IPAC2016 - List of Authors (Hama, H.)

Paper	Title	Page
MOPMB029	Development Status of Linear Focal Cherenkov Ring Camera	152
	K. Nanbu, T. Abe, H. Hama, F. Hinode, S. Kashiwagi, T. Muto, I. Nagasawa, H. Saito, K. Takahashi, C. Tokoku Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
	Linear focal Cherenkov ring camera (LFC-Camera) has been developed for single shot measurement of longitudinal phase space distribution of quasi-relativistic electron beam, where the electron's velocity still depends on its energy. The LFC-camera employs velocity dependence of opening angle of Cherenkov light produced by electron beam to observe its energy (momentum) distribution. Since the Cherenkov light contains the time information if the radiator medium is thin enough, we can get the longitudinal phase space distribution measuring both time and energy spectra simultaneously using a streak camera. We employ a thin silica aerogel with water-free hydrophobic treatment as Cherenkov radiator. We have evaluated characteristics of the silica aerogel radiator, and demonstration of the LFC-camera at a beam diagnosis section of t-ATCS is being proceeded.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB029
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MOPOW001	Status of the 1.3 GeV Booster Synchrotron for Generating High Energy Gamma Rays at Tohoku University	701
	F. Hinode, H. Hama, S. Kashiwagi, T. Muto, I. Nagasawa, K. Nanbu, Y. Shibasaki, K. Takahashi, C. Tokoku Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
	The reconstruction work of accelerator complex for the Great East Japan Earthquake in March 2011 had been conducted in Research Center of Electron Photon Science, Tohoku University. Since restoration of the user machine time in 2013, the approved beam time have been regularly implemented as scheduled. Currently, the 1.3 GeV Booster STorage (BST) ring has been well utilized to generate the high energy gamma-rays as before the disaster. The high energy gamma-rays were produced via Bremsstrahlung by inserting an internal target wire to the beam orbit after the beam acceleration. Since the user machine time was recovered, there were some improvements so far, i.e. realignment of synchrotron magnets, orbit correction in energy ramping process by updating the control of power supplies for steering magnets etc., which brought an increase of the beam current in the maximum energy. Present operational status and recent progress of beam performance in the BST ring are reported.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW001
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TUPOW009	Generation of Coherent Undulator Radiation using Extremely Short Electron Bunch at t-ACTS, Tohoku University	1760
	S. Kashiwagi, T. Abe, H. Hama, F. Hinode, T. Muto, I. Nagasawa, K. Nanbu, H. Saito, Y. Shibasaki, K. Takahashi, C. Tokoku Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
	An accelerator test facility, t-ACTS, was established at Research Center for Electron Photon Science, Tohoku University, in which an intense coherent terahertz (THz) radiation is generated from an extremely short electron bunch. Velocity bunching scheme in a traveling-wave accelerating structure is employed to produce the short electron bunch, and a production of sub-picosecond electron bunch was demonstrated. A long-period linear undulator, which has 25 periods with a period length of 10 cm and a peak magnetic field of 0.41 T, has been developed to produce intense coherent THz radiation. Properties of the radiation from the THz undulator such as radiation fields, spectrum and angular distribution were numerically investigated based on the parameters of short electron bunch and THz undulator. By optimization of bunch compression, it is possible to extract a coherent radiation of fundamental mode excluding higher-order mode. The detail of the numerical studies for the coherent undulator radiation will be reported in the conference.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW009
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TUPOW010	Production of Ultra-short Electron Pulse and Observation of Coherent Transition Radiation at t-ACTS, Tohoku University	1763
	T. Abe, H. Hama, F. Hinode, S. Kashiwagi, T. Muto, I. Nagasawa, K. Nanbu, H. Saito, Y. Shibasaki, K. Takahashi, C. Tokoku Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
	A test-Accelerator as Coherent Terahertz Source (t-ACTS) project has been under development at Research Center for Electron Photon Science, Tohoku University. In order to generate a coherent radiation in terahertz (THz) region, it is necessary to produce sub-picosecond electron pulses. Velocity bunching scheme is employed for the short electron pulse production in t-ACTS. We experimentally confirmed the production of short electron pulse under 500 fs by measuring the bunch length using a streak camera. Coherent transition radiation in THz region was produced by which the short electron pulses pass through a vacuum-metal interface. Several radiation properties including　spatial distribution, polarization and spectrum were measured and compared with theoretical calculations. The details of the beam experiment at t-ACTS are described.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW010
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TUPOW011	Profile Measurements of Bremsstrahlung Gamma-Rays from Tungsten Plates for Radioactive Isotope Production via Photonuclear Reaction using a 60 MeV Electron Linac	1766
	K. Takahashi, H. Hama, F. Hinode, S. Kashiwagi, H. Kikunaga, T. Muto, I. Nagasawa, K. Nanbu, Y. Shibasaki, T. Suda, C. Tokoku, K. Tsukada Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
	Radioactive isotopes have been produced via photo-nuclear reaction using a 60 MeV high-power electron linac for research fields of nuclear chemistry and radioac-tive analysis at Research Center for Electron Photon Science (ELPH), Tohoku University. The electron beam with an average current more than 100 μA is transported to an electron-bremsstrahlung gamma-ray converter of 2 mm thickness platinum or tungsten plate at the irradiation station. A target of 10 mm diameter is placed 3 cm behind a converter. It is enclosed with a quartz glass in the water cooling system and is irradiated for photonuclear reaction. Since the correlation between the spatial profile of bremsstrahlung gamma-rays at the target position and accelerator parameters is of our primary interest, nickel thin films are irradiated and the profiles of bremsstrahlung gamma-rays are measured by intensity distribution measurements of 57Ni radioactivity using the phosphorus imaging plate. In the meantime, the beam emittance and Twiss parameters are measured.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW011
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Paper

Title

Page

Development Status of Linear Focal Cherenkov Ring Camera

152

K. Nanbu, T. Abe, H. Hama, F. Hinode, S. Kashiwagi, T. Muto, I. Nagasawa, H. Saito, K. Takahashi, C. Tokoku
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan

Linear focal Cherenkov ring camera (LFC-Camera) has been developed for single shot measurement of longitudinal phase space distribution of quasi-relativistic electron beam, where the electron's velocity still depends on its energy. The LFC-camera employs velocity dependence of opening angle of Cherenkov light produced by electron beam to observe its energy (momentum) distribution. Since the Cherenkov light contains the time information if the radiator medium is thin enough, we can get the longitudinal phase space distribution measuring both time and energy spectra simultaneously using a streak camera. We employ a thin silica aerogel with water-free hydrophobic treatment as Cherenkov radiator. We have evaluated characteristics of the silica aerogel radiator, and demonstration of the LFC-camera at a beam diagnosis section of t-ATCS is being proceeded.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB029

Export •

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

MOPOW001

Status of the 1.3 GeV Booster Synchrotron for Generating High Energy Gamma Rays at Tohoku University

701

F. Hinode, H. Hama, S. Kashiwagi, T. Muto, I. Nagasawa, K. Nanbu, Y. Shibasaki, K. Takahashi, C. Tokoku
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan

The reconstruction work of accelerator complex for the Great East Japan Earthquake in March 2011 had been conducted in Research Center of Electron Photon Science, Tohoku University. Since restoration of the user machine time in 2013, the approved beam time have been regularly implemented as scheduled. Currently, the 1.3 GeV Booster STorage (BST) ring has been well utilized to generate the high energy gamma-rays as before the disaster. The high energy gamma-rays were produced via Bremsstrahlung by inserting an internal target wire to the beam orbit after the beam acceleration. Since the user machine time was recovered, there were some improvements so far, i.e. realignment of synchrotron magnets, orbit correction in energy ramping process by updating the control of power supplies for steering magnets etc., which brought an increase of the beam current in the maximum energy. Present operational status and recent progress of beam performance in the BST ring are reported.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW001

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TUPOW009

Generation of Coherent Undulator Radiation using Extremely Short Electron Bunch at t-ACTS, Tohoku University

1760

S. Kashiwagi, T. Abe, H. Hama, F. Hinode, T. Muto, I. Nagasawa, K. Nanbu, H. Saito, Y. Shibasaki, K. Takahashi, C. Tokoku
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan

An accelerator test facility, t-ACTS, was established at Research Center for Electron Photon Science, Tohoku University, in which an intense coherent terahertz (THz) radiation is generated from an extremely short electron bunch. Velocity bunching scheme in a traveling-wave accelerating structure is employed to produce the short electron bunch, and a production of sub-picosecond electron bunch was demonstrated. A long-period linear undulator, which has 25 periods with a period length of 10 cm and a peak magnetic field of 0.41 T, has been developed to produce intense coherent THz radiation. Properties of the radiation from the THz undulator such as radiation fields, spectrum and angular distribution were numerically investigated based on the parameters of short electron bunch and THz undulator. By optimization of bunch compression, it is possible to extract a coherent radiation of fundamental mode excluding higher-order mode. The detail of the numerical studies for the coherent undulator radiation will be reported in the conference.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW009

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TUPOW010

Production of Ultra-short Electron Pulse and Observation of Coherent Transition Radiation at t-ACTS, Tohoku University

1763

T. Abe, H. Hama, F. Hinode, S. Kashiwagi, T. Muto, I. Nagasawa, K. Nanbu, H. Saito, Y. Shibasaki, K. Takahashi, C. Tokoku
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan

A test-Accelerator as Coherent Terahertz Source (t-ACTS) project has been under development at Research Center for Electron Photon Science, Tohoku University. In order to generate a coherent radiation in terahertz (THz) region, it is necessary to produce sub-picosecond electron pulses. Velocity bunching scheme is employed for the short electron pulse production in t-ACTS. We experimentally confirmed the production of short electron pulse under 500 fs by measuring the bunch length using a streak camera. Coherent transition radiation in THz region was produced by which the short electron pulses pass through a vacuum-metal interface. Several radiation properties including　spatial distribution, polarization and spectrum were measured and compared with theoretical calculations. The details of the beam experiment at t-ACTS are described.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW010

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TUPOW011

Profile Measurements of Bremsstrahlung Gamma-Rays from Tungsten Plates for Radioactive Isotope Production via Photonuclear Reaction using a 60 MeV Electron Linac

1766

K. Takahashi, H. Hama, F. Hinode, S. Kashiwagi, H. Kikunaga, T. Muto, I. Nagasawa, K. Nanbu, Y. Shibasaki, T. Suda, C. Tokoku, K. Tsukada
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan

Radioactive isotopes have been produced via photo-nuclear reaction using a 60 MeV high-power electron linac for research fields of nuclear chemistry and radioac-tive analysis at Research Center for Electron Photon Science (ELPH), Tohoku University. The electron beam with an average current more than 100 μA is transported to an electron-bremsstrahlung gamma-ray converter of 2 mm thickness platinum or tungsten plate at the irradiation station. A target of 10 mm diameter is placed 3 cm behind a converter. It is enclosed with a quartz glass in the water cooling system and is irradiated for photonuclear reaction. Since the correlation between the spatial profile of bremsstrahlung gamma-rays at the target position and accelerator parameters is of our primary interest, nickel thin films are irradiated and the profiles of bremsstrahlung gamma-rays are measured by intensity distribution measurements of 57Ni radioactivity using the phosphorus imaging plate. In the meantime, the beam emittance and Twiss parameters are measured.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW011

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