Physikalisch-Technische Bundesanstalt

Review of the Radon Tracer Method for GHG emission estimates: development, application guidelines, improvements, and caveats

Abstract. The Radon Tracer Method (RTM) is an established, independent top-down method that can be used to cross-check bottom-up greenhouse gas (GHG) emission estimates. Furthermore, as uncertainties of Atmospheric Transport Models are reduced, the RTM can provide a convenient me...

Nanoscale Mapping of Internal Magnetization Dynamics Reveals How Disorder Shapes Heat Generation in Magnetic Particle Hyperthermia

Abstract Magnetic particle hyperthermia relies on the efficient conversion of magnetic field energy into heat, yet the microscopic mechanisms governing this process within individual particles remain poorly understood. Here, we combine AC magnetometry experiments with dynamic mic...

High‐Density Magnetomyography With Optical Magnetometers Reveals Spatiotemporal Patterns of Evoked Muscle Activity

ABSTRACT Magnetomyography (MMG) holds great potential as a contactless alternative to electromyography (EMG). However, the spatiotemporal dynamics of the myomagnetic field in vivo remain largely unknown, limiting signal interpretability and hence the use of MMG. Here, the myomagn...

A thorium-229 optical nuclear clock with feedback loop

Abstract The laser-accessible nuclear transition in the thorium-229 isotope has been identified as a candidate for realizing an optical nuclear clock 1 that might outperform current optical clocks based on electron-shell transitions in atoms or ions 2 . It is expected to be more...

Discovering how ice crystals grow using neural ODEs and symbolic regression

Depositional ice growth strongly influences the evolution and lifetime of ice-containing clouds on Earth and Mars, yet its physics remain uncertain because the earliest stages of ice-crystal growth cannot be directly observed and are sparsely sampled in laboratory settings. Here,...

Thermal characterization of lithium iron phosphate pouch cells using a spatially resolving isoperibolic calorimeter

Abstract Thermal characterization of lithium-ion batteries is essential for optimal battery designs and their safe operation. In the present study, an in-house-built spatially resolving isoperibolic calorimeter was used to characterize the thermal behavior of a large-format comme...

Filling the gaps in high-priority reference materials for implementing metrological traceability in laboratory medicine

Abstract The global harmonization of measurements in laboratory medicine is facilitated by the development and implementation of reference measurement systems, including suitable certified reference materials (CRMs). There are, however, a relatively small number of CRM producers...

Road transport of trapped antiprotons

Abstract Low-energy antiprotons confined in ultrahigh-vacuum Penning traps 1 enable precision investigations of charge, parity and time-reversal (CPT) invariance 2 to test the fundamental symmetry between matter and antimatter. These studies are driven by the search for physics b...

Continuous-wave laser absorption spectroscopy of the thorium-229 nucleus

Abstract The low-energy nuclear transition in thorium-229 (Th-229) has been excited in thorium-doped crystals with laser light 1–3 , opening the path towards a highly stable and robust solid-state optical nuclear clock 4 . The required laser radiation at 148-nm wavelength has so...

International Intercomparison of Primary Photovoltaic Reference Cell Calibrations With Excellent Agreement

This study presents the results of an international intercomparison of primary calibration methods for photovoltaic (PV) reference devices according to IEC 60904‐4. The comparison involves three leading calibration laboratories—PTB, NLR, and AIST—representing independent traceabi...

X-ray absorption and resonant x-ray emission at the carbon edge of Li2CO3

While highly successful, density functional theory is known to have limitations owing to its neglect of many-body electron-electron interactions. This neglect leads to errors in the single-particle energies, leading to underestimated bandgaps and bandwidths as well as errors in b...

Reproducible human reward imaging phenotypes exhibit differential sensitivity to dopamine D2 receptor antagonism

Abstract Human reward processing varies along cue-centric and outcome-centric axes, but a reproducible mechanistic account of individual variation in incentive salience attribution has been lacking. Using fMRI across five cohorts (N-total=1,251; N1=890; N2=245; N3=34; N4=48; N5=3...

Fetal Magnetocardiography Using Optically Pumped Magnetometers: A Literature Review

Fetal magnetocardiography (fMCG) provides direct non-invasive assessment of fetal cardiac electrophysiology, enabling detailed evaluation of cardiac rhythm, conduction, and repolarization. However, the clinical adoption of conventional fMCG has been limited by its reliance on sup...

Plastic incompatibility stresses arising from slip and twinning in extruded AZ31 magnesium alloy: In-situ synchrotron diffraction analysis using self-consistent modeling

This study presents a comprehensive investigation into the bulk internal stress evolution within an extruded AZ31 magnesium alloy subjected to both in-situ uniaxial tensile and compressive loading. Using energy-dispersive synchrotron X-ray diffraction (ED XRD), first-order macros...