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Additional data for the deliverable "D1: Inter-laboratory comparison report for low-level radionuclide detection by mass spectrometry"
No full textThis dataset describes the results of an interlaboratory comparison exercise, focusing on comparing the capabilities of different mass spectrometers for low-level radioactivity measurement. Participating labs around Europe were asked to determine activity levels for a range of actinides (²³⁴U, ²³⁶U, ²³⁷Np, ²³⁹Pu, ²⁴⁰Pu, ²⁴¹Am, NatU and ²³⁹/²⁴⁰Pu) and ⁹⁰Sr. Standards were prepared from starting materials at NPL through a series of dilutions using a dedicated source preparation facility and characterised for their activity per unit mass and impurities using a combination of decay counting and mass spectrometric techniques. Standards were distributed to participating laboratories along with a form for submitting the results and details of the measurements made. There were delays in sending of the materials to the participating laboratories, however, results were submitted for all radionuclides using multiple techniques. This provides valuable information on the capabilities of mass spectrometry for low-level radionuclide measurement and can inform the development of future standards and comparison exercises.Description of the individual files:
* Table06 = Assigned values for radionuclide standards used in the comparison exercise.
* Table07 = Values for radionuclides used in isotopic ratio standards for the comparison exercise.
* Table09 = Table of results and performance for ⁹⁰Sr standard.
* Table10 = Table of results and performance for ²³⁴U standard.
* Table11 = Table of results and performance for ²³⁶U standard.
* Table12 = Table of results and performance for ²³⁷Np standard.
* Table13 = Table of results and performance for ²³⁹Pu standard.
* Table14 = Table of results and performance for ²⁴⁰Pu standard.
* Table15 = Table of results and performance for ²⁴¹Am standard.
* Table16 = Table of results for uranium mixed standard.
* Table17 = Table of results and performance for Plutonium mix standard.
Common information:
* Research object = Single and mixed radionuclide standard solutions.
* Method = Decay counting and mass spectrometric techniques.
* Format = XLSX, TSV (tab separated)
* Recommended software = Excel, LibreOffice, OnlyOffice
* Variables =
+ Activity in Bq/g
+ Isotope Ratios in mol/mol
+ DoE (Degree of Equivalence) = difference between the measured value xi and the reference value xref.
+ E_n = ratio of the DoE to the own uncertainty u(DoE) = √[u²(xi )+u²(xref)] . E_n < 1 means a good correspondence of the measurement result with the reference value.The project 21GRD09 MetroPOEM has received funding from the European Partnership on Metrology, co-financed from the European Union’s Horizon Europe Research and Innovation Programme and by the Participating States
Sortierung mehrdimensionaler Objekte als graphentheoretisches und algorithmisches Problem
No full textBücher nach der Farbe des Buchrückens zu sortieren und den kürzesten Weg zu finden, der verschiedene Orte verbindet, haben eines gemeinsam: mehrdimensionale Sortierung. Die Arbeit zeigt, dass die eindimensionale Sortierung ein Spezialfall n-dimensionaler Sortierung ist, äquivalent zum NP-schweren Problem des kürzesten Hamilton-Pfads. Eine interaktive Webanwendung veranschaulicht den Beweis und erlaubt es, verschiedene mehrdimensionale Objekte mit unterschiedlichen Algorithmen selbst zu sortieren.Junge Wissenschaft. Paper 03/2025In der Jungen Wissenschaft werden Forschungsarbeiten von Schüler/innen, die selbstständig, z.B. in einer Schule oder einem Schülerforschungszentrum, durchgeführt wurden, veröffentlicht
Spezifische Empfehlungen zur harmonisierten Erstellung von Digitalen Kalibrierscheinen (DCCs) für Messgrößen der Laboratoriumsmedizin : Expertenbericht DKD-E 12-1
No full textDieser Expertenbericht, bei dem es sich um eine fachspezifische Ergänzung zum übergeordneten Expertenbericht „DKD-E 0-3 Allgemeine Konventionen und Empfehlungen zur harmonisierten Erstellung von Digitalen Kalibrierscheinen (DCCs)“ handelt, erläutert den Aufbau eines Good Practice DCC (GP DCC) für die Zertifizierung von Referenzmethodenwerten. Das im Bericht vorgestellte Good Practice-Beispiel enthält alle Elemente, die voraussichtlich im Rahmen der Kalibrierungen für Referenzmethodenwerte vorkommen können und kann somit als harmonisierte Grundlage für die Erstellung individueller DCCs dienen
Development of a Dielectric Waveguide Microcalorimeter as the Primary Standard for Millimeter-Wave Power Measurements
No full textThe rapid growth of telecommunication applications requires support from reliable millimeter-wave power measurement standards and systems. A highly accurate and precise measurement system is essential not only for validating the performance of telecommunication devices but also for ensuring safety, meeting regulatory requirements, and improving system efficiency. Currently, microcalorimeters, which serve as the primary measurement standard for radio frequency (RF) power at National Metrology Institutes (NMIs), are limited at frequencies up to 170 GHz. However, there is a growing demand for measurement standards at higher frequencies, such as those required for the sixth-generation (6G) technology for wireless communications. This dissertation focuses on developing a millimeter-wave power measurement standard and system for the frequency range of 140 GHz to 220 GHz to support telecommunications infrastructure.
Millimeter-wave technology applications, whose frequency range is not covered by existing standards, have encouraged research to find solutions. The development of microcalorimeters for the millimeter-wave range is challenging, primarily due to significant losses in the transmission lines. Since a microcalorimeter is a heat-measuring instrument, fluctuations in ambient temperature further complicate its implementation. In this work, a microcalorimeter was designed with a twin-line structure, featuring a symmetrically arranged transfer standard and a dummy load. The dummy load serves as the temperature reference, while the transfer standard is connected to a feeding line, and the dummy load to a dummy line. Both lines were constructed from dielectric waveguides, rather than metal waveguides as used in many conventional microcalorimeters. The feeding line utilizes metal waveguides as a transition section to connect the dielectric waveguide with rectangular waveguide (WR) devices, particularly WR-5 standardized devices.
A dielectric waveguide microcalorimeter was fabricated as the primary measurement standard for millimeter-wave power, demonstrating good performance. Effective transmission line matching has been achieved by tapering the ends of the dielectric rod waveguide and shaping the hollow metal waveguide into a trumpet structure. Enclosing the microcalorimeter in thermal jackets maintains a stable temperature. The twin-line structure minimizes the effects of temperature variations. The dielectric waveguide microcalorimeter is utilized to calibrate power sensors, establishing measurement traceability for millimeter-wave devices. This microcalorimeter represents a novel application of dielectric waveguides in the WR-5 band, contributing to quality assurance in the development of telecommunications systems.PTB-Bericht Diss-2
Production of radioactive traceable reference materials for measuring radioactive pollutants in the environment
No full textThere are very few radioactive environmental reference materials (RM) traceable to the International System of Units. Existing radioactive RMs for environmental samples that can be measured by mass spectrometry are even more limited and their characterisation does not always include relevant parameters such as isotopic ratios. This paper focuses on the development of two environmentally relevant candidate RMs, one liquid and one solid, which could be used for routine quality control measurements. The liquid RM was prepared by spiking seawater sampled from the North Sea, and therefore the matrix is representative of a real environmental sample, while the solid RM was prepared using a synthetic approach by spiking a mixture of silica precursors before a sol-gel reaction. The homogeneity, between-bottles and within-bottles, of both RMs was assessed using gamma-ray spectrometry and mass spectrometry. For the liquid RM, the variation among sub-samples was due mainly to the within-bottle variance, and was lower than 1 %, for all the radionuclides tested. For the solid RM, the 241Am content measured with gamma-ray spectrometry revealed a statistically significant variation between-bottles, but was lower than 1 %. The 238U and 239Pu contents, measured by mass spectrometry, showed higher measurement variability (~5 %), with the main contribution coming from within the bottles
Liste der bei der PTB angezeigten und geprüften Schusswaffen gemäß § 9 Abs. 2 Nr. 1 Beschussgesetz (BeschG)
No full textListe der bei der PTB angezeigten und geprüften Schusswaffen gemäß § 9 Abs. 2 Nr. 1 Beschussgesetz (BeschG
Liste der von der PTB erteilten Bauartzulassungen nach § 7 Beschussgesetz (BeschG)
No full textListe der von der PTB erteilten Bauartzulassungen nach § 7 Beschussgesetz (BeschG
Progress achieved in EURAMET project 21GRD09 MetroPOEM: Metrology for the harmonisation of measurements of environmental pollutants in Europe
No full textThe European Green Deal’s ambition for zero pollution requires development of highly sensitive techniques to detect ultra-low amounts of pollutants and determine their isotope ratios, where mass spectrometry is a key method. The project bridges the traceability gap between activity and mass measurements – particularly estimation of mass bias – and establishes new tools for pollutant tracing. SI-traceable reference materials and measurement procedures are being developed that significantly reduce measurement uncertainty and detection limits, to enable tracking pollution sources by commonly available mass spectrometers. This project supports strategies described by the European Metrology Network on pollution monitoring and the established EMN on radiation protection. Main areas of work are:
• Development of low-level radionuclide standards for 90Sr and a series of actinides,
• Development of SI traceable high-precision analytical methods for isotope ratio determination of Li, B, Cr, Cd, Ni, Sb, Pb, and U in environmental matrices applicable to single and multi-collector ICP-MS systems.
• Generation of two reference materials – seawater and silica – spiked with radionuclides
• Production of certified seawater reference material for isotope ratio to validate analytical methods, support proficiency testing, and ensure quality control in future monitoring.
• Communication of project outcomes include peer reviewed papers, good practice guides, workshops, conference presentations and more
New generation of quantum Hall resistance standards based on n- and p-type epitaxial graphene
No full textElectrical quantum standards, e.g., quantum resistance, current, and voltage, have played a decisive role in modern metrology, particularly since the International System of Units (SI) revision in 2019. The SI unit of electrical resistance, the ohm, is implemented by a quantum Hall resistance (QHR) based on the quantum Hall effect. Furthermore, other SI units, such as the farad, the ampere, and the kilogram (realized by Kibble balance), essentially require QHR standards in their traceability route to realize their SI units. Therefore, QHR standards play an essential role in implementing the new SI. Conventional GaAs heterostructure QHR standards with the quantized resistance value of RH = h/2e2 (filling factor ν = 2) are operating under the extreme conditions of high magnetic flux density B > 10 T, limited current I 100 µA), and higher T (≥ 4.2 K) is the cornerstone of the electrical quantum standards.
In the past decade, epitaxial graphene on SiC has emerged as a promising alternative to GaAs heterostructures for primary QHR standards with a 10-9 accuracy (nΩ/Ω) because epitaxial graphene is promising to realize the SI unit of resistance under relaxed conditions of B, I, and T. In this study, large-scale, high-quality single-layer epitaxial graphene is grown on semi-insulating SiC substrates. A simple, efficient, and cost-effective fabrication process based on optical lithography is successfully developed to fabricate twelve identical graphene QHR devices into a centimeter graphene chip. The intrinsic high carrier density of the as-grown epitaxial graphene is reduced and tailored by F4-TCNQ molecular doping. By precisely adjusting the F4-TCNQ dopant concentration, the carrier density is tuned to the desired values spanning from intrinsic n-type to the p-type regimes for developing QHR standards. A physical model in terms of the energy band diagram is established to explain the electron transfer mechanism between the F4-TCNQ and epitaxial graphene/SiC surface.
Furthermore, the n- and p-type epitaxial graphene is used to successfully develop the primary QHR standards, which can operate under relaxed conditions. The n-type graphene QHR standards achieved a high accuracy of less than 2 nΩ/Ω (two parts per billion, k = 2) at a moderate magnetic flux density of B = 4.5 T, high current of I = 232.5 μA, and easier to access temperature of T = 4.2 K, simultaneously. To our knowledge, this is the best performance of graphene QHR standards achieved in literature so far. The graphene QHR standards have maintained the 2 nΩ/Ω accuracy in terms of time over 2.5 years, multiple cool-down cycles over fifteen times, and long-distance shipment over 800 km between two metrology institutes. More importantly, this dissertation first systematically demonstrated that p-type epitaxial graphene can also be used for primary resistance standards, as accurate (10-9 accuracy) as GaAs and n-type graphene counterparts for realizing the SI unit ohm in quantum resistance metrology. Furthermore, a contour plot of graphene QHR standards is proposed to reveal the correlation of the quantization regime (10-9 accuracy) with magnetic field and carrier density. The contour plots serve to benchmark the graphene QHR device according to end users’ specifications. When implemented, graphene QHR standards may lead to broader dissemination of primary resistance standards beyond national metrology institutes, extending to commercial calibration laboratories and industry on-site.PTB-Bericht Diss-1
Liste der bei der PTB angezeigten und geprüften Schusswaffen gemäß § 9 Abs. 2 Nr. 1 Beschussgesetz (BeschG)
No full textListe der bei der PTB angezeigten und geprüften Schusswaffen gemäß § 9 Abs. 2 Nr. 1 Beschussgesetz (BeschG