Differential absorption imaging for elemental analysis of thin samples using a soft laser-plasma X-ray source

The differential X-ray imaging technique is a powerful tool for the detection of small concentrations of contrast agents in samples, as demonstrated recently by many biological and medical applications using synchrotron radiation. In this paper, we present an implementation of this technique using a laser-plasma soft X-ray source combined with an X-ray imaging system based upon a spherically bent Bragg crystal. Using a test sample containing a solution of LiBr of known concentration, we demonstrate that the use of our table-top configuration is suitable to detect Br inside our sample via differential imaging at the L2 edge of Br at 7.7684Å.