Evaluation of extremely small horizontal emittance

T. Okugi, T. Hirose, H. Hayano, S. Kamada, K. Kubo, T. Naito, K. Oide, K. Takata, Seishi Takeda, N. Terunuma, N. Toge, J. Urakawa, S. Kashiwagi, M. Takano, D. McCormick, M. Minty, M. Ross, M. Woodley, F. Zimmermann, J. Corlett

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


The KEK Accelerator Test Facility (KEK-ATF) was constructed to develop technologies for producing a low-emittance beam which will be required by future linear colliders. The KEK-ATF consists of an injector linac, a damping ring, and a beam extraction line. The basic optical structure of the damping ring is a FOBO lattice, which reduces the horizontal dispersion at the center of the bending magnets and, as a consequence, can produce an extremely small emittance beam. To verify the performance of such a unique, low-emittance lattice, it is crucial to measure the horizontal emittance. The horizontal emittance was measured using wire scanners in the beam extraction line. Since the horizontal beam position was not stable, we established a method to correct the measured beam size for position fluctuation ("jitter") and we succeeded in the observation of the so far smallest horizontal emittance in any accelerator. The measured horizontal emittance was 1.37 ± 0.03 nm at a beam energy of 1.285 GeV and a bunch population of (3-5) × 109, in agreement with the design value of 1.27-1.34 nm at the beam energy and the bunch population.

Original languageEnglish
Article number022801
Pages (from-to)6-15
Number of pages10
JournalPhysical Review Special Topics - Accelerators and Beams
Issue number2
Publication statusPublished - 1999
Externally publishedYes

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Physics and Astronomy (miscellaneous)
  • Surfaces and Interfaces


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