Bericht des Internationalen Atomgewichts‐Ausschusses für 1909

Abstract

1)raiichb:iren Iieihen ergeben l I = 1 .(lO7S'i irn Mittel, wahrend M o r 1 e J -.

Discovery of gallium, germanium, lutetium, and hafnium isotopes

“…60 Ga was produced via projectile fragmentation and identified with the SISSI/LISE facility by measuring the time-of-flight through the separator and the ∆E-E in a silicon detector telescope. A lower limit for the half-life was established, "We find clear evidence for 60 Ga, 64 As, 69,70 Kr, and 74 Sr." 61…”

“…"Very many gamma rays with various half-lives were observed after the bombardment, but all could be assigned to some known isotopes produced by fast neutrons on Ge, except for three distinct gamma rays with energies 0.58, 2.3, and 2.6 Mev which decayed with a half-life of about 8 min... Therefore this activity is assigned to Ga 74 ." This half-life is consistent with the currently adopted value of 8.12(12) m. Earlier measurements incorrectly assigned half-lives of 6(1) d [34] and 9 d [41] to 74 Ga. 75…”

“…A pure germanium oxide target was irradiated with 50 MeV and 100 MeV X-rays and 73 Ga was formed in the photonuclear reaction 74 Ge(γ,p). Decay curves and β-ray spectra were measured following chemical separation.…”

“…Therefore this activity is assigned to Ga 74 ." This half-life is consistent with the currently adopted value of 8.12(12) m. Earlier measurements incorrectly assigned half-lives of 6(1) d [34] and 9 d [41] to 74 Ga. 75…”

“…In 1923 Aston reported the discovery of stable 70 Ge, 72 Ge, and 74 Ge in "The isotopes of germanium" [55]. A pure germanium oxide sample was transformed into a fluorine compound and used in the Cavendish mass spectrograph.…”