| 摘要 |
<p>For isotopes decaying by capture of an inner shell electron by the nucleus, coincident emission of X-ray and gamma photons may occur. The X-ray results from the drop of an outer shell electron to fill the S shell. The gamma results from the transition of the excited daughter nucleus to a lower energy state. The invention disclosed is a Coincident Gamma and X-ray Detector (CGXD) which achieves extraordinary background rejection by a synergistic combination of coincident counting and other background suppresion measures. Whereas the background registred by single gamma counters is of the order of 20-40 counts per minute, a CGXD optimized for the electron capture radioisotope I<125> has a background of about one count per day.</p> |
