Absolute cross-sections from X–γγ coincidence measurements

An activation technique using coincidences between characteristic X-rays and γγ-rays to obtain absolute cross-sections is described. This method is particularly useful in the case of nuclei that decay by electron capture. In addition to the reduction of possible contamination, an improved detection sensitivity is achieved as compared to inclusive measurements, thereby allowing the extraction of absolute fusion cross-sections in the nano-barn range. Results of this technique for Li6+Pt198 system, at energies around the Coulomb barrier are described. Future applications with low intensity radioactive ion beams are also discussed.