Calorimetric AC Loss Measurement of 1.3-M Model Dipole Magnets by Using A 1.8 K Cryostat

  • Y. Morita
  • K. Hara
  • N. Higashi
  • A. Kabe
  • H. Kawamata
  • Y. Kojima
  • H. Nakai
  • T. Ohmori
  • T. Takahashi
  • S. Taneda
  • A. Terashima
  • A. Yamanishi
  • K. Hosoyama

Abstract

To measure AC losses of dipole magnet by the calorimetric method, the magnets were cooled to 1.8 K with 120 liters of pressurized superfluid helium, using a 1.8 K cryostat. Heat dissipated in the magnet during a ramp cycle was measured by observing the temperature of the superfluid helium. AC losses were evaluated by the production of the heat capacity and temperature rise of helium. The 1.8 K cryostat consisted of a 4.2 K helium vessel, a 1.8 K pressurized superfluid helium vessel, and heat exchangers (1.8 K saturated helium pot and precooler). Liquid helium from the 4.2 K vessel, cooled to 2.5 K in the pre-cooler, expanded in the 1.8 K saturated helium pot. It cooled the magnet and pressurized superfluid helium to 1.8 K. Evaporated helium gas in the pot was evacuated by a pumping unit. The magnets were model dipole magnets fabricated at KEK for SSC dipole magnet R&D. The overall length is 1.3 m and inner aperture of the coil is 50 mm. Two types of magnet were made to study the AC properties: Type 1 with 6 μm NbTi filament cables and Type 2 with 2.5 μm filament cables. AC losses were measured in a ramp cycle from 500 to 5(X)0 A with 5 second duration at the flat top. Ramp rates were varied from 70 to 400 A/s. Results show that the Type 2 magnet had smaller AC loss than the Type 1.

Keywords

Furnace Helium Lamination Carbon Iron 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    K. Hosoyama, “Fabrication and Test of a 5-cm Aperture, 1-m Long SSC Collider Dipole Magnet,” Proc. Third International Symposium on the Super Collider, 1992.Google Scholar

Copyright information

© Springer Science+Business Media New York 1994

Authors and Affiliations

  • Y. Morita
    • 1
  • K. Hara
    • 1
  • N. Higashi
    • 1
  • A. Kabe
    • 1
  • H. Kawamata
    • 1
  • Y. Kojima
    • 1
  • H. Nakai
    • 1
  • T. Ohmori
    • 3
  • T. Takahashi
    • 2
  • S. Taneda
    • 4
  • A. Terashima
    • 1
  • A. Yamanishi
    • 3
  • K. Hosoyama
    • 1
  1. 1.National Laboratory for High Energy PhysicsTsukuba, IbarakiJapan
  2. 2.Hitachi WorksHitachi Ltd.Hitachi-shi, IbarakiJapan
  3. 3.Ishikawajima-Harima Heavy Industries Co., Ltd.yokohamaJapan
  4. 4.Kobe Steel Co., Ltd.Kobe, HyogoJapan

Personalised recommendations