EXOTRAP · Pushing the limits of online mass spectrometry

Mass measurements of utmost accuracy are extremely relevant for many physics areas: For particles like the electron or the nucleons, the mass represents fundamental properties of building blocks of nature. For complex composite quantum mechanical systems such as molecules, atoms and nuclei, masses allow to determine the binding energy of the system and thus give access to all fundamental physical forces acting between its constituents. Furthermore, mass measurements allow tests of symmetry concepts in physics and searches of physics beyond the Standard Model. Accurate mass determinations are also essential for reliable nucleosynthesis calculations in astrophysics or for testing mass models applied for theoretical mass predictions of even more exotic isotopes. Penning traps have solved the problem of isobaric and also very often that of isomeric contamination and are presently the mass spectrometers enabling the highest accuracy and resolving power. For a stable particle or stable nuclide, its mass can be determined with a relative accuracy reaching 10-11 and by performing the complete experiment with only one single ion. In the case of radionuclides, masses could be measured with a relative mass uncertainty better than 10-8 (e.g. Mg-22), a resolving power approaching 10 million (Hg isotopes), production rates as low as 1 ion/s (No-252), half-lives as low as 10 ms (Li-11), and for singly or maximum doubly ionized ions. However, these impressive performances in accuracy, resolving power, sensitivity and applicability could not be achieved simultaneously for one specific species. Therefore, this project aims at pushing the present limits of online mass spectrometry even further, thus allowing studies of nuclides and physics questions inaccessible before. To reach this goal all limiting factors will be studied in detail and theoretical and experimental work will be undertaken to increase the accuracy, resolving power, and sensitivity of the method.