IPAC2017 - List of Authors (Terunuma, N.)

Paper	Title	Page
MOPAB111	Diffraction Radiation for Non-Invasive, High-Resolution Beam Size Measurements in Future Linear Colliders	381
SUSPSIK079	use link to see paper's listing under its alternate paper code
	M. Bergamaschi, R. Kieffer, T. Lefèvre, S. Mazzoni CERN, Geneva, Switzerland A. Aryshev, N. Terunuma KEK, Ibaraki, Japan M. Bergamaschi, P. Karataev, K.O. Kruchinin JAI, Egham, Surrey, United Kingdom M. Bergamaschi, P. Karataev, K.O. Kruchinin Royal Holloway, University of London, Surrey, United Kingdom
	Next generation linear colliders such as the Compact Linear Collider (CLIC) or the International Linear Collider (ILC) will accelerate particle beams with extremely small emittance. The high current and small size of the beam (micron-scale) due to such small emittance require non-invasive, high-resolution techniques for beam diagnostics. Diffraction Radiation (DR), a polarization radiation that appears when a charged particle moves in the vicinity of a medium, is an ideal candidate being non-invasive and allowing beams as small as a few tens of microns to be measured. Since DR is sensitive to beam parameters other than the transverse profile (e.g. its divergence and position), preparatory simulations have been performed with realistic beam parameters. A new dedicated instrument was installed in the KEK-ATF2 beam line in February 2016. At present DR is observed in the visible wavelength range, with an upgrade to the ultraviolet (200nm) planned for spring 2017 to optimize sensitivity to smaller beam sizes. Presented here are the latest results of these DR beam size measurements and simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB111
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MOPAB128	The Design of a Non-Destructive Single-Shot Longitudinal Bunch Profile Monitor using Smith-Purcell Radiation	433
	H. Harrison, G. Doucas, I.V. Konoplev, A.J. Lancaster, H. Zhang JAI, Oxford, United Kingdom A. Aryshev, M. Shevelev, N. Terunuma, J. Urakawa KEK, Ibaraki, Japan
	Funding: This work was supported by the: the STFC UK, the Leverhulme Trust, the JAI (University of Oxford) and the Photon and Quantum Basic Research Coordinated Development (Japan). The conceptual design for a single-shot longitudinal bunch profile monitor using coherent Smith-Purcell radiation (cSPr) has recently been completed. The exploitation of the directionality and the polarization of cSPr to reduce the length of the monitor and to eliminate background radiation are discussed. The linear polarization of cSPr will be used to separate the signal from background radiation and experiments to test this design will be presented. Alongside the conceptual design an investigation to optimize the number of detection channels needed to produce high quality longitudinal bunch profile reconstructions has been carried out. It has been determined that the number of detection channels can be reduced compared to previous experiments if measurement uncertainty and background radiation are minimized effectively.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB128
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MOPIK009	Characterization of Cold Model Cavity for Cryocooled C-Band 2.6-Cell Photocathode RF Gun at 20 K	518
	T. Tanaka, K. Hayakawa, Y. Hayakawa, K. Nakao, K. Nogami, T. Sakai, K. Takatsuka LEBRA, Funabashi, Japan M.K. Fukuda, D. Satoh, T. Takatomi, N. Terunuma, J. Urakawa, M. Yoshida KEK, Ibaraki, Japan
	Funding: This work was partly supported by the Photon and Quantum Basic Research Coordinated Development Program of the Japanese Ministry of Education, Culture, Sports, Science, and Technology (MEXT). A cryocooled C-band 2.6-cell photocathode RF electron gun has been studied at Nihon University in cooperation with KEK. The cold model cavity with an input coupler was completed in spring 2016. The RF characteristics measured at room temperature were in agreement with the prediction by the CST Studio simulation. The RF characteristics at 20 K have been measured using a rather simple cavity-cooling vacuum system that was built by using existing components for tentative experiments. A thin-wall stainless-steel R48 waveguide with copper-plated inner walls has been used for the RF power transmission from the room-temperature input port to the 20-K cooled coupler waveguide. The unloaded Q-value of 73000 has been obtained by the reflection coefficient measurement at 20 K, which is in agreement with the result of the CST Studio simulation using the cavity surface resistance predicted by the theory of the anomalous skin effect.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK009
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TUPIK097	Improving the Performance of an Orbit Feed-forward Based on Quadrupole Motion at the KEK ATF	1931
	D.R. Bett, C. Charrondière, M. Patecki, J. Pfingstner, D. Schulte, R. Tomás CERN, Geneva, Switzerland P. Burrows, G.B. Christian, C. Perry JAI, Oxford, United Kingdom A. Jeremie IN2P3-LAPP, Annecy-le-Vieux, France K. Kubo, S. Kuroda, T. Naito, T. Okugi, T.T. Tauchi, N. Terunuma KEK, Ibaraki, Japan
	The high luminosity requirement for a future linear collider sets a demanding limit on the beam quality at the Interation Point (IP). Even the natural motion of the ground could misalign the quadrupole magnets to such an extent that the resulting dipole kicks would require compensation. The novel technique described in this paper uses seismometers to measure the positions of the quadrupole magnets in real time and a kicker to counteract the effect of their misalignment. The prototype system deployed at the Accelerator Test Facility (ATF) at KEK in Japan has already demonstrated a reduction in the pulse-to-pulse vertical position jitter of the beam by about 10%. Based on the observed correlation of the beam position to the quadrupole positions the maximum possible jitter reduction from such a system is estimated to be about 25%. This paper details the latest improvements made to the system with the aim of achieving this limit.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPIK097
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WEPVA018	Drive-Witness Acceleration Scheme Based on Corrugated Dielectric mm-Scale Capillary	3292
	K. Lekomtsev, S.T. Boogert, P. Karataev, A. Lyapin JAI, Egham, Surrey, United Kingdom A. Aryshev, M. Shevelev, N. Terunuma, J. Urakawa KEK, Ibaraki, Japan A.A. Tishchenko MEPhI, Moscow, Russia
	Funding: This project has received funding from the European Union Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 655179. In this paper, we investigate a corrugated mm-scale capillary as a compact accelerating structure in a drive-witness acceleration scheme, and suggest a methodology to measure acceleration of a witness bunch. Two typical measurements and the energy gain in a witness bunch as a function of the distance between bunches are discussed. A corrugated capillary is considered as an accelerator/decelerator with an adjustable wakefield pattern depending on a transverse beam position.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA018
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THOAB3	Ultrafast Relativistic-Energy Electron Microscopy
	J. Yang, K. Kan, T. Kondoh, K. Tanimura, Y. Yoshida ISIR, Osaka, Japan N. Terunuma, J. Urakawa KEK, Ibaraki, Japan
	An ultrafast electron microscopy (UEM) using a relativistic-energy femtosecond-pulse electron beam has being developed at Osaka University. We succeeded to generate a 100-fs-pulse electron beam with energy of 3.1 MeV using a photocathode RF gun. In the demonstrations of UEM, we succeeded to observe the TEM imaging of polystyrene and gold nanoparticles by the accumulating measurement of 3.1-MeV femtosecond electron pulses. The relativistic-energy single-pulse electron imaging is also available under the low-magnification observation, i.e. 300 times. The UEM has also been succeeded for the study of the ultrafast structural dynamics in materials with the single-shot electron diffraction observation.
	Slides THOAB3 [12.396 MB]
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THPVA002	Numerical Investigation of Beam Halo From Beam Gas Scattering in KEK-ATF	4410
	R.J. Yang, P. Bambade LAL, Orsay, France K. Kubo, T. Okugi, N. Terunuma, D. Zhou KEK, Ibaraki, Japan
	To demonstrate the final focus schemes of the Future Linear Collider (FLC), the Accelerator Test Facility 2 (ATF2) at KEK is devoted to focus the beam to a RMS size of a few tens of nanometers (nm) vertically and to provide stability at the nm level at the virtual Interaction Point (IP). However, the loss of halo particles upstream will introduce background to the diagnostic instrument measuring the ultra-small beam, using a laser interferometer monitor. To help the realization of the above goals and beam operation, understanding and mitigation of beam halo are crucial. In this paper, we present the systematical simulation of beam halo formation from beam gas Coulomb scattering (BGS) in the ATF damping ring. The behavior of beam halo with various machine parameters is also discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA002
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THPVA141	Non-Destructive Measurement of Electron Microbunch Separation	4798
SUSPSIK122	use link to see paper's listing under its alternate paper code
	H. Zhang, G. Doucas, H. Harrison, I.V. Konoplev, A.J. Lancaster JAI, Oxford, United Kingdom A. Aryshev, M. Shevelev, N. Terunuma, J. Urakawa KEK, Ibaraki, Japan
	With the development of femtosecond lasers, the generation of micro-bunched beams directly from a photocathode becomes routine; however, the monitoring of the separation is still a challenge. We present the results of proof-of-principle experiments measuring the distance between two bunches via the amplitude modulation analysis of a monochromatic radiation signal. Good agreement with theoretical prediction is shown.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA141
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TUPIK075	ATF2 Beam Halo Collimation System Background and Wakefield Measurements in the 2016 Runs	1864
	N. Fuster-Martínez, A. Faus-Golfe IFIC, Valencia, Spain P. Bambade, A. Faus-Golfe, S. Wallon, R.J. Yang LAL, Orsay, France K. Kubo, T. Okugi, T. Tauchi, N. Terunuma Sokendai, Ibaraki, Japan S. Kuroda KEK, Ibaraki, Japan I. Podadera, F. Toral CIEMAT, Madrid, Spain G.R. White SLAC, Menlo Park, California, USA
	A single vertical beam halo collimation system has been installed in ATF2 in March 2016 to reduce the background in the IP and Post-IP region. In this paper, we present the results of an experimental program carried out during 2016 in order to demonstrate the efficiency of the vertical collimation system and measure the wakefields induced by such a system. Furthermore, a comparison of the measurements of the collimation system wakefield impact with CST PS numerical simulations and analytical calculations is also presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPIK075
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Paper

Title

Page

MOPAB111

Diffraction Radiation for Non-Invasive, High-Resolution Beam Size Measurements in Future Linear Colliders

381

SUSPSIK079

use link to see paper's listing under its alternate paper code

M. Bergamaschi, R. Kieffer, T. Lefèvre, S. Mazzoni
CERN, Geneva, Switzerland
A. Aryshev, N. Terunuma
KEK, Ibaraki, Japan
M. Bergamaschi, P. Karataev, K.O. Kruchinin
JAI, Egham, Surrey, United Kingdom
M. Bergamaschi, P. Karataev, K.O. Kruchinin
Royal Holloway, University of London, Surrey, United Kingdom

Next generation linear colliders such as the Compact Linear Collider (CLIC) or the International Linear Collider (ILC) will accelerate particle beams with extremely small emittance. The high current and small size of the beam (micron-scale) due to such small emittance require non-invasive, high-resolution techniques for beam diagnostics. Diffraction Radiation (DR), a polarization radiation that appears when a charged particle moves in the vicinity of a medium, is an ideal candidate being non-invasive and allowing beams as small as a few tens of microns to be measured. Since DR is sensitive to beam parameters other than the transverse profile (e.g. its divergence and position), preparatory simulations have been performed with realistic beam parameters. A new dedicated instrument was installed in the KEK-ATF2 beam line in February 2016. At present DR is observed in the visible wavelength range, with an upgrade to the ultraviolet (200nm) planned for spring 2017 to optimize sensitivity to smaller beam sizes. Presented here are the latest results of these DR beam size measurements and simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB111

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MOPAB128

The Design of a Non-Destructive Single-Shot Longitudinal Bunch Profile Monitor using Smith-Purcell Radiation

433

H. Harrison, G. Doucas, I.V. Konoplev, A.J. Lancaster, H. Zhang
JAI, Oxford, United Kingdom
A. Aryshev, M. Shevelev, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan

Funding: This work was supported by the: the STFC UK, the Leverhulme Trust, the JAI (University of Oxford) and the Photon and Quantum Basic Research Coordinated Development (Japan).
The conceptual design for a single-shot longitudinal bunch profile monitor using coherent Smith-Purcell radiation (cSPr) has recently been completed. The exploitation of the directionality and the polarization of cSPr to reduce the length of the monitor and to eliminate background radiation are discussed. The linear polarization of cSPr will be used to separate the signal from background radiation and experiments to test this design will be presented. Alongside the conceptual design an investigation to optimize the number of detection channels needed to produce high quality longitudinal bunch profile reconstructions has been carried out. It has been determined that the number of detection channels can be reduced compared to previous experiments if measurement uncertainty and background radiation are minimized effectively.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB128

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MOPIK009

Characterization of Cold Model Cavity for Cryocooled C-Band 2.6-Cell Photocathode RF Gun at 20 K

518

T. Tanaka, K. Hayakawa, Y. Hayakawa, K. Nakao, K. Nogami, T. Sakai, K. Takatsuka
LEBRA, Funabashi, Japan
M.K. Fukuda, D. Satoh, T. Takatomi, N. Terunuma, J. Urakawa, M. Yoshida
KEK, Ibaraki, Japan

Funding: This work was partly supported by the Photon and Quantum Basic Research Coordinated Development Program of the Japanese Ministry of Education, Culture, Sports, Science, and Technology (MEXT).
A cryocooled C-band 2.6-cell photocathode RF electron gun has been studied at Nihon University in cooperation with KEK. The cold model cavity with an input coupler was completed in spring 2016. The RF characteristics measured at room temperature were in agreement with the prediction by the CST Studio simulation. The RF characteristics at 20 K have been measured using a rather simple cavity-cooling vacuum system that was built by using existing components for tentative experiments. A thin-wall stainless-steel R48 waveguide with copper-plated inner walls has been used for the RF power transmission from the room-temperature input port to the 20-K cooled coupler waveguide. The unloaded Q-value of 73000 has been obtained by the reflection coefficient measurement at 20 K, which is in agreement with the result of the CST Studio simulation using the cavity surface resistance predicted by the theory of the anomalous skin effect.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK009

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

TUPIK097

Improving the Performance of an Orbit Feed-forward Based on Quadrupole Motion at the KEK ATF

1931

D.R. Bett, C. Charrondière, M. Patecki, J. Pfingstner, D. Schulte, R. Tomás
CERN, Geneva, Switzerland
P. Burrows, G.B. Christian, C. Perry
JAI, Oxford, United Kingdom
A. Jeremie
IN2P3-LAPP, Annecy-le-Vieux, France
K. Kubo, S. Kuroda, T. Naito, T. Okugi, T.T. Tauchi, N. Terunuma
KEK, Ibaraki, Japan

The high luminosity requirement for a future linear collider sets a demanding limit on the beam quality at the Interation Point (IP). Even the natural motion of the ground could misalign the quadrupole magnets to such an extent that the resulting dipole kicks would require compensation. The novel technique described in this paper uses seismometers to measure the positions of the quadrupole magnets in real time and a kicker to counteract the effect of their misalignment. The prototype system deployed at the Accelerator Test Facility (ATF) at KEK in Japan has already demonstrated a reduction in the pulse-to-pulse vertical position jitter of the beam by about 10%. Based on the observed correlation of the beam position to the quadrupole positions the maximum possible jitter reduction from such a system is estimated to be about 25%. This paper details the latest improvements made to the system with the aim of achieving this limit.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPIK097

Export •

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

WEPVA018

Drive-Witness Acceleration Scheme Based on Corrugated Dielectric mm-Scale Capillary

3292

K. Lekomtsev, S.T. Boogert, P. Karataev, A. Lyapin
JAI, Egham, Surrey, United Kingdom
A. Aryshev, M. Shevelev, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan
A.A. Tishchenko
MEPhI, Moscow, Russia

Funding: This project has received funding from the European Union Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 655179.
In this paper, we investigate a corrugated mm-scale capillary as a compact accelerating structure in a drive-witness acceleration scheme, and suggest a methodology to measure acceleration of a witness bunch. Two typical measurements and the energy gain in a witness bunch as a function of the distance between bunches are discussed. A corrugated capillary is considered as an accelerator/decelerator with an adjustable wakefield pattern depending on a transverse beam position.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA018

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THOAB3

Ultrafast Relativistic-Energy Electron Microscopy

J. Yang, K. Kan, T. Kondoh, K. Tanimura, Y. Yoshida
ISIR, Osaka, Japan
N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan

An ultrafast electron microscopy (UEM) using a relativistic-energy femtosecond-pulse electron beam has being developed at Osaka University. We succeeded to generate a 100-fs-pulse electron beam with energy of 3.1 MeV using a photocathode RF gun. In the demonstrations of UEM, we succeeded to observe the TEM imaging of polystyrene and gold nanoparticles by the accumulating measurement of 3.1-MeV femtosecond electron pulses. The relativistic-energy single-pulse electron imaging is also available under the low-magnification observation, i.e. 300 times. The UEM has also been succeeded for the study of the ultrafast structural dynamics in materials with the single-shot electron diffraction observation.

Slides THOAB3 [12.396 MB]

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THPVA002

Numerical Investigation of Beam Halo From Beam Gas Scattering in KEK-ATF

4410

R.J. Yang, P. Bambade
LAL, Orsay, France
K. Kubo, T. Okugi, N. Terunuma, D. Zhou
KEK, Ibaraki, Japan

To demonstrate the final focus schemes of the Future Linear Collider (FLC), the Accelerator Test Facility 2 (ATF2) at KEK is devoted to focus the beam to a RMS size of a few tens of nanometers (nm) vertically and to provide stability at the nm level at the virtual Interaction Point (IP). However, the loss of halo particles upstream will introduce background to the diagnostic instrument measuring the ultra-small beam, using a laser interferometer monitor. To help the realization of the above goals and beam operation, understanding and mitigation of beam halo are crucial. In this paper, we present the systematical simulation of beam halo formation from beam gas Coulomb scattering (BGS) in the ATF damping ring. The behavior of beam halo with various machine parameters is also discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA002

Export •

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

THPVA141

Non-Destructive Measurement of Electron Microbunch Separation

4798

SUSPSIK122

use link to see paper's listing under its alternate paper code

H. Zhang, G. Doucas, H. Harrison, I.V. Konoplev, A.J. Lancaster
JAI, Oxford, United Kingdom
A. Aryshev, M. Shevelev, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan

With the development of femtosecond lasers, the generation of micro-bunched beams directly from a photocathode becomes routine; however, the monitoring of the separation is still a challenge. We present the results of proof-of-principle experiments measuring the distance between two bunches via the amplitude modulation analysis of a monochromatic radiation signal. Good agreement with theoretical prediction is shown.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA141

Export •

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

TUPIK075

ATF2 Beam Halo Collimation System Background and Wakefield Measurements in the 2016 Runs

1864

N. Fuster-Martínez, A. Faus-Golfe
IFIC, Valencia, Spain
P. Bambade, A. Faus-Golfe, S. Wallon, R.J. Yang
LAL, Orsay, France
K. Kubo, T. Okugi, T. Tauchi, N. Terunuma
Sokendai, Ibaraki, Japan
S. Kuroda
KEK, Ibaraki, Japan
I. Podadera, F. Toral
CIEMAT, Madrid, Spain
G.R. White
SLAC, Menlo Park, California, USA

A single vertical beam halo collimation system has been installed in ATF2 in March 2016 to reduce the background in the IP and Post-IP region. In this paper, we present the results of an experimental program carried out during 2016 in order to demonstrate the efficiency of the vertical collimation system and measure the wakefields induced by such a system. Furthermore, a comparison of the measurements of the collimation system wakefield impact with CST PS numerical simulations and analytical calculations is also presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPIK075

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