1 July 2009 11.424 GHz High Gradient Testing of a T18 TW Structure Using a Fast Response Protection and Power Recirculating System Work performed under the auspices of the U.S. Department of Energy SBIR Grant No. DE-FG02-08ER85197 HAIMSON RESEARCH CORPORATION 2 July 2009 Objective: To Compare the High Gradient Performance of a Dual Feed T18 TW Linac Structure when Driven by a Resonant Ring Power Amplifier and when Load Terminated and Excited Directly with a High Power Klystron. HAIMSON RESEARCH CORPORATION July 2009 Content: 1. Describe Advantageous Operating Characteristics of Resonant Ring Driven TW Linacs. 2. Discuss Design Features of the Planned 11.424 GHz Power Recirculating System dart HAIMSON RESEARCH CORPORATION 4 July 2009 RF LOAD BRIDGE BALANCE PROCESSOR RF SOURCE RF MONITOR RF BRIDGE 1 PS 2 3 PA = (1 + n)PS ELECTRON SOURCE 4 TEST LINAC PL PF = nPS SPECTROMETER HAIMSON RESEARCH CORPORATION 5 July 2009 NORMAL LINAC OPERATION RF Source Power Bridge Load Power Linac Input Power Linac Reflected Power WITH ARC IN LINAC Showing that when an Arc Occurs in the Linac, the Linac Input Power (blue) is Rapidly Truncated and, for the Remaining Portion of the Klystron RF Pulse the Bridge Input Power (red) is Automatically Directed into the Bridge Load (green). Thus, the Linac Power Amplifying Bridge Assists in Automatically Protecting both the RF Source and the High Gradient Linac Structure. “Design Features and Initial RF Performance of a Gradient Hardened 17 GHz TW Linac Structure,” in Advanced Accelerator Concepts, AIP Conf. Proc., No. 1086, pp. 464-469, 2008. HAIMSON RESEARCH CORPORATION 6 July 2009 View of All-Copper 17 GHz Linac Structure and 4X Peak Power Amplifier System. HAIMSON RESEARCH CORPORATION 7 July 2009 HAIMSON RESEARCH CORPORATION 8 July 2009 LINAC POWER BUILDUP, PA/PS 3.0 99.11% OverCoupled 2.5 C = .613 89.7% C = .831 2.66 PL/PS = 0 2.20 2.0 98.8% PL/PS = 99.90% 17.3% 1.5 Critically Coupled 1.0 f = 11.424 GHz 0.5 0 Bridge Coupling Coefficient = C Feedback Loop Loss, = 2.05 dB 0 100 200 300 400 500 BUILD-UP TIME FOR A 38ns LOOP TRANSIT (ns) HAIMSON RESEARCH CORPORATION July 2009 9 0.7 3.5 f = 11.424 GHz (PL/PS) n = 1.98 0.5 613 .650 2.39 1.37 3.0 . 2.05 1.66 C = .579 0.4 2.5 2.0 (PA/PS) 0.3 1.5 PS = Source Power n = Bridge Ratio = Loop Loss (dB) C = Bridge Coupling Coefficient Loop Transit Time = 38 ns 0.2 0.1 0 0 50 100 150 200 250 300 350 400 450 1.0 LINAC INPUT POWER (PA/PS) RF LOAD POWER (PL/PS) 0.6 = 1.78 dB 0.5 500 0 550 ELAPSED TIME (ns) HAIMSON RESEARCH CORPORATION 10 July 2009 Mode Converter Used with the T18 Structure Ez Field Pattern at f = 11424 MHz HRC 7131 Resonant Ring Phase Study 03/13/09 HAIMSON RESEARCH CORPORATION 11 July 2009 Design Parameters of an 11.4GHz Dual Resonant Ring System Configured for High Gradient Testing of the CLIC/KEK/SLAC (T18) Linac Structure System Operating Frequency . . . . . . . . . 11.424 GHz Test Linac Attenuation Parameter (). . . . . . Test Linac Harmonic Mean Group Velocity (vg)hm . . . . . . . . . . . . 0.21 Np 0.016 c Total Loss in Feedback Loop () . . . . . . . . 2.05 dB Resonant Ring Transit Time . . . . . . . . . . 38 ns Resonant Ring Total Phase Length . . . . . . Resonant Ring Phase Dispersion . . . . . . . WR90 Rectangular Waveguide Phase/Length Relationship . . . . . . . . . Length/Phase Relationship . . . . . . . . . 17280 deg 15 deg/MHz 11.2 deg/mm .089 mm/deg HAIMSON RESEARCH CORPORATION 12 July 2009 RF Bridge Ratio [n=(TC/C)2] . . . . . . . . . . 1.66 RF Power Buildup (n+1) . . . . . . . . . . . . 2.66 RF Bridge Transmission Coefficient {TC= [n(n+1)]1/2} . . . . . . . . . . . . . . 0.790 RF Bridge Coupling Coefficient [C=(n+1) -1/2] . . . . . . . . . . . . . . . . 0.613 Linac Steady-State Input Power (PA) . . . . . 65 MW Unloaded Average Accelerating Gradient . . . 108 MV/m Klystron Power . . . . . . . . . . . . . . . . 26 MW HAIMSON RESEARCH CORPORATION 13 July 2009 An 11.424 MHz Dual Resonant Ring System for High Gradient Testing CLIC/KEK/SLAC T18 Structures Power Distribution to Achieve an Unloaded Accelerating Gradient of 108 MV/m 21.4 MW 32.5 MW 21.4 MW 32.5 MW 26 MW HAIMSON RESEARCH CORPORATION 14 July 2009 -4.77 dB (1/3) Directional Coupler 0.900” 2.4076” 0.5381” 1.4104” 0.4928” r=0.250” r=0.0625” @ 600 MW, 1.435” height: |Esmax| = ~45.6 MV/m |Hsmax| = ~160 kA/m C. Nantista ’03 15 July 2009 HAIMSON RESEARCH CORPORATION 16 July 2009 With Adaptive Meshing M = 1177344 21/15/10R6 HAIMSON RESEARCH CORPORATION 17 July 2009 HAIMSON RESEARCH CORPORATION 18 July 2009 11.424 GHz High Gradient Testing of a T18 TW Structure Using a Fast Response Protection and Power Recirculating System Work performed under the auspices of the U.S. Department of Energy SBIR Grant No. DE-FG02-08ER85197 HAIMSON RESEARCH CORPORATION 19 AAC2008 s11cfsh5.epw TRIPLE HYBRID M (PA/PS) 0.8 = 1.25 dB = 1.35 dB (PL/PS) 4 3 TEST DATA 0.4 M 0.2 R 0 50 PSh DC = 1.15 dB 0.6 0 R 5 W 100 2 f = 17.1 GHz n = 3.0 c = 0.5 =FTotal Loss in Feedback Loop DC 150 200 ELAPSED TIME (ns) 1 LINAC INPUT POWER (PA/PS) 17 GHz TWRK RF LOAD POWER (PL/PS) 1.0 0 250 F (b) R F LOAD DC HYBRID (A) R DC F FC INJECTOR 22 CAVITY TEST LINAC 94 CAVITY TW LINAC SPECTROMETER LOAD F FC DC R (B) F R HYBRID LOAD DC HAIMSON RESEARCH CORPORATION