IPAC2012 - List of Authors (Iwasaki, M.)

Paper	Title	Page
TUPPR007	Beam Background and MDI Design for SuperKEKB/Belle-II	1825
	H. Nakayama, M. Iwasaki, K. Kanazawa, Y. Ohnishi, S. Tanaka, T. Tsuboyama KEK, Ibaraki, Japan H. Nakano Tohoku University, Graduate School of Science, Sendai, Japan
	The Belle experiment, operated at the asymmetric electron-positron collider KEKB, had accumulated a data sample with an integrated luminosity of more than 1 ab⁻¹ before the shutdown in June 2010. We have started upgrading both the accelerator and the detector, SuperKEKB and Belle-II, to achieve the target luminosity of 8×10³⁵ cm⁻² s⁻¹. With the increased luminosity, the beam background will be severe. The development of Machine- Detector Interface (MDI) design is crucial to cope with the increased background and protect Belle-II detector. We will present the estimation of impact from each beam background sources at SuperKEKB, such as Touschek-scattering, Beam-gas scattering, radiative Bhabha process, etc.. We will also present our countermeasures against them, such as collimators to stop scattered beam particles, Tungsten shield to protect inner detectors from shower particles, and dedicated beam pipe design around interaction point to stop synchrotron radiation, etc.

WEEPPB013	Direct Wind Superconducting Corrector Magnets for the SuperKEKB IR	2191
	B. Parker, M. Anerella, J. Escallier, A.K. Ghosh, A.K. Jain, A. Marone, P. Wanderer BNL, Upton, Long Island, New York, USA Y. Arimoto, M. Iwasaki, N. Ohuchi, M. Tawada, K. Tsuchiya, H. Yamaoka, Z.G. Zong KEK, Ibaraki, Japan
	Upgrade of the KEKB asymmetric e⁺e⁻ collider for a forty-fold luminosity increase, denoted SuperKEKB, is now underway. For SuperKEKB the beam crossing angle is increased to provide separate focusing channels for the incoming and outgoing electron and positrons beams in new superconducting Interaction Region (IR) magnets. Two functional classes of superconducting corrector magnets are needed to meet SuperKEKB beam optics goals. Dipole, skew-dipole, skew-quadrupole and octupole coil windings will be inserted inside the bores of the main IR quadrupoles to make magnet center alignments, roll adjustments and non-linear optics corrections. A second class of high-order magnetic multipole corrector coils is needed to compensate the non-linear fringe field experienced by the circulating beam that passes just outside the main quadrupole coils that are closest to the Interaction Point (IP). Near the IP there is no space for magnetic yokes or other passive shielding to diminish the fringe field. At the time of this conference the SuperKEKB corrector magnet production will be under way. The SuperKEKB correction coil design and our production technique are reviewed in this paper.

THPPD023	Solenoid Field Calculation of the SuperKEKB Interaction Region	3548
	N. Ohuchi, Y. Arimoto, M. Iwasaki, H. Koiso, A. Morita, Y. Ohnishi, K. Oide, M. Tawada, K. Tsuchiya, H. Yamaoka KEK, Ibaraki, Japan
	The SuperKEKB is the electron-positron collider, and the target luminosity is 8×10³⁵ cm^-2s⁻¹, which is 40 times larger than the attained luminosity of KEKB. The beam final focus system consists of many types of superconducting magnets as 8 quadrupoles, 40 correctors and 4 compensation solenoids. These focusing magnets and correctors are designed to be operated inside the particle detector, Belle, and under the solenoid field of 1.5 T. From the analysis of beam optics, the solenoid field profile has serious impact on the beam vertical emittance. We designs the solenoid field profile along the Belle axis in a 2-dimensional model as the first step, and now we developed this model to the 3-dimensional calculation in detail. The solenoid field profiles along the both beam lines are generated with the combine solenoid field by the Belle solenoid and the compensation solenoids, and the magnetic components of the magnets and the magnetic shields on the beam lines. The model is very complicate. From the calculation results, we will discuss the influence on the beam optics and the final focusing magnet system.

Paper

Title

Page

Beam Background and MDI Design for SuperKEKB/Belle-II

1825

H. Nakayama, M. Iwasaki, K. Kanazawa, Y. Ohnishi, S. Tanaka, T. Tsuboyama
KEK, Ibaraki, Japan
H. Nakano
Tohoku University, Graduate School of Science, Sendai, Japan

The Belle experiment, operated at the asymmetric electron-positron collider KEKB, had accumulated a data sample with an integrated luminosity of more than 1 ab⁻¹ before the shutdown in June 2010. We have started upgrading both the accelerator and the detector, SuperKEKB and Belle-II, to achieve the target luminosity of 8×10³⁵ cm⁻² s⁻¹. With the increased luminosity, the beam background will be severe. The development of Machine- Detector Interface (MDI) design is crucial to cope with the increased background and protect Belle-II detector. We will present the estimation of impact from each beam background sources at SuperKEKB, such as Touschek-scattering, Beam-gas scattering, radiative Bhabha process, etc.. We will also present our countermeasures against them, such as collimators to stop scattered beam particles, Tungsten shield to protect inner detectors from shower particles, and dedicated beam pipe design around interaction point to stop synchrotron radiation, etc.

WEEPPB013

Direct Wind Superconducting Corrector Magnets for the SuperKEKB IR

2191

B. Parker, M. Anerella, J. Escallier, A.K. Ghosh, A.K. Jain, A. Marone, P. Wanderer
BNL, Upton, Long Island, New York, USA
Y. Arimoto, M. Iwasaki, N. Ohuchi, M. Tawada, K. Tsuchiya, H. Yamaoka, Z.G. Zong
KEK, Ibaraki, Japan

Upgrade of the KEKB asymmetric e⁺e⁻ collider for a forty-fold luminosity increase, denoted SuperKEKB, is now underway. For SuperKEKB the beam crossing angle is increased to provide separate focusing channels for the incoming and outgoing electron and positrons beams in new superconducting Interaction Region (IR) magnets. Two functional classes of superconducting corrector magnets are needed to meet SuperKEKB beam optics goals. Dipole, skew-dipole, skew-quadrupole and octupole coil windings will be inserted inside the bores of the main IR quadrupoles to make magnet center alignments, roll adjustments and non-linear optics corrections. A second class of high-order magnetic multipole corrector coils is needed to compensate the non-linear fringe field experienced by the circulating beam that passes just outside the main quadrupole coils that are closest to the Interaction Point (IP). Near the IP there is no space for magnetic yokes or other passive shielding to diminish the fringe field. At the time of this conference the SuperKEKB corrector magnet production will be under way. The SuperKEKB correction coil design and our production technique are reviewed in this paper.

THPPD023

Solenoid Field Calculation of the SuperKEKB Interaction Region

3548

N. Ohuchi, Y. Arimoto, M. Iwasaki, H. Koiso, A. Morita, Y. Ohnishi, K. Oide, M. Tawada, K. Tsuchiya, H. Yamaoka
KEK, Ibaraki, Japan

The SuperKEKB is the electron-positron collider, and the target luminosity is 8×10³⁵ cm^-2s⁻¹, which is 40 times larger than the attained luminosity of KEKB. The beam final focus system consists of many types of superconducting magnets as 8 quadrupoles, 40 correctors and 4 compensation solenoids. These focusing magnets and correctors are designed to be operated inside the particle detector, Belle, and under the solenoid field of 1.5 T. From the analysis of beam optics, the solenoid field profile has serious impact on the beam vertical emittance. We designs the solenoid field profile along the Belle axis in a 2-dimensional model as the first step, and now we developed this model to the 3-dimensional calculation in detail. The solenoid field profiles along the both beam lines are generated with the combine solenoid field by the Belle solenoid and the compensation solenoids, and the magnetic components of the magnets and the magnetic shields on the beam lines. The model is very complicate. From the calculation results, we will discuss the influence on the beam optics and the final focusing magnet system.