Vibrational characteristics of a superconducting magnetic bearing employed for a prototype polarization modulator

Yuki Sakurai, Tomotake Matsumura, Hajime Sugai, Nobuhiko Katayama, Hiroyuki Ohsaki, Yutaka Terao, Yusuke Terachi, Hirokazu Kataza, Shin Utsunomiya, Ryo Yamamoto

Research output: Contribution to journalConference articlepeer-review

8 Citations (Scopus)

Abstract

We present the vibrational characteristics of a levitating rotor in a superconducting magnetic bearing (SMB) system operating at below 10 K. We develop a polarization modulator that requires a continuously rotating optical element, called half-wave plate (HWP), for a cosmic microwave background polarization experiment. The HWP has to operate at the temperature below 10 K, and thus an SMB provides a smooth rotation of the HWP at the cryogenic temperature of about 10 K with minimal heat dissipation. In order to understand the potential interference to the cosmological observations due to the vibration of the HWP, it is essential to characterize the vibrational properties of the levitating rotor of the SMB. We constructed a prototype model that consists of an SMB with an array of high temperature superconductors, YBCO, and a permanent magnet ring, NdFeB. The rotor position is monitored by a laser displacement gauge, and a cryogenic Hall sensor via the magnetic field. In this presentation, we present the measurement results of the vibration characteristics using our prototype SMB system. We characterize the vibrational properties as the spring constant and the damping, and discuss the projected performance of this technology toward the use in future space missions.

Original languageEnglish
Article number012091
JournalJournal of Physics: Conference Series
Volume871
Issue number1
DOIs
Publication statusPublished - Jul 26 2017
Externally publishedYes
Event29th International Symposium on Superconductivity, ISS 2016 - Tokyo, Japan
Duration: Dec 13 2016Dec 15 2016

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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