V.M. Zhabitsky, N. Lebedev, E. Gorbachev (JINR), U. Blell, P. Spiller (GSI)

1. JINR The Transverse Damping Systems for the SIS100 & SIS300 Synchrotrons at the Facility of Antiproton and Ion Research (FAIR at GSI) V.M. Zhabitsky, N. Lebedev, E. Gorbachev (JINR), U. Blell, P. Spiller (GSI) 5th Workshop on Scientific Cooperation between German Research Centres and JINR 18 January 2005

2. JINR The LHC Transverse Damping SystemCERN – Russia - JINR • CERN • W.Hofle, LHC ADT Project Engineer (Damper), T.Linnecar, LHC A Project Engineer (RF), R.Louwerse, J.-F.Malo, J.Tuckmantel • JINR • V.M.Zhabitsky, N.I.Lebedev, E.V.Gorbachev, A.A.Fateev, A.A.Makarov, V.A.Melnikov, S.V.Rabtsoun, V.A.Bogdanov, N.V.Pilyar, V.G.Shabratov, K.P.Sychev, M.G.Pushkin, B.G.Komarov, V.I.Koryako, V.V.Kovalev + 10 pers. JINR- CERN - GSI

3. Key Technologies in Accelerator: • Magnets • B, Q • RF System • E • Feedback Systems • N, ε JINR- CERN - GSI

4. FAIR at GSI • Highest beam intensities • Brilliant beam quality • Higher beam energies • Highest beam power JINR- CERN - GSI

5. Bunch current Vacuum chamber Induced current Differential current Induced magnetic field Bunch Coherent Transverse Oscillation • If the bunch is displaced form the centre of the vacuum chamber it will drive a differential wall current. • This leads to a magnetic field, which deflects the bunch. JINR- CERN - GSI

6. W. HofleCERN AB/RF Transverse Feedback (“LHC Damper”) • Example SPS (CNGS type beam, 1 batch, 1013 protons): • 3 ms growth rate • 0.5 ms damping time • 50 + turns relative silence at injection damper being switched on 7 ms (300 turns) after injection injection with damper off JINR- CERN - GSI

7. Transverse Feedback System with areal-time digital signal processing: damping of transverse injection oscillations, feedback curing transverse coupled bunch instabilities, excitation of transverse oscillations for beam measurements and other applications. JINR SIS100 & SIS300 Dampers General Parameters of SIS100 & SIS300 Machine Circumference: 1191.96 m Beam revolution frequency: 104.1 - 251.3 kHz Beam revolution time: 9.61 - 3.98 μs Horizontal tune at injection: QH=26.9 Vertical tune at injection: QV=16.7 Energy (238U): 0.092 – 34 GeV/u Intensity (238U73+, 238U28+): 0.09 - 0.47 - 1.1 A JINR- CERN - GSI

8. JINR- CERN - GSI

9. Basic Parameters • damping of transverse injection oscillations • ∫(E┴ + β0cB┴)ds ≈ ±6.0 kV (δQ - ?) • feedback curing transverse coupled bunch instabilities • ∫(E┴ + β0cB┴)ds ≈ ±1.3 kV • Strength of the kicker: • ∫(E┴ + β0cB┴)ds ≈ ±9.3 kV • Electric kicker (L=0.5m, Δ=10cm): U = ±1.86 kV JINR- CERN - GSI

10. Bandwidth and Frequencies • fmin= min|k - Q|f0 = 0.1f0 = 10.4 kHz • fmax ≤ fb/2 • fmax (for kicker) ≤ 1/4πσt = 3.2 MHz (σt=25ns) • Bunch r.m.s. spectral frequency:<f> = 1/2πσt = 6.4 MHz • Stability of high order harmonics - ? • Sampling rate: 20MSPS • Transverse emittance growth rate: • τ-1 = (4/3) f0 2-2(b-1) δQ2 • τ = 84 hours (f0 = 104kHz; b=12-1; δQ = 0.005) JINR- CERN - GSI

11. JINR SIS100 & SIS300 Dampers JINR- CERN - GSI

12. JINR Kicker A fragment of an assembly drawing of a vertical kicker: 1 - the vacuum tank, 2 - electrodes, 3 - ceramic rings, 4 - the fixing device of the electrode module, 5 - the high voltage connection, 6 - a plate for installation of target alignment, 7 - the higher order mode connection. • High voltage on electrodes: ±1400 V • Bandwidth: 10 – 3200 kHz • Operating vacuum: 5∙10-12 mbar JINR- CERN - GSI

13. JINR Power Amplifier • Class of operation: AB • Input amplitude: ±150 V • Output amplitude: ±1400 V • Bandwidth: 10 – 3200 kHz JINR- CERN - GSI

14. JINR LHC Damper: investigationsof a cascode amplifier The experimental results confirm a possibility of realisation of amplifier on the basis of the circuit with parallel control (cascode), which is considered as a perspective development of the system. JINR- CERN - GSI

15. Driver Amplifier Front view Rear view • Class of operation: A • Input amplitude: ±1 V • Output amplitude: ±150 V • Bandwidth: 10 – 3200 kHz Top view View on transformers JINR- CERN - GSI

16. JINR Central Signal Processing • Field Programmable Gate Array(FRGA) technology • Clock frequency: 8fRF≤ 20MHz • Digital input signal: ±12 bit • Analog output amplitude: ±1 V • Signal processing resolution: 12 bit • Programmable delay: 3 - 10μs, ++50ns • Fine delay: 1 – 50ns, ++1ns (??) JINR- CERN - GSI

17. The Transverse Damping Systems for the SIS100 & SIS300 Synchrotrons at the Facility of Antiproton and Ion Research (FAIR at GSI) Status (November 2004): Technical proposal was prepared by: • Accelerator Development Group,Gesellschaft für Schwerionenforschung mbH Darmstadt • Laboratory of Particle Physics of the Joint Institute for Nuclear Research JINR- CERN - GSI

18. JINR The LHC Transverse Damping SystemCERN – Russia - JINR The Damper is in the list of the systems that must operate already for first beam injection. Therefore the schedule of construction, installation and testing the Damper in the machine must be completed before November 2006. JINR- CERN - GSI

19. JINR LHC Damper. Layout of one transverse feedback system. There are four independent systems, one per plane (H/V) and beam. • JINR’s obligations: • 20 deflectors, • 40 amplifiers. JINR- CERN - GSI

20. JINR The LHC Transverse Damping SystemCERN – Russia - JINR Wideband amplifiers Electrostatic kicker The design stage was successfully completed at the Laboratory of Particle Physics (JINR) and its results were accepted by CERN. Modern simulation methods based on Microsim PSpice™ and Inventor™ were used. JINR- CERN - GSI

21. The LHC Transverse Damping System JINR Final amplifier design Assembly of the amplifier and the kicker at the tests bench. LPP, October 2004. JINR- CERN - GSI

22. The LHC Transverse Damping System JINR Radiophysical characteristics of the power amplifier:7.5 kV; 10 kHz – 10 MHz. LPP, JINR, 10-15 December 2004. JINR- CERN - GSI

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