A5078492907- Radioactive Decay and Measurement Techniques
- Radioactivity and Radon Measurements
- Scientific Measurement and Uncertainty Evaluation
- Radioactive contamination and transfer
- Nuclear physics research studies
- Quantum Chromodynamics and Particle Interactions
- Radiation Detection and Scintillator Technologies
- Nuclear Physics and Applications
- Medical Imaging Techniques and Applications
- Quantum Mechanics and Non-Hermitian Physics
- Radiation Therapy and Dosimetry
- Radiopharmaceutical Chemistry and Applications
- Particle physics theoretical and experimental studies
- Atomic and Molecular Physics
- Cold Atom Physics and Bose-Einstein Condensates
- Advanced X-ray and CT Imaging
- High-pressure geophysics and materials
- Radiation Effects in Electronics
- Dental Radiography and Imaging
- Computational Physics and Python Applications
- Nonlinear Waves and Solitons
- Radiation Shielding Materials Analysis
- Relativity and Gravitational Theory
- Matrix Theory and Algorithms
- Chemical Thermodynamics and Molecular Structure
Institute of Radiation Physics
2009-2023
University of Lausanne
2004-2023
University Hospital of Lausanne
2016-2023
Swiss Federal Institute of Metrology
2010-2020
Australian Nuclear Science and Technology Organisation
2017
University of Oxford
1988-2000
University of Surrey
1990-1995
In view of the current interest in relativistic spin-1 systems and recent work on Dirac oscillator, we introduce Duffin-Kemmer-Petiau (DKP) equation obtained by using an external potential linear r. Since spin-0 representation leads to a harmonic oscillator non-relativistic limit becomes with spin-orbit coupling Thomas form for vector bosons, call DKP oscillator. This is generalization quantum scalar bosons. We show that it conserves total angular momentum exactly solvable both calculate...
The hypothesis that proximity to the Sun causes variation of decay constants at permille level has been tested and disproved. Repeated activity measurements mono-radionuclide sources were performed over periods from 200 days up four decades 14 laboratories across globe. Residuals exponential nuclear curves inspected for annual oscillations. Systematic deviations a purely curve differ one data set another are attributable instabilities in instrumentation measurement conditions. most stable...
In view of recent interest in the use Duffin-Kemmer-Petiau (DKP) relativistic equation, authors consider some its properties which are needed for practical calculations. They also address unresolved problem spinless DKP boson a central field and derive system first-order coupled differential radial equations enable energy eigenvalues as well full wavefunctions to be evaluated. As an example they calculate free spherical waves then solve pionic atom with point Coulomb interaction only.
Claims that proximity to the Sun causes variation of decay constants at permille level have been investigated for alpha decaying nuclides. Repeated rate measurements 209Po, 226Ra, 228Th, 230U, and 241Am sources were performed over periods 200 d up two decades various nuclear metrology institutes around globe. Residuals from exponential curves inspected annual oscillations. Systematic deviations a purely curve differ in amplitude phase one data set another appear attributable instabilities...
In view of current interest in the use Duffin–Kemmer–Petiau (DKP) relativistic equation, problem vector DKP boson a central field is resolved and system first-order coupled differential radial equations needed for an exact calculation eigenvalues as well full ten-component spinor derived. This practical importance problems involving massive bosons fields. formalism applied to free-particle, spherically symmetric square Coulomb problems.
The hypothesis that seasonal changes in proximity to the Sun cause variation of decay constants at permille level has been tested for radionuclides disintegrating through electron capture and beta plus decay. Activity measurements 22Na, 54Mn, 55Fe, 57Co, 65Zn, 82+85Sr, 90Sr, 109Cd, 124Sb, 133Ba, 152Eu, 207Bi sources were repeated over periods from 200 d up more than four decades 14 laboratories across globe. Residuals exponential nuclear curves inspected annual oscillations. Systematic...
Claims that proximity to the Sun causes variations of decay constants at permille level have been investigated for beta-minus decaying nuclides. Repeated activity measurements 3H, 14C, 60Co, 85Kr, 90Sr, 124Sb, 134Cs, 137Cs, and 154Eu sources were performed over periods 259 d up 5 decades various nuclear metrology institutes. Residuals from exponential curves inspected annual oscillations. Systematic deviations a purely curve differ in amplitude phase one data set another appear attributable...
We introduce the extended Duffin-Kemmer-Petiau (DKP) oscillator obtained by combining two relativistic quantum models. In a study analogous to Kukulin, Loyola and Moshinsky's work on Dirac oscillators, we investigate whether this version has shells controllably independent from spin-orbit coupling. This DKP is found be exactly solvable for natural parity states. calculate discuss both natural- unnatural-parity eigenspectra of its spin-1 representation.
Abstract When verifying the validity of exponential-decay law through 137 precise decay rate measurement series at various nuclear laboratories, minor violations have been observed in shape annual cycles residuals with different amplitudes and phase shifts. The timing amplitude these deviations compared local weather data it appears that ambient humidity is highly correlated instabilities radioactivity measurements. In fact, when compensating for a linear relationship absolute air, most are...
We propose a generic S = 1 relativisitic oscillator model which extends the class of relativistic bosonic oscillators. The Duffin-Kemmer-Petiau (DKP) we introduced in an earlier work can be recovered as element family DKP oscillators that realized within this model. present formalism for exact quantum mechanical treatment and, illustration, compute eigenvalues particular
44Sc is a promising radionuclide for positron emission tomography (PET) in nuclear medicine. As part of the implementation production site 44Sc, precise knowledge activity product necessary. At Paul Scherrer Institute (PSI) and University Bern (UniBE), produced by enriched 44CaO-target irradiation with cyclotron. The two sites use different techniques measurement, namely dose calibrator at PSI gamma-ray spectrometry system UniBE PSI. In this work, was PSI, samples were prepared dedicated...
The β--particle-emitting erbium-169 is a potential radionuclide toward therapy of metastasized cancer diseases. It can be produced in nuclear research reactors, irradiating isotopically-enriched 168Er2O3. This path, however, not suitable for receptor-targeted therapy, where high specific molar activities are required. In this study, an electromagnetic isotope separation technique was applied after neutron irradiation to boost the activity by separating 169Er from 168Er targets. efficiency...
Abstract Background 161 Tb draws an increasing interest in nuclear medicine for therapeutic applications. More than 99% of the emitted gamma and X-rays have energy below 100 keV. Consequently, precise activity measurement becomes inaccurate with radionuclide dose calibrators when using inappropriate containers or calibration factors to account attenuation this low radiation. To evaluate ionization chamber response, sample must be well known. This can performed standards traceable Système...
The half-lives of 44Sc and 44mSc were measured by following their decay rate using several measurement systems: two ionization chambers three γ-spectrometry detectors with digital and/or analogue electronics. For 44Sc, the result was combination seven half-life values giving a 4.042(7) h, which agrees last reported value 4.042(3) h confirms near to 2% deviation from recommended 3.97(4) h. Scandium-44 is present as an impurity in production cyclotron proton irradiation. Its determined...
Detailed uncertainty reporting is imperative for proficiency tests and comparison exercises because uncertainties need to be comparable trusted by all the participants. Even though participants do their best follow Guide Expression of Uncertainty in Measurement, ambiguities divergences about evaluation remain. Consequently, analyze situation, CCRI (II) Uncertainties Working Group proposed a exercise (CCRI(II)-S7) relatively simple primary activity measurement: standardization 60Co source...