Metrology Laboratory Research Articles

Long-term stability analysis and its relationship with the steel structure of gauge blocks from several manufacturers

Gauge blocks are one of the most widespread measurement standards (etalons) in dimensional metrology laboratories. Among all its properties, it is worth highlighting the importance of dimensional stability. This property allows to classify these measuring instruments in quality grades. Although the gauge blocks should be dimensionally stable, it can be observed that there is a drift that can be observed when the calibration history is revised. In this document, authors present a statistical method for the estimation of the dimensional stability of gauge blocks using the calibration history of samples from the main manufacturers. In addition, all the samples have been subjected to metallographic analysis to evaluate the structure.

Developing RF Power Sensor Calibration Station in Direct Comparison Transfer System using Vector Network Analyzer

Calibration of RF power sensors is crucial issue in RF power measurements. Many calibration laboratories use the direct comparison transfer system with a signal generator and a power splitter. Increasing performance of modern vector network analyzers makes it possible to perform a power sensor calibration with acceptable uncertainties. The main advantage when using a VNA is a simple measurement setup with a wide frequency range (up to 50 GHz, limited only by the VNA and the standard power sensor), where all of required components, i.e. signal generator, a directional coupler and a reference power indicator are built in the VNA technology. This paper reports performing a VNA-based RF power sensors calibration for 10 MHz – 18 GHz band, carried out in the Laboratory of Electric, Electronic and Optoelectronic Metrology at the National Institute of Telecommunications in Warsaw, Poland. In order to validate the proposed solution two of power sensors were calibrated at a reference laboratory. The validation consisted of two steps. At first, one of those characterized power sensors was calibrated at our laboratory in direct comparison transfer system. Finally, the results obtained from the VNA-based system were compared with the previously obtained ones.

THE IN-SITU CALIBRATION METHOD FOR AMBIENT DOSE EQUIVALENT DOSEMETERS.

Ambient dose equivalent dosemeters are widely distributed in nuclear facilities for routine continuous monitoring or nuclear accident emergency monitoring, they are inconvenient to be disassembled and sent to the metrology laboratory for calibration. To ensure the accuracy of such dosemeters, the research of in-situ calibration method has been carried out. Ambient dose equivalent secondary standard ionization chamber and portable gamma ray irradiation facility have been designed for in-situ calibration. The experiments of in-situ calibration were carried out in five typical sites located in China Institute of Atomic Energy, results showed that the relative deviation between in-situ calibration factors and metrology laboratory calibration factors are within 5%.The combined standard uncertainty of the in-situ calibration factor is 2.8%, and the expanded uncertainty is 5.6% (k=2).The in-situ calibration method can meet the calibration requirements of the fixed ambient dose equivalent dosemeters.

The implementation of a calibration plan of instruments in a metrological laboratory

It is noticeable the importance of calibrating measuring instruments, as this process seeks to ensure metrological reliability. Therefore, it becomes possible to verify if the instruments present consistent results. This way, the metrological laboratory needs to keep its equipment calibrated, aiming to offer a satisfactory service to its customers. As the periodicity of instrument calibration is variable, i.e., they have different periods, due to the fact that this time depends on the usage frequency of the equipment, its manufacturing nature, the quality of its material, the environment in which it is being submitted, among other factors. This period variability leads to problems in the quality of the provided services, increase the costs in the logistics sector, in addition to causing managerial difficulties. For this reason, a calibration plan was presented, based on historical data of standard unavailability, aiming to estimate fixed calibration periods and, consequently, mitigate the observed problems.

Statistics in Metrology: International Key Comparisons and Interlaboratory Studies

Stochastic modeling and analysis of international key compar isons (interlaboratory comparisons) pose several fundamental questions for statistical methodology. A key comparison (KC) is specifically designed to derive the key comparison reference value and to assess conformance of cal ibrations by participating national metrology laboratories at a few, “key”, settings for a particular measurement process. An approach to the statis tical study of key comparisons data is proposed using a model taken from meta-analysis. This model leads to a class of weighted means estimators for the consensus value and to a method of assessing the uncertainty of the resulting estimates.

Demonstration of a trapped-ion atomic clock in space

Atomic clocks, which lock the frequency of an oscillator to the extremely stable quantized energy levels of atoms, are essential for navigation applications such as deep space exploration1 and global navigation satellite systems2, and are useful toolswith which to address questions in fundamental physics3-6. Such satellite systems use precise measurement of signal propagation times determined by atomic clocks, together with propagation speed, to calculate position. Although space atomic clocks with low instability are an enabling technology for global navigation, they have not yet been applied to deep space navigation and have seen only limited application to space-based fundamental physics, owing to performance constraints imposed by the rigours of space operation7. Methods of electromagnetically trapping and cooling ions have revolutionized atomic clock performance8-13. Terrestrial trapped-ion clocks operating in the optical domain have achieved orders-of-magnitude improvements in performance over their predecessors and have become a key component in national metrology laboratory research programmes13, but transporting this new technology into space has remained challenging. Here we show the results from a trapped-ion atomic clock operating in space. On the ground, NASA's Deep Space Atomic Clock demonstrated a short-term fractional frequency stability of 1.5×10-13/τ1/2 (where τ is the averaging time)14. Launched in 2019, the clock has operated for more than 12months in space and demonstrated there a long-term stability of 3×10-15 at 23days (no drift removal), and an estimated drift of 3.0(0.7)×10-16 per day. Each of these exceeds current space clock performance by up to an order of magnitude15-17. The Deep Space Atomic Clock is particularly amenable to the space environment because of its low sensitivity to variations in radiation, temperature and magnetic fields. This level of space clock performance will enable one-way navigation in which signal delay times are measured in situ, making near-real-time navigation of deep space probes possible18.

Efficacy of one-step and multi-step polishing systems in finishing direct composite restoration: a non-randomised controlled experimental trial

Background. The variety of polishing systems and tools available for finishing direct composite restorations may perplex the dentist.Objectives. An effect evaluation in one- and multi-step composite polishing tools using model specimens of GC Gradia Direct and 3M ESPE Filtek Ultimate restoratives.Methods. The prepared specimens of GC Gradia Direct and 3M ESPE Filtek Ultimate restorative composites were exposed in laboratory to the Kenda Maximus, Dentsply PoGo, Kagayaki RoundFlex, Shofu Super-Snap, Kagayaki Ensmart Pin, EVE Composoft polishing systems and Daiyamondo Kagayaki paste. The polishing systems distinguished by brand, technical and performance characters.Surface microgeometry in all 16 samples was estimated in the Laboratory of Optical Metrology, Institute of Design and Technology for Scientific Instrument Engineering, Novosibirsk, using a MNP-1 light interferometric nanoprofile microscope and at the shared core facilities of the Research and Education Centre “Nanomaterial Diagnostics and Properties” of Kuban State University, Krasnodar, using a JEOL JSM-7500F scanning electron microscope.Results. Optical profilometry and scanning electron microscopy were used to estimate surface roughness in 16 specimens exposed to polishing for one minute. The polishing tools Kenda Maximus, Dentsply PoGo, Kagayaki RoundFlex, Shofu Super-Snap, Kagayaki Ensmart Pin, EVE Composoft, as well as Daiyamondo Kagayaki paste used in instrumental polishing, revealed a varied performance. Optical profilometry exhibited the GC Gradia Direct and Filtek Ultimate specimens to possess the lowest average roughness in two cases: 1) after multi-step polishing with Kagayaki Ensmart Pin tools with Daiyamondo Kagayaki paste (average roughness corresponded to Sa — 0.214 pm in GC Gradia Direct and Sa — 0.248 pm — in Filtek Ultimate), 2) in application of the Kenda Maximus monopolishing tool (roughness values of Sa — 0.211 and Sa — 0.242 pm, respectively). Surface roughness after multi-step machining with EVE Composoft silicone polishers was average Sa — 0.579 and Sa — 0.549 pm in both samples and was reported the highest. Scanning electron microscopy confirmed the optical profilometry estimates.Conclusion. The assay showed that the specimen machining with a sole Kenda Maximus diamond abrasive tool and several Kagayaki Ensmart Pin silicone polishing heads followed by a Daiyamondo Kagayaki diamond abrasive paste application produced very similar surface roughness values, which were graded the lowest with GC Gradia Direct and 3M ESPE Filtek Ultimate composite samples using scanning electron microscopy and optical profilometry.

Photoacoustic Laser System for Food Fraud Detection.

Economically motivated adulterations of food, in general, and spices, in particular, are an emerging threat to world health. Reliable techniques for the rapid screening of counterfeited ingredients in the supply chain need further development. Building on the experience gained with CO2 lasers, the Diagnostic and Metrology Laboratory of ENEA realized a compact and user-friendly photoacoustic laser system for food fraud detection, based on a quantum cascade laser. The sensor has been challenged with saffron adulteration. Multivariate data analysis tools indicated that the photoacoustic laser system was able to detect adulterants at mass ratios of 2% in less than two minutes.

Hydrostatic Determination of Test Weight Density and Uncertainty Evaluation by Monte Carlo Method

This paper presents the characterization of the hydrostatic weighing facility of the National Metrology Laboratory (NML) of the Philippines. The study aimed to evaluate its suitability for determination of solid density. It was used to hydrostatically measure the density of a stainless steel (OIML Class F1) test weight weighing 200 g. The measurement result obtained was 7.5827 g cm-3 ± 0.0041 g cm-3 at an approximately 95 % level of confidence. The uncertainty evaluated by the Law of Propagation of Uncertainty (LPU) according to JCGM 100:2008 (GUM) was verified by the Monte Carlo method (MCM), which gave a result of 0.0040 g cm-3. The value determined for the solid density of the sample with its associated expanded uncertainty was found to be within the tolerance interval between 7.39 g cm-3 and 8.73 g cm-3 as required in OIML R111-1 for Class F1 test weights.

Development of food industry metrological assurance complex

The paper considers the contribution of experts from the Laboratory of Metrology of Moisture Measurement and Reference Materials to the improvement of the food industry metrological assurance system. The information on the results of the development of forty types of reference materials (RM) for the composition of various nutrition, food staples and nutritional supplement in the period 2008-2020 is generalized. The development of each new RM type included preparation of the material, research for its stability and homogeneity, and determination of certified value with the appliance of State primary (GET 173) and secondary (GVET 176-1) standards, as well as primary reference measurement procedures and conducting the interlaboratory experiment for checking the applicability of the RM. The creation in 2008 of GET 173 was accompanied by the development of RMs for the composition of grains and dry milk product. The approval in 2010 of GVET 176-1 allowed to add in the RM the certified value for the mass fraction of nitrogen (protein). As a result of successful participation in comparisons, UNIIM got 6 items of calibration and measurement capabilities on measurements of mass fraction of nitrogen in glycine, milk powder, grain, egg powder, cereal and feed-stuff in the BIPM database. 35 types of RM for the composition of dairy and meat products, egg powder, infant food, oil and starch products together with the development of primary reference measurement procedures for measurement of fat, crude fat, ash and carbohydrates mass fraction were created between 2016 and 2019. Moreover, the RM for the composition of nutritional supplement (glycine, melamine, cystine) and dairy products for metrological assurance of IR-analysers as well as RM for the composition of reconstituted milk were developed for the control of measurement results by the enzyme-linked immunosorbent assay (ELISA). Developed RM were systemized on fields of the appliance of Technical regulations of Customs Union and the sectors of the international food triangle model. These RMs allow providing the measurement uniformity of the identification indicators and the nutritional value of food products and food staples.

SYSTEM OF STANDARDIZATION AND METROLOGICAL SUPPORT OF SPEED DEFECTIVE MEANS OF RAILS IN THEIR PRODUCTION AND OPERATION

The importance of standardization and metrological support for high-speed rail flaw detection is noted. JSC “Firm TVEMA” has created a service for quality, factory testing and metrological support. The data on the development and development of the production of JSC “Firma TVEMA” of a complex of removable and mobile technical means of NDT with maximum automation of instrument control and processing of control data, creation of a quality service, factory testing and metrological support are given. It is shown that the service includes structural subdivisions: the department of metrology and quality, a metrological laboratory, a testing laboratory, a technical control bureau that provide scientific and methodological support for the development of measuring instruments, testing, verification and calibration of flaw detection instruments during their production and operation. JSC “Firma TVEMA” organized the production and delivery of models of rail defects to railways with primary certification by the metrological laboratory for dynamic testing of mobile NDT vehicles. A test section was put into operation at the Experimental Ring of JSC VNIIZhT with certified defect models, which made it possible to accumulate research material for the further development of high-speed flaw detectors.

Guest Editorial

Part A of this Special Issue (SI) on Instrumentation and Measurement in Canada was presented in the April 2021 Issue. Here, we continue the SI in Part B, starting with the topic of Measurement Fundamentals which opens with three articles from Canada's National Research Council (NRC). It's not surprising to see three articles from NRC, considering that it comprises Canada's various metrology, standards, and calibration laboratories, centers, and services.

Preliminary measurements using a Triple to Double Coincidence Ratio (TDCR) Liquid Scintillator Counter System

The preliminary measurements using a Triple to Double Coincidence Ratio (TDCR) Liquid Scintillator Counter System developed by the Nuclear Metrology Laboratory (LMN) at IPEN, is presented. The TDCR system makes use of three photomultipliers positioned at 120° relative angle, operating in coincidence. For this preliminarymeasurement, 14C was selected to be standardized; 14C was chosen due to be a pure beta emitter with low end-point energy of 156 keV, which is suitable to be measured by the TDCR system. This solution was previously calibrated by the efficiency tracing technique using a 4p(PC)b-g coincidence system, employing 60Co as a tracer. The activity of the 14C solution by efficiency tracing technique was determined by using the extrapolation technique, changing the beta efficiency by pulse height discrimination. In order to determine the final activity, a Monte Carlo simulation was used to generate the extrapolation curve. The Software Coincidence System (SCS) developed by the LMN was used for both systems to register the events. MICELLE 2 code was used to calculate the theoretical TDCR efficiency. Measurements using HIDEX, a commercial liquid scintillator system, were also carried out and the results from the three methods were compared, showing a good agreement.

Precise temperature controlling algorithm for metrological adiabatic calorimeters based on proportional-integration (α) thermal energy

Thermal metrology laboratory at the National Institute of Standards (NIS-Egypt) has been working to realize the International Temperature Scale-1990 (Preston-Thomas in Metrologia 27:3–10, 1990). High-precision thermal control is required especially with low-temperature fixed points that were realized within adiabatic calorimeters. In this study, a new algorithm module has been developed to control precisely the accurate temperature based on equal partitioning the temperature domain to be equivalent to the sensitivity of controlling thermometer (0.00391 K−1). The algorithm technique is required to maintain and stabilize the temperature of an adiabatic evacuated copper can that is located inside a thermally isolated calorimeter; the modified fractional proportional-integration function and sensitivity partial temperature function (SPTF) for temperature control have been designed and developed. The improved discrete SPTF has showed a thermal stability better than 28 ± 1.8 mK at temperature extremely close to the triple point of water cell (Tcell = 273.16 K) with reliable response time within 18 ± 1 min of performance. The thermal parameters of the new adiabatic calorimeter have been calculated such as the heat capacity of the load and the thermal resistance between the regulated shield and the measuring sample. The estimated uncertainty related to the measurements has been improved to ± 0.28 mK.

Influence of the dosimeter calibration conditions on the mean glandular dose in mammography

Digital technology in mammography and breast tomosynthesis introduced the use of W and Rh target x-ray tubes with Al, Mo, Rh and Ag additional filters. In Brazil, due to the limited capability of metrology laboratories, x-ray dosimetry in mammography is done with different types of dosimeters that may not be calibrated for such specific clinical beams. The objective of this work was to study the influence of different calibration conditions on the determination of the mean glandular dose in dosimetry in mammography beams.

Strategy for traceability in electrical calibration laboratories using precision digital multimeters

This paper presents a strategy developed by Eletrobras Eletronorte Metrology Laboratory for traceability establishment of electrical calibrations, using a precision digital multimeter as reference standard. A method that uses the precision digital multimeter calibration report results at different points from those calibrated is shown and discussed, and some considerations to this method are done.

First Latin American and Caribbean interlaboratory comparison exercise for SSDLs on reference irradiation capabilities in personal dose equivalent

A comparison exercise of Latin American and Caribbean Secondary Standards Dosimetry Laboratories (SSDLs) was jointly organized by the International Atomic Energy Agency (IAEA) and the Ionizing Radiation Metrology Laboratory at the Federal University of Pernambuco (LMRI-DEN/UFPE). This exercise was organized during an IAEA regional meeting on the review and update of calibration capabilities in Latin America, held in Recife, during the period from 23 to 27 April 2018 under the technical cooperation project ME-RLA 9085-170572. Fifteen participating SSDLs were required to irradiate optically stimulated personal dosimeters in terms of the personal dose equivalent Hp(10) in 137Cs radiation quality. In addition, the IAEA Dosimetry Laboratory in Seibersdorf, Austria, and the National Physical Laboratory in Teddington, Middlesex, UK participated in this exercise as reference institutes. Each participant received 10 dosimeters that were hand-carried directly to the SSDL. Two nominal dose values of 2 mSv and 4 mSv were selected for this exercise. The participants irradiated the dosimeters using the setup and the procedures which are normally used in their standard laboratory for Hp(10) dosimeter irradiations. The dosimeters were evaluated as they were received by the coordinating laboratory, using a single BeOSL Reader. The results show that, except for one laboratory, the differences between the dosimeter reading and the assigned values were within 10%; this is consistent with the expanded uncertainty. The results indicate that most of the participant laboratories have a good capability to irradiate personal dosimeters in the quantity Hp(10).

Estimating quality of indirect measurements of sea water sound velocity by CTD data

The publication presents the results of calculations of the uncertainty estimates for indirect measurements of the sound velocity using CTD data. The sound velocity dependence on the input parameters was analyzed. The input parameters include absolute salinity, temperature and hydrostatic pressure. The diagrams of the sensitivity coefficients of the dependence of the sound velocity on the input parameters are constructed, which are applicable for practical calculations. For various classes of measurement instruments the diagrams of the measurement uncertainty components on each of three input parameters and the diagram of the combined standard uncertainty of the indirect measurements of the sound velocity were calculated. The uncertainty estimate diagrams for the sound velocity measurement in the sea water can be used in oceanography investigations and for the work of metrological laboratories. The authors defined the potential applications of CTD probes with various precision for the indirect measurements of sound velocity.

Simplification of null method measurement system to build a standalone DC voltage standard traceability system in the SNSU - BSN electrical metrology laboratory

Since 1987, electrical laboratory of SNSU was built a traceability capability of DC voltage unit from PJVS up to two Multifunction Calibrator instruments. Therefore, the dissemination accuracy was performed gradually from PJVS to two multifunctions calibrator through a standard cell instrument. The two units of multifunction calibrators instruments are used as working standards instrument and should be maintained its traceability. One of the multifunction calibrator (MCS) instrument that is traceable to the standard cell instrument will be disseminated it accuracy to the other multifunction calibrator (MCU) instrument was done in these research. A potentiometer principle was basically used as a subtractor system that subtract the MCS value from the MCU value. Uncertainty analysis is carried out in this paper to validate the characteristics of the method against the NULL method based on the error number (En) reaching -0.1

Revisiting the limits of photon momentum based optical power measurement method, employing the case of multi-reflected laser beam

In this work, we review the viability and precision of the photon-momentum-based optical power measurement method that employs an amplification effect caused by a multi-reflected laser beam trapped in an optical cavity. Measuring the total momentum transfer of the absorbed and re-emitted photons from a highly reflective surface (reflection of the laser beam from an optical mirror) as a force provides the possibility of measuring the optical power with direct traceability to SI units. Trial measurements were performed at two different metrology laboratories: the laboratory for mass/force at the Technical University of Ilmenau, and the clean room laser radiometry laboratory at PTB, with a portable force measurement setup consisting of two electromagnetic force compensation balances. We compared the results of the optical power measurements performed with the force measurement setup, via the photon-momentum-based method, with those performed using a calibrated reference standard detector traceable to PTB’s primary standard for optical power, the cryogenic radiometer. The comparison was carried out for an optical power range between 1 W and 10 W at a wavelength of 532 nm, which corresponds to a force of approximately 2000 nN at the upper limit, yielding approximately 2.3% relative standard uncertainty in the case of 33 reflections. Thus, conflating the high-precision force metrology technique at μN to nN levels with the optical setup required to achieve specular multi-reflection configuration of the laser beam, where a macroscopic optical cavity with ultra-high reflective mirrors (>99.995%) can adjustably be suspended from the force sensors, depending on required geometry of reflections, we show that the uncertainty of the optical power measurements upon further increase of the nominally applied optical power, the number of laser beam reflections, or the reflectivity coefficient of the mirrors can be markedly reduced.