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What‘s new at BESSY P. Kuske. Overview Shut Down Activities Top Up Activities – Successful Test Run – Kicker Development – Injection Efficiency Accelerator Physics – CSR Bursts New Project: B ERL inPro – other talk Summary. Features of the BESSY Light Source. Storage Ring:
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What‘s new at BESSY P. Kuske Overview Shut Down Activities Top Up Activities – Successful Test Run – Kicker Development – Injection Efficiency Accelerator Physics – CSR Bursts New Project: BERLinPro – other talk Summary
Features of the BESSY Light Source Storage Ring: 14 straight sections: 12 wiggler/undulators – 6 APPLE II-type VUV-range, polarisation 50 MeV microtron ~20 pC „single“ bunch up to 50 keV with 4 sc WLS IR tocoherent THz-radiation bending magnets Synchrotron: White circuits at 10 Hz, full energy injection: 1.72 GeV time resolution: 4 weeks single bunch, pulse duration 40 – 100 ps ~2 weeks low alpha/short bunch operation, pulse duration few ps fs-slicing operational, pulse <150 fs
Shut Down Activities • increasing user demands for special filling modes – fs-slicing • first preparations for LINAC installation during the next 2 years • initial operation of LINAC and microtron in parallel • LINAC is ordered E. Weihreter
Shut Down Activities • improvement of reliability and performance: • repair of the septum: exchange of the copper wires and more ceramic spacers October 2007 • replacement of ceramic windows for cavity RF-couplers • installation of 8 fast corrector magnet PS for tests of a fast orbit feedback system • re-shimming of APPLE undulator • survey of the storage ring and the experimental area V. Dürr with his team, and others
Shut Down Activities • septum magnet moved ~8mm closer to the beam • swapping of injection kicker coils and PS • – powering neighboring magnets by one PS • – expect 20 fold orbit stability improvement O. Dressler, J. Feikes
Top Up – Test Run in January 2008 • one week for preparations and • one week test run with selected user groups on dipole-, undulator- and sc wiggler-beam lines • remotely controlled experiments – experimental hall was inaccessible • rather large orbit transients due to injections every 20-30 seconds tolerable • time between injections sufficiently long for the PTB (radiometry and metrology) • especially on the sc wiggler the stability (spot size and position) greatly improved EPAC ‘08
Top Up – New Injection Scheme M. Dirsat
Top Up – New Injection Scheme structure has been fabricated and a pulsed PS is under development for field quality checks M. Dirsat, O. Dressler
Top Up – New Injection Scheme kicker tank wakefields? M. Dirsat, V. Dürr
Top Up – Injection Efficiency UE112ID7R active compensation of dynamic field components in the linear/inclined mode 32 flat wires along the ID-chamber with 14 individual PS J. Bahrdt, et al., PAC ’07, EPAC ‘08
Top Up – Injection Efficiency UE112ID7R prediction (dashed) measurement (solid) successful active compensation WS Non-Linear Beam Dynamics, ESRF ‘08
Top Up – Injection Efficiency impact of chromaticities, x,y: operation at low x,y requires careful adjustments of the transverse feedback systems
Top Up – Injection Efficiency impact of insertion device: nom. tune no IDs better tune U125ID2R – gap=15.7 mm 3Qx + 2 Qy – resonance critical at the nom. working point red dots – beam loss >2% WS Non-Linear Beam Dynamics, ESRF ‘08
Top Up – Injection Efficiency slow diffusion due to the U125ID2R – losses after 5000 turns: 3Qx + 2 Qy vertical scraper moved in 0.2mm steps: intensity dependence: many open questions
Accelerator Physics – CSR-bursts worm drive – simple picture for a longitudinal instability driven by a fixed frequency broad band resonator toothed worm wheel ~ particle distribution in the longitudinal phase space, number of teeth ~ azimuthal mode number thread of the screw-like worm ~ resonator frequency for instability: worm and wheel must fit the longer the bunch the higher is the frequency of the first unstable azimuthal mode picture too simple?
Accelerator Physics – CSR-bursts UE112ID7R result of a numerical solution of the Vlasov-Fokker-Planck-equation with broad band resonator impedance with Rs=10 kOhm, Q=1, Fres varied BESSYII-parameters with fixed rms-bunchlength=10.7ps linear dependence as already noticed by A. Mosnier, 1999 BBR-impedance model realistic?
Accelerator Physics – CSR-bursts Result of numerical solution of the Vlasov-Fokker-Planck-equation Broad band impedance with Fres=30 GHz, Rs=10 kOhm, Q=1 BESSYII-parameters with rms-bunchlength=10.7ps Longitudinal phase space in units of natural ‘s CSR-power in log-scale 0 GHz 400
Accelerator Physics – CSR-bursts Result of numerical solution of the Vlasov-Fokker-Planck-equation Broad band impedance with Fres=30 GHz, Rs=10 kOhm, Q=1 BESSYII-parameters with rms-bunchlength=10.7ps Longitudinal phase space in units of natural ‘s CSR-power in log-scale 0 GHz 400
Accelerator Physics – CSR-bursts Result of numerical solution of the Vlasov-Fokker-Planck-equation Broad band impedance with Fres=30 GHz, Rs=10 kOhm, Q=1 BESSYII-parameters with rms-bunchlength=10.7ps Longitudinal phase space in units of natural ‘s CSR-power in log-scale 0 GHz 400
Accelerator Physics – CSR-bursts Result of numerical solution of the Vlasov-Fokker-Planck-equation Broad band impedance with Fres=30 GHz, Rs=10 kOhm, Q=1 BESSYII-parameters with rms-bunchlength=10.7ps Longitudinal phase space in units of natural ‘s CSR-power in log-scale 0 GHz 400
Accelerator Physics – CSR-bursts Result of numerical solution of the Vlasov-Fokker-Planck-equation Broad band impedance with Fres=30 GHz, Rs=10 kOhm, Q=1 BESSYII-parameters with rms-bunchlength=10.7ps Longitudinal phase space in units of natural ‘s CSR-power in log-scale 0 GHz 400
Accelerator Physics – CSR-bursts Result of numerical solution of the Vlasov-Fokker-Planck-equation Broad band impedance with Fres=30 GHz, Rs=10 kOhm, Q=1 BESSYII-parameters with rms-bunchlength=10.7ps Longitudinal phase space in units of natural ‘s CSR-power in log-scale 0 GHz 400
Accelerator Physics – CSR-bursts Result of numerical solution of the Vlasov-Fokker-Planck-equation Broad band impedance with Fres=30 GHz, Rs=10 kOhm, Q=1 BESSYII-parameters with rms-bunchlength=10.7ps Longitudinal phase space in units of natural ‘s CSR-power in log-scale 0 GHz 400
Accelerator Physics – CSR-bursts Result of numerical solution of the Vlasov-Fokker-Planck-equation Broad band impedance with Fres=30 GHz, Rs=10 kOhm, Q=1 BESSYII-parameters with rms-bunchlength=10.7ps Longitudinal phase space in units of natural ‘s CSR-power in log-scale 0 GHz 400
Accelerator Physics – CSR-bursts Result of numerical solution of the Vlasov-Fokker-Planck-equation Broad band impedance with Fres=30 GHz, Rs=10 kOhm, Q=1 BESSYII-parameters with rms-bunchlength=10.7ps Longitudinal phase space in units of natural ‘s CSR-power in log-scale 0 GHz 400
Accelerator Physics – CSR-bursts Result of numerical solution of the Vlasov-Fokker-Planck-equation Broad band impedance with Fres=30 GHz, Rs=10 kOhm, Q=1 BESSYII-parameters with rms-bunchlength=10.7ps Longitudinal phase space in units of natural ‘s CSR-power in log-scale 0 GHz 400
Accelerator Physics – CSR-bursts Result of numerical solution of the Vlasov-Fokker-Planck-equation Broad band impedance with Fres=30 GHz, Rs=10 kOhm, Q=1 BESSYII-parameters with rms-bunchlength=10.7ps Longitudinal phase space in units of natural ‘s CSR-power in log-scale 0 GHz 400
Accelerator Physics – CSR-bursts Result of numerical solution of the Vlasov-Fokker-Planck-equation Broad band impedance with Fres=30 GHz, Rs=10 kOhm, Q=1 BESSYII-parameters with rms-bunchlength=10.7ps Longitudinal phase space in units of natural ‘s CSR-power in log-scale 0 GHz 400
Accelerator Physics – CSR-bursts Result of numerical solution of the Vlasov-Fokker-Planck-equation Broad band impedance with Fres=30 GHz, Rs=10 kOhm, Q=1 BESSYII-parameters with rms-bunchlength=10.7ps Longitudinal phase space in units of natural ‘s CSR-power in log-scale 0 GHz 400
Accelerator Physics – CSR-bursts Result of numerical solution of the Vlasov-Fokker-Planck-equation Broad band impedance with Fres=30 GHz, Rs=10 kOhm, Q=1 BESSYII-parameters with rms-bunchlength=10.7ps Longitudinal phase space in units of natural ‘s CSR-power in log-scale 0 GHz 400
Accelerator Physics – CSR-bursts Result of numerical solution of the Vlasov-Fokker-Planck-equation Broad band impedance with Fres=30 GHz, Rs=10 kOhm, Q=1 BESSYII-parameters with rms-bunchlength=10.7ps Longitudinal phase space in units of natural ‘s CSR-power in log-scale 0 GHz 400
Accelerator Physics – CSR-bursts Result of numerical solution of the Vlasov-Fokker-Planck-equation Broad band impedance with Fres=30 GHz, Rs=10 kOhm, Q=1 BESSYII-parameters with rms-bunchlength=10.7ps Longitudinal phase space in units of natural ‘s CSR-power in log-scale 0 GHz 400
Accelerator Physics – CSR-bursts UE112ID7R measurement – frequency of the CSR-signal close to the longitudinal threshold as a function of the bunch length as expected from the simple model bunch length proportional to Fsyn
Accelerator Physics – CSR-bursts time dependent CSR-bursts observed in frequency domain: 0=14 ps, nom. optics, with 7T-WLS CSR-bursting threshold stable, time independent CSR spectrum of the CSR-signal: Longitudinal Stability of Short Bunches at BESSY, Peter Kuske, 7th of November 2005, Frascati
Accelerator Physics – CSR-bursts Fourier spectra of the time dependent CSR-signals as a function of single bunch current: CSR-signal as a function of time at Isb=160 A Longitudinal Stability of Short Bunches at BESSY, Peter Kuske, 7th of November 2005, Frascati
Summary UE112ID7R BESSY II is operating reliable and in a mixture of modes within the next 2 years: Top Up operation and fast orbit feedback system challenges: LINAC installation, new kicker development, … interesting physics: impact of IDs – transverse beam dynamics CSR-bursts – longitudinal beam dynamics future project – BERLinPro: – cw sc RF-technology – gun development (Zeuthen, Rossendorf) operation of the MLS – the Metrology Light Source structural changes within the new Helmholtz-center