The MIVand MVAbsorption Edges of⁶⁸Er

The M, and M, Absorption Edges of 68Er X-ray absorption in the M,,v region by 68Er has been observed hitherto only by Lindberg (1931) who, however, faded to observe any sign of the normal M, and M, edges but found instead a pair of narrow absorption lines close to the expected position of the M, edge.He obtained a simlar remarkable result for 70Yb-in this case a single sharp absorption line at 8138 x.u., agam close to the expected Mv edge.The Yb result has been confirmed in this laboratory