11 Application of Accelerators and Storage Rings
755
11.5 Heavy Ion Accelerators for Nuclear Physics
N. Angert · O. Boine-Frankenheim
11.5.1 Accelerator Facilities for Heavy Ion Nuclear Physics:
Background and Aims
Nuclear spectroscopy, reaction studies, and nuclear astrophysics using beams of
accelerated heavy ions have been research fields in nuclear physics since the middle
of last century. An especially interesting topic is the search for new super-heavy
elements (SHE) using fusion reactions between medium-mass ions, with energies
of 4–5 MeV/u (around the Coulomb barrier), and very heavy target nuclei. Such
studies have been conducted for many years now at LBL, Berkeley; GSI, Darmstadt;
JINR, Dubna; RIKEN, Saitama, and other laboratories [148]. Using the cold fusion
technique to produce super-heavy compound nuclei, the element chart has been
expanded up to element Z = 118 in recent years using actinide target nuclei
[149]. Today, a growing research community is conducting experiments in nuclear
spectroscopy, mass and life time measurements as well as in the nuclear chemistry
of super-heavy elements [150].
Since the mid-1980s the availability of medium-energy ion beams up to
100 MeV/u in a new generation of normal conducting sector cyclotron [151]
and superconducting cyclotron facilities [152] has provided access to radioactive
isotopes in unexplored regions of the nuclear chart, far from stable isotopes.
Fragmentation and fission of heavy projectile nuclei in thin light element targets
were used to produce fast exotic nuclei using the in-flight method. Light exotic
nuclei produced in this way such as 11 Li have exhibited the new phenomenon
of neutron halos [153, 154]. In other exotic nuclei produced using this method,
changes have been detected in the neutron shell structure for large N/Z-ratios
shedding new light on nucleon-nucleon interaction. Precision studies of masses, life
times, and new decay channels have revealed interesting phenomena, extended the
understanding of nuclear forces, and raised new questions. In addition, experiments
with unstable nuclei have contributed to a better understanding of an increasing
number of observations in astronomy.
A new era in nuclear astrophysics has opened up with the rare-ion beam facilities
dedicated to the measurement of nuclear reactions involving post-accelerated shortlived nuclides of particular relevance to astrophysics. Whereas at large facilities
such as RHIC and LHC the aim is to simulate the early state of the universe
in the laboratory, exotic beam facilities will increase our understanding of the
development of stars and the creation of heavy elements. It is estimated that more
than 8000 isotopes may remain bound, with only about a third of them having
already been identified. Nuclear behaviour is expected to change significantly in the
yet unexplored regions. Figure 11.37 shows, as an example, the landmark results
755
11.5 Heavy Ion Accelerators for Nuclear Physics
N. Angert · O. Boine-Frankenheim
11.5.1 Accelerator Facilities for Heavy Ion Nuclear Physics:
Background and Aims
Nuclear spectroscopy, reaction studies, and nuclear astrophysics using beams of
accelerated heavy ions have been research fields in nuclear physics since the middle
of last century. An especially interesting topic is the search for new super-heavy
elements (SHE) using fusion reactions between medium-mass ions, with energies
of 4–5 MeV/u (around the Coulomb barrier), and very heavy target nuclei. Such
studies have been conducted for many years now at LBL, Berkeley; GSI, Darmstadt;
JINR, Dubna; RIKEN, Saitama, and other laboratories [148]. Using the cold fusion
technique to produce super-heavy compound nuclei, the element chart has been
expanded up to element Z = 118 in recent years using actinide target nuclei
[149]. Today, a growing research community is conducting experiments in nuclear
spectroscopy, mass and life time measurements as well as in the nuclear chemistry
of super-heavy elements [150].
Since the mid-1980s the availability of medium-energy ion beams up to
100 MeV/u in a new generation of normal conducting sector cyclotron [151]
and superconducting cyclotron facilities [152] has provided access to radioactive
isotopes in unexplored regions of the nuclear chart, far from stable isotopes.
Fragmentation and fission of heavy projectile nuclei in thin light element targets
were used to produce fast exotic nuclei using the in-flight method. Light exotic
nuclei produced in this way such as 11 Li have exhibited the new phenomenon
of neutron halos [153, 154]. In other exotic nuclei produced using this method,
changes have been detected in the neutron shell structure for large N/Z-ratios
shedding new light on nucleon-nucleon interaction. Precision studies of masses, life
times, and new decay channels have revealed interesting phenomena, extended the
understanding of nuclear forces, and raised new questions. In addition, experiments
with unstable nuclei have contributed to a better understanding of an increasing
number of observations in astronomy.
A new era in nuclear astrophysics has opened up with the rare-ion beam facilities
dedicated to the measurement of nuclear reactions involving post-accelerated shortlived nuclides of particular relevance to astrophysics. Whereas at large facilities
such as RHIC and LHC the aim is to simulate the early state of the universe
in the laboratory, exotic beam facilities will increase our understanding of the
development of stars and the creation of heavy elements. It is estimated that more
than 8000 isotopes may remain bound, with only about a third of them having
already been identified. Nuclear behaviour is expected to change significantly in the
yet unexplored regions. Figure 11.37 shows, as an example, the landmark results