A5012601353- Atomic and Molecular Physics
- Radioactive element chemistry and processing
- Radioactive contamination and transfer
- Nuclear Physics and Applications
- Advanced Chemical Physics Studies
- Nuclear Materials and Properties
- Nuclear physics research studies
- Cold Atom Physics and Bose-Einstein Condensates
- Rare-earth and actinide compounds
- Neutrino Physics Research
- Radioactive Decay and Measurement Techniques
- Dark Matter and Cosmic Phenomena
- Radioactivity and Radon Measurements
- Nuclear reactor physics and engineering
- Particle physics theoretical and experimental studies
- Scientific Measurement and Uncertainty Evaluation
- Ion-surface interactions and analysis
- Mass Spectrometry Techniques and Applications
- Superconductivity in MgB2 and Alloys
- Superconducting and THz Device Technology
- Laser-induced spectroscopy and plasma
Johannes Gutenberg University Mainz
2019-2025
Quasi non-desctructive actinide isotope detection and imaging on the 100nm scale advances single particle nuclear forensics.
Radioactive particles, so-called hot are of great importance in the risk assessment environmental pollution and human health hazards. Since most these particles only a couple micrometers size thus have correspondingly small atomic inventory, information on origin composition is difficult to obtain. Many analytical methods do not give insight into isotopic details or require complete use up particle. Resonant laser secondary neutral mass spectrometry (rl-SNMS) has been proven be well-suited...
Abstract The atomic structure of neptunium (Np) was investigated by two-step resonance ionization spectroscopy. study involved exploring ground-state transitions as well following to high-lying states just below the potential (IP) or auto-ionizing above IP. That resulted in identification schemes, suitable for trace analysis and nuclear investigations. lifetimes two excited located at 25,342.48 $$\, \text {cm}^{-1} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow>...
Abstract Resonance ionization mass spectroscopy has proven to be a very efficient and selective method for the spatially resolved ultratrace determination of actinide contaminations, analysis specific element isotopic distributions on surfaces environment particles. We report identification highly element-selective optical excitation schemes identified this purpose, with particular focus precise isobaric ratios 235 U 239 Pu as well 243 Am 241 Pu. The chosen two-step were characterized...
We report on high-resolution laser spectroscopy studies $^{249\text{--}253}\mathrm{Cf}$ with spectral linewidths in the order of 100 MHz carried out at RISIKO mass separator Mainz University. In total three atomic ground-state transitions were investigated and hyperfine parameters for odd-$A$ isotopes isotope shift all examined have been determined from measured spectra. The measurements allowed tracking changes mean-squared charge radii across deformed nuclear shell closure $N=152$, whereby...
Laser resonance ionization spectroscopy was performed on the rare einsteinium isotopes $^{253\ensuremath{-}255}\mathrm{Es}$ at RISIKO mass separator in Mainz. With low sample sizes ranging down to femtograms, prominent 352 nm-ground-state transition measured all three isotopes, and four additional ground-state transitions were $^{254}\mathrm{Es}$. Hyperfine-structure analysis resulted assigned spin values of $I(^{254}\mathrm{Es})=7$ $I(^{255}\mathrm{Es})=7/2$. From extracted coupling...
Abstract Resonance ionization mass spectrometry is an efficient tool to detect minute amounts of long-lived radio-isotopes in environmental samples. Applying resonant excitation and with pulsed laser radiation within a hot cavity atomizer enables the sensitive detection precise quantification actinide isotopes. Due inherently element selective process, this method ensures ultimate suppression contaminations from other elements molecules. The characterization in-source resonance U, Th, Np, Am...
Two lowest-energy odd-parity atomic levels of actinium, $7{s}^{2}7p{^{2}P}_{1/2}^{o}$, $7{s}^{2}7p{^{2}P}_{3/2}^{o}$, were observed via two-step resonant laser-ionization spectroscopy and their respective energies measured to be 7477.36(4) $12\text{ }276.59(2)\text{ }\text{ }{\mathrm{cm}}^{\ensuremath{-}1}$. The lifetimes these states determined as 668(11) 255(7) ns, respectively. In addition, we the effect hyperfine structure on line for transition ${^{2}P}_{3/2}^{o}$. These properties...
The quantum-mechanical nuclear-shell structure determines the stability and limits of existence heaviest nuclides with large proton numbers Z ≳ 100 (refs.
Laser resonance ionization at the RISIKO 30 kV mass separator has been used to produce isotopically and isobarically pure well quantified 222Rn emanation standards. Based upon laser-spectroscopic preparation studies, ion implantation into aluminum tungsten targets carried out, providing overall efficiencies of 40% up 60%. The absolute implanted activity 226Ra was determined by technique defined solid-angle α-particle spectrometry, where excellent energy resolution observed. coefficient...
The atomic structure of californium is probed by two-step resonance ionization spectroscopy. Using samples with a total amount about 2×1010 Cf atoms (ca. 8.3 pg), ground-state transitions as well to high-lying Rydberg states and auto-ionizing above the potential are investigated lifetimes various levels measured. These investigations lead identification efficient schemes, important for trace analysis nuclear investigations. Most measurements conducted on 250Cf. In addition, isotope shift...
Abstract Resonance ionization mass spectrometry is an ultra-sensitive and highly element selective tool for spectroscopy, detection of atoms thus enables rare isotope determination. In combination with spatially resolved sputtering neutrals by initial ion beam, e.g. within a commercial secondary spectrometer, isobar analysis technique resolution on the micrometer scale particles surfaces realized. Detection minuscule amounts specific actinides, plutonium, in environmental technical samples...
Abstract We report on the investigation of atomic structure curium ( $$Z=96$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>Z</mml:mi> <mml:mo>=</mml:mo> <mml:mn>96</mml:mn> </mml:mrow> </mml:math> ) by resonance ionization spectroscopy. Three different excited energy levels were populated from $$5f^{7}6d7s^{2}\,^{9}D^{o}_{2}$$ <mml:mn>5</mml:mn> <mml:msup> <mml:mi>f</mml:mi> <mml:mn>7</mml:mn> </mml:msup> <mml:mn>6</mml:mn> <mml:mi>d</mml:mi>...
Excited atomic states of neutral einsteinium were investigated by resonant laser ionization using 10 pg $(2\ifmmode\times\else\texttimes\fi{}{10}^{10}$ atoms) $^{254}\mathrm{Es}$. Ten transitions from the ${5f}^{11}7s{}^{2}^{4}I_{15/2}^{o}$ ground state to even-parity in detail, via studies lifetimes and further excitation steps into higher-lying odd-parity below above first potential. This led identification 37 previously unknown energy levels region between...
Abstract The ECHo experiment aims at determining the effective electron neutrino mass by analyzing endpoint of 163 Ho capture spectrum. High energy resolution detectors with a well-tailored detector response are essential ingredient for success experiment. Metallic magnetic calorimeter arrays enclosing have been chosen first MMC array, ECHo-1k, showed excellent performances an average 5.5 eV FWHM @ 5.9 keV. Based on results obtained ECHo-1k optimization studies paved way towards new design...
We report on the production of ultra-pure samples long-lived radioisotope 53 Mn for precision measurements its half-life. Activated from a copper beam dump PSI, which was irradiated with 590 MeV protons, were used extraction manganese fraction. Following initial radiochemical purification, efficient three-photon laser resonance ionization inside hot-cavity ion source applied subsequent isotope selection in 30 keV high transmission magnetic mass separator. A new scheme developed and...
The definition of the absolute neutrino mass scale is one main goals Particle Physics today. study end-point regions $\beta$- and electron capture (EC) spectrum offers a possibility to determine effective (anti-)neutrino in completely model independent way, as it only relies on energy momentum conservation. ECHo (Electron Capture $^{163}$Ho) experiment has been designed attempt measure by performing high statistics resolution measurements $^{163}$Ho spectrum. To achieve this goal, large...
Zusammenfassung Durch die Kombination von Resonanzionisation und kommerzieller Sekundärionen‐Massenspektrometrie ist es möglich, elementare Zusammensetzung Isotopenverhältnisse kleinsten Partikeln zu bestimmen. Dabei erlaubt Auswahl geeigneter Anregungsleitern effektive Unterdrückung isobarer Störungen. Das Verfahren kann eingesetzt werden, um den Ursprungsreaktor Kernbrennstofffragmenten in der Umwelt identifizieren. Im Zuge aktuellen Ereignisse Ukraine lassen sich auf diese Weise alte...