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Laser Spectroscopy
Lasers are applied in the atomic physics group at GSI for a wide range of fundamental research.
The combination with the accelerator structure at GSI provides many possibilities for unique and ground-breaking experiments.
They are used, e.g., for testing fundamental symmetries, for the determination of ground state properties of stable and exotic nuclei,
and for the investigation of the atomic structure of Actinides and super heavy elements.
Moreover, laser forces are also used to manipulate stored ions in the experimental storage ring ESR.
The following list provides links to different laser spectroscopic experiments, which are performed at GSI.
Many of these investigations are related to projects that are planned for the future GSI facility FAIR.
In order to support laser spectroscopy experiments, GSI can provide modern laser equipment, pulsed lasers like Nd-YAG and tuneable dye lasers,
continuous wave (cw) pump lasers as well as tuneable single-frequency lasers.
Even a modern frequency comb based on femtosecond fibre laser systems is available.
TIME - A test of Time dilation at the ESR
(University Mainz, LMU Munich, MPIK Heidelberg, MPQ Munich)
The core of special relativity (SR) as a theory of local spacetime is Lorentz invariance,
which is one of the most fundamental symmetries that guide the construction of all quantum field theories.
Additionally, general relativity contains SR as a limiting case. Because of this fundamental role there is much interest in experimental tests of SR.
One of the pillars of SRT-tests is time dilation, which can be measured via the optical Doppler effect as already proposed by Einstein in 1907.
The first experiment of this kind was performed by Ives and Stilwell (IS) in 1938 by measuring the Doppler-shifted frequencies νp and νa of the Hβ line (ν0)
of a hydrogen beam in parallel and antiparallel direction using a conventional spectrometer.
The most precise Ives-Stilwell experiment was recently finished at the Test Storage Ring TSR (Link) at the MPIK in Heidelberg (Link).
At GSI, this experiment will be repeated at the Experimental Storage Ring since it can provide ions at considerably higher speed and
therefore allows for significantly improved precision. 7Li+ ions stored in the ESR are used as moving clocks at 34% of the speed of light
and saturation spectroscopy is applied to precisely measure the resonance frequency of the 3S1(F = 5/2)→3P2(F = 7/2) transition.
More details can be found here.
(Participating Institutes: MPIK Heidelberg, Universität Mainz, MPQ Munich)
ToPLiS – Two Photon Lithium Spectroscopy and the charge radius of Li-11
First Nuclear Charge Radius Determinnation of the Halo Nucleus Li-11
(University Tübingen, University Mainz, TRIUMF, PNNL, University Windsor, University New Brunswick)
The ToPLiS (Two-Photon Lithium Spectroscopy) collaboration has measured for the first time nuclear charge radii of short-lived isotopes
lighter than neon. A novel laser spectroscopic on-line technique was developed that combines Doppler-free two-photon spectroscopy and
resonance ionization mass spectrometry. With this technique it was possible to reach high efficiency and high accuracy at the same time.
This is necessary because only a few thousands atoms per second are produced of the exotic species Li-11 and the nuclear volume effect,
which carries the charge radius information, is only a tiny fraction of the measured quantity, the so-called isotope shift.
For more information, click
here.
BeTINa - A Paul Trap for the Investigation of the Charge radius of Be-11
(University Mainz, University Tübingen, University Ulm, ISOLDE, PNNL, University Windsor, University New Brunswick)
The BeTINa (Beryllium Trap for the Investigation of Nuclear charge radii) collaboration wants to measure the charge radius of the
one-neutron halo nucleus Be-11 by performing precision spectroscopy on laser-cooled ions in a radiofrequency (RF) Paul trap.
Radioactive beryllium ions will be produced at ISOLDE and then trapped in two-stage Paul-trap. One stage is used for capturing
and precooling, the second one for high precision spectroscopy. Learn more about this project below.
Click Here...
LaSpec
Laser Spectroscopy of radioactive beams from the Super-Fragment-Separator at FAIR's low energy beamline.
(University Mainz, Universiteit Leuven, University of Jyväskylä, Johannes Gutenberg Universität, LMU Munich, MPIK Heidelberg, EKU Tübingen, University of Manchester, CERN, LLNL, PNNL)
Laser spectroscopy of short-lived isotopes far from stability provides nuclear ground state properties like nuclear charge radii and
electromagnetic moments in a model-independent way. Halos are exotic nuclei that contain weakly bound nucleons (in most cases these are neutrons)
that can stroll far away from a compact nuclear core. The structure of these nuclei – even so they were discovered more than twenty years ago –
is still not sufficiently well understood. Precision laser spectroscopy on these isotopes can provide important information about nuclear charge radii,
but such experiments are challenging since halo-isotopes are short-lived with usual lifetimes in the milliseconds range and can only be produced in
minute quantities. Two collaborations, lead by the Helmholtz Young Investigators Group "LaserSpHERe" at the University of Mainz and GSI,
have accepted this challenge.
Laser cooling of stored ion beams with relativistic energies
(LMU Munic)
SpecTrap – Highly Charged Ions nearly at rest in a Penning trap
(Texas A&M, LLNL, Imperial College London, University of Mainz, TU Darmstadt)
SpecTrap is a cryogenic Penning trap setup designed to capture and store highly-charged ions extracted from an EBIS or from
any other external source. The cryogenic surrounding allows for efficient cooling of the ions during storage,
thus opening the possibility for precision experiments with ions nearly at rest. Its optical accessibility furthermore allows
laser cooling, laser excitation and optical observation, making it an ideal tool for precision spectroscopy of highly charged
ions. At GSI, RETrap will be used for precision laser spectroscopy experiments with highly-charged ions, which are delivered
by the HITRAP setup.
Fine Structure in lithium like ions
X-Ray laser spectroscopy
SHIPTRAP
The Actinides and beyond
Laser Spectroscopy of radioactive Isotopes
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Laser Spectroscopy of "man-made" elements
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