Results of AC loss measurements on heat treated SSC cables

Abstract

Dipole magnets designed for the SSC have shown anomalous ramp rate dependence, and it is thought that interstrand coupling may contribute to this effect. This article describes measurements made on cable samples which were prepared and measured under circumstances which approximate those which an actual magnet conductor will experience.Subjecting the cable to pressure during heat treatment and during measurement significantly increases the eddy current loss, but it is not altogether clear that the increase results primarily from interstrand coupling.

Ac Losses of Superconducting Accelerator Magnets

“…The lower solid line represents the estimated loss using Eqs. (4)- (7). The open circles present data from calorimetric measurements of dissipation at superfluid helium.…”

Influence of strand surface condition on interstrand contact resistance and coupling loss in NbTi-wound Rutherford cables

“…However, detailed studies of the sensitivity of coupling loss to cable curing conditions (heat treatment temperature, uniaxial pressure, and the gaseous environment) began during the construction of SSC magnets, particularly those of the High Energy Booster ring, and has continued during the development of the LHC dipoles, e.g. [11][12][13][14][15][16][17][18][19][20][21][22][23]. Extensive study of direct interstrand contact resistance has also been made [18,24].…”

“…Occasionally the uncured cable was measured under pressure [19]. In a number of practically important studies stacks of cable pieces were epoxy bonded at temperature and under pressure (the curing process) [11,[15][16][17]21,59], unloaded, and then measured under zero pressure [15,16,59], or under applied pressure [15,16].…”