1 / 18

FBCT experience at Desy

FBCT experience at Desy. Presenter : Matthias Werner, DESY At CERN Workshop: „ Improving the accuracy of the BCT measurements in the LHC“ January 2011. About this presentation :.

latona
Download Presentation

FBCT experience at Desy

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. FBCT experienceatDesy Presenter: Matthias Werner, DESY At CERN Workshop:„Improvingtheaccuracyofthe BCT measurements in theLHC“ January 2011

  2. Aboutthispresentation: • This presentationconsistsmainlyofinformationfromour BCT expert Reinhard Neumann andshowsdevelopmentsofourformer BCT expert Willi Radloff. • I just presenttheirresults.

  3. FBCTs usedat DESY • Bergoz FBCTs e.g. for Petra acceleratorfor high bandwidth • Inhousedevelopment (byW.Radloff) e.g. for FLASH and XFEL acceleratorforlow beam positiondependence.

  4. FBCTs withreduced beam positiondependence • The monitorsareequippedwith 4 symmetriccoilstominimize beam positiondependence. • In the original design, eachcoilhas 10 turns. • In theactual design for FLASH, eachcoilhas 1 turn and an RF transformer (w1/w2 = 1/10), resulting in increasedbandwidth(in theorderof 100 MHz) foroptimized design, but decreasedamplitude. • The currentsofthe 4 coilsareaddedupby a summingnetworkcombinedwith an impedancematchingtransformer (improvedversionunderdevelopment). • Unconfirmedtestsshowed an amplitudechangeof ±0.3% forpositionchangesof ±6 mm – thiscouldbefurtherimprovedbytrimming.

  5. Pickup and Electronics

  6. Halfcore in PEEK-Carrier

  7. Both Halfcores Fully equipped beam transformer halfcores

  8. Split Pickup Electrode Transformer halfcores embedded in shielding halfcovers

  9. Toroid TTF2- Dump Complete, with cables, combiner and filter

  10. Toroid in TTF2 Linac LP-Filter Combiner

  11. Precision of BCTs at DESY Info from Reinhard Neumann: • Uptonow, a precisionof ≈1% (reproducibility, not absolute accuracy) offullrange was achieved, this was enoughforthe Desy accelerators, so no furtherdevelopment was donetoimprovetheprecision.

  12. Whatcanaffectprecisionandresolutionof a BCT? • Calibrationmethod • Amplitude stabilityofsignalprocessingchain • Temperaturedependence • Beam positiondependence • Baseline suppression: Take zeroreferencefrombunchgaporbeforeeverybunch? • Lowpassfilterdirectly after BCT orprocessing a high bandwidthsignal? • Interference: symmetricorasymmetricdatatransmission? • Signal processingprinciple: integratingover a windoworsampling a filteredsignal? • Noise in thesignalprocessingchain: Amplifier, Integrator (ifany), ADC • Digital processingalgorithm

  13. Thankyou!

  14. Transparenciesbeyondthepresentationattheworkshop

  15. Hardware Schematics of the PC based Bunch Current Monitor

  16. 100 MHz Amplifier

  17. Typesof BCTs at DESY Info from Reinhard Neumann: • At Petra (light source, max. plannedbunchfrequency = 500 MHz): • BCT: Bergoz type (Spec: BW=2GHz, rise time 175 ps) – onlyonecoil • Considerablepositiondependenceobserved • Acquisition: Oscilloscope (8 bitresolution) • FLASH accelerator (max. bunchfrequency = 9 MHz): • BCT: „Radloff“-Type (selfmadewith 4 coils) • Acquisition: VME ADC modules(14 bit, 2 samples per bunch) • Other acceleratorsandtransportlines: • BCT: „Radloff“-Type (selfmadewith 4 coils) • Acquisition: PC ADC boards

  18. Impedancematchingat BCT coiloutput • Numberofturns on thetoroidandImpedanceratioofsuccessive RF transformersdeterminesimpedancematching. • Whatisthesourceimpedanceofthecoils? • Forsometermination, wegetoptimumamplitude, formaximumbandwithweneed a lowerterminationresistance. • Whatistheoptimumforourcase? (Especiallyimportantifresolutionis limited bynoise.)

More Related