0000000001093043
AUTHOR
M. Oinonen
"Safe" Coulomb excitation of 30Mg.
We report on the first radioactive beam experiment performed at the recently commissioned REX-ISOLDE facility at CERN in conjunction with the highly efficient $\gamma$ -spectrometer MINIBALL. Using $^{30}$Mg ions accelerated to an energy of 2.25MeV/u together with a thin $^{nat}$Ni target, Coulomb excitation of the first excited 2+ states of the projectile and target nuclei well below the Coulomb barrier was observed. From the measured relative de-excitation $\gamma$ -ray yields the B(E2; 0$^{+}_{gs} \rightarrow 2^{+}_{1}$) value of $^{30}$Mg was determined to be 241(31)$e^{2}$fm$^{4}$. Our result is lower than values obtained at projectile fragmenttion facilities using the intermediate-ene…
Mass measurements on neutron-deficient Sr and neutron-rich Sn isotopes with the ISOLTRAP mass spectrometer
Abstract The atomic masses of 76,77,80,81,86,88 Sr and 124,129,130,131,132 Sn were measured by means of the Penning trap mass spectrometer ISOLTRAP at ISOLDE/CERN. 76 Sr is now the heaviest N = Z nucleus for which the mass is measured to a precision better than 35 keV. For the tin isotopes in the close vicinity of the doubly magic nucleus 132 Sn, mass uncertainties below 20 keV were achieved. An atomic mass evaluation was carried out taking other experimental mass values into account by performing a least-squares adjustment. Some discrepancies between older experimental values and the ones reported here emerged and were resolved. The results of the new adjustment and their impact will be pr…
Intruder features in the island of inversion : The 33Mg case
The 33 Na β decay was studied online using mass separation techniques and a first description of the level structure of the neutron-rich isotope 33 Mg , with N = 21 , has been obtained. The experiment involved the measurement of β-γ, β-γ-γ, and β − n − γ coincidences as well as neutron spectra by time-of-flight technique. The first low energy level scheme for the daughter nucleus 33 Mg is given with five bound states. Spin and parity assignments are proposed according to β feedings and γ-ray multipolarities. β-strength distribution is evaluated, taking into account 1 n - and 2 n -emission channels and it is compared with the calculated GT strength distribution. In particular, the 1 p − 1 h …
The ALICE experiment at the CERN LHC
Journal of Instrumentation 3(08), S08002 (2008). doi:10.1088/1748-0221/3/08/S08002
Proton dripline studies at ISOLDE: 31Ar and 9C
In this contribution examples of the application of new technologies to disentangle the mechanism of beta-delayed multiparticle emission are given. In particular the mechanism of β-delayed two-proton emission from 31Ar has be resolved and proved to be sequential, a preview of 9C-decay data is discussed. peerReviewed
Spectroscopy of 34,35Si by beta decay : sd-fp shell gap and single-particle states
The 34,35Al b decays have been studied at the CERN online mass separator ISOLDE by b-g, b-g-g, and b-n-g measurements in order to corroborate the low-level description of 34Si and to obtain the first information on the level structure of the N521 isotope 35Si. Earlier observed g lines in 34Al decay were confirmed and new g transitions following both b decay and b-delayed neutron emission have been established. The first level scheme of 35Si includes three excited states at 910, 974, and 2168 keV. Indication is found for Jp 5(3/2)2 and (3/2)1 for the first two excited states, respectively. Beta-decay half-life of T1/2538.6(4) ms and b-delayed neutron branching value Pn541(13)% were measured …
The ALICE Collaboration
The production of mesons containing strange quarks (KS, φ) and both singly and doubly strange baryons ( , , and − + +) are measured at mid-rapidity in pp collisions at √ s = 0.9 TeV with the ALICE experiment at the LHC. The results are obtained from the analysis of about 250 k minimum bias events recorded in 2009. Measurements of yields (dN/dy) and transverse momentum spectra at mid-rapidity for inelastic pp collisions are presented. For mesons, we report yields (〈dN/dy〉) of 0.184 ± 0.002(stat.) ± 0.006(syst.) for KS and 0.021 ± 0.004(stat.) ± 0.003(syst.) for φ. For baryons, we find 〈dN/dy〉 = 0.048 ± 0.001(stat.) ± 0.004(syst.) for , 0.047 ± 0.002(stat.) ± 0.005(syst.) for and 0.0101 ± 0.0…