RT Journal Article
T1 MATS and LaSpec: High-precision experiments using ion traps and lasers at FAIR
A1 Rodríguez Rubiales, Daniel
A1 Blaum, K.
A1 Nörtershäuser, W.
A1 García Ramos, José Enrique
K1 Física nuclear
AB Nuclear ground state properties including mass, charge radii, spins and moments can bedetermined by applying atomic physics techniques such as Penning-trap based massspectrometry and laser spectroscopy. The MATS and LaSpec setups at the low-energybeamline at FAIR will allow us to extend the knowledge of these properties further into theregion far from stability.The mass and its inherent connection with the nuclear binding energy is a fundamentalproperty of a nuclide, a unique “fingerprint”. Thus, precise mass values are important for avariety of applications, ranging from nuclear-structure studies like the investigation of shellclosures and the onset of deformation, tests of nuclear mass models and mass formulas, totests of the weak interaction and of the Standard Model. The required relative accuracy rangesfrom 10-5 to below 10-8 for radionuclides, which most often have half-lives well below 1 s.Substantial progress in Penning trap mass spectrometry has made this method a prime choicefor precision measurements on rare isotopes. The technique has the potential to provide highaccuracy and sensitivity even for very short-lived nuclides. Furthermore, ion traps can be usedfor precision decay studies and offer advantages over existing methods.With MATS (Precision Measurements of very short-lived nuclei using an AdvancedTrapping System for highly-charged ions) at FAIR we aim to apply several techniques to veryshort-lived radionuclides: High-accuracy mass measurements, in-trap conversion electron andalpha spectroscopy, and trap-assisted spectroscopy. The experimental setup of MATS is aunique combination of an electron beam ion trap for charge breeding, ion traps for beampreparation, and a high precision Penning trap system for mass measurements and decaystudies.For the mass measurements, MATS offers both a high accuracy and a high sensitivity. Arelative mass uncertainty of 10-9 can be reached by employing highly-charged ions and a nondestructiveFourier-Transform Ion-Cyclotron-Resonance (FT-ICR) detection technique onsingle stored ions. This accuracy limit is important for fundamental interaction tests, but alsoallows for the study of the fine structure of the nuclear mass surface with unprecedentedaccuracy, whenever required. The use of the FT-ICR technique provides true single ionsensitivity. This is essential to access isotopes that are produced with minimum rates whichare very often are the most interesting ones. Instead of pushing for highest accuracy, the highcharge state of the ions can also be used to reduce the storage time of the ions, hence makingmeasurements on even shorter-lived isotopes possible.Decay studies in ion traps will become possible with MATS. Novel spectroscopic tools forin-trap high-resolution conversion-electron and charged-particle spectroscopy from carrierfreesources will be developed, aiming e.g. at the measurements of quadrupole moments andE0 strengths. With the possibility of both high-accuracy mass measurements of the shortestlivedisotopes and decay studies, the high sensitivity and accuracy potential of MATS isideally suited for the study of very exotic nuclides that will only be produced at the FAIRfacility.Laser spectroscopy of radioactive isotopes and isomers is an efficient and modelindependentapproach for the determination of nuclear ground and isomeric state properties.Hyperfine structures and isotope shifts in electronic transitions exhibit readily accessibleinformation on the nuclear spin, magnetic dipole and electric quadrupole moments as well asroot-mean-square charge radii. The dependencies of the hyperfine splitting and isotope shift on the nuclear moments and mean square nuclear charge radii are well known and thetheoretical framework for the extraction of nuclear parameters is well established. Theseextracted parameters provide fundamental information on the structure of nuclei at the limitsof stability. Vital information on both bulk and valence nuclear properties are derived and anexceptional sensitivity to changes in nuclear deformation is achieved. Laser spectroscopyprovides the only mechanism for such studies in exotic systems and uniquely facilitates thesestudies in a model-independent manner.The accuracy of laser-spectroscopic-determined nuclear properties is very high.Requirements concerning production rates are moderate; collinear spectroscopy has beenperformed with production rates as few as 100 ions per second and laser-desorption resonanceionization mass spectroscopy (combined with β-delayed neutron detection) has been achievedwith rates of only a few atoms per second.This Technical Design Report describes a number of complementary experimental devicesfor laser spectroscopy, which will provide a complete system with respect to the physics andisotopes that can be studied. Since MATS and LaSpec require high-quality low-energy beams,the two collaborations have a common beamline to stop the radioactive beam of in-flightproduced isotopes and prepare them in a suitable way for transfer to the MATS and LaSpecsetups, respectively.
PB Springer
SN 1951-6355
YR 2010
FD 2010-05
LK http://hdl.handle.net/10272/5524
UL http://hdl.handle.net/10272/5524
LA eng
NO Rodríguez Rubiales, D., Blaum, K., Nörtershäuser, W., García Ramos, J.E... [et al.]: "MATS and LaSpec: High-precision experiments using ion traps and lasers at FAIR". European Physical Journal - Special Topics. Vol. 183, n. 1, p. 1-123 (2010). ISSN 1951-6355
DS Repositorio Institucional de la Universidad de Huelva
RD 30 may 2026