• R. Stassen, F.J. Etzkorn, R. Maier, D. Prasuhn, H. Stockhorst
  FZJ, Jülich
• L. Thorndahl
  CERN, Geneva

The COoler SYnchrotron COSY at the Forschungszentrum Jülich is operating now since 1992. Up to 5*10¹⁰ protons can be delivered over a momentum range of 600 MeV/c to 3.6 GeV/c. The prototype of the HESR barrier bucket cavity was installed into COSY and many measurements have been performed. Especially the co-operation of barrier bucket with stochastic cooling has been studied. During the measurements the internal WASA Pellet target was available which is similar to the PANDA target at the HESR. A 1.2m long cryo-tank has been designed and installed to measure the sensitivities of new pickup structures for the HESR stochastic cooling system. Tank design and structures arrangement correspond to the projected HESR stochastic cooling layout. The recent results will be presented.

• E.N. Zaplatin, R. Maier, M. Pap, R. Stassen, R. Tölle
  FZJ, Jülich
• W. Behr, H. Glueckler, W. Guenther, J. Wolters
  Forschungszentrum Jülich GmbH, Institut fur Nuklearchemie (INC), Jülich

The paper describes the design, fabrication and first test results of the triple-spoke cavity (resonant frequency 352 MHz, beta=0.48) developed at Forschungszentrum Jülich in the frame of High Intensity Pulsed Proton Injector project. The cavity has 5 cm diameter beam aperture, a transverse radius of 21.7 cm and the whole length of 78 cm. An initial wall thickness of niobium sheets used for cavity fabrication was around 4 mm. The RF cavity design has been adapted to two main goals - the simplest technology of cavity manufacture and for the prime goal of the project to achieve the best possible structural parameters (Lorenz force frequency shift and a resonant frequency pressure dependence). Intense cavity structural analyses have been conducted and the further prospectives on cavity developments are also presented. Construction of the niobium cavity prototype has been completed, the cavity has been chemically processed. Results of initial cold test are discussed.

• H. Stockhorst, R. Maier, D. Prasuhn, R. Stassen
  FZJ, Jülich
• T. Katayama
  CNS, Saitama
• L. Thorndahl
  CERN, Geneva

The High Energy Storage Ring (HESR) of the future International Facility for Antiproton and Ion Research (FAIR) at the GSI in Darmstadt will be built as an anti-proton cooler ring in the momentum range from 1.5 to 15 GeV/c. An important and challenging feature of the new facility is the combination of phase space cooled beams with internal targets. In addition to electron cooling transverse and longitudinal stochastic cooling are envisaged to accomplish these goals. A detailed numerical analysis of the Fokker-Planck equation for longitudinal filter and time-of-flight cooling including an internal target and intrabeam scattering has been carried out to demonstrate the stochastic cooling capability. Model predictions have been compared to experimental cooling results with internal targets at the COSY facility. Experimental results at COSY to compensate the large mean energy loss induced by an internal Pellet target similar to that being used by the PANDA experiment at the HESR with a barrier bucket cavity (BB) will be presented. Experimental tests of stochastic filter cooling with internal target and BB operation as well as expected cooling properties for the HESR are discussed.