Ion implantation of 226Ra for a primary 222Rn emanation standard

Laser resonance ionization at the RISIKO 30 kV mass separator has been used to produce isotopically and isobarically pure and well quantified 222Rn emanation standards. Based upon laser-spectroscopic preparation studies, ion implantation into aluminum and tungsten targets has been carried out, providing overall implantation efficiencies of 40% up to 60%. The absolute implanted activity of 226Ra was determined by the technique of defined solid-angle α-particle spectrometry, where excellent energy resolution was observed. The 222Rn emanation coefficient of the produced targets was studied using α-particle and γ-ray spectrometry, and yielded results between 0.23 and 0.34, with relative uncertainty on the order of 1%. No dependence exceeding a 1% change of the emanation on humidity could be identified in the range of 15 %rH to 75 %rH, whereas there were hints of a slight correlation between the emanation and temperature. Additionally, and as expected, the emanation coefficient was found to be dependent on the target material as well as the implanted dose. © 202

Advancing Radiation-Detected Resonance Ionization towards Heavier Elements and More Exotic Nuclides

RAdiation-Detected Resonance Ionization Spectroscopy (RADRIS) is a versatile method for highly sensitive laser spectroscopy studies of the heaviest actinides. Most of these nuclides need to be produced at accelerator facilities in fusion-evaporation reactions and are studied immediately after their production and separation from the primary beam due to their short half-lives and low production rates of only a few atoms per second or less. Only recently, the first laser spectroscopic investigation of nobelium (Z=102) was performed by applying the RADRIS technique in a buffer-gas-filled stopping cell at the GSI in Darmstadt, Germany. To expand this technique to other nobelium isotopes and for the search for atomic levels in the heaviest actinide element, lawrencium (Z=103), the sensitivity of the RADRIS setup needed to be further improved. Therefore, a new movable double-detector setup was developed, which enhances the overall efficiency by approximately 65% compared to the previously used single-detector setup. Further development work was performed to enable the study of longer-lived (t₁/₂>1 h) and shorter-lived nuclides (t₁/₂<1 s) with the RADRIS method. With a new rotatable multi-detector design, the long-lived isotope 254Fm (t₁/₂=3.2 h) becomes within reach for laser spectroscopy. Upcoming experiments will also tackle the short-lived isotope 251No (t₁/₂=0.8 s) by applying a newly implemented short RADRIS measurement cycle

The Electron Capture in 163^{163} Ho Experiment - a Short Update

The definition of the absolute neutrino mass scale is one of the main goals of the Particle Physics today. The study of the end-point regions of the β- and electron capture (EC) spectrum offers a possibility to determine the effective electron (anti-)neutrino mass in a completely model independent way, as it only relies on the energy and momentum conservation. The ECHo (Electron Capture in 163Ho) experiment has been designed in the attempt to measure the effective mass of the electron neutrino by performing high statistics and high energy resolution measurements of the 163 Ho electron capture spectrum. To achieve this goal, large arrays of low temperature metallic magnetic calorimeters (MMCs) implanted with with 163Ho are used. Here we report on the structure and the status of the experiment

Highly efficient isotope separation and ion implantation of 163Ho^{163}Ho for the ECHo project

The effective electron neutrino mass measurement at the ECHo experiment requires high purity $^{163}$Ho, which is ion implanted into detector absorbers. To meet the project specifications in efficiency and purity, the entire process chain of ionization, isotope separation, and implantation of $^{163}$Ho was optimized. A new two-step resonant laser ionization scheme was established at the $30\, kV$ magnetic mass separator RISIKO. This achieved ionization and separation efficiencies with an average of $69(5)_\textrm{stat}(4)_\textrm{sys}\,\%$ using intra-cavity frequency doubled Ti:sapphire lasers. The implantation of a $^{166\textrm{m}}$Ho impurity is suppressed about five orders of magnitude by the mass separation. A dedicated implantation stage with focusing and scanning capability enhances the geometric implantation efficiency into the ECHo detectors to $20(2)\,\%$

Measurement of the laser resonance ionization efficiency for lutetium

The development of a highly efficient resonance ionization scheme for lutetium is presented. A laser ion source, based on the all-solid-state Titanium:sapphire laser system, was used at the 30 keV RISIKO off-line mass separator to characterize different possible optical excitation schemes in respect to their ionization efficiency. The developed laser resonance ionization scheme can be directly applied to the use at radioactive ion beam facilities, e. g. at the CERN-MEDICIS facility, for large-scale production of medical radioisotopes

Development of a recoil ion source providing slow Th ions including 229(m)^{229(m)}Th in a broad charge state distribution

Ions of the isomer $^{229m}$Th are a topic of high interest for the construction of a "nuclear clock" and in the field of fundamental physics for testing symmetries of nature. They can be efficiently captured in Paul traps which are ideal for performing high precision quantum logic spectroscopy. Trapping and identification of long-lived $^{232}$Th$^{+}$ ions from a laser ablation source was already demonstrated by the TACTICa collaboration on Trapping And Cooling of Thorium Ions with Calcium. The $^{229m}$Th is most easily accessible as $\alpha$-decay daughter of the decay of $^{233}$U. We report on the development of a source for slow Th ions, including $^{229(m)}$Th for the TACTICa experiment. The $^{229(m)}$Th source is currently under construction and comprises a $^{233}$U monolayer, from which $^{229(m)}$Th ions recoil. These are decelerated in an electric field. Conservation of the full initial charge state distribution of the $^{229(m)}$Th recoil ions is one of the unique features of this source. We present ion-flight simulations for our adopted layout and give a final design. This source will provide Th ions in their original charge state at energies suitable for capture in a linear Paul trap for spectroscopy investigations.Comment: 6 pages, 3 figures, PLATAN19 conference proceeding published in Hyperfine Interact 202