Demonstration of a 17-GHz, high-gradient accelerator with a photonic-band-gap structure

• Published in: Physical review letters 2005-08, Vol.95 (7), p.074801.1-074801.4, Article 074801
• Main Authors: SMIRNOVA, Evgenya I, KESAR, Amit S, MASTOVSKY, Ivan, SHAPIRO, Michael A, TEMKIN, Richard J
• Format: Article
• Language: English
• Subjects: Charged-particle beams; Electromagnetism; electron and ion optics; ELECTRON BEAMS; Electrostatic, collective, and linear accelerators; Exact sciences and technology; Experimental methods and instrumentation for elementary-particle and nuclear physics; Fundamental areas of phenomenology (including applications); GHZ RANGE 01-100; INSTABILITY; KLYSTRONS; MEV RANGE 01-10; MEV RANGE 10-100; Nuclear physics; Optical materials; Optics; Other advanced accelerator concepts; PARTICLE ACCELERATORS; Photonic bandgap materials; Physics; PULSES; RF SYSTEMS; TESTING; WAKEFIELD ACCELERATORS
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/PhysRevLett.95.074801

We report the testing of a high gradient electron accelerator with a photonic-band-gap (PBG) structure. The photonic-band-gap structure confines a fundamental TM(01)-like accelerating mode, but does not support higher-order modes (HOM). The absence of HOM is a major advantage of the PBG accelerator, since it suppresses dangerous beam instabilities caused by wakefields. The PBG structure was designed as a triangular lattice of metal rods with a missing central rod forming a defect confining the TM(01)-like mode and allowing the electron beam to propagate along the axis. The design frequency of the six-cell structure was 17.14 GHz. The PBG structure was excited by 2 MW, 100 ns pulses. A 16.5 MeV electron beam was transmitted through the PBG accelerator. The observed electron beam energy gain of 1.4 MeV corresponds to an accelerating gradient of 35 MV/m, in excellent agreement with theory.