Production,Lx-ray identification, and decay of the nuclide105260

Abstract

The nucljde 105 has been produced jn the Cf(' N, 4') reaction and its docay properties investigated. The a-decay branch of 1.52~0.13-sec ' 105 has been measured to be (90.4~0.6)% with spontaneous-fission decay the remainder [(9. 6+0.6)%]. Measured a-particle energies and intensities (% per decay) are 9.041+ 0.014 MeV (48 + 5), 9.074~0.014 MeV (25 + 3), and 9.120 + 0.017 MeV (17 + 3). Characteristic Lseries x rays of element 103 were observed in coincidence with these a-particle groups, thus providing elemental identification. The ' Lr aMecay daughter was observed in a direct time-correlated genetic linkage, thus providing the mass number assignment. The absence of characteristic Lor K-series x rays of element 104 in time coincidence with, but preceding, spontaneous-fission-decay events, has allowed an upper limit of 2.5% to be placed on the electron-capture decay branch of ' 105 to the elusive nuclide 0.1-sec '~104. If 104 is a spontaneous-fission emitter with a half-life & 100 p.sec, as some predictions would indicate, then the electron-capture decay branch of ' 105 is &0.2%. RADIOACTIVITY 105 [from Cf( N, 4s) reactionj; measured &f/2 EẼ

Spontaneous fission and alpha-decay properties of neutron deficient isotopes 257−253104 and 258106

“…The energy agrees with the value reported for the low energy line of 257 Lr [19]. 8870 keV: About 10% of the events contributing to this energy, which was previously assigned to 257 Lr [18,19], are correlated to 253 No. We thus interprete this line as a mixture of 257 Lr and 257 104.…”

“…8636 keV: none of the 16 events observed is correlated to 253 No. Therefore this line cannot be attributed to 257 104. α-decay energies close to this value are known for 258 Lr [18,19] and for 256 Lr [19], yet an assignment to any of these nuclei was not likely. 258 Lr cannot be produced directly in that reaction, since its neutron number is by one higher than that of the compound nucleus 258 104.…”

“…In the present experiment we observed a total of about 1100 α-decays in the region E α = (8200-9100) keV that could be attributed predominantly to 257 104 or its EC-decay daughter 257 Lr [18,19]. About 30% of these events were followed by α-decays in the region E α = (7900-8200) keV, which were assigned to 253 No [20,21].…”

The Transuranium Elements: From Neptunium and Plutonium to Element 112

“…Unfortunately, the quality of the alpha data is poor and even in 1971 papers by Druin ef nl. [39] >258~r (a, 3.9s These results were later confirmed by Bemis et al [42], using an L X-ray-alpha coincidence technique.…”

Production and Decay Properties of272111 and its Daughter Nuclei

“…Bemis et al 12) reported that 260 Db decays with a half-life of 1:52 AE 0:13 s, three values of 9.041, 9.074, and 9.120 MeV for decay, and a 9.6% spontaneous-fission branch.…”