IBIC2017 - List of Authors (Toyama, T.)

Paper	Title	Page
TUPCF13	New Design of a Tapered-Coupler BPM Toward Simpler Geometry and Flatter Frequency Response	237
	T. Toyama, T. Koseki, H. Kuboki J-PARC, KEK & JAEA, Ibaraki-ken, Japan A. Ichikawa, K.G. Nakamura, T. Nakaya, W. Uno Kyoto University, Kyoto, Japan M. Okada KEK, Ibaraki, Japan
	The tapered-coupler stripline beam position monitor has been used for the intra-bunch feedback system in the J-PARC MR. It should be realized with a special shaped striplines, for example, whose width is tailored exponentially and whose gap distances between the inner surface of the beam pipe should be also decreasing as a exponential function in order to keep the characteristic impedance 50 ohm. This 3D varying geometry makes it difficult to achieve the good balance between the electrode responses to the beam. We present a new design method with a groove, which may give simpler geometry and flatter frequency response.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2017-TUPCF13
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TUPCF11	Upgrade of the Beam Position Monitoring System at the J-PARC Main Ring for High Intensity Operation	229
	A. Kobayashi, H. Kuboki, K. Satou, T. Toyama KEK, Tokai, Ibaraki, Japan
	For the T2K neutrino oscillation experiment upgrade programs of J-PARC are on-going for higher beam intensity. The ultimate goal is to achieve a beam power of 1.3 MW in the main ring, a significant increase more than triple intensity compared to the presently achieved power of 470 kW. Beam loss is a cause of the limitation on the proton bunch intensity. A precise orbit correction is necessary in order to reduce the beam loss. Beam position monitor (BPM) is a vital element providing accurate measurements of the beam positions for the control of closed orbit distortion (COD). Currently an apparent dependence of COD RMS on the beam intensity is observed (about 30 μ m). In order to understand the nature of the phenomenon, investigations are being made on the BPM response and its intensity dependence as well as on the effects of wake field, beam bumps to COD and septum. Status of the studies will be discussed. Also presented are new design of BPM for improved position resolution and stability, and its expected performance.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2017-TUPCF11
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

New Design of a Tapered-Coupler BPM Toward Simpler Geometry and Flatter Frequency Response

237

T. Toyama, T. Koseki, H. Kuboki
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
A. Ichikawa, K.G. Nakamura, T. Nakaya, W. Uno
Kyoto University, Kyoto, Japan
M. Okada
KEK, Ibaraki, Japan

The tapered-coupler stripline beam position monitor has been used for the intra-bunch feedback system in the J-PARC MR. It should be realized with a special shaped striplines, for example, whose width is tailored exponentially and whose gap distances between the inner surface of the beam pipe should be also decreasing as a exponential function in order to keep the characteristic impedance 50 ohm. This 3D varying geometry makes it difficult to achieve the good balance between the electrode responses to the beam. We present a new design method with a groove, which may give simpler geometry and flatter frequency response.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2017-TUPCF13

Export •

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

TUPCF11

Upgrade of the Beam Position Monitoring System at the J-PARC Main Ring for High Intensity Operation

229

A. Kobayashi, H. Kuboki, K. Satou, T. Toyama
KEK, Tokai, Ibaraki, Japan

For the T2K neutrino oscillation experiment upgrade programs of J-PARC are on-going for higher beam intensity. The ultimate goal is to achieve a beam power of 1.3 MW in the main ring, a significant increase more than triple intensity compared to the presently achieved power of 470 kW. Beam loss is a cause of the limitation on the proton bunch intensity. A precise orbit correction is necessary in order to reduce the beam loss. Beam position monitor (BPM) is a vital element providing accurate measurements of the beam positions for the control of closed orbit distortion (COD). Currently an apparent dependence of COD RMS on the beam intensity is observed (about 30 μ m). In order to understand the nature of the phenomenon, investigations are being made on the BPM response and its intensity dependence as well as on the effects of wake field, beam bumps to COD and septum. Status of the studies will be discussed. Also presented are new design of BPM for improved position resolution and stability, and its expected performance.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2017-TUPCF11

Export •

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