FEL oscillation with a high extraction efficiency at JAEA ERL FEL

Nobuyuki Nishimori, R. Hajima, H. Iijima, N. Kikuzawa, E. Minehara, R. Nagai, T. Nishitani, M. Sawamura

Research output: Contribution to conferencePaperpeer-review

2 Citations (Scopus)


One of challenges that high-power FEL oscillators driven by energy recovery linac (ERL) are facing is to increase the extraction FEL efficiency as high as possible. The high-efficiency oscillation relaxes the total beam current needed for high-power lasing and makes the optical micropulse length shorter, which is useful for various applications. Two triple bend achromatic arcs have been used in a recovery loop for an ERL FEL at Japan Atomic Energy Agency (JAEA). The return arc after an undulator has an energy acceptance of 15%, which is large enough to recover the electron beam used for high-efficiency FEL oscillation. Recently we have achieved the efficiency exceeding 2%, which accompanies large energy spread, by doubling the electron bunch repetition rate. The FEL efficiency has been measured from the horizontal profiles of the exhausted electron beam with a wire scanner installed at a dispersive point in the return arc. The other arc placed upstream of the undulator has been found to work as a bunch compressor for the high-efficiency FEL oscillation.

Original languageEnglish
Number of pages8
Publication statusPublished - 2006 Dec 1
Event28th International Free Electron Laser Conference, FEL 2006 - Berlin, Germany
Duration: 2006 Aug 272006 Sep 1


Other28th International Free Electron Laser Conference, FEL 2006

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

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