{Upsilon}(1S){yields}{gamma}f{sub 2}{sup '}(1525); f{sub 2}{sup '}(1525){yields}K{sub S}{sup 0}K{sub S}{sup 0} decays

We report on a study of exclusive radiative decays of the {Upsilon}(1S) resonance into a final state consisting of a photon and two K{sub S}{sup 0} candidates. We find evidence for a signal for {Upsilon}(1S){yields}{gamma}f{sub 2}{sup '}(1525); f{sub 2}{sup '}(1525){yields}{gamma}K{sub S}{sup 0}K{sub S}{sup 0}, at a rate B({Upsilon}(1S){yields}{gamma}f{sub 2}{sup '}(1525))=(4.0{+-}1.3{+-}0.6)x10{sup -5}, consistent with previous observations of {Upsilon}(1S){yields}{gamma}f{sub 2}{sup '}(1525); f{sub 2}{sup '}(1525){yields}K{sup +}K{sup -}, and isospin. Combining this branching fraction with existing branching fraction measurements of {Upsilon}(1S){yields}{gamma}f{sub 2}{sup '}(1525) and J/{psi}{yields}{gamma}f{sub 2}{sup '}(1525), we obtain the ratio of branching fractions: B({Upsilon}(1S){yields}{gamma}f{sub 2}{sup '}(1525))/B(J/{psi}{yields}{gamma}f{sub 2}{sup '}(1525))=0.09{+-}0.02, approximately consistent with expectations based on soft-collinear effective theory.