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The chopper structure-recent developments F. Caspers, Y. Cuvet

The chopper structure-recent developments F. Caspers, Y. Cuvet. Where are we today According to the original planning, detailed technical drawings should have been ready in June 2004 and all the hardware for the pre-prototype in Sept. 2004

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The chopper structure-recent developments F. Caspers, Y. Cuvet

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  1. The chopper structure-recent developments F. Caspers, Y. Cuvet • Where are we today • According to the original planning, detailed technical drawings should have been ready in June 2004 and all the hardware for the pre-prototype in Sept. 2004 • but there were considerable delays due to other priorities at CERN in 2004 • Sinceend of December 2004 the detailed technical drawings are ready and have been checked • We expect the delivery of all bits and pieces by end of March 2005 • Assembly by end of May 2005 chopper structure-recent developments Caspers, Cuvet

  2. Substrate: alumina 3 mm (50 ) 3 mm thick  = 9.6 0.45 mm 6 mm (100 42.5 mm Just a reminder what its about • A double meander structure (400mm length) printed on an alumina substrate has been designed and developed four our application + parameters (v/c=8%) beam Metallization: Molybden/mangan + silver chopper structure-recent developments Caspers, Cuvet

  3. Some details (1) The printed meander lines on alumina with metallic back-plane chopper structure-recent developments Caspers, Cuvet

  4. Some details (2) chopper structure-recent developments Caspers, Cuvet

  5. Some details (3) Only upper plate cooling circuit shown here chopper structure-recent developments Caspers, Cuvet

  6. Some details (4) chopper structure-recent developments Caspers, Cuvet

  7. Some details (5) chopper structure-recent developments Caspers, Cuvet

  8. Some details (6) chopper structure-recent developments Caspers, Cuvet

  9. Some details (7) chopper structure-recent developments Caspers, Cuvet

  10. Some details (8) chopper structure-recent developments Caspers, Cuvet

  11. What happened in the meantime(1) • There are considerations and evolutions on the power amplifier side, which could permit us, to come to a coaxial (instead of triax) version. • If successful wrt power amplifier, we could rather easily modify the chopper structure to coax. • In this case we would not need to carry out a precise determination of the cross-over frequency between standing wave and traveling wave mode of operation chopper structure-recent developments Caspers, Cuvet

  12. What happened in the meantime (2) • A detailed investigation of heating of the meander lines as well as heat transfer to the water cooled back plane (in UHV) • We had already tested a meander structure in air with 10 Ampere DC current  result ok. • But in vacuum there is not too much convection (hopefully) and there were question marks on the heat transfer by conduction and/or radiation between the alumina ceramic and aluminum back-plane (gap of a few micron). In short we can expect a good heat transfer via “tunneling” chopper structure-recent developments Caspers, Cuvet

  13. CERN : Joule heated trace on a ceramics substrate Thermal analysis (1) By: Dr.J Adam Flomerics Assumption: Ceramic substrate with cooled back-plate 160 x 100 x3 mm Conducting strip:35 micron copper, 1.8 mm width, 48 Ampere chopper structure-recent developments Caspers, Cuvet

  14. Thermal analysis (2) Heating example of printed 35 micron strip on 0.5 mm thick alumina –no back plane –in air. Width of alumina substrate = 100 mm By: Dr.J Adam Flomerics chopper structure-recent developments Caspers, Cuvet

  15. Thermal analysis (3) Heating example of printed 35 micron strip on 1 mm thick alumina –no back plane –in air. Width of alumina substrate = 100 mm By: Dr.J Adam Flomerics chopper structure-recent developments Caspers, Cuvet

  16. Thermal analysis (4) Heating example of printed 35 micron strip on 3 mm thick alumina –back plane watercooled. IDC = 13 A Temperature of metal strip[ deg C] Width of alumina substrate = 100 mm By: Dr.J Adam Flomerics Width of metal strip [mm] chopper structure-recent developments Caspers, Cuvet

  17. Thermal analysis (refs) Literaturangaben Weitere Infos zum Thema Strombelastbarkeit, insbesondere berechnete Strombelastbarkeitsdiagramme, in: Adam, J.: “New Correlations Between Electrical Current and Temperature Rise in PCB Traces”. Proc. 20th IEEE SEMI-THERM Symposium, 292-299 (2004) [2] Adam, J.: „Neues von der Strombelastbarkeit von Leiterbahnen“, DVS/GMM-Fachtagung „Elektronische Baugruppen - Aufbau- und Fertigungstechnik. GMM-Fachbericht 44, 117-123 (2004) http://www.flomerics.de/Produkte/Flotherm/Beispiele.html [1] Adam, J.: „Strombelastbarkeit von Leiterbahnen III. Weitere Diagramme für Multilayer und Umrechnungsregeln“, PLUS 6 Heft 4, 513-518 (2004) Adam, J. : „IPC-2152 : Neue Richtwerte für die Strombelastbarkeit von Leiterzügen in Leiterplatten“. Konferenzband 11. FED-Konferenz Ludwigsburg, 11-331 (2003) Adam, J.: „Strombelastbarkeit von LeiterbahnenII. Die IPC-Richtlinie IPC-D-275: Mythos und Wirklichkeit“, PLUS 4 Heft 11, 1817-1823 (2002) Adam, J.: „Strombelastbarkeit von LeiterbahnenI. Grundlagen“, PLUS 4 Heft 10, 1669-1673 (2002) By: Dr.J Adam Flomerics chopper structure-recent developments Caspers, Cuvet

  18. The latest planning Finalizing design drawings • mid May until mid July 2004 => Dec 2004 Implementation of hardware (preprototype) • mid July until end of August 2004 =>May2005 • But so far everything looks fine, just delayed.. And there is also interest by LBNL and ANL in this kind of printed meander on alumina chopper structure-recent developments Caspers, Cuvet

  19. MEBT Chopper Developmentat LBNL for RIA S. De Santis J. Byrd J. Staples D. Li R. Keller In collaboration with F. Caspers, CERN This page and the following 5 slides are copied (with permission) from Berkeley Natl. Lab - Accelerator and Fusion research division chopper structure-recent developments Caspers, Cuvet

  20. Chopper RFQ RFQ High Voltage platform +100 kV Rare Isotope Accelerator RIA: Accelerator system for the production of unstable isotopes. 400 kW beams from H+ to U+28. Four energy regimes for secondary beams: from stopped beams to 400 MeV/u of in-flight fragments. RF chopper: an essential com- ponent for providing individual intensity adjustment to the beams. Deflects parts of the beam from the RFQ to a high-power stopping target. chopper structure-recent developments Caspers, Cuvet

  21. Chopper Specifications Transit time > bunch separation (17.4 ns) Energy after RFQ Wide range of isotopes from H+ to U+28 82 mrad deflection for U+28 of 200 keV/u < 17.4 ns separation between bunches Half the RFQ frequency Can chop off every 2nd bunch chopper structure-recent developments Caspers, Cuvet

  22. chopper structure-recent developments Caspers, Cuvet

  23. Pulse Generator • Most challenging component: 4.2 kVpp, with 12 ns max. rise time and variable-length flat-top. • Two sine-wave generators at 28.75 and 86.25 MHz. • CERN SPL design suggests two amplifiers for operation in quasi-static mode during flat-tops and in travelling wave mode during switching. This greatly reduces high power dissipation. chopper structure-recent developments Caspers, Cuvet

  24. First Development Stepsat LBNL • Extensive modelling of the meander line structure (Microwave Studio, thermal modelling) • Technology/fabrication tests -> -> -> -> prototype chopper structure-recent developments Caspers, Cuvet

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