Development of Stripline Kicker for APS Yifan Su

Development of Stripline Kicker for APS Yifan Su, Cornell University Mentor: Zachary A. Conway Lee Teng Internship Presentation 09 August 2017

Overview APS-U Fast Kicker Model § Intro & Motivation § Goals § Approaches: 1. Theory 2. Simulation 3. Experimental Measurement § Result & Conclusion 760 x 110 x 645 mm Lx. Wx. H 28. 6 kg (63 lbs)

Introduction & Motiation Advanced Photon Source Upgrade (APS-U) Criteria: § transverse beam emittance < 100 pm § on-axis swap-out beam injection § Approximately 20 ns duty cycle v 6 ns rise-time v 6 -ns flattop v 6 -7 ns fall-time § 30 k. V deferential voltage to transfer the 6 Ge. V electron beams 09 August 2017 3

Kicker Components - 1 MDC Vacuum Products Spool APS-U Fast Kicker Prototype Part View 50 W Feedthrough Assembly Adjustable Bellows Spool Central Body Tooling Ball Inner Conductor Extension Rod Tapered End Group Stripline (Blade) 50 W feedthrough assembly details on next slide. 4

Kicker Components – 2: Feedthrough Assembly 50 W Feedthrough 0. 305 m (12”) Outer Conductor Extension Tube Screw x 3 RF Spring Inner Conductor Extension Rod RF Spring Stripline Blade 5

Goal: 1. Optimize the kicker impedance (50 Ohms) and examine impedance response to blade position perturbation. § Minimize the reflected wave amplitude at the interface § Avoid perturbing adjacent bunches with reflected waves § Avoid excessive reflection back to the pulser to avoid damage § Reduce dispersion and wave distortion of the pulse § Couple out the beam Wakefield driven excitations of the kicker 2. Characterize the feed through via Time Domain Reflectometry (TDR) § Impedance § Symmetry 09 August 2017 6

Approach 1 -Theoretical model § Shielded Dual Conductor model: Impedance: where b is inner conductor radius, c is outer radius, h is half center- to center distance, σ=h/c, ν=h/b, and η=377Ω: 09 August 2017 7

Approach 2: Simulation § CST Microwave Studio 1. shielded dual conductor 2. Blade model imported from Autodesk Inventor § Hexagonal Mesh § Only interested in Odd TEM mode 09 August 2017 8

Approach 3: Network Analyzer measurement § Fixtures for setting distance between blades § Blade position controlled by screws § Network Analyzer Set-up 09 August 2017 9

Results & Conclusion • The system is resistant to small perturbations in blade positions, but when the position offset becomes larger, the impedance change is much faster. • TDR shows that there are two approximately symmetric impedance continuity of about 42 Ohms caused by the two feed through. The impedance of the transverse kicker given by TDR is 52 Ohms. 09 August 2017 10

Reference § [1] C. Belver-Aguilar, A. Faus-Golfe, F. Toral, M. J. Barnes, Phys. Rev. ST Accel. Beams 17, 071003 (2014) § [2] Description of Injection in the APS Storage Ring, L. Emery (April 2002) § [3] E. I. Green, F. A. Leibe, and H. E. Curtis, Bell System Tech. Journal. , 15, pp. 248 -284 (April 1936) § [4] Fields and waves in communication electronics, 3 rd ed. , Simon Ramo, J. W. Whinnery, and T. V. Duzer, pp. 250. § [5] A. Xiao , M. Borland, C. Yao, Proc. PAC 2013, WEPSM 13 (2013) 09 August 2017 11