Publications by authors named "Timo Dickel"

Article Synopsis
  • Radioactive nuclei that live for millions of years help us understand the Sun's formation and the nucleosynthesis happening when it was born, with lead (Pb) being a key example.
  • Recent measurements of the weak decay of ionized thallium (Tl) provided a more accurate half-life, which was found to be 4.7 times longer than previously thought, thus reducing uncertainty in our calculations.
  • Using these improved decay rates, researchers calculated lead yields in asymptotic giant branch (AGB) stars, confirmed isolation times for solar material, and validated the theory that the Sun formed in a long-lived molecular cloud.
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Article Synopsis
  • * The new mass data, with a precision around 1 keV/c², supports the robustness of the N=50 neutron shell closure and enables comparisons with advanced theoretical models for understanding nuclear properties.
  • * The study also highlights the challenges faced by theoretical approaches, like ab initio calculations and density functional theory, in accurately predicting ground-state properties in the silver isotopic chain near the proton dripline.
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A compact ion source combining electron impact and thermal ionization has been developed and commissioned in two Multiple-Reflection Time-Of-Flight Mass Spectrometer (MR-TOF-MS) setups at the Fragment Separator Ion Catcher at the GSI Helmholtz Centre for Heavy Ion Research, Darmstadt, Germany, and at TRIUMF's Ion Trap for Atomic and Nuclear science at TRIUMF Canada's particle accelerator center, Vancouver, Canada. The ion source is notable for its compact dimensions of 50 mm in height and 68 mm in diameter. The ion source is currently in daily operation at both facilities.

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Molecules containing short-lived, radioactive nuclei are uniquely positioned to enable a wide range of scientific discoveries in the areas of fundamental symmetries, astrophysics, nuclear structure, and chemistry. Recent advances in the ability to create, cool, and control complex molecules down to the quantum level, along with recent and upcoming advances in radioactive species production at several facilities around the world, create a compelling opportunity to coordinate and combine these efforts to bring precision measurement and control to molecules containing extreme nuclei. In this manuscript, we review the scientific case for studying radioactive molecules, discuss recent atomic, molecular, nuclear, astrophysical, and chemical advances which provide the foundation for their study, describe the facilities where these species are and will be produced, and provide an outlook for the future of this nascent field.

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Owing to the favorable depth-dose distribution and the radiobiological properties of heavy ion radiation, ion beam therapy shows an improved success/toxicity ratio compared to conventional radiotherapy. The sharp dose gradients and very high doses in the Bragg peak region, which represent the larger physical advantage of ion beam therapy, make it also extremely sensitive to range uncertainties. The use of -radioactive ion beams would be ideal for simultaneous treatment and accurate online range monitoring through PET imaging.

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High-accuracy mass measurements of neutron-deficient Yb isotopes have been performed at TRIUMF using TITAN's multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS). For the first time, an MR-TOF-MS was used on line simultaneously as an isobar separator and as a mass spectrometer, extending the measurements to two isotopes further away from stability than otherwise possible. The ground state masses of ^{150,153}Yb and the excitation energy of ^{151}Yb^{m} were measured for the first time.

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Several techniques are under development for image-guidance in particle therapy. Positron (β) emission tomography (PET) is in use since many years, because accelerated ions generate positron-emitting isotopes by nuclear fragmentation in the human body. In heavy ion therapy, a major part of the PET signals is produced by β-emitters generated projectile fragmentation.

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A novel method for (ultra-)high-resolution spatial mass separation in time-of-flight mass spectrometers is presented. Ions are injected into a time-of-flight analyzer from a radio frequency (rf) trap, dispersed in time-of-flight according to their mass-to-charge ratios and then re-trapped dynamically in the same rf trap. This re-trapping technique is highly mass-selective and after sufficiently long flight times can provide even isobaric separation.

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