13 research outputs found
Scientific program of the Super-FRS collaboration : report of the collaboration to the FAIR management
Spectroscopy of -nucleus bound states at GSI and FAIR --- very preliminary results and future prospects ---
The possible existence of \eta'-nucleus bound states has been put forward
through theoretical and experimental studies. It is strongly related to the
\eta' mass at finite density, which is expected to be reduced because of the
interplay between the anomaly and partial restoration of chiral
symmetry. The investigation of the C(p,d) reaction at GSI and FAIR, as well as
an overview of the experimental program at GSI and future plans at FAIR are
discussed.Comment: 7 pages, 3 figures; talk at the International Conference on Exotic
Atoms and Related Topics (EXA2014), Vienna, Austria, 15-19 September 2014. in
Hyperfine Interactions (2015
Experimental program of the Super-FRS Collaboration at FAIR and developments of related instrumentation
The physics program at the super-conducting fragment separator (Super-FRS) at FAIR, being operated in a multiple-stage, high-resolution spectrometer mode, is discussed. The Super-FRS will produce, separate and transport radioactive beams at high energies up to 1.5 AGeV, and it can be also used as a stand-alone experimental device together with ancillary detectors. Various combinations of the magnetic sections of the Super-FRS can be operated in dispersive, achromatic or dispersion-matched spectrometer ion-optical modes, which allow measurements of momentum distributions of secondary-reaction products with high resolution and precision. A number of unique experiments in atomic, nuclear and hadron physics are suggested with the Super-FRS as a stand-alone device, in particular searches for new isotopes, studies of hyper-nuclei, delta-resonances in exotic nuclei and spectroscopy of atoms characterized by bound mesons. Rare decay modes like multiple-proton or neutron emission and the nuclear tensor force observed in high momentum regime can be also addressed. The in-flight radioactivity measurements as well as fusion, transfer and deep-inelastic reaction mechanisms with the slowed-down and energy-bunched fragment beams are proposed for the high-resolution and energy buncher modes at the Super-FRS. (C) 2016 Elsevier B.V. All rights reserved.Peer reviewe
The science case of the FRS Ion Catcher for FAIR Phase-0
The FRS Ion Catcher at GSI enables precision experiments with thermalized projectile and fission fragments. At the same time it serves as a test facility for the Low-Energy Branch of the Super-FRS at FAIR. The FRS Ion Catcher has been commissioned and its performance has been characterized in five experiments with 238U and 124Xe projectile and fission fragments produced at energies in the range from 300 to 1000 MeV/u. High and almost element-independent efficiencies for the thermalization of short-lived nuclides produced at relativistic energies have been obtained. High-accuracy mass measurements of more than 30 projectile and fission fragments have been performed with a multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) at mass resolving powers of up to 410,000, with production cross sections down to the microbarn-level, and at rates down to a few ions per hour. The versatility of the MR-TOF-MS for isomer research has been demonstrated by the measurement of various isomers, determination of excitation energies and the production of a pure isomeric beam. Recently, several instrumental upgrades have been implemented at the FRS Ion Catcher. New experiments will be carried out during FAIR Phase-0 at GSI, including direct mass measurements of neutron-deficient nuclides below 100Sn and neutron-rich nuclides below 208Pb, measurement of β-delayed neutron emission probabilities and reaction studies with multi-nucleon transfer.Peer reviewe
Radioactive Beams for Image-Guided Particle Therapy : The BARB Experiment at GSI
Several techniques are under development for image-guidance in particle therapy. Positron (beta(+)) emission tomography (PET) is in use since many years, because accelerated ions generate positron-emitting isotopes by nuclear fragmentation in the human body. In heavy ion therapy, a major part of the PET signals is produced by beta(+)-emitters generated via projectile fragmentation. A much higher intensity for the PET signal can be obtained using beta(+)-radioactive beams directly for treatment. This idea has always been hampered by the low intensity of the secondary beams, produced by fragmentation of the primary, stable beams. With the intensity upgrade of the SIS-18 synchrotron and the isotopic separation with the fragment separator FRS in the FAIR-phase-0 in Darmstadt, it is now possible to reach radioactive ion beams with sufficient intensity to treat a tumor in small animals. This was the motivation of the BARB (Biomedical Applications of Radioactive ion Beams) experiment that is ongoing at GSI in Darmstadt. This paper will present the plans and instruments developed by the BARB collaboration for testing the use of radioactive beams in cancer therapy.Peer reviewe
A novel method for the measurement of half-lives and decay branching ratios of exotic nuclei
A novel method for simultaneous measurement of masses, Q-values, isomer excitation energies, half-lives and decay branching ratios of exotic nuclei has been demonstrated. The method includes first use of a stopping cell as an ion trap, combining storage of mother and daughter nuclides for variable durations in a cryogenic stopping cell (CSC), and afterwards the identification and counting of them by a multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS). We utilized our method to record the decay and growth of the 216Po and 212Pb isotopes (alpha decay) and of the 119m2Sb isomer ( t1/2=850Âą90 ms) and 119gSb isotope (isomer transition), obtaining half-lives consistent with literature values. The amount of non-nuclear-decay losses in the CSC up to âź10 s is negligible, which exhibits its extraordinary cleanliness. For 119Sb isotopes, we present the first direct measurements of the mass of its ground state, and the excitation energy and decay branching ratios of its second isomeric state (119m2Sb). This resolves discrepancies in previous excitation energy data, and is the first direct evidence that the 119m2Sb isomer decays dominantly via Îł emission. These results pave the way for the measurement of branching ratios of exotic nuclei.peerReviewe
Isobaric charge-exchange reactions: a tool to study the excitation of baryonic resonances in exotic nuclear matter
Excitation of baryonic resonances in stable medium-mass nuclei of Sn
Isobaric charge-exchange reactions induced by beams of 112Sn have been
investigated at the GSI facilities using the fragment separator FRS. The
high-resolving power of this spectrometer makes it possible to obtain the
isobaric charge-exchange cross sections with an accuracy of 3% and to separate
quasi-elastic and inelastic contributions in the missing-energy spectra, in
which the inelastic component is associated to the in-medium excitation of
baryonic resonances such as the resonance. We report on the results
obtained for the (p,n) and (n,p) channels excited by using different targets
that cover a large range in neutron excess.Comment: arXiv admin note: text overlap with arXiv:2004.0640
Missing-mass spectroscopy of the C(p ,d ) reaction near the ΡⲠ-meson production threshold
Excitation-energy spectra of C nuclei near the -meson
production threshold have been measured by missing-mass spectroscopy using the
C(,) reaction. A carbon target has been irradiated with a 2.5 GeV
proton beam supplied by the synchrotron SIS-18 at GSI to produce
meson bound states in C nuclei. Deuterons emitted at in the
reaction have been momentum-analyzed by the fragment separator (FRS) used as a
high-resolution spectrometer. No distinct structure due to the formation of
-mesic states is observed although a high statistical sensitivity
is achieved in the experimental spectra. Upper limits on the formation cross
sections of -mesic states are determined, and thereby a constraint
imposed on the -nucleus interaction is discussed.Comment: 13 pages, 14 figures, accepted for publication in Physical Review