Decay-correlated time-of-flight mass spectroscopy using multi-reflection time-of-flight mass spectrographs

In recent years, multi-reflection time-of-flight mass spectrographs (MRTOF-MS) have proven to be superbly valuable tools for online determinations of atomic masses. Recently, they have achieved mass resolving powers m/Δm≈10⁶ with flight times t<20 ms for A/q~100 ions. They are also able to simultaneously analyse multiple isobar chains, making them a highly efficacious tool for use with in-flight fission and fragmentation, as well as multi-nucleon transfer reactions.

By constructing specialized ion detectors that allow for precise determination of ion impact timing and can also detect radioactive decays, we have found that the MRTOF-MS can become an even more effective tool. Such detectors allow decay-correlated mass spectroscopy. Such decay-correlated time-of-flight measurements allow for a strong suppression of stable molecular background ions that are always extracted from even the cleanest gas stopping cell. This allows for high-confidence in measurements of very low yield species such as superheavy nuclides. When dealing with alpha-decaying species (such as superheavy nuclides) we can gate on specific decay energies to use decay correlated mass spectroscopy to further enhance confidence in the identity of the mass-analyzed nuclides. Using decay-correlations we can also perform half-life measurements simultaneous to mass measurements, which further increases the efficacious utilization of limited online machine time while also allowing for a further confirmation of the identity of exotic nuclides whose masses have not been previously determined.

We will present some of our recent work in measuring dubnium isotopes through decay-correlated mass spectroscopy, along with some preliminary results showing the utility for beta-decaying nuclides. We will also present future plans for development of version capable of performing gamma (and x-ray) correlated mass spectroscopy to enhance the identification of neutron-rich nuclides produced in multi-nucleon reactions.