This novel type of Ionization Cooling is an effective method in order to enhance the (strong) interaction probability of slow (few MeV/ A) ions stored in a small ring. The many traversals through a thin target strongly improve the nuclear reaction rate with respect to a single-pass collision, in a steady configuration in which ionization losses of a target ''foil'' (typically few hundred mg/cm 2 thick) are continuously recovered by an RF-cavity. With a flat foil, betatron oscillations are ''cooled'', but the momentum spread diverges exponentially, since faster (slower) particles ionize less (more) than the average. In order to ''cool'' the beam also longitudinally, a chromaticity has to be introduced with a wedge-shaped ''foil''. Therefore, in equilibrium conditions, multiple scattering and straggling are both balanced by phase-space compression. p. 485] is designed to cool the direct beam until it has been compressed and extracted for further use. In practice, this limits its applicability to non-interacting muon beams. Instead, in this new method, applicable to strongly interacting collisions, the circulating beam is not extracted. Ionization cooling provides ''in situ'' storage of the beam until it is converted by a nuclear interaction with the target.Simple reactions-for instance 7 Li þ D ! 8 Li þ p-are more favourably produced in the ''mirror'' kinematical frame, namely with a heavier ion colliding against a gas-jet D 2 target. Kinematics is generally very favourable, with angles in a narrow angular cone (around $101 for the mentioned reaction) and with a relatively concentrated outgoing energy spectrum which allows an efficient collection of 8 Li as a neutral gas in a tiny volume, a technology perfected by ISOLDE at high temperatures.The method should be capable of producing a ''table top'' storage ring with an accumulation rate in excess of 10 14 8 Li radioactive ion/s. It has however a much more general applicability to many other nuclear reactions. r
Abstract. The neutron time-of-flight facility n TOF features a white neutron source produced by spallation through 20 GeV/c protons impinging on a lead target. The facility, aiming primarily at the measurement of neutron-induced reaction cross sections, was operating at CERN between 2001 and 2004, and then underwent a major upgrade in 2008. This paper presents in detail all the characteristics of the new neutron beam in the currently available configurations, which correspond to two different collimation systems and two choices of neutron moderator. The characteristics discussed include the intensity and energy dependence of the neutron flux, the spatial profile of the beam, the in-beam background components and the energy resolution/broadening. The discussion of these features is based on dedicated measurements and Monte Carlo simulations, and includes estimations of the systematic uncertainties of the mentioned quantities.
We propose to install a storage ring at an ISOL-type radioactive beam facility for the first time. Specifically, we intend to install the heavy-ion, low-energy ring TSR at the HIE-ISOLDE facility in CERN, Geneva. Such a facility will provide a capability for experiments with stored secondary beams that is unique in the world. The envisaged physics programme is rich and varied, spanning from investigations of nuclear groundstate properties and reaction studies of astrophysical relevance, to investigations with highly-charged ions and pure isomeric beams. The TSR can also be used to remove isobaric contaminants from stored ion beams and for systematic studies within the neutrino beam programme. In addition to experiments performed using beams recirculating within the ring, cooled beams can also be extracted and exploited by external spectrometers for high-precision measurements. The existing TSR, which is presently in operation at the Max-Planck Institute for Nuclear Physics in Heidelberg, is well-suited and can be employed for this purpose. The physics cases, technical details of the existing ring facility and of the beam requirements at HIE-ISOLDE, together with the cost, time and manpower estimates for the transfer, installation and commissioning of the TSR at ISOLDE are discussed in the present technical design report.
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