IBIC2015 - List of Authors (Mitsuhashi, T.M.)

Paper	Title	Page
TUCLA03	Design of Coronagraph for the Observation of Beam Halo at LHC	288
	T.M. Mitsuhashi KEK, Ibaraki, Japan E. Bravin, O.R. Jones, F. Roncarolo, H. Schmickler, G. Trad CERN, Geneva, Switzerland
	In the LHC, the beam halo due to higher beam energy and intensities will increase the impact on LHC machine protection and on luminosity performance. Measurement of the beam halo distribution is therefore important for understanding and controlling the beam halo. A coronagraph was designed for the observation of the beam halo population. A new optical design of the coronagraph is made for the halo observation in the LHC. For convenience of masking the core image, we need a large transverse magnification. For this purpose, a telephoto lens arrangement is applied to the adjective lens to extend the focal length to obtain a large transverse magnification. The result of diffraction analysis, the contrast is estimated better than 10⁶. Since the beam halo is estimated to 10⁴ -10⁵ of the core intensity, the coronagraph is estimated to have enough contrast for the observation of beam halo distribution at LHC. This paper describes the detail study of the coronagraph for the LHC for the observation of transverse profile of the beam halo with a contrast down to a level of 10^-6 compared to the peak intensity of the beam core.
	Slides TUCLA03 [15.524 MB]
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TUPB021	Characterization of the SR Visible Beam Polarization State at SPEAR3	364
	C.L. Li East China University of Science and Technology, Shanghai, People's Republic of China W.J. Corbett SLAC, Menlo Park, California, USA T.M. Mitsuhashi KEK, Ibaraki, Japan
	Synchrotron radiation has the well-known property of horizontal field polarization in the midplane with increasingly elliptical polarization in the vertical plane. By measuring the beam intensity transmitted through a linear polarizer, it is possible to characterize the beam polarization state, determine the Stokes' parameters and solve for the beam polarization ellipse in the visible portion of the SR spectrum. The results can be compared with Schwinger's equations for synchrotron radiation taking into account the effect of extraction mirrors.
	Poster TUPB021 [1.605 MB]
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TUPB024	Beam Halo Measurement Utilizing YAG:Ce Screen	373
	T. Naito, T.M. Mitsuhashi KEK, Ibaraki, Japan
	Funding: Photon and Quantum Basic Research Coordinated Development Program from the Ministry of Education, Culture, Sports, Science and Technology, Japan. At the ATF2 project, we are aiming to produce an extremely small beam having a vertical beam size of 37 nm. The beam halo surrounding of beam core will make a background for the beam size measurement using the Laser interferometer beam size monitor. The understanding of beam halo distribution is important for measurement of the beam size at the final focus point of ATF2. In order to measure the beam halo distribution, we developed a beam halo monitor based on fluorescence screen. A YAG:Ce screen, which has 1 mm slit in the center is set in the beam line. The image on fluorescence screen is observed by imaging lens system and CCD camera. In this configuration, the beam in the core will pass through the slit. The beam in the surrounding halo will hit the fluorescence screen, and we can observe the distribution of beam halo. The intensity contrast of beam halo to the beam core is measured by scanning the beam position for the fixed fluorescence screen position. The results of observation of beam halo are presented.
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Paper

Title

Page

Design of Coronagraph for the Observation of Beam Halo at LHC

288

T.M. Mitsuhashi
KEK, Ibaraki, Japan
E. Bravin, O.R. Jones, F. Roncarolo, H. Schmickler, G. Trad
CERN, Geneva, Switzerland

In the LHC, the beam halo due to higher beam energy and intensities will increase the impact on LHC machine protection and on luminosity performance. Measurement of the beam halo distribution is therefore important for understanding and controlling the beam halo. A coronagraph was designed for the observation of the beam halo population. A new optical design of the coronagraph is made for the halo observation in the LHC. For convenience of masking the core image, we need a large transverse magnification. For this purpose, a telephoto lens arrangement is applied to the adjective lens to extend the focal length to obtain a large transverse magnification. The result of diffraction analysis, the contrast is estimated better than 10⁶. Since the beam halo is estimated to 10⁴ -10⁵ of the core intensity, the coronagraph is estimated to have enough contrast for the observation of beam halo distribution at LHC. This paper describes the detail study of the coronagraph for the LHC for the observation of transverse profile of the beam halo with a contrast down to a level of 10^-6 compared to the peak intensity of the beam core.

Slides TUCLA03 [15.524 MB]

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reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text, ※ RIS/RefMan, ※ EndNote (xml)

TUPB021

Characterization of the SR Visible Beam Polarization State at SPEAR3

364

C.L. Li
East China University of Science and Technology, Shanghai, People's Republic of China
W.J. Corbett
SLAC, Menlo Park, California, USA
T.M. Mitsuhashi
KEK, Ibaraki, Japan

Synchrotron radiation has the well-known property of horizontal field polarization in the midplane with increasingly elliptical polarization in the vertical plane. By measuring the beam intensity transmitted through a linear polarizer, it is possible to characterize the beam polarization state, determine the Stokes' parameters and solve for the beam polarization ellipse in the visible portion of the SR spectrum. The results can be compared with Schwinger's equations for synchrotron radiation taking into account the effect of extraction mirrors.

Poster TUPB021 [1.605 MB]

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reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text, ※ RIS/RefMan, ※ EndNote (xml)

TUPB024

Beam Halo Measurement Utilizing YAG:Ce Screen

373

T. Naito, T.M. Mitsuhashi
KEK, Ibaraki, Japan

Funding: Photon and Quantum Basic Research Coordinated Development Program from the Ministry of Education, Culture, Sports, Science and Technology, Japan.
At the ATF2 project, we are aiming to produce an extremely small beam having a vertical beam size of 37 nm. The beam halo surrounding of beam core will make a background for the beam size measurement using the Laser interferometer beam size monitor. The understanding of beam halo distribution is important for measurement of the beam size at the final focus point of ATF2. In order to measure the beam halo distribution, we developed a beam halo monitor based on fluorescence screen. A YAG:Ce screen, which has 1 mm slit in the center is set in the beam line. The image on fluorescence screen is observed by imaging lens system and CCD camera. In this configuration, the beam in the core will pass through the slit. The beam in the surrounding halo will hit the fluorescence screen, and we can observe the distribution of beam halo. The intensity contrast of beam halo to the beam core is measured by scanning the beam position for the fixed fluorescence screen position. The results of observation of beam halo are presented.

Export •

reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text, ※ RIS/RefMan, ※ EndNote (xml)