Confirmation of production of element 110 by the (208)Pb(64-Ni,n)reaction

We report the experimental confirmation of the production of element110. In the bombardment of a 208Pb target with a 309~;MeV 64Ni beam, we have observed two chains of time- and position-correlated events. Each chain consisted of the implantation of an evaporation residue followed by the emission of alpha-particles. We attribute these two chains to the decay of 271-110 produced with a cross section of 8.3 (+11/-5.3)pb

The cyro-thermochromatographic separator (CTS): A new detection and separation system for highly volatile osmium and hassium (element 108) tetroxides

We implemented a new concept for heavy element chemistry research using an ion separator to separate the desired products from the beam, transfer products and other undesirable by-products prior to chemical studies. First, a Recoil product Transfer Chamber (RTC) was designed and attached to the Berkeley Gas-filled Separator (BGS) to collect and transfer the recoiling products to the chemical separation system. The RTC consists of a wire-grid-supported thin mylar foil ({le}) 200 {micro}g/cm{sup 2} that separates the BGS detector chamber, at 1.3 mbar pressure, from the chemistry system at different pressures ranging from 480 mbar to 2000 mbar. The overall transport efficiency ranged between 30% and 15%, compared to the activity measured in the focal plane detector of the BGS. The CTS was designed as a separation and {alpha}-decay detection system for the highly volatile tetroxides of osmium and hassium, element 108. The CTS, shown in figure 1, consists of two rows of 32-{alpha} detectors arranged along a negative temperature gradient. The tetroxides adsorb on the surface of one of the silicone photodiodes at a certain deposition temperature, and the nuclide is then identified by the {alpha}-decay. To test the CTS with the expected hassium homologue osmium, different {alpha}-active osmium isotopes were produced using the nuclear reactions {sup 118}Sn({sup 56}Fe, 4,5n) {sup 170,169}Os and {sup 120}Sn({sup 56}Fe, 4,5n) {sup 172,171}Os. After preseparation in the BGS, a mixture of 90% helium and 10% oxygen was used to transport the osmium to a quartz tube heated to 1225 K, where OsO{sub 4} was formed. The negative temperature gradient in the CTS ranged from 248 K to 173 K. Using a flow rate of 500 mL/min, most of the osmium activity was adsorbed at a temperature of about 203 K. From the measured {alpha}-activity distribution, an adsorption enthalpy of 40 {+-} 1 kJ/mol for OsO{sub 4} on the detector surface was calculated using Monte Carlo simulations. The results show that the CTS is working properly and can be used for experiments studying the chemical properties of hassium

New insights into neutron-rich nuclei at high spin

With new high statistic data, new isotopes and new high-spin structures are observed in neutron-rich nuclei populated in the spontaneous fission of $^{252}$Cf. The $^{135}$Te levels are extended, and many new levels in $^{139,141}$Ba observed. The coexistence of collective and single particle-hole states is found in $^{135}$Te. The $N=83$ $^{135}$Te and $^{139}$Ba show marked differences associated with differences in their particle and hole states. New levels in $^{141}$Ba complete evidence for two opposite-parity doublets characteristic of stable octupole deformation. In $^{114,116}$Pd a second backbend is observed for the first time in this mass region and the backbend in $^{118}$Pd occurs earlier than in ^{112\mbox{-}116}Pd because of a reduction in pairing. Gamma-type vibrational bands are seen up to 13$^+$ to 15$^+$ in $^{104,106}$Mo, ^{108\mbox{-}112}Ru, and ^{112\mbox{-}116}Pd. Their behavior reflects prolate to triaxial shapes in these nuclei. The levels of $^{162,164}$Gd are observed for the first time. As $N$ increases toward mid-shell at 104, the moments of inertia in $N=100$ $^{164}$Gd show an unexpected decrease compared to $N=98$ $^{162}$Gd. The levels in $^{162,164}$Gd form remarkable shifted identical bands with nuclei separated by 2n, 2p, $\alpha$, and 2$\alpha$

Shape trends and triaxiality in neutron-rich odd-mass Y and Nb isotopes

New level schems of Y and Nb isotopes are proposed based on measurements of prompt gamma rays from 252Cf fission at Gammasphere. Shape trends regarding triaxiality and quadrupole deformations are studied