Peculiarities of isotopic temperatures obtained from p+A collisions at 1 GeV

Nuclear temperatures obtained from inclusive measurements of double isotopic yield ratios of fragments produced in 1 GeV p + A collisions amount to about 4 MeV nearly independent from the target mass.Comment: 4 pages, 4 figures, to be submitted to Eur. Phys. J.

Atomic spectroscopy studies of short-lived isotopes and nuclear isomer separation with the ISOLDE RILIS

The Resonance Ionization Laser Ion Source (RILIS) at the ISOLDE on-line isotope separator is based on the selective excitation of atomic transitions by tunable laser radiation. Ion beams of isotopes of 20 elements have been produced using the RILIS setup. Together with the mass separator and a particle detection system it represents a tool for high-sensitive laser spectroscopy of short-lived isotopes. By applying narrow-bandwidth lasers for the RILIS one can study isotope shifts (IS) and hyperfine structure (HFS) of atomic optical transitions. Such measurements are capable of providing data on nuclear charge radii, spins and magnetic moments of exotic nuclides far from stability. Although the Doppler broadening of the optical absorption lines limits the resolution of the technique, the accuracy of the HFS measurements examined in experiments with stable Tl isotopes approaches a value of 100 MHz. Due to the hyperfine splitting of atomic lines the RILIS gives an opportunity to separate nuclear isomers. Isomer selectivity of the RILIS has been used in studies of short-lived Ag, Cu and Pb isotopes

Early onset of ground-state deformation in the neutron-deficient polonium isotopes

In-source resonant ionization laser spectroscopy of the even-$A$ polonium isotopes $^{192-210,216,218}$Po has been performed using the $6p^37s$ $^5S_2$ to $6p^37p$ $^5P_2$ ($\lambda=843.38$ nm) transition in the polonium atom (Po-I) at the CERN ISOLDE facility. The comparison of the measured isotope shifts in $^{200-210}$Po with a previous data set allows to test for the first time recent large-scale atomic calculations that are essential to extract the changes in the mean-square charge radius of the atomic nucleus. When going to lighter masses, a surprisingly large and early departure from sphericity is observed, which is only partly reproduced by Beyond Mean Field calculations.Comment: As submitted to PR

Shapes of the 192,190^{192,190}Pb ground states from beta decay studies using the total absorption technique

The beta decay of $^{192,190}$Pb has been studied using the total absorption technique at the ISOLDE(CERN) facility. The beta-decay strength deduced from the measurements, combined with QRPA theoretical calculations, allow us to infer that the ground states of the $^{192,190}$Pb isotopes are spherical. These results represent the first application of the shape determination method using the total absorption technique for heavy nuclei and in a region where there is considerable interest in nuclear shapes and shape effects

Coulomb excitation of 73Ga

The B(E2; Ii -> If) values for transitions in 71Ga and 73Ga were deduced from a Coulomb excitation experiment at the safe energy of 2.95 MeV/nucleon using post-accelerated beams of 71,73Ga at the REX-ISOLDE on-line isotope mass separator facility. The emitted gamma rays were detected by the MINIBALL-detector array and B(E2; Ii->If) values were obtained from the yields normalized to the known strength of the 2+ -> 0+ transition in the 120Sn target. The comparison of these new results with the data of less neutron-rich gallium isotopes shows a shift of the E2 collectivity towards lower excitation energy when adding neutrons beyond N = 40. This supports conclusions from previous studies of the gallium isotopes which indicated a structural change in this isotopical chain between N = 40 and N = 42. Combined with recent measurements from collinear laser spectroscopy showing a 1/2- spin and parity for the ground state, the extracted results revealed evidence for a 1/2-; 3/2- doublet near the ground state in 73 31Ga42 differing by at most 0.8 keV in energy

β\beta-decay half-life of 70^{70}Kr: a bridge nuclide for the rp-process beyond A = 70

The $\beta$-decay half-life of $^{70}$Kr has been measured for the first time at the ISOLDE PSB Facility at CERN. Mass separated $^{70}$Kr ions were produced by 1 GeV proton induced spallation reactions in a Nb foil. The measured half-life is 57(21) ms. This value is consistent with the half-life calculated assuming a pure Fermi decay, but is clearly lower than the value used in a recent rp-process reaction flow calculation. The result shows that the reaction flow via two-proton-capture of $^{68}$Se is 2.5 times faster than previously calculated assuming an astrophysical temperature of 1.5 GK and a density of 10$^{6}$g/cm$^{3}$

Vector and Tensor Analyzing Powers of the H(d,gamma)He-3 capture reaction

Precise measurements of the deuteron vector analyzing power Ayd and the tensor analyzing power Ayy of the H(d,gamma)He-3 capture reaction have been performed at deuteron energies of 29MeV and 45MeV. The data have been compared to theoretical state-of-the-art calculations available today. Due to the large sensitivity of polarization observables and the precision of the data light could be shed on small effects present in the dynamics of the reaction.Comment: 11 pages, 24 figures, submitted for publication to PRC, revised after referee proces

β\beta- decay of the proton-rich Tz=−1/2_{z} = -1/2 nucleus, 71^{71}Kr

$\beta$- decay of the T$_{z}$ = - 1/2 nuclide $^{71}$Kr has been studied at the ISOLDE PSB Facility at CERN. $^{71}$Kr ions were produced in spallation reactions in a Nb foil using the 1 GeV proton beam and studied by means of $\beta$-delayed proton, $\beta$- and $\gamma$-ray spectroscopy. The half-life and the $\beta$-decay energy of $^{71}$Kr were determined using the decay of protons and positrons. These results: T$_{1/2}$ = 100 ± 3 ms and $Q_\textrm{EC}$ = 10$^{14}$ ± 0.32 MeV and the first observation of the b-branch to the 207 keV level in $^{71}$Br makes the extension of the systematics of Gamow-Teller matrix elements of mirror nuclei up to A = 71 possible. Gamow-Teller strength of the same magnitude as that of the $fp$-shell mirror nuclei is observed for the ground state transition

Magnetic moments of 68^{68}Cug,m^{g,m} and 70^{70}Cug,m1,m2^{g,m_{1},m_{2}} nuclei measured by in-source laser spectroscopy

We have obtained information on the atomic hyperfine splitting and, hence, on magnetic moments in neutron rich $^{68, 70}$Cu isotopes by scanning the frequency of the narrow-band laser of the first excitation step in the resonance ionization laser ion source. The deduced magnetic moments are $\mu( ^{68}$Cu$^{g}$, I$^{\pi}$ = 1$^+$) = +2.48(2)(7)$\mu_{N}$ ; $\mu(^{68}$Cu$^{m}$, I$^{\pi}$=6$^{-}$) = +1.24(4)(6)$\mu_{N}$ and $\mu(^{70}$Cu$^{m_{2}}$, I$^{\pi}$=1$^{+}$) = +1.86(4)(6)$\mu_{N}$ ; $\mu(^{70}$Cu$^{g}$, I$^{\pi}$=6$^{-}$) = +1.50(7)(8)$\mu_{N}$. The results of the scans analysis point out on existence of a new isomer in $^{70}$Cu$^{m_{1}}$. It's deduced magnetic moment is (-)3.50(7)(11)$\mu_{N}$ that is in a good agreement with I$^{\pi}$=3$^{-}$ assignment. The method of in-source atomic spectroscopy, as well as the analysis of the obtained data, is described. The results are discussed in terms of single-particle configurations coupled to the $^{68}$Ni core