Development of 222Rn Emanation Sources with Integrated Quasi 2π Active Monitoring

In this work, a novel approach for the standardization of low-level 222Rn emanation is presented. The technique is based on the integration of a 222Rn source, directly, with an α-particle detector, which allows the residual 222Rn to be continuously monitored. Preparation of the device entails thermal physical vapor deposition of 226RaCl2 directly onto the surface of a commercially available ion implanted Si-diode detector, resulting in a thin-layer geometry. This enables continuous collection of well resolved α-particle spectra of the nuclei, decaying within the deposited layer, with a detection efficiency of approximately 0.5 in a quasi 2π geometry. The continuously sampled α-particle spectra are used to derive the emanation by statistical inversion. It is possible to achieve this with high temporal resolution due to the small background and the high counting efficiency of the presented technique. The emanation derived in this way exhibits a dependence on the relative humidity of up to 15% in the range from 20% rH to 90% rH. Traceability to the SI is provided by employing defined solid-angle α-particle spectrometry to characterize the counting efficiency of the modified detectors. The presented technique is demonstrated to apply to a range covering the release of at least 1 to 210 222Rn atoms per second, and it results in SI-traceable emanation values with a combined standard uncertainty not exceeding 2%. This provides a pathway for the realization of reference atmospheres covering typical environmental 222Rn levels and thus drastically improves the realization and the dissemination of the derived unit of the activity concentration concerning 222Rn in air.

Investigation of High-Temperature Normal Infrared Spectral Emissivity of ZrO2 Thermal Barrier Coating Artefacts by the Modified Integrated Blackbody Method

Zirconium oxide (ZrO2) is widely used as the thermal barrier coating in turbines and engines. Accurate emissivity measurement of ZrO2 coating at high temperatures, especially above 1000 °C, plays a vital role in thermal modelling and radiation thermometry. However, it is an extremely challenging enterprise, and very few high temperature emissivity results with rigorously estimated uncertainties have been published to date. The key issue for accurately measuring the high temperature emissivity is maintaining a hot surface without reflection from the hot environment, and avoiding passive or active oxidation of material, which will modify the emissivity. In this paper, a novel modified integrated blackbody method is reported to measure the high temperature normal spectral emissivity of ZrO2 coating in the temperature range 1000 °C to 1200 °C and spectral range 8 μm to 14 μm. The results and the associated uncertainty of the measurement were estimated and a relative standard uncertainty better than 7% (k = 2) is achieved.

Development and research of the parameters control system of the artificial ecosystem environment by the fuzzy-logic system

The paper considers the solution of scientific and practical problem of development and research of control system of parameters of environment of artificial ecosystem, creation of structural and basic electric scheme of system, drawing up of algorithm of its work. The study consists of statistical processing of the results of direct repeated measurements of soluble oxygen level, pH, temperature in the aquarium of the artificial ecosystem, analysis of errors and total standard uncertainty of measurement results, construction of a system with fuzzy logic to determine the impact of aquatic parameters on aquarium water quality. The system makes it possible to measure illuminance up to 45,000 lux, air temperature in the range from 12 to 42 0C, water temperature in the range from 15 to 28 0C, pH level from 5 to 9, dissolved oxygen level from 5 to 10 mg / l, has a proximity sensor , has the ability to turn on, if necessary, heating, water aeration, additional light sources. The measurement error on each of the channels does not exceed 2.5%. The need to create a control system arose due to the fact that there is a need to ensure the natural development of plants and fish in an artificial ecosystem that mimics the environment as close as possible to the natural one. In order for the ecosystem to perform its functions, it is necessary to timely control these parameters and respond quickly to the parameters exceeding the critical values. This task can be accomplished only by creating a control system. In order to bring people closer to the wildlife of exotic countries of the world, you can create corners of wildlife at school, enterprise, institution. An artificial ecosystem, which is a clear and versatile example of wildlife, will help students in the formation of a new culture of relationships with nature, the environment, and allow workers to relax morally by observing wildlife. Such a fruitful rest affects the recovery of people. The artificial ecosystem helps to involve children with talent in research work, in designing projects, performing works related to creativity.

Effects of rotation errors on goniometric measurements

Goniometric measurements are essential for the determination of many optical quantities, and quantifying the effects of errors in the rotation axes on these quantities is a complex task. In this paper, we show how a measurement model for a four-axis goniometric system can be developed to allow the effects of alignment and rotation errors to be included in the uncertainty of the measurement. We use three different computational methods to propagate the uncertainties due to several error sources through the model to the rotation angles and then to the measurement of bidirectional reflectance and integrated diffuse reflectance, a task that would otherwise be intractable. While all three methods give the same result, the GTC Python package is the simplest and intrinsically provides a full uncertainty budget, including all correlations between measurement parameters. We then demonstrate how the development of a measurement model and the use of GTC has improved our understanding of the system. As a consequence, taking advantage of negative correlations between measurements in different geometries allows us to minimise the total uncertainty in integrated diffuse reflectance, lowering the standard uncertainty from 0.0029 to 0.0015.

FACILITY FOR CALIBRATION OF PHOTOMETERS FOR TEMPORAL LIGHT MODULATION

We developed a facility for calibration of TLM (temporal light modulation) photometers. The facility is based on a laser-fed reference source, of which the radiance can be modulated with an acousto-optic modulator (AOM). A system of photodiodes, amplifiers, and an analog-to-digital converter (ADC) is used to sample the temporally modulated radiance of the source. With the facility a TLM photometer was calibrated for display contrast ratio RMS (root mean square) with an absolute combined standard uncertainty of 0,037 %. In addition, the facility has been characterised with the aim of measuring flicker and stroboscopic effect, considering the Ecodesign ‘Single Lighting Regulation’. The frequency response of the facility shows to be sufficient to accommodate measurements of flicker and the stroboscopic effect.

Determination of probe non-linearity and error due to measurement position for direct measurement type of gauge block comparator and its measurement uncertainty

The non-linearity of probes is one of the important components in gauge block calibration by the mechanical comparative method of two gauges blocks at the same nominal length. However, an advanced method for gauge block calibration is a mechanical direct measurement method of two gauge blocks showing the greatest difference in nominal length of 25 mm. This method uses a special probe based on the interferential scanning principle to produce the signals to measure the displacement. In this paper, non-linearity and error due to measurement position were investigated as they related to the accuracy of measurement results. The differences in central length of pairs of standard gauge blocks made of steel were measured by optical interferometry with the measurement uncertainty (k=2) 23 nm. Length in the range of 5 μm to 25 mm was used in the experiment. Non-linearity of the probe was evaluated by the simple linear regression model. Various factors such as origin setting point, temperature, and vibration have been analysed. In the preliminary experiment, the non-linearity, position error, repeatability and retrace error over the measuring range 25 mm are 13 nm, -18 nm, 15 nm, and 10 nm respectively. The standard uncertainty of direct measurement type caused by non-linearity is 4 nm.

Automatic Measurement System of High Resistance up to100TΩ

To solve the problems exist in the measurements high resistances in range of 1 MΩ~100 TΩ, such as low precision, poor repeatability, long time consuming and easy to be affected by the external environment, an adapted Wheatstone bridge for high resistances is described. The system uses two DC voltage sources to build a standard proportion, a pico-ammeter as the Null-indicator. The automatic balancing of the bridge is realized through the balance algorithm. The measurement software is compiled to realize the automatic measurement of high resistance. The shielding system is studied, the methods to improve the accuracy are summarized. The experimental results show that the standard uncertainty at 100GΩ reaches 3.2×10−5. The system can meet the calibration requirements of high value resistance, and has been applied in practical work.

The New 1 kN·m Torque Standard Machine in National Institute of Metrology, China

A 1 kN-m deadweight torque standard machine is established in National Institute of Metrology, China. The torque range is 5N·m-1200 N·m. The deadweights utilized in the machine can generate the torque of 1200 N·m, 600N·m, 360N·m, 240N·m, 120N·m and 60 N·m, respectively. The torque can be applied both in clock-wise and counter clock-wise direction in sequencial loading process. The aerostatic bearing is introduced to the torque standard machine in order to eliminate the influence of friction. The symmetric V type rotor and stator are used to provide the reliable support both in axial and radial direction. The material of the lever arm is invar alloy, performing with the minimum deformation with the change of the ambient temperature. The counter torque part will make the precise adjustment to make a horizontal alignment of the lever arm. The relative standard uncertainty of the torque generated by the machine is less than 1e-5.

Intercomparison of O₂ ∕ N₂ ratio scales among AIST, NIES, TU, and SIO based on a round-robin exercise using gravimetric standard mixtures

A study was conducted to compare the δ(O2/N2) scales used by four laboratories engaged in atmospheric δ(O2/N2) measurements. These laboratories are the Research Institute for Environmental Management Technology, Advanced Industrial Science and Technology (EMRI/AIST); the National Institute for Environmental Studies (NIES); Tohoku University (TU); and Scripps Institution of Oceanography (SIO). Therefore, five high-precision standard mixtures for the O2 molar fraction gravimetrically prepared by the National Metrology Institute of Japan, AIST (NMIJ/AIST) with a standard uncertainty of less than 5 per meg (0.001 ‰) were used as round-robin standard mixtures. EMRI/AIST, NIES, TU, and SIO reported the analyzed values of the standard mixtures on their own δ(O2/N2) scales, and the values were compared with the δ(O2/N2) values gravimetrically determined by NMIJ/AIST (the NMIJ/AIST scale). The δ(O2/N2) temporal drift in the five standard mixtures during the intercomparison experiment from May 2017 to March 2020 was corrected based on the δ(O2/N2) values analyzed before and after the laboratory measurements by EMRI/AIST. The scales are compared based on offsets in zero and span. The relative span offsets of EMRI/AIST, TU, NIES, and SIO scales against the NMIJ/AIST scale were -0.11%±0.10%, -0.10%±0.13%, 3.39 %±0.13 %, and 0.93 %±0.10 %, respectively. The largest offset corresponded to a 0.30 Pg yr−1 decrease and increase in global estimates for land biospheric and oceanic CO2 uptakes based on trends in atmospheric CO2 and δ(O2/N2). The deviations in the measured δ(O2/N2) values on the laboratory scales from the NMIJ/AIST scale are 65.8±2.2, 425.7±3.1, 404.5±3.0, and 596.4±2.4 per meg for EMRI/AIST, TU, NIES, and SIO, respectively. The difference between atmospheric δ(O2/N2) values observed at Hateruma Island (HAT; 24.05∘ N, 123.81∘ E), Japan, by EMRI/AIST and NIES were reduced from -329.3±6.9 to -6.6±6.8 per meg by converting their scales to the NMIJ/AIST scale.

Development of multi-systems for measurement of radionuclide absolute activity

The development of a multi-systems triple-to-double coincidence ratio (TDCR) and coincidence 4pb-g methods, based on liquid scintillation to radionuclide standardization is presented in this work. The adjustments of multi-systems were made using standards of 3H and 14C and 60Co. The initial stage was performing measurements of pure beta-emitters 3H, 63Ni, and 90Sr90Y standard solutions by TDCR. The results were consistent within the standard uncertainty. Measurements will be performed with a beta-gamma 60Co in a comparison to the SIR / BIPM to assess the multi-system's performance.