Fine Structure in theKX-Ray Absorption Edge of Gallium

The absorption of x-rays by a Ga foil in the region extending from the main $K$ absorption edge of Ga toward shorter wave-lengths for a distance of about 250 volts has been investigated by the ionization method. The absence of any extended fine structure at room temperature is confirmed. The temperature of the Ga has been reduced to -67°C and -140°C, and a progressive appearance of extended fine structure has been noted as the temperature decreased. Checks have been made to prove the validity of the conclusions. The results of the investigation are presented in graphical and tabular form. A value of 1192.5 x.u. for the wave-length of the main $K$ absorption edge of Ga is determined. This value is believed to be more accurate than the value of 1190.2 x.u. found in most tables.