J. Dietrich

ANKE, a new facility for medium energy hadron physics at COSY-Jülich

Abstract ANKE is a new experimental facility for the spectroscopy of products from proton-induced reactions on internal targets. It has recently been implemented in the accelerator ring of the cooler synchrotron COSY of the Forschungszentrum Julich (FZ-Julich), Germany. The device consists of three dipole magnets, various target installations and dedicated detection systems. It will enable a variety of hadron-physics experiments like meson production in elementary proton–nucleon processes and studies of medium modifications in proton–nucleus interactions.

COSY- 11, an internal experimental facility for threshold measurements

Abstract The COSY-11 installation is an internal experiment at the cooler synchrotron and storage ring COSY Julich. It has been designed for full geometrical acceptance close to threshold for meson production studies, especially in the 1 GeV/ c 2 mass range. The experimental setup makes use of a regular C-type COSY dipole magnet, following a cluster target, to separate reaction products from the beam and to analyze their momenta, thus allowing the observation of charged reaction products at small angles with beam energies close to threshold. Resonances will be identified by missing mass reconstructions from measured four-momenta of two outgoing protons in the predominantly studied pp → ppX reaction. In addition, charged mesons either produced directly or from decays of X will be detected. The different components of the experimental facility are presented.

Electron and stochastic cooling at COSY

The synchrotron and storage ring COSY delivers proton beams with momenta between 300 and 3500 MeV/c for internal and external experiments. It is operating both with electron and stochastic cooling. The electron cooling is used mainly at the injection energy with 22 keV electrons to increase the intensity of the polarised proton beam with a combined cooling stacking injection. In addition, the electron-cooled proton beam is used for diagnostic purposes of machine parameters. The stochastic cooling for COSY is working in the proton momentum range between 1.5 and 3.5 GeV/c and is up to now only used for equilibrium experiments with thin internal targets and long #at top times. The longitudinal stochastic cooling system is extended by a fast frequency variable optical notchlter to make use of a supercycle in COSY with from cycle to cycle varying #at top energies. The results of the electron cooling and stacking injection as well as the good results of the optical notchlter for the stochastic cooling will be presented. ( 2000 Elsevier Science B.V. All rights reserved.

COSY-SCL, the superconducting injector linac for COSY

The superconducting injector linac COSY-SCL is being designed and constructed at the Forschungszentrum Juelich. The train goal of the new injector is to fill the cooler synchrotron COSY with polarized protons as well as with polarized deuterons up to the space-charge limit at injection energy. COSY-SCL is characterized by a base frequency of 160 MHz, 25 kV ion-source extraction voltage, a pulse length of up to 500 /spl mu/s, a maximum repetition rate of 2 Hz, injection into the linac at /spl beta/=0.073 and injection into COSY at kinetic energies of 52 MeV for protons and 56 MeV for deuterons, respectively. The injector configuration is presented, and its main subsystems-ion source (CIPIOS from IUCF for polarized H/sup -/ and D/sup -/), RFQ (built in co-operation with the University of Frankfurt), linac (based on half-wave resonators operating at 160 and 320 MHz)- are described and discussed. The present status of the project is reported.

Acceleration of Polarized Protons and Deuterons at COSY

At the cooler synchrotron COSY, protons and deuterons are accelerated up to 3.65 GeV/c. Vertically polarized proton beams with more than 70% polarization have been delivered in recent years to internal as well as to external experiment areas at different momenta up to the maximum momentum of COSY. In a strong‐focusing synchrotron like COSY, imperfection and intrinsic resonances cause polarization losses during acceleration. The existing magnet system of COSY allows to overcome all imperfection resonances by exciting adiabatic spin flips without polarization losses. A tune‐jump system consisting of two fast quadrupoles has been developed to handle intrinsic resonances in COSY. This magnet system is being successfully utilized at all intrinsic resonances in the momentum range of COSY. For the acceleration of vertically polarized deuterons, additional correction provisions are not necessary to preserve polarization during acceleration because depolarizing resonances are not crossed in the momentum range of C...

The cooler synchrotron COSY in Jülich

Abstract COSY Julich is a cooler synchrotron and storage ring with a proton momentum range from 270 to 3300 MeV/c. It has been conceived to deliver high precision beams for medium energy physics. To accomplish this goal two cooling systems are foreseen: an electron cooling system for the momentum range up to 645 MeV/c and a stochastic cooling system which covers the upper momentum range from 1500 to 3300 MeV/c. Proton beams in a wide momentum range have been delivered to internal as well as external experiments. The beam properties measured by these experiments and the main parameters of COSY are presented.

First internal and external experiments at COSY Juelich

Abstract The inauguration of the cooler synchrotron COSY Julich was celebrated on April 1st, 1993. After the first successful acceleration to proton momenta above 800 GeV/ c , beamtimes for experiments were scheduled in parallel to further machine development. The first experiment was the internal target experiment EDDA, which investigated the energy dependence of the p-p interaction. It makes use of a 3 × 4 μ m 2 thin CH 2 fiber as an internal target. The thickness of the fiber is more than adequate to achieve high luminosities, so the intensity of the stored beam has to be reduced to 10 7 p. On the other hand, it is thin enough to achieve beam lifetimes of 3 s at 1.4 GeV/ c . Details of the target fabrication and the first experimental results will be discussed. Both external experimental facilities at COSY, the time-of-flight spectrometer, and the magnetic spectrometer BIG KARL use a liquid hydrogen (deuterium) target. The first experiments were carried out at proton energies between 300 MeV and 500 MeV. Also, these experimental data will be presented. Two further internal experiments are prepared for the installation into the COSY ring. The target for the first experiment is a gas-jet target, the second experiment uses ribbon targets for the interaction. The status of both experimental setups will be shown.

Overcoming Depolarizing Resonances at COSY

At the cooler synchrotron COSY, polarized protons and deuterons are accelerated up to 3.65 GeV/c. In a strong‐focusing synchrotron like COSY, imperfection and intrinsic resonances cause polarization losses during acceleration. During the acceleration of polarized protons, five imperfection resonances are crossed. The existing magnet system of COSY allows to overcome all imperfection resonances by exciting adiabatic spin flips without polarization losses. The number of intrinsic resonances depends on the superperiodicity of the lattice. A tune‐jump system consisting of two fast quadrupoles has been developed to handle intrinsic resonances in COSY. Vertically polarized proton beams with more than 75% polarization have been delivered in recent years to internal as well as to external experiment areas at different momenta up to the maximum momentum of COSY. For the acceleration of polarized deuterons, additional correction provisions are not necessary to preserve polarization during acceleration. In this pape...

Status of the cooler synchrotron Cosy-Juelich

The cooler synchrotron COSY delivers unpolarized and polarized protons and deuterons in the momentum range 300 MeV/c up to 3.65 GeV/c. Electron cooling at injection level and stochastic cooling covering the range from 1.5 GeV/c up to maximum momentum are available to prepare high precision beams for internal as well as external experiments in hadron physics. The beam is fed to external experiments by a fast kicker extraction or by stochastic extraction. Results of extracted electron cooled beams and developments to increase the number of stored particles and to increase the degree of polarization during acceleration are reported

Acceleration of the polarized proton beam in the Cooler Synchrotron COSY

A concept has been developed and realized to accelerate vertically polarized protons in the Cooler Synchrotron COSY at the Forschungszentrum Julich up to the maximum momentum of 3300 MeV/c. In addition, different Siberian snake schemes for COSY have been investigated to deliver a longitudinally polarized beam.