentation Tester (UNHT3 HTV), utilizing active surface referencing and non-contact heating capable of performing measurements up to 800 °C. This nanoindenter is based on the proven Ultra Nano-Hardness Tester (UNHT) design that uses two indentation axes: one for indentation and another for surface referencing. Differential displacement measurement between the two axes enables stable measurements to be performed over long durations. A vacuum level of 10-7 mbar prevents sample surface oxidation at elevated temperatures. The indenter, reference, and sample are heated independently using integrated infrared heaters. The instrumental design details for developing a reliable and accurate high temperature nanoindenter are described. High temperature calibration procedures to minimize thermal drift at elevated temperatures are reported. Indentation data on copper, fused silica, and a hard coating show that this new generation of instrumented indenter can achieve unparalleled stability over the entire temperature range up to 800 °C with minimum thermal drift rates of <2 nm/min at elevated temperatures.

Study of the dynamic of crystallization of an amorphous Fe40Ni40P14B6 ribbon through Johnson-Mehl-Avrami model

The study of the crystallization process of an amorphous Fe40Ni40P14B6 ribbon which is grown by the melt-spinning is reported. Differential scanning calorimetry (DSC), thermogravimetry (TGA), X-ray diffraction and magnetization measurements are used to investigate its dynamic of crystallization. DSC measurements show that a well-pronounced exothermic peak corresponding to first crystallization changes as function of the heating rate. For using the temperature calibration procedure of the thermogravimetric equipment, we are able to observe both the transition magnetic temperature of amorphous phase and the crystallization step observed in the differential scanning calorimetry measurements. The analysis of the dynamic of crystallization through Johnson-Mehl-Avrami (JMA) model allows us to state that the nucleation and grain growth processes occur by diffusion controlled growth. The analysis of the X-ray diffraction ex situ carried out after heating confirm the appearing of nanocrystalline Fe3B0.63P0.37 and Ni3P grains (of ≈40 nm) which are likely embedded inside a residual amorphous matrix. Finally, the increasing the crystallized fraction takes an important role on saturation magnetization and magnetic anisotropy.

A Sub-millikelvin Calibration Facility in the Range 0 $$^{\circ }$$ ∘ C to 30 $$^{\circ }$$ ∘ C

A new sub-millikelvin calibration facility for the range 0 \(^{\circ }\)C to 30 \(^{\circ }\)C is described, that allows calibration of customer thermometers, other than standard platinum resistance thermometers, with an uncertainty lower than 1 millikelvin. The improvements with respect to the traditional calibration facility are reported with particular emphasis on the temperature control (better than 0.2 mK), resistance measurement and calibration procedure. The new facility was validated by using 6 standard platinum resistance thermometers and the calibration uncertainty in the range from 0 \(^{\circ }\)C to 30 \(^{\circ }\)C amounted to 0.31 mK–0.35 mK. To demonstrate the potentiality of this facility, two oceanographic thermometers, Sea-Bird Electronics SBE 3 and SBE 35, were calibrated with an expanded uncertainty of 0.8 mK (\(k=2\)).

ECOC comparison exercise with identical thermal protocols after temperature offset correction – instrument diagnostics by in-depth evaluation of operational parameters

Abstract. A comparison exercise on thermal-optical elemental carbon/organic carbon (ECOC) analysers was carried out among 17 European laboratories. Contrary to previous comparison exercises, the 17 participants made use of an identical instrument set-up, after correcting for temperature offsets with the application of a recently developed temperature calibration kit (Sunset Laboratory Inc, OR, US). Temperature offsets reported by participants ranged from −93 to +100 °C per temperature step. Five filter samples and two sucrose solutions were analysed with both the EUSAAR2 and NIOSH870 thermal protocols. z scores were calculated for total carbon (TC); nine outliers and three stragglers were identified. Three outliers and eight stragglers were found for EC. Overall, the participants provided results between the warning levels with the exception of two laboratories that showed poor performance, the causes of which were identified and corrected through the course of the comparison exercise. The TC repeatability and reproducibility (expressed as relative standard deviations) were 11 and 15% for EUSAAR2 and 9.2 and 12% for NIOSH870; the standard deviations for EC were 15 and 20% for EUSAAR2 and 20 and 26% for NIOSH870. TC was in good agreement between the two protocols, TCNIOSH870 = 0.98 × TCEUSAAR2 (R2 = 1.00, robust means). Transmittance (TOT) calculated EC for NIOSH870 was found to be 20% lower than for EUSAAR2, ECNIOSH870 = 0.80 × ECEUSAAR2 (R2 = 0.96, robust means). The thermograms and laser signal values were compared and similar peak patterns were observed per sample and protocol for most participants. Notable deviations from the typical patterns indicated either the absence or inaccurate application of the temperature calibration procedure and/or pre-oxidation during the inert phase of the analysis. Low or zero pyrolytic organic carbon (POC), as reported by a few participants, is suggested as an indicator of an instrument-specific pre-oxidation. A sample-specific pre-oxidation effect was observed for filter G, for all participants and both thermal protocols, indicating the presence of oxygen donors on the suspended particulate matter. POC (TOT) levels were lower for NIOSH870 than for EUSAAR2, which is related to the heating profile differences of the two thermal protocols.

Plasmonic pumping of excitonic photoluminescence in hybrid MoS2-Au nanostructures.

We report on the fabrication of monolayer MoS2-coated gold nanoantennas combining chemical vapor deposition, e-beam lithography surface patterning, and a soft lift-off/transfer technique. The optical properties of these hybrid plasmonic-excitonic nanostructures are investigated using spatially resolved photoluminescence spectroscopy. Off- and in-resonance plasmonic pumping of the MoS2 excitonic luminescence showed distinct behaviors. For plasmonically mediated pumping, we found a significant enhancement (∼65%) of the photoluminescence intensity, clear evidence that the optical properties of the MoS2 monolayer are strongly influenced by the nanoantenna surface plasmons. In addition, a systematic photoluminescence broadening and red-shift in nanoantenna locations is observed which is interpreted in terms of plasmonic enhanced optical absorption and subsequent heating of the MoS2 monolayers. Using a temperature calibration procedure based on photoluminescence spectral characteristics, we were able to estimate the local temperature changes. We found that the plasmonically induced MoS2 temperature increase is nearly four times larger than in the MoS2 reference temperatures. This study shines light on the plasmonic-excitonic interaction in these hybrid metal/semiconductor nanostructures and provides a unique approach for the engineering of optoelectronic devices based on the light-to-current conversion.

The influence of temperature calibration on the OC–EC results from a dual-optics thermal carbon analyzer

Abstract. Thermal–optical analysis (TOA) is a widely used technique that fractionates carbonaceous aerosol particles into organic and elemental carbon (OC and EC), or carbonate. Thermal sub-fractions of evolved OC and EC are also used for source identification and apportionment; thus, oven temperature accuracy during TOA analysis is essential. Evidence now indicates that the "actual" sample (filter) temperature and the temperature measured by the built-in oven thermocouple (or set-point temperature) can differ by as much as 50 °C. This difference can affect the OC–EC split point selection and consequently the OC and EC fraction and sub-fraction concentrations being reported, depending on the sample composition and in-use TOA method and instrument. The present study systematically investigates the influence of an oven temperature calibration procedure for TOA. A dual-optical carbon analyzer that simultaneously measures transmission and reflectance (TOT and TOR) is used, functioning under the conditions of both the National Institute of Occupational Safety and Health Method 5040 (NIOSH) and Interagency Monitoring of Protected Visual Environment (IMPROVE) protocols. The application of the oven calibration procedure to our dual-optics instrument significantly changed NIOSH 5040 carbon fractions (OC and EC) and the IMPROVE OC fraction. In addition, the well-known OC–EC split difference between NIOSH and IMPROVE methods is even further perturbed following the instrument calibration. Further study is needed to determine if the widespread application of this oven temperature calibration procedure will indeed improve accuracy and our ability to compare among carbonaceous aerosol studies that use TOA.

Differential alternating current chip calorimeter for in situ investigation of vapor-deposited thin films

Physical vapor deposition can be used to produce thin films with interesting material properties including extraordinarily stable organic glasses. We describe an ac chip calorimeter for in situ heat capacity measurements of as-deposited nanometer thin films of organic glass formers. The calorimetric system is based on a differential ac chip calorimeter which is placed in the vacuum chamber for physical vapor deposition. The sample is directly deposited onto one calorimetric chip sensor while the other sensor is protected against deposition. The device and the temperature calibration procedure are described. The latter makes use of the phase transitions of cyclopentane and the frequency dependence of the dynamic glass transition of toluene and ethylbenzene. Sample thickness determination is based on a finite element modeling of the sensor sample arrangement. In the modeling, a layer of toluene was added to the sample sensor and its thickness was varied in an iterative way until the model fit the experimental data.

Calibration and performance of a fast-scanning DSC—Project RHC

This paper presents the calibration and evaluation of a Rapid Heat-Cool DSC (RHC), a fast-scanning calorimeter capable of controlled heating rates of up to 2000 K min −1. As the use of high scan rates increases the influence of thermal lag, a thorough analysis of the instrument performance was made. This encompasses a rigorous temperature calibration procedure, a study of the influence of sample mass and heating rate on the extrapolated onset temperature, and the analysis of the symmetry of the thermal lag in heating and cooling using phase transitions in liquid crystals. The calibration of the heat flow rate is evaluated using indium for a broad range of sample masses and heating rates, and verified by heat capacity measurements on polystyrene for a wide temperature range. The performance of the RHC proves to be very good, with estimated errors on temperature and heat flow rate (heat capacity) of 0.1 K and 2%, respectively.

Spatio-temporal noise and drift in fiber optic distributed temperature sensing

Distributed temperature sensing (DTS) allows for simultaneous measurement at many remote locations along an optical fiber probe and is a valuable tool in a broad range of applications, such as downhole oil production, dike structural monitoring or fire protection. The specific requirements on spatial, temporal and temperature resolution and on absolute measurement uncertainty vary with the applications. We investigate the spatio-temporal noise and drift properties of two exemplary Raman backscatter DTS systems and discuss the effect of spatial and temporal data averaging. An Allan deviation analysis provides insight into the optimal degree of averaging for a given distance range along the fiber probe. A temperature calibration procedure is employed to retrieve the temperature sensitivity of the DTS system and to compensate for the systematic spatial slope of recorded DTS temperature measurement traces. In response to small temperature steps of a thermally homogeneous and stable water bath environment, we observe a temperature resolution of approximately 0.05 °C at a chosen 1000 m sampling distance along the fiber probe.

Low-Cost Calibration Techniques for Smart Temperature Sensors

Smart temperature sensors generally need to be trimmed to obtain measurement errors below ±2°C. The associated temperature calibration procedure is time consuming and therefore costly. This paper presents two, much faster, voltage calibration techniques. Both make use of the fact that a voltage proportional to absolute temperature (PTAT) can be accurately generated on chip. By measuring this voltage, the sensor's actual temperature can be determined, whereupon the sensor can be trimmed to correct for its dominant source of error: spread in the on-chip voltage reference. The first calibration technique consists of measuring the (small) PTAT voltage directly, while the second, more robust alternative does so indirectly, by using an external reference voltage and the on-chip ADC. Experimental results from a prototype fabricated in 0.7 ?m CMOS technology show that after calibration and trimming, these two techniques result in measurement errors (±3?) of ±0.15°C and ±0.25°C, respectively, in a range from -55°C to 125°C.

Comparison between satellite and ship measurements of sea surface temperature in the north-east Atlantic Ocean

Abstract A comparison is made between in situ measurements of sea surface temperature (SST) in the north-east Atlantic Ocean, obtained during Cruise 145 of RRS Discovery, and SSTs derived from several overpasses of the Advanced Very High Resolution Radiometer on the NOAA-7 satellite during the same period in March 1984. The objective of the analysis was to test the ability of the satellite to map the detailed features of SST structure and to examine the performance of atmospheric correction and temperature calibration procedures in this context. Gross comparison between all the cloud-free ship and satellite data confirms agreement normally within 1 degC. More detailed comparison of SST structure along the cruise tracks shows that the satellite data are able to identify features with a resolution of 0.3°C.

An evaluation of the temperature control system of the centrifichem 400

We evaluated the manufacturer's temperature calibration procedure for the Union Carbide Centrifichem 400 using a procedure developed in our laboratories. We substituted a Yellow Springs, Inc., Model 45 CU Cuvette Thermometer with a thermistor probe for the mercury thermometers. This dramatically shortened the time required for temperature measurements by eliminating the time required for the mercury thermometers to equilibrate. The cuvette temperature measurements with the YSI 45 CU accurately reflect the analyzer equilibrium temperature only when the YSI 45 CU thermistor probe is in the same cuvette as the analyzer thermistor. We also evaluated the accuracy and precision of the temperature control system and the time required to reach thermal equilibrium. We found that temperature equilibration occurs in less than a minute and has a range of less than ±0.1°C from the mean temperature. Our procedure for monitoring temperature equilibration gave improved accuracy and precision.

The design and calibration of a soft straining/heating rod for in situ deformation experiments in a 1MV electron microscope

A side entry specimen rod is described which has been constructed to enable microstructural changes in miniature tensile specimens to be observed in an AEI EM7 one million volt electron microscope. The specimens may be deformed under constant or fluctuating load at elevated temperatures and may be tilted ±20° about the rod axis. The necessary friction and temperature calibration procedures are discussed and the values of the relevant parameters for quantitative analysis of in situ creep experiments are presented. The rod has been used to study the microstructureal changes occuring during the deformation of superplastic alloys and other materials under creep conditions.