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4.3.7 Ground-State Properties
Figure 8. Angular correlation of protons measured in (p,2p)
reactions in inverse kinamatics at GSI with the proton-rich halo
nucleus 17 Ne. The strong kinematical correlation characteristic
for the quasi-free nucleon-knockout reaction is clearly visible.
((p,2p),(p,pn)) in inverse kinematics at high energies
(Figure 8) which are less surface dominated. In addition,
this technique enables the reaction kinematics to
be over-determined by measuring in addition to the two
nucleons the excitation energy and momentum of the
heavy residue, thus selecting the one-step direct reactions
by controlling and understanding the final-state
interaction. Therefore, the planned systematic study of
single-particle occupancies in N/Z asymmetric nuclei is
expected to shed light on short- and long-range nucleonnucleon
correlations in nuclei. Further aspects that will
be investigated are the population of unbound nuclear
systems beyond the neutron dripline as well as cluster
structures in exotic nuclei which will be studied through
measurements of alpha knockout cross-sections. An
attractive extension of this programme are future measurements
with polarized proton targets and high-energy
radioactive beams. This programme will be fully exploited
at the FAIR-R 3 B facility where dedicated neutron and
proton detection systems are foreseen for quasi-freescattering
experiments.
New discoveries in the field of nuclear reaction dynamics
at low and intermediate energies will also be delivered
from studies to be carried out with the next-generation
ISOL facilities and finally with the EURISOL facility.
Charge and matter radii,
nuclear moments and spins
Charge radii for an isotopic chain provide information
on the distribution of protons inside the nucleus and
how this distribution is modifi ed by adding or removing
neutrons. Therefore, this is a very sensitive probe
to study the proton-neutron interaction as well as the
evolution of collective behaviour along an isotopic chain.
Comparison of charge and matter radii provides a direct
tool for studying the onset of halos and skins.
Nuclear magnetic and quadrupole moments, together
with the nuclear spin of a state, largely determine its
nuclear structure. These observables are sensitive to both
single-particle and collective behaviour in atomic nuclei
and therefore constitute very stringent probes for testing
nuclear models at the extremes of spin and isospin.
The future with laser spectroscopy
methods at ISOL facilities
Laser spectroscopy methods allow measurement of the
nuclear charge radius, spin, magnetic dipole moment
and the electric quadrupole moment if a sufficiently high
resolution can be achieved. Several developments to
enhance the sensitivity of the present laser techniques
and to extend their applicability to a wider range of elements
are ongoing. The collinear resonance ionization
spectroscopy method, presently under development at
ISOLDE, will allow measurements at high resolution and
sensitivity (down to 10/s) extending present studies to
more exotic regions. Very exotic species will be in reach
with the expected increase in intensity at HIE-ISOLDE or
DESIR at SPIRAL2. In the latter facility, in combination
with beams from S3, very exotic refractory elements will
be available for the first time. To apply collinear laser
spectroscopy to a wide range of elements, the ongoing
developments at JYFL for laser pumping in an RFQ
cooler/buncher are very promising.
A complementary tool is the in-source laser spectroscopy
method, which is highly sensitive (< 1/s) and ideal
for intermediate and heavy element studies, as shown
at ISOLDE. Recently, this method was also applied on
ions stopped in a gas-cell at LISOL (CRC, Louvain la
Neuve). This is an extremely promising tool for laser
spectroscopy studies at the focal point of a wide range
spectrometer such as S3, allowing studies along the N=Z
line, on refractory elements and very heavy elements.
High-precision laser spectroscopy studies for atomic
and nuclear physics research or studies using laserpolarized
beams for solid-state and life sciences all
Perspectives of Nuclear Physics in Europe – NuPECC Long Range Plan 2010 | 121