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Status of the Stochastic Cooling Investigations for HESR. H. Stockhorst Forschungszentrum Jülich GmbH. EU Design Study Committee Meeting at the GSI January 19, 2006. What was done so far What has to be done. in Theory and Hardware. Stochastic Cooling Simulations.
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Status of the Stochastic Cooling Investigations for HESR H. StockhorstForschungszentrum Jülich GmbH EU Design Study Committee Meeting at the GSI January 19, 2006 What was done so far What has to be done in Theory and Hardware
Stochastic Cooling Simulations • In 2005 the initial beam parameters in the HESR and the desired beam parameters necessary in the experiments were fixed (HL- and HR-Mode). • Analytical and numerical cooling simulations with an enhanced model for longitudinal filter cooling(Fokker-Planck equation) which include - beam-target interaction: o growth of rms o mean energy loss - intra beam scattering H. Stockhorst
Cooling Concepts for the HESR • High Resolution Mode (HR)Luminosity L = 2 1031 cm-2 s-1 Number of Anti-Protons N = 1010 Target Area Density NT = 4 1015 atoms/cm2 - momentumrange: 1.5 GeV/c up to 9 GeV/c - desired relative rms-momentum spread: 1 x 10-5 • High Luminosity Mode (HL)Luminosity L = 2 1032 cm-2 s-1 Number of Anti-Protons N = 1011 Target Area Density NT = 4 1015 atoms/cm2 - momentumrange: 1.5 GeV/c up to 15 GeV/c - desired relative rms-momentum spread: 1 x 10-4 - compensate target-beam heating H. Stockhorst
Longitudinal Cooling Summary (2 – 4) GHz system equilibrium rel. momentum spread cooling down time if mean energy loss in the target is compensated: analytical formula for equilibrium rel. momentum spread H. Stockhorst
Stochastic Cooling Performance • For all energies above T = 3 GeV almost the same equilibrium relative momentum spread values are attained. • Target heating can be compensated in HL-Mode. • In the HR-Mode a relative momentum spread 4 10-5 can be achieved within 200 s. • As compared to electron cooling: IBS plays (almost) no roleif the beam is only longitudinally cooled. • Below T = 8 GeV transverse cooling is needed and can be achieved with the (2 – 4) GHz system. • Beam size at the target can be adjusted for optimum overlap. H. Stockhorst
Numerical Solution of the Fokker-Planck Equationfor Filter Cooling • To include mean energy loss due to the target (if not compensated). H. Stockhorst
Numerical Solution of the Fokker-Planck Equation HR-Mode at p = 4 GeV/c: Normalized beam distributions:t = 0 s (black), t = 10 s (brown), t = 30 s (orange), t = 50 s (green) and t = 200 s (blue). The red line is proportional to the drift term. The black curve includes mixing from PU to KI. H. Stockhorst
Numerical Solution of the Fokker-Planck Equation HR-Mode at p = 4 GeV/c: In equilibrium:energy deviatian – 0.4 MeV In equilibrium:relative rms-momentum spread:5 x 10-5 mean energy loss compensated: 4 x 10-5 Mean energy loss compensated H. Stockhorst
Summary including mean energy loss in the target: • HR-Mode:rms 5 x 10-5 for T > 3 GeV • HL-Mode:rms 2 x 10-4 for T > 3 GeV • Final beam distribution fits into the acceptance limit. • Transverse cooling should be applied to limit emittance increase (losses in PU and KI). H. Stockhorst
What will be done in theory? In collaboration with T. Katayama: • Include mixing from pickup to kicker in the model. • In February 2006 start of stochastic cooling experiments at COSY with - internal target to test the cooling model. - barrier bucket RF system. H. Stockhorst
Hardware Developments (2 – 4) GHz: • First ideas for printed loop couplers with high sensitivity for (2 – 4) GHz • Combined structures surround the beam toenhance the sensitivitywith low impedance • No moveable plates Preliminary H. Stockhorst
cm Low noise amplifier MITEQ • Tests of commercial low noise amplifiers (MITEQ)- gain 43 dB- noise figure < 0.4 dB- group delay measurements < 25 ps- phase response < 20 • Test of material for coupling structures, TMM3 temperature stable microwave laminate - vacuum test - cooling test (liquid Nitrogen LN) H. Stockhorst
What will be done in hardware? • Cooperation with L. Thorndahl (CERN) • Development of printed loop couplers with high sensitivity for (2 – 4) GHz H. Stockhorst
Thank You for Your Attention H. Stockhorst