Vol. 21 No. 1 - NuPECC

laboratory portrait
Figure 8. Barrier bucket cavity installed in the COSY ring (left) and octagonal
slot-coupler for stochastic beam cooling in HESR (right).
monitor based on measuring elastic
scattering in the Coulomb-strong
interaction interference region. This
system is based on tracking the antiprotons
scattered near the beam axis
with multiple layers of silicon strip
detectors.
Search for an Electric Dipole
Moment (EDM) of Protons and
Deuterons
Searches for EDM are a forefront
research issue, because finding a nonzero
EDM would be a major discovery
pointing to physics beyond the
Standard Model of elementary particle
physics. Impressive upper limits
(neutron equivalent in the order of
10 −26 e·cm) have been obtained in
recent years. These are further pushed
by upgrading existing experiments on
electrons and muons, heavy atoms and
molecules, and in particular also the
neutron, and by designing new ones.
The IKP is planning to search for
EDM in a storage ring with a statistical
sensitivity of few 10 −29 e·cm per
year, pushing the limits even further
and with the potential of an actual particle-EDM
discovery. For such studies
a completely new approach has
recently been proposed for protons,
deuterons and possibly also 3 He,
which will rely on the time development
of a horizontal spin component
of these particles in a new class of
storage rings. In the course of this, it
has become obvious, that COSY—
with its polarized beams, including the
new hardware (like a low-β section
and a Siberian snake) and the target
and detector systems—is very close to
being a test-bench for polarimetry,
spin coherence time investigations,
and so on.
An R&D program at the COSY
storage ring within an international
collaboration (EDM@COSY) already
proved the required sensitive and efficiency
of deuteron polarimetry. All of
the information gleaned during these
studies will be incorporated into a
design for a prototype polarimeter
that will be tested on the COSY ring.
The next step will be the investigation
and optimization of spin coherence
time in COSY. The natural spin
coherence time of horizontal polarization
needs to be determined and
extended by bunching the beam and
improvements to the ring lattice by
means of high-order field corrections.
Intense R&D work has also to be
performed before the design of the
final EDM ring can be started. Main
objectives are the development of
high-sensitivity beam positioning
monitors and combined electrostatic/
magnetic field deflectors with cuttingedge
field quality. The coil and conductor
plate configuration has to be
optimized with respect to field quality
and stability and a prototype deflector
to be build and tested to ensure its
performance.
Laser-Particle Acceleration
The physics of laser-plasma interactions
has undergone dramatic
improvements in recent years. By
directing a multi-TW, ultra-short laser
pulse onto a thin foil or a gas, it is
now possible to produce high-energy
proton, ion, and electron beams. It is
a yet untouched issue whether the
laser-generated beams are or can be
spin-polarized and, thus, whether
laser-based polarized sources are
conceivable. One may either think of
a spatial separation of certain spin
states by the huge magnetic field gradients
that are inherently generated
in the laser-generated plasmas, or of
pre-polarized target particles that
Figure 9. Prototypes of straw detectors
for the PANDA experiment.
12 Nuclear Physics News, Vol. 21, No. 1, 2011