[en] The author discusses parity nonconservation and the weak nuclear force, general experimental notes, realisable experimental possibilities, theory of optical rotation, experiments in optical rotation, circular dichroism, hydrogen-like ions, and hydrogen. In conclusion the latest work in the field is reviewed. ( H.J.P.)

[en] A small storage ring, ASTRID, for ions and electrons has been constructed in Aarhus. It is a dual-purpose machine, serving as a storage ring for either ions or electrons for synchrotron-radiation production. The ring has for more than one year been operational with ions and is presently being commissioned for electron storage. In the following both running modes will be described

[en] The energy loss of high-energy (βγ > approx. 1) particles traversing thin (< approx. 1 mm) targets is discussed both from a theoretical and experimental point of view. Energy losses are deduced from the measured number of electron-hole pairs created in semiconductor detectors (Si and Ge). Experimental energy-loss distributions are compared to calculations. For thick targets, the measured distributions agree with the Landau function. For thin targets, it is necessary to take the binding effects of the target electrons into account. The influence of channeling on the energy loss of high-energy particles is also briefly discussed. 38 refs.; 21 figs.; 3 tabs

[en] When charged particles pass through a crystal along a crystallographic direction, the coherent scattering on the lattice atoms forces the particles to follow the lattice direction. The transmission through an aligned crystal is very different from the passage through an amorphous foil, and drastically changes the interaction with the crystal atoms. This channeling effect has many applications at low energy within both fundamental and applied physics. Also when the crystal is bent, the particles will follow the crystallographic direction. In this way, a crystal can deflect a high-energy beam corresponding to a magnetic field around 1000 T, although with some losses. The lecture will be biased towards high energies (>1 GeV), and results from recent bending and extraction experiments at CERN will be presented. (orig.)

[en] After an introduction to the general concepts of cooling of charged particle beams, some specific cooling methods are discussed, namely stochastic, electron and laser cooling. The treatment concentrates on the physical ideas of the cooling methods and only very crude derivations of cooling times are given. At the end three other proposed cooling schemes are briefly discussed. (orig.)

[en] The design of a new type of storage ring for heavy ions using electrostatic deflection and focusing devices is described. At low energy, where the velocity is low for heavy ions, electrostatic bends and quadrupoles are more efficient than magnetic ones. Furthermore, electrostatic devices are more compact and easier to construct than magnetic devices. These and other features, e.g. no magnetic fields, makes such storage rings attractive for many atomic-physics experiments, and also for basic research in neighboring fields such as chemistry and biology. (orig.)

[en] Two years ago, a small electrostatic storage ring ELISA (electrostatic ion storage ring, Aarhus) was put into operation. The design of this small 7 m circumference ring was based on electrostatic deflection plates and quadrupoles. This is in contrast to the larger ion storage rings, which are based on magnetic focusing and deflection. The result is a small, relatively inexpensive, storage ring being able to store ions of any mass and any charge at low energy (< 22 keV). The average residual-gas pressure is around 10^-11 mbar resulting in storage times of several tens of seconds for singly charged ions. The maximum number of singly charged ions that can be stored is a few 10⁷. Several experiments have already been performed in ELISA. These include lifetime studies of metastable ions and studies of fullerenes and metal-cluster ions. Lasers are also used for excitation of the circulating ions. Heating/cooling of the ring is possible. Cooling of the ring leads to significantly lower pressures, and correspondingly longer lifetimes. A change of the temperature of the vacuum chambers surrounding the ion beam also leads to a change of the spectrum of the black-body radiation, which has a significant influence on weakly bound negative ions. At the time of writing, at least two other electrostatic storage rings are being built, and more are planned. In the following, the electrostatic storage ring ELISA will be described, and results from some of the initial experiments demonstrating the performance will be shown. The relative merits of such a ring, as opposed to the larger magnetic rings and the smaller ion traps will be discussed. The potential for highly charged ions will be briefly mentioned. (orig.)

[en] A report of recent results on electron cooling of D^- at an energy of 1.6 MeV in the ASTRID storage ring is given. The longitudinal velocity spread has been reduced from ∼4x10^-4 (FWHM) to ∼7x10^-5 (FWHM) at a current of ∼0.1 μA. A drift in the mean velocity of the cooled beam has been reduced by application of a small RF signal on four sets of plates in the cooler. Initially, the velocity spread is found to decrease with ion current, indicating equilibrium between cooling and intra-beam scattering, whereas at later times (lower current) the velocity spread becomes constant, indicating equilibrium with the electron beam. To diagnose cooling, a simple system allowing to follow the frequency width and position of a Schottky harmonic on a sub-second time-scale, has been developed. The system uses a standard data acquisition card to digitize a down-mixed Schottky-signal and a FFT routine in Labview on a standard PC. The electron-cooled ion-beam is used for high-resolution vacuum ultra-violent spectroscopy of H^- and D^- in the region near the H(n=2) threshold. The velocity spread of the ion beam can be directly extracted from these experiments

[en] Negative heavy ions can be stored for several seconds in the Aarhus STorage RIng Denmark (ASTRID), allowing long-time observation of particles. A direct application of the long storage times is the measurements of ∼ 10 μs - 100 ms autodetachment lifetimes of ions which are almost inaccessible via traditional beam techniques. The measurement of structural or dynamic properties of weakly bound negative-ion systems provides an excellent test of calculations on many-body systems in atomic physics. Experiments with ⁴He^- lifetimes have been conducted with the ASTRID storage ring, experimental technique established. Magnetic field-induced effects in the ring and influence of blackbody radiation were studied. The lifetime studies will be further developed to allow studies of highly excited negative ions such as Li^-(1s2s2p²⁵P) and of molecular ions, in particular of He₂. The storage ring can also be utilized to study auto-ionizing, positively charged atomic or molecular ions or long-lived ions decaying by photon emission. A few experiments utilizing these possibilities are being planned. (EG) (12 refs.)

[en] One of the experiments to be performed under the ASACUSA collaboration at the CERN Antiproton Decelerator is a measurement of the energy loss of low energy antiprotons in thin foils. An electrostatic spectrometer has been developed for this task. We describe the design and initial tests of the apparatus with protons. By changing a high-voltage applied on the target the energy of the projectile ions at impact on the target can easily be varied. In this way we have measured the stopping-power and the energy-loss straggling for protons over a wide energy range to below one keV