Storage rings as detectors for relic gravitational-wave background ?
  We argue that storage rings can be used for the detection of low-frequency gravitational-wave background. We explain the systematic shrinkage of the machine circumference of the storage ring of the SPring-8, observed by Takao and Shimada (Proceedings of EPAC 2000, Vienna, 2000, p.1572), by the influence of the relic gravitational-wave background. We show that the systematic shrinkage of the machine circumference can be explained by a relic gravitational-wave background even if it is treated as a stochastic system incoming on the plane of the machine circumference from all quarters of the Universe. We show that the rate of the systematic shrinkage of the machine circumference does not depend on the radius of the storage ring and it should be universal for storage rings with any radius. 
A. N. Ivanov, A. P. Kobushkin, M. Wellenzohn