Precision atomic physics techniques for nuclear physics with radioactive beams

Abstract

Atomic physics techniques for the determination of ground-state properties of radioactive isotopes are very sensitive and provide accurate masses, binding energies, Q-values, charge radii, spins, and electromagnetic moments. Many fields in nuclear physics benefit from these highly accurate numbers. They give insight into details of the nuclear structure for a better understanding of the underlying effective interactions, provide important input for studies of fundamental symmetries in physics, and help to understand the nucleosynthesis processes that are responsible for the observed chemical abundances in the Universe. Penning-trap and and storage-ring mass spectrometry as well as laser spectroscopy of radioactive nuclei have now been used for a long time but significant progress has been achieved in these fields within the last decade. The basic principles of laser spectroscopic investigations, Penning-trap and storage-ring mass measurements of short-lived nuclei are summarized and selected physics results are discussed. † going to cryogenic temperatures, or enhancing the induced signal by using higher charge states and/or longer accumulation times. Ideal applications for this method are mass measurements of super-heavy element (SHE) isotopes for nuclear structure studies as they are performed at SHIPTRAP [25,26]. SHE are produced in minuscule quantities, and typically have half-lives of hundreds of milliseconds to a few seconds. A proof-ofprinciple experiment is planned at the TRIGA reactor facility TRIGA-TRAP at Mainz University [27] and applications for HITRAP with highly charged ions are foreseen [28]. Requirements for Mass Measurements of Radioactive IonsThe specific requirements for the mass measurements of radioactive ions stem from the parameters of the ions themselves. For example the required sensitivity (depending on the production yield) and measurement speed (depending on the half-life) as well as the envisaged application which dictates the required precision. In order to be meaningful, all measurements should deliver reliable data, hence precise and accurate. The physics requirements can be categorized with the corresponding relative precision as follows:• nuclear structure, δm/m ≈ 1 × 10 −7• nuclear astrophysics, δm/m ≈ 1 × 10 −7/−8 • test of fundamental symmetries, neutrino physics, δm/m ≈ 1 × 10 −8/−9

In-gas-cell laser spectroscopy of the magnetic dipole moment of the N≈126 isotope Pt199

“…If both δν A,A and δ r 2 A,A for stable isotopes are known, K MS and F 248 can be evaluated to deduce δ r 2 A,A from the measured δν A,A . Generally, the term of the mass shift (approximately a few 10 MHz) is about two orders of magnitude smaller than the term of the field shift (approximately a few GHz) in the present high Z = 78 region [35], and the mass shift term can be neglected in the present case. The factor F 248 was evaluated to be 17.0 ± 1.8 GHz/fm 2 from the measured δν A,A and δ r 2 A,A , and the reported δ r 2 A,A [26] for even Pt in Table II by .…”

Dawning of the N=32 Shell Closure Seen through Precision Mass Measurements of Neutron-Rich Titanium Isotopes

“…Sudden and locally steep drops in the two-neutron separation energies (S 2n ) are also typical indicators of strong shell effects and are accessible through precision mass spectrometry techniques [6]. Mass studies performed at several facilities reveal strong shell effects at N = 32 in the 19 In contrast, the S 2n surface is smooth in this region for 23 V and beyond, indicating that the shell has quenched.…”

TSR: A Storage Ring for HIE-ISOLDE

“…Light elements are difficult to study using traditional laser spectroscopy for a number of reasons [11]. They are produced in ISOL mainly as molecules unsuitable for studying hyperfine effects.…”