ISOMER SHIFT CALIBRATION OF Fe57 BY LIFE-TIME VARIATIONS IN THE ELECTRON CAPTURE DECAY OF Fe52 M. BOGE, P. AURIC, R. BOUCHEZ, A. MEYKENS, R. COUSSEMENT et J. LADRIÈRE J. Phys. Colloques, 37 C6 (1976) C6-707 DOI: 10.1051/jphyscol:19766147