IPAC2017 - List of Authors (Mitsuhashi, T.M.)

Paper	Title	Page
MOOCB3	Intensity Interferometer to Measure Bunch Length at SPEAR3	60
	W.J. Corbett SLAC, Menlo Park, California, USA T.M. Mitsuhashi KEK, Ibaraki, Japan
	Electron bunch length in a storage ring is typically measured with streak cameras, electro-optic devices or non-linear cross-correlation techniques with a range of system complexity, signal-to-noise ratios and cost. Another straight-forward method is to construct an 'intensity interferometer' utilizing a coincidence detector to record simultaneous photon arrival events. In this configuration, visible SR light is passed through a narrow bandpass filter followed by a small pinhole to generate a stream of single-mode monochromatic wavepackets. As the interferometer delay is scanned across an electron bunch, two-photon events occurring within the longitudinal coherence time of the light cause a reduction in the measured coincidence rate. The resulting autocorrelation of the optical pulse duration reveals the electron bunch length, independent of synchrotron oscillation motion. In this paper we comment on the theory and report on preliminary measurements carried out at SPEAR3.
	Slides MOOCB3 [2.606 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOOCB3
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TUOAB2	First Observation of the LHC Beam Halo Using a Synchrotron Radiation Coronagraph	1244
	T.M. Mitsuhashi KEK, Ibaraki, Japan E. Bravin, F. Roncarolo, G. Trad CERN, Geneva, Switzerland
	A test coronagraph for the observation of beam halo has been installed in the Synchrotron radiation monitor line LHCB2 in 2015. This coronagraph is commissioned with LHC operation at 450GeV (injection energy). After some optical testing of the coronagraph with visible Synchrotron radiation in B2, we try to observe artificially-made beam halo. The beam halo of 10^-3 order of magnitude against the beam core is excited by the kicker of the transverse damper. We have succeeded to observe a diffraction noise free image of beam halo. The effect of beam collimator is also observed. Reduction of beam halo intensity was found nicely proportional to the simultaneously-recorded beam loss.
	Slides TUOAB2 [8.302 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUOAB2
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Intensity Interferometer to Measure Bunch Length at SPEAR3

60

W.J. Corbett
SLAC, Menlo Park, California, USA
T.M. Mitsuhashi
KEK, Ibaraki, Japan

Electron bunch length in a storage ring is typically measured with streak cameras, electro-optic devices or non-linear cross-correlation techniques with a range of system complexity, signal-to-noise ratios and cost. Another straight-forward method is to construct an 'intensity interferometer' utilizing a coincidence detector to record simultaneous photon arrival events. In this configuration, visible SR light is passed through a narrow bandpass filter followed by a small pinhole to generate a stream of single-mode monochromatic wavepackets. As the interferometer delay is scanned across an electron bunch, two-photon events occurring within the longitudinal coherence time of the light cause a reduction in the measured coincidence rate. The resulting autocorrelation of the optical pulse duration reveals the electron bunch length, independent of synchrotron oscillation motion. In this paper we comment on the theory and report on preliminary measurements carried out at SPEAR3.

Slides MOOCB3 [2.606 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOOCB3

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUOAB2

First Observation of the LHC Beam Halo Using a Synchrotron Radiation Coronagraph

1244

T.M. Mitsuhashi
KEK, Ibaraki, Japan
E. Bravin, F. Roncarolo, G. Trad
CERN, Geneva, Switzerland

A test coronagraph for the observation of beam halo has been installed in the Synchrotron radiation monitor line LHCB2 in 2015. This coronagraph is commissioned with LHC operation at 450GeV (injection energy). After some optical testing of the coronagraph with visible Synchrotron radiation in B2, we try to observe artificially-made beam halo. The beam halo of 10^-3 order of magnitude against the beam core is excited by the kicker of the transverse damper. We have succeeded to observe a diffraction noise free image of beam halo. The effect of beam collimator is also observed. Reduction of beam halo intensity was found nicely proportional to the simultaneously-recorded beam loss.

Slides TUOAB2 [8.302 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUOAB2

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)