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Experience with Liberas during PETRA III commissioning

Experience with Liberas during PETRA III commissioning. Gero Kube , Igor Krouptchenkov, Frank Schmidt-Föhre DESY / MDI. Introduction BPM System Commissioning Experience Critical Issues. PETRA III @ DESY. Parameters:. circumference: 2304 m energy: 6 GeV emittance: 1 nmrad

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Experience with Liberas during PETRA III commissioning

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  1. Experience with Liberas during PETRA III commissioning Gero Kube, Igor Krouptchenkov, Frank Schmidt-Föhre DESY / MDI • Introduction • BPM System • Commissioning Experience • Critical Issues

  2. PETRA III @ DESY Parameters: • circumference:2304 m • energy: 6 GeV • emittance: 1 nmrad • emittance coupling : 1% (10 pmrad!) • current: 100 (200) mA • # bunches: 40 / 960 • straight sections: 9 • undulators: 14 • undulator length: 2, 5, 10 (20) m • supplement to X-FEL •  cost effective! Libera User Meeting, June 22, 2009 Gero Kube, DESY / MDI

  3. PETRA III @ DESY Damping Wiggler Sections new Experimental Hall PETRA III: Conversion of the former storage ring PETRA II into a light source C=2304m !!! Libera User Meeting, June 22, 2009 Gero Kube, DESY / MDI

  4. PETRA III Diagnostics • PETRA III: • 228 BPMs • → 226 for Orbit • → 227 Libera Brilliance • 6 Current Monitors • 2 Stripline-BPMs and • 2 Button-BPMs for • Multibunch Feedback • 1 Button-BPM for longi- • tudinal Feedback • 1 Wall Gap Monitor • 1 Laser-Wirescanner • 2 Beamlines for Emit- • tance Diagnostics • 3 Screens • Transfer Lines: • 20 BPMs • 10 Current Monitors • 4 Wall Gap Monitors • 11 Screens Libera User Meeting, June 22, 2009 Gero Kube, DESY / MDI

  5. Libera Brilliance for PETRA • → software release 1.82 BPM System • Overview Libera User Meeting, June 22, 2009 Gero Kube, DESY / MDI

  6. usual • DESY Console Console Server (TINE) CSPI Interface Server (Tango, EPICS,…) Server (Tango, EPICS,…) Server (Tango, EPICS,…) 1:1 1:N x CSPI Interface CSPI Interface CSPI Interface Libera Libera Libera Libera Libera Libera Pickup Pickup BPM System: Differences • Fast Data Stream (FOFB) • latency of standard FA data stream • → O(270 μsec) • new data output: Molex • → reduced latency O(130 μsec) • → in-house processing of raw data → not in use until now • Server Architecture Libera User Meeting, June 22, 2009 Gero Kube, DESY / MDI

  7. accelerator sections • different vacuum chamber cross-sections • → 8 different pickup types • large circumference N:2 • scattered infrastructure • → located in 8 „old“ experimental halls • and the new experimental hall NW: 2 NE: 2 EXP: 10 W: 2 E: 2 SE: 2 SW: 2 S: 2 number of racks in hall Accelerator Geometry: Implications • cable lengths (10 m … 200 m) • → 3 different cable types for loss compensation • (RFA 1/2´´-, 3/8 ´´-, 7/8´´-50) → 227 individual gain settings Libera User Meeting, June 22, 2009 Gero Kube, DESY / MDI

  8. OOArc OOStr NOOct UNEnt / UNExt DWRac DWOct UNCtd Pickup Types Libera User Meeting, June 22, 2009 Gero Kube, DESY / MDI

  9. UNExt DWRac OOArc UNCtd NOOct OOStr Pickup Types Libera User Meeting, June 22, 2009 Gero Kube, DESY / MDI

  10. Temperature Stabilization • old 7 octants • Liberas in temperature-stabilized hutches (together with feedback electronics) • → ± 1° C • new experimental hall • hall itself is temperature-stabilized • → ± 0.1° C Libera User Meeting, June 22, 2009 Gero Kube, DESY / MDI

  11. Read-Out Electronics • Electronic Racks Libera Brilliance Fiber Links (for FOFB) Signal-Combiner Libera Clock-Splitter Libera Brilliance Ethernet Switches (for Liberas) Libera User Meeting, June 22, 2009 Gero Kube, DESY / MDI

  12. Strategy • triggered data on demand (DD) acquisition (→ injection trigger) • observation of BPM sum signal • → fix gain setting (-55 dBm), but AGC works well • timing: adjust hardware trigger delay • → maximum of sum signal appears in same turn • → ADC signal in same channels • fine tuning via machine time (MT) phase delay • → optimize intensity of sum signal wrt. neighbour turns Beam Steering • Conditions • only one screen monitor behind injection • → beam steering depends on reliability of BPM system Libera User Meeting, June 22, 2009 Gero Kube, DESY / MDI

  13. BPM sum signal injection point • April 12: first turns • April 13: first stored beam • → single bunch, 20 μA (~ 109 particles) current monitor signal Beam Steering (2) • Milestones • April 3: first beam in PETRA • April 10: all magnet power supplies available Libera User Meeting, June 22, 2009 Gero Kube, DESY / MDI

  14. Result injection point not connected Libera Trigger Delays • individual adjustment • required for first turn (DD) measurements • adjusting via hardware trigger delay • → ADC signal from single bunch in samechannel • fine tuning via MT phase delay Libera User Meeting, June 22, 2009 Gero Kube, DESY / MDI

  15. tune settings integer part: SA acquisition fractional part: DD acquisition • adjustment of injection kicker strength • DD mode • → reduce • oscillation • amplitude Commissioning • correction of closed orbit • SA mode: AGC & DSC & switching on Libera User Meeting, June 22, 2009 Gero Kube, DESY / MDI

  16. Commissioning (2) • high level applications (examples) Dispersion (hor.) Dispersion (vert.) BBA ORM Tests Libera User Meeting, June 22, 2009 Gero Kube, DESY / MDI

  17. Beam Current Dependency • dependency on position readout • single bunch (→ real beam) • SA acquisition: • →DSC on, crossbar switching on • 100 samples for each bunch current • → mean and variance of pos. readout attenuator switching Libera User Meeting, June 22, 2009 Gero Kube, DESY / MDI

  18. offset tune: +400 Offset Tune • test measurement with „ideal“ beam • 40 bunches, I ≈ 16-20 mA • (with several re-injections) • AGC on • → Gain: -37…-39 dBm • SA acquisition: • →DSC on, crossbar switching on • compensation tune on/off • 500 samples for each offset tune • → mean and variance of pos. readout Libera User Meeting, June 22, 2009 Gero Kube, DESY / MDI

  19. Reliability: Fault Finding • monitoring of health parameters • resolution • ADC data • q-value Libera User Meeting, June 22, 2009 Gero Kube, DESY / MDI

  20. defect fan Fault Finding: Examples • defect bit on digital board Libera User Meeting, June 22, 2009 Gero Kube, DESY / MDI

  21. Faults • Libera fault statistics → Σ = 28 • further inconvenience • unstable synchronization wrt. system clock • problem of Libera or system clock? → under investigation Libera User Meeting, June 22, 2009 Gero Kube, DESY / MDI

  22. Summary & Acknowledgment • description of PETRA III – BPM system • machine commissioning worked well & straight forward • → extensive use of TbT capability in combination with high precision in • SA mode • fine tuning of monitor resolution together with investigation of • resolution dependent influences recently started • unexpected high failure rate • → 28 out of 246 devices! • thanks • … to Kees Scheidt (ESRF) and Günther Rehm (Diamond) for fruitful discussions • and important hints concerning Libera functionality and commissioning experience. • … to Andrej Kosicek, Peter Leban, and Ales Bardorfer (I-Tech) for their support . Libera User Meeting, June 22, 2009 Gero Kube, DESY / MDI

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