Spectroscopy near the proton drip-line in the A=130 mass region (original) (raw)
Related papers
Spectroscopy near the proton drip line in the deformed A= 130 mass region: The^{126} Pr nucleus
Physical Review C, 2001
CM Petrache 1, M. Nespolo 2, S. Brant 3, G. Lo Bianco 1, D. Bazzacco 2, S. Lunardi 2, P. Spolaore 4, M. Axiotis 4, N. Blasi 5, G. de Angelis 4, T. Kröll 2, N. Marginean 4, T. Martinez 4, R. Menegazzo 2, DR Napoli 4, B. Quintana 2, A. Saltarelli 1, A. Ventura 6, and D. Vretenar 3
Physical Review C, 2001
␥-ray transitions have been identified for the first time in the near-drip-line nucleus 126 Pr, making it the lightest odd-odd praseodymium nucleus in which excited states have been reported. Evidence is presented for two rotational bands in 126 Pr, one strongly coupled and the other doubly decoupled. In addition, the preliminary reports of a band in 128 Pr are confirmed. The signature inversion phenomenon and trends in the energy staggering of the h 11/2 h 11/2 bands are discussed for the Cs, La, and Pr nuclei.
In-beam γ-ray spectroscopy at the proton dripline: 23Al
Physics Letters B, 2008
We report on the first in-beam γ -ray spectroscopy of 23 Al using two different reactions at intermediate beam energies: inelastic scattering off 9 Be and heavy-ion induced one-proton pickup, 9 Be( 22 Mg, 23 Al + γ )X, at 75.1 MeV/nucleon. A γ -ray transition at 1616(8) keV-exceeding the proton separation energy by 1494 keV-was observed in both reactions. From shell model and proton decay calculations we argue that this γ -ray decay proceeds from the core-excited 7/2 + state to the 5/2 + ground state of 23 Al. The proposed nature of this state, [ 22 Mg(2 + 1 ) ⊗ πd 5/2 ] 7/2 + , is consistent with the presence of a γ -branch and with the population of this state in the two reactions.
Spectroscopy of the proton drip-line nucleus203Fr
Physical Review C, 2013
The nucleus 203 Fr has been studied through γ-ray and electron spectroscopy, using the recoil-decay tagging technique. A 13/2 + state, with a half-life of 0.37(5) μs, has been observed in 203 Fr. Both the α-decay branch and the internal de-excitation of the 1/2 + isomer in 203 Fr have been studied. Furthermore, the corresponding 1/2 + state, with a half-life of 0.31(8) s, has been found in 199 At. In addition, transitions feeding the 9/2 − ground state of 203 Fr have been identified. The observed level pattern suggests that the ground state is still spherical.
Proton emission from drip-line nuclei157Taand161Re
Physical Review C, 1997
Proton radioactivities from 157 Ta and 161 Re are reported. Fusion-evaporation residues from the reaction of 270 MeV 58 Ni ions on 102 Pd and 106 Cd targets were separated according to M /Q and implanted into a double-sided silicon strip detector. One line from 157 Ta was observed with a proton energy of 927͑7͒ keV ͓t 1/2 ϭ10.1(4) ms, b p ϭ3.4(12)%͔ from the s 1/2 ground state. A new alpha decay transition with energy 6117͑4͒ keV was also observed from this state. Two proton lines from 161 Re were observed with energies 1192͑6͒ keV ͓t 1/2 ϭ0.37(4) ms, b p ϭ100(7)%͔ and 1315͑7͒ keV ͓t 1/2 ϭ16(1) ms, b p ϭ4.8(6)%͔ from the s 1/2 and h 11/2 states, respectively. ͓S0556-2813͑97͒50204-4͔
2002
A new 7 s isomer in the drip line nucleus 140 Dy was selected from the products of the 54 Fe (315 MeV)ϩ 92 Mo reaction by a recoil mass spectrometer and studied with recoil-delayed ␥-␥ coincidences. Five cascading ␥ transitions were interpreted as the decay of an I ϭ8 Ϫ ͕9/2 Ϫ ͓514͔ 7/2 ϩ ͓404͔͖ K isomer "T 1/2 ϭ7.0(5) s… via the ground-state band. The probability of proton emission from 141 Ho to the 0 ϩ ground state and to the 2 ϩ excited state in 140 Dy is discussed.
Shell structure beyond the proton drip line studied via proton emission from deformed 141Ho
Physics Letters B, 2008
Fine structure in proton emission from the 7/2 − [523] ground state and from the 1/2 + [411] isomer in deformed nucleus 141 Ho was studied by means of fusion-evaporation reactions and digital signal processing. Proton transitions to the first excited 2 + state in 140 Dy, with the branching ratio of I gs p (2 + ) = 0.9 ± 0.2% and I m p (2 + ) = 1.7 ± 0.5%, were observed. The data are analyzed within the non-adiabatic weak coupling model assuming a large quadrupole deformation of the daughter nucleus 140 Dy as predicted by the self-consistent theory. Implications of this result on coexistence effects around N = 74 are discussed.
Systematic study of energy-spin entry distributions at the proton dripline in the A∼170 region
Nuclear Physics A, 2001
Proton-rich Pt, Au and Hg nuclei have been populated following the bombardment of g2,g4*g6M~ targets by beams of 84Sr. Comparisons are made between the entry distributions associated with both low-and high-spin 173-177A~ isomers, as well as the more stable Pt and Hg isobars, as a function of neutron number. This is the first time that a systematic study of such distributions has been conducted for nuclei near and beyond the proton dripline.
High-spin states beyond the proton drip-line: Quasiparticle alignments in 113Cs
Physics Letters B, 2015
Excited states have been studied in the deformed proton emitter 113 Cs. Gamma-ray transitions have been unambiguously assigned to 113 Cs by correlation with its characteristic proton decay, using the method of recoil-decay tagging. Two previously identified rotational bands have been observed and extended to tentative spins of 45/2 and 51/2 h, with excitation energies over 8 MeV above the lowest state. These are the highest angular momenta and excitation energies observed to date in any nucleus beyond the proton drip-line. Transitions in the bands have been rearranged compared to previous work. A study of aligned angular momenta, in comparison to the predictions of Woods-Saxon cranking calculations, is consistent with the most intense band being based on the π g 7/2 [422]3/2 + configuration, which would contradict the earlier πh 11/2 assignment, and with the second band being based on the πd 5/2 [420]1/2 + configuration. The data suggest that the band based upon the πh 11/2 configuration is not observed.
Observation of narrow states in nuclei beyond the proton drip line:^{15} F and^{16} Ne
Physical Review C, 2009
Two high-lying states in 15 F and 16 Ne, unbound with respect to one-proton (1p) and two-proton (2p) emissions, have been observed in fragmentation of 17 Ne at intermediate energies. They undergo mainly sequential emissions of protons via intermediate states in 14 O and 15 F and have decay energies of 7.8(2) and 7.6(2) MeV, respectively. The widths of the newly-observed states in 15 F and 16 Ne are much smaller than the Wigner limits for single-particle configurations, of 0.4(4) and 0.8(−4 +8) MeV, respectively. In addition, narrow widths of 0.2(2) MeV are derived for two other high-lying states in 15 F with Q p of 4.9 and 6.4 MeV, which match features of the recently-predicted narrow odd-parity 15 F states with two valence protons in the sd shell. All energies and widths have been obtained by analyzing angular correlations of the decay products, p-p-14 O and p-p-13 N, whose trajectories have been measured by a tracking technique with silicon microstrip detectors.