Paper |
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MOPB63 |
Emittance Measurement using X-ray Beam Profile Monitor at KEK-ATF |
215 |
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- T. Naito, H. Hayano, K. Kubo, S. Kuroda, N. Nakamura, T. Okugi, H. Sakai, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan
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The X-ray profile monitor (XPM) is used for the beam size measurement in the KEK-ATF damping ring(ATF-DR) at all times. The XPM consists of a crystal monochromator, two Fresnel zone plates(FZPs) and X-ray CCD camera. Two FZPs make the imaging optics. The design resolution of the selected wavelength 3.8nm is less than 1μm, which is sufficiently small for the emittance measurement of the ATF-DR. However, the measured results at the early stage were affected by the mechanical vibration. This paper describes the improvement of the resolution and the measurement results.
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TUCC04 |
Measurement of Nanometer Electron Beam Sizes with Laser Interference using IPBSM |
310 |
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- J.N. Yan, S. Komamiya, M. Oroku, T.S. Suehara, Y. Yamaguchi, T. Yamanaka
University of Tokyo, Tokyo, Japan
- S. Araki, T. Okugi, T. Tauchi, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan
- Y. Kamiya
ICEPP, Tokyo, Japan
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At ATF2, the Local Chromaticity Correction focusing scheme is to be verified through realizing its design vertical e- beam size (σy ) of 37 nm. The 'IPBSM', installed at ATF2's virtual IP, is the only existing beam size monitor capable of measuring σy < 100 nm, making it indispensable for ATF's goals and R&D at future LCs. This owes to a novel technique of colliding e- beam against laser interference fringes. σy is derived from the modulation depth of resulting Compton photons, which is large for small σy. The measurable range from O(10) nm ~ a few μm, is controlled by switching between laser crossing angles θ = 174° , 30°, and 2° - 8° . In early 2011, measuring σy < 300 nm was hindered by an immense earthquake and heavy signal jitters. The ensuing recovery and upgrades stabilized the laser system and improved resolution to 5%. In spring 2012, we commissioned advanced crossing angle modes by consistently measuring σy ≥ 150 nm. Our goals for the autumn 2012 run is to stably measure σy < 50 nm. Major hardware upgrades during the summer aim at more reliable alignment and optimization of specialized functions to suppress bias factors.
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Slides TUCC04 [10.535 MB]
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