Calibration Services Research Articles

EVALUATION ON THE CONSISTENCY OF CALIBRATION RESULTS BETWEEN REFERENCE STANDARDS OF PNEUMATIC PRESSURE BALANCE BASED ON NON-FULL RANGE CALIBRATION

<p>To provide calibration services for pressure measuring devices, SNSU-BSN has several piston-cylinder standard that may traceable to different National Metrology Institute (NMIs). Non-full range calibration of pressure balance has been performed to evaluate the consistency of calibration results between those standard, especially for establishing self-traceability in the future. In this research, a piston-cylinder unit S/N 1926 with medium pressure range of 1750 kPa, was calibrated with low pressure range S/N 978 of 350 kPa and high pressure range S/N 1054 of 7000 kPa. The calibration was performed with cross-float method to evaluate the effective area of piston-cylinder at null pressure and reference temperature of 20⁰C (<em>A<sub>0,20</sub></em>) and distortion coefficient (λ) as the 1926 main parameters. The obtained value, respectively are (1.961 166 × 10<sup>-4</sup> ± 4.4 × 10<sup>-9</sup>) m<sup>2 </sup>and (-1.67 × 10<sup>-12</sup> ± 9.4 × 10<sup>-13</sup>) Pa<sup>-1 </sup>from 978 and (1.961166 × 10<sup>-4</sup> ± 5.1 × 10<sup>-9</sup>) m<sup>2</sup> and (-1.58 × 10<sup>-12</sup> ± 8.4 × 10<sup>-13</sup>) Pa<sup>-1 </sup>from 1054. The result of 1926 from both methods shows good conformity with Normalized Error (En) of 0.0007 and 0.069, respectively. Linearity of effective area changes to the pressure is very consistent in both low and high pressure range. Validation results by using PTB-Germany results, shows the relative different for <em>A<sub>0</sub></em> and <em>λ</em> obtained are less than 0,1 × 10<sup>-6</sup> and 6%,respectively. Therefore, the pneumatic pressure balance of SNSU-BSN is traceable, consistent with each other and capable for disseminating the pressure unit along all primary pressure standard owned with high agreement compared to those of other advance NMIs.</p>

Radiometric Survey in Mammography: Review of regulations, recommendations, field and laboratories practices and first tests.

A review about Radiometric Survey in Mammography (RSM) in terms of regulatory documents, recommendations, radiation meters, besides field and laboratories practices shows that there is not many specific information about how these radiation area monitoring tests shall be performed. A search on the website of the most known manufacturers of radiation meters was made, but only one fully comply the requirements for RSM application. Tests with four laboratorial reference chambers, but none specific to RSM, were made submitting them to ISO N 20, 25 and 30 calibration setup (Based on document ISO 4037-1:1996) and their behavior in terms of HVL’s and air kerma rate measurements was compared to endorse some evaluations. The result of this work suggests that some RSM performed in Brazil, with nonspecific chambers and calibration can have underestimation of until 60% in those measurements, once a lack of specific information and specific calibration services in this country contributes for this scenario.

Results from the national intercomparison for rise time and bandwidth measurements within the German Calibration Service (Deutscher Kalibrierdienst – DKD)

Abstract. An intercomparison in the framework of the German Calibration Service (Deutscher Kalibrierdienst – DKD) was carried out. Two different travelling standards were used to measure the 10 % to 90 % rise time of a pulse generator and the 10 % to 90 % rise time, −3 dB bandwidth and attenuation at 500 MHz of an oscilloscope. Fourteen participants performed the measurements from September 2015 until May 2016.

Building Open Access to Research (OAR) Data Infrastructure at NIST.

As a National Metrology Institute (NMI), the USA National Institute of Standards and Technology (NIST) scientists, engineers and technology experts conduct research across a full spectrum of physical science domains. NIST is a non-regulatory agency within the U.S. Department of Commerce with a mission to promote U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology in ways that enhance economic security and improve our quality of life. NIST research results in the production and distribution of standard reference materials, calibration services, and datasets. These are generated from a wide range of complex laboratory instrumentation, expert analyses, and calibration processes. In response to a government open data policy, and in collaboration with the broader research community, NIST has developed a federated Open Access to Research (OAR) scientific data infrastructure aligned with FAIR (Findable, Accessible, Interoperable, Reusable) data principles. Through the OAR initiatives, NIST’s Material Measurement Laboratory Office of Data and Informatics (ODI) recently released a new scientific data discovery portal and public data repository. These science-oriented applications provide dissemination and public access for data from across the broad spectrum of NIST research disciplines, including chemistry, biology, materials science (such as crystallography, nanomaterials, etc.), physics, disaster resilience, cyberinfrastructure, communications, forensics, and others. NIST’s public data consist of carefully curated Standard Reference Data, legacy high valued data, and new research data publications. The repository is thus evolving both in content and features as the nature of research progresses. Implementation of the OAR infrastructure is key to NIST’s role in sharing high integrity reproducible research for measurement science in a rapidly changing world.

Determination of the Scattered Radiation at the Neutron Calibration Laboratory of IPEN using the Shadow Cone Method

Because of the increase in the demand for the calibration of neutron detectors, there is a need for new calibration services. In this context, the Calibration Laboratory of Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, which already offers calibration services of radiation detectors with standard X, gamma, beta and alpha beams, has recently projected a new test laboratory for neutron detectors. This work evaluated the contribution of dispersed neutron radiation in this laboratory, using the Cone Shadow Method and a Bonner Sphere Spectrometer to take the measurements at a distance of 100 cm from the neutron source. The dosimetric quantities Ambient Dose Equivalent Rate (Ḣ*(10)) and Ambient Dose Equivalent Conversion Coefficient (h*(10)) were obtained at the laboratory, allowing the calibration of detectors.

An Automated Calibration System for Blood Pressure Measurement Traceability

The present study proposes an automated system to calibrate the measurement standards used for blood pressure traceability. Sphygmomanometers are the main devices used for noninvasive blood pressure measurement and are periodically verified in order to maintain their metrological characteristics. The verification is conducted using a working standard as reference. The calibration of those standards in an accredited laboratory ensures the traceability chain with known measurement errors and uncertainties, since both are a vital component for proper diagnosis of diseases like hypertension. The proposed system aims to decrease the influence of the metrologist over the calibrations, avoiding mistakes that may invalidate the results, as well as to optimize the workforce demanded for the increasing demand for calibration services. An interlaboratory comparison was also conducted to the Brazilian National Pressure Laboratory of INMETRO, the National Institute of Metrology in Brazil, for validation of the proposed method. The normalized error showed that the system produces reliable results. The results also showed that the inflation/deflation pump and valve are critical components of the system.

Statistical reassessment of calibration and measurement capabilities based on key comparison results

According to the CIPM mutual recognition arrangement, a calibration and measurement capability (CMC) uncertainty for a laboratory offering a particular calibration or measurement service is normally expressed at a 95 % level of confidence. When laboratories’ CMC claims are unsupported by the relevant key comparison (KC), after publishing the final report of the KC, modified values may have to be assigned to their CMC uncertainties. In many cases when CMCs apply to a continuous interval of values such as mass fraction or wavelength, KCs are carried out for selected discrete values of the quantity concerned. Since the comparison at each discrete value may only support the CMC uncertainty at that point, it is not immediately apparent how to modify the CMC uncertainties. Under realistic assumptions, we developed a method that is applicable in such an instance and for which the reported CMC uncertainties are amplified so that they are underpinned by the results of the KC. The amplification factors depend on the laboratories’ degrees of equivalence (DoEs) for these discrete values, judiciously adjusted to achieve consistency with the key comparison reference values. The method is based on the patterns in the individual behaviour of the DoEs of the participating laboratories for the discrete values, implying the presence of correlation associated with the DoE values. It applies when the weighted mean of some or all of the measured values reported by the participating laboratories in the KC is used to obtain the KC reference value.

Volume Measurement of Large Volumetric Vessel Using Tap Water

Being a National Metrology Institute (NMI) of India, CSIR-National Physical Laboratory, India (NPLI), provides calibration services to the industries to improve the quality of products. In the last couple of years, NPLI has provided number of calibration services of volumetric vessels up to 2000 L (unique facility in India) to the petroleum industries, flow meter manufacturing industries, etc. In general, for the calibration of volumetric instruments, distilled water is used as the medium but in the case of large volumetric vessels (say 2000 L), the use of distilled water is not practical. Hence, tap water is used and every time the density of tap water is measured against distilled water to improve the accuracy of the measurement. In this process, we have achieved measurement uncertainty less than 50 mL in 2000 L. But due to influencing factors of environmental conditions of laboratory, change of density of supplied tap water, conversion factors of tap water and distilled water in desire temperature, we have restricted our calibration and measurement capability (CMC) up to 100 mL in 2000 L. In this paper, we have discussed the detailed procedure of volume measurement of 2000-L volumetric vessel and its associated uncertainty calculations using gravimetric method.

Conventional and new traceability schemes of organic standards for safe water supply in Japan

Metrological traceability to the International System of Units (SI) is required to ensure reliability of analytical results. For this purpose, SI-traceable standard solutions of respective analytes are essential for common analytical methods such as chromatography. However, it is not so easy to fulfill demands due to the existence of a vast number of targets, especially in the case of organic analysis. Because high-purity organic materials which are raw materials of standard solutions must be characterized by compound-independent methods, the mass balance approach (subtraction method) and the primary methods of measurement (e.g. the freezing point depression method and titrimetry) are used. Recently, quantitative NMR (qNMR) has been popularized.The National Metrology Institute of Japan, the National Institute of Advanced Industry, Science and Technology (NMIJ/AIST) has been supplying many types of reference materials including high-purity organic materials and organic standard solutions. In 2015, the demand of traceable reference materials for drinking water analyses rose by an amendment of a notification under the Waterworks Act of Japan. In this manuscript, NMIJ’s efforts such as supplying certified reference materials and providing calibration services in this field are outlined. Among them, direct characterization of multi-components standard solutions by qNMR/chromatography or post-column reaction gas chromatography is an efficient approach to realize new traceability schemes without the step of a purity assessment of each reference material.

The Design and Theoretical Analysis of Comparison Device of Strain Sensor for Bridge Health Monitoring

The strain monitoring information of bridge health monitoring system plays an important role in the safe operation of the bridge, at present, the monitoring methods are mainly use strain monitoring sensors to obtain the bridge strain information in real time, the strain monitoring sensor can be divided into three categories: electric resistance strain sensor, vibrating wire strain sensor, fiber-optic strain sensor according to the test principle. At this stage, in order to meet the metrological traceability requirements of the strain monitoring sensor with the increasing use of strain monitoring sensors, the research institute of highway ministry of transport designed an equi-intensity cantilever beam device for online calibration service in the laboratory based on finite element analysis and mathematical model validation, combining with the disciplines professional knowledge of transportation engineering, mechanical design, machining and materials engineering and so on, and the equi-intensity cantilever beam device can realize the metrological traceability of different types of strain monitoring sensors for the traffic monitoring.

OC-0079 Expanding Calibration Service for LDR Brachytherapy Seeds by Photon Fluence Determination

OC-0079 Expanding Calibration Service for LDR Brachytherapy Seeds by Photon Fluence Determination

Contribution of the scattered radiation on the neutron beam fluence at the calibration laboratory of IPEN

In recent years, an upsurge in demand for neutron calibrations has been experienced in Brazil and several other countries in Latin America, mainly due to the increase in oil prospection and extraction procedures. The only laboratory for calibration of neutron detectors in Brazil is located at the Institute for Radioprotection and Dosimetry (IRD/CNEN), Rio de Janeiro. This laboratory is the national standard dosimetry laboratory in Brazil. With the increase in the demand for the calibration of neutron detectors, the need for more calibration services became evident. In this context, the Calibration Laboratory of IPEN/CNEN, São Paulo, which already offers calibration services of radiation detectors with standard X, gamma, beta and alpha beams, recently projected a new calibration laboratory for neutron detectors. One of the main problems in this kind of calibration laboratory is related to the knowledge of scattered radiation. In order to evaluate it, simulations were performed without the presence of the structural elements and with the complete room. Thirteen measurement points were evaluated at various distances. As part of the characterization process of the radiation fields of the new Neutron Calibration Laboratory, this work presents results on the influence of the radiation scattered by the structural components of the room: walls, doors, ceiling and floor, in different calibration positions, on the detector response. Therefore, the neutron radiation attenuation and the scattering parameters were determined at different source-detector distances, through computational simulation, using the MCNP5 Monte Carlo code.

New air speed calibration system at NMIJ for air speeds up to 90 m/s

National Metrology Institute of Japan (NMIJ) has established a high air speed standard facility and has been providing a calibration service since 2015. The facility has an air speed range of 40 m/s to 90 m/s with a relative expanded uncertainty (k = 2) of 0.63%. The purpose of this primary standard is mainly to contribute to the improvement of meteorological observation research and to the evaluation of flow field inside a turbo machine and around a high speed vehicle. The reference air speed is derived from the national primary gas flowrate standard of Japan. A conversion device from flowrate to air speed is installed in the test line of the closed-loop calibration facility. The reference air speed at the nozzle exit of the conversion device is obtained by comparing the integral of the air speed profiles and the reference volume flowrate. The total pressure tube used as a transfer standard is then calibrated against the reference air speed at the center of the nozzle exit. The Eiffel-type wind tunnel, which is a working standard for the daily calibration service, is calibrated using this total pressure tube. The present paper describes the calibration system, the traceability chain, and an uncertainty analysis using a validation method.

Application of Charge-Sensitive Preamplifier for the Calibration of Partial Discharge Calibrators Below 1 pC

Modern partial discharge (PD) calibrators often have their lowest range below 1 pC. However, traceable calibration services below 1-pC charges are not widely available, or their uncertainties are relatively high because of low signal levels. We have applied a commercial charge-sensitive preamplifier for the low-level calibration of PD calibrators. This calibration method both improves the signal-to-noise ratio and performs the analog integration of the PD pulse. The drooping response of the preamplifier is corrected using software. Comparison with a reference PD calibrator supports an expanded uncertainty less than 1% down to 0.1 pC and 3% for 0.01 pC.

Extension of the range of profile surface roughness measurements using metrological atomic force microscope

The calibration service of profile surface roughness by using a metrological atomic force microscope is now available at National Metrology Institute of Japan (NMIJ), AIST. The calibration method is designed by referring to ISO 19606: 2017 (JIS R 1683: 2014). The scope of the ISO 19606: 2017, however, is limited to roughness measurements of surfaces with an arithmetical mean roughness, Ra, in the range of about 1 nm–30 nm. Currently there is strong demand for the measurement of surface roughness of more than 30 nm in the precision machining industry and for the measurement of surface roughness of sub-nanometer order in the semiconductor industry. In order to meet such demand, it is necessary to extend the range of surface roughness measurements in the NMIJ's calibration service. In this study, authors performed surface roughness measurements using a metrological AFM and evaluated their uncertainties. As a result of a series of measurements and evaluation of their uncertainties, it has been found that the calibration range can be extended to surfaces with an arithmetical mean roughness, Ra, in the range of about 0.2 nm–100 nm. The measurement results and the future challenges are reported in this paper.

Calibration Method for Microwave Digestion System

The article describes the importance of microwave digestion system in many different scientific fields, and proposes a calibration method for lack of calibration specification in China. The method focuses on temperature, pressure and output power. It defines their measuring points, technical requirements. An experiment is carried out to calibrate the output power with its expanded measurement uncertainty. The calibration method can be referenced in daily calibration service of such apparatus.

Remote Robot-Sensor Calibration Service

Cyber physical systems (CPSs) are integrating computation, networking, and physical processes. CPSs facilitate improvements especially for asset management. The authors have contributed to robot automation with CPS technologies by a pilot system to support setup and maintenance of sensor-based robot systems with remote calibration services. This paper has focused to support remotely-located technology specialists as well as local field personnel by appropriate user interface design. A design example is given for a remote robot-sensor calibration procedure. In the user interface design, the authors follow loosely the Ecological Interface Design (EID) approach.

CCQM-K95.1 Low-polarity analytes in a botanical matrix: polycyclic aromatic hydrocarbons (PAHs) in tea

Extraction, chromatographic separation, and quantification of low-concentration organic compounds in complex matrices are core challenges for reference material producers and providers of calibration services. Evidence of successful participation in formal, relevant international comparisons is needed to document measurement capability claims made by national metrology institutes (NMIs) and designated institutes (DIs). To enable NMIs and DIs to update or establish their claims, in 2014 the Organic Analysis Working Group (OAWG) initiated CCQM-K95.1 “Low-Polarity Analytes in a Botanical Matrix: Polycyclic Aromatic Hydrocarbons (PAHs) in Tea”. This was a follow-on comparison from CCQM-K95 which was completed in 2014.The polycyclic aromatic hydrocarbons (PAHs) benz[a]anthracene (BaA) and benzo[a]pyrene (BaP) are considered priority pollutants by U.S. Environmental Protection Agency and are regulated contaminants in food, pose chromatographic separation challenges, and for which exist well-characterized measurement procedures and standard materials. BaA and BaP in a smoked tea were therefore selected as representative target measurands for CCQM-K95.1. Ten NMIs participated in CCQM-K95.1. The consensus summary mass fractions for the two PAHs are in the range of (50 to 70) ng/g with relative standard deviations of (6 to 10) %.Successful participation in CCQM K95.1 demonstrates the following measurement capabilities in determining mass fraction of organic compounds, with molar mass of 100 g/mol to 500 g/mol and having polarity pKow −2, in a botanical matrix ranging in mass fraction from 10 ng/g to 1000 ng/g: (1) value assignment of primary reference standards (if in-house purity assessment carried out), (2) value assignment of single and/or multi-component organic solutions, (3) extraction of analytes of interest from the matrix, (4) cleanup and separation of analytes of interest from interfering matrix or extract components, and (5) separation and quantification using gas chromatography or liquid chromatography.KEY WORDS FOR SEARCHbenz[a]anthracene (BaA), benzo[a]pyrene (BaP), gas chromatography(GC), isotope dilution (ID), liquid chromatography (LC), mass spectrometry (MS), polycyclic aromatic hydrocarbon (PAH), yerba mate teaMain textTo reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Absolute Calibration of the European Sentinel-3A Surface Topography Mission over the Permanent Facility for Altimetry Calibration in west Crete, Greece

This work presents calibration results for the altimeter of Sentinel-3A Surface Topography Mission as determined at the Permanent Facility for Altimetry Calibration in west Crete, Greece. The facility has been providing calibration services for more than 15 years for all past (i.e., Envisat, Jason-1, Jason-2, SARAL/AltiKa, HY-2A) and current (i.e., Sentinel-3A, Sentinel-3B, Jason-3) satellite altimeters. The groundtrack of the Pass No.14 of Sentinel-3A ascends west of the Gavdos island and continues north to the transponder site on the mountains of west Crete. This pass has been calibrated using three independent techniques activated at various sites in the region: (1) the transponder approach for its range bias, (2) the sea-surface method for the estimation of altimeter bias for its sea-surface heights, and (c) the cross-over analysis for inspecting height observations with respect to Jason-3. The other Pass No.335 of Sentinel-3A descends from southwest of Crete to south and intersects the Gavdos calibration site. Additionally, calibration values for this descending pass are presented, applying sea-surface calibration and crossover analysis. An uncertainty analysis for the altimeter biases derived by the transponder and by sea-surface calibrations is also introduced following the new standard of Fiducial Reference Measurements.

Remote calibration of time from NTP servers

The Network Time Protocol (NTP), is used for time synchronization in most networked equipment. Seen as capable of 50 ms accuracy or better, it lacks calibration for metrological traceability to its reference, Coordinated Universal Time (UTC). In response to client requests for traceability, the National Research Council (NRC) has begun to monitor NTP servers and document their traceability. We use an NTP calibrator at NRC to measure the time offset of a remote client’s NTP server with respect to UTC(NRC). Standard NTP methods and systems are utilized, even for the NTP calibrator in the NRC Time Laboratory. The service aims at broad applicability rather than low uncertainty and can provide traceability to any networked computer that is configured as an NTP server. As with any calibration service, measurement results and the associated uncertainties are reported for each monitored NTP server for quality system records and auditing purposes, and we also make available near-real-time results and alerts.