Forschungszentrum Jülich In der Helmholtz-Gemeinschaft Rolf Stassen IKP/ COSY Darmstadt 1 Status report HESR 1: RF Cavity

Forschungszentrum Jülich In der Helmholtz-Gemeinschaft Rolf Stassen IKP/ COSY Darmstadt 2 Personal Dr. Alexander Schnase left FZJ – JAERI/J-PARC (Japan) We could win over Dr. Sorin Papureanu to reactivate the old tube amplifier (3-4 Month at beginning of 2007)

Forschungszentrum Jülich In der Helmholtz-Gemeinschaft Rolf Stassen IKP/ COSY Darmstadt 3 objectives low loss injection scheme and adequate acceleration/deceleration structure for the HESR Barrier bucket to compensate mean energy lost together with stochastic cooling (-> HESR3)

Forschungszentrum Jülich In der Helmholtz-Gemeinschaft Rolf Stassen IKP/ COSY Darmstadt 4 2 prototype cavities designed and under construction 1 RF accelerating Cavity (1,5 – 15 GeV/c, high power) with FineMet y FT-3M cores 1 barrier bucket (lower power, high bandwidth) filled with VitroPerm F500 All FineMet y cores delivered (main costs: 100k) Extensive tests required Additional 1kW broadband amplifier needed for barrier bucket cavity Hardware status

Forschungszentrum Jülich In der Helmholtz-Gemeinschaft Rolf Stassen IKP/ COSY Darmstadt 5 Barrier bucket cavity

Forschungszentrum Jülich In der Helmholtz-Gemeinschaft Rolf Stassen IKP/ COSY Darmstadt 6 RF Tests for HESR at COSY Signal synthesis to generate barrier bucket stimulation signal Known barrier bucket signal (single sinus, 10*f0) Measurement of gap-voltage Calculation of transfer-function (fourier series, 20 harmonics) Determination of modified stimulation signal

Forschungszentrum Jülich In der Helmholtz-Gemeinschaft Rolf Stassen IKP/ COSY Darmstadt 7 Pre-distorted Arbitrary Waveform Generator Signal AWG-signal Gap-voltage Beam-phase-monitor Gap-voltage COSY Injection Frequency ~ HESR Revolution frequency

Forschungszentrum Jülich In der Helmholtz-Gemeinschaft Rolf Stassen IKP/ COSY Darmstadt 8 First barrier bucket beam in COSY AWG-signal Beam-phase-monitor capacitive probe: field of operation? Gap-voltage

Forschungszentrum Jülich In der Helmholtz-Gemeinschaft Rolf Stassen IKP/ COSY Darmstadt 9 Higher energies (f 0 = 1.56 MHz) At higher energies no compensated Barrier bucket signal possible due to Bandwidth limitation of amplifier Using the USE-Kicker as barrier Bucket cavity

Forschungszentrum Jülich In der Helmholtz-Gemeinschaft Rolf Stassen IKP/ COSY Darmstadt 10 Next RF Tests for HESR at COSY Barrier bucket together with stochastic cooling to compensate the mean energy lost Signalgeneration for USE-Kicker Compensation of mean energy lost Additional longitudinal stochastic cooling

Forschungszentrum Jülich In der Helmholtz-Gemeinschaft Rolf Stassen IKP/ COSY Darmstadt 11 Schedule 2nd annual report: signal synthesis, design of cavities COSY shutdown dec-jan 2006/2007: preparing the USE- Kicker for barrier bucket tests in COSY with stochastic cooling Feb-June: Reactivating the (20kW) Tube-amplifier (S. Papureanu) FineMet y tests within the cavities during 2007 Final report end 2007 Thanks for your attention