A detailed β -decay study of the low- and high-spin states in Bi 216 has been performed at the ISOLDE Decay Station at the CERN-ISOLDE facility. In total, 48 new levels and 83 new transitions in the ...β -decay daughter Po 216 were identified. Shell-model calculations for excited states in Bi 216 and Po 216 were performed using the H208 and the modified Kuo-Herling particle effective interactions. Based on the experimental observations and the shell-model calculations, the most likely spin and parity assignments for the β -decaying states in Bi 216 are ( 3 − ) and ( 8 − ) , respectively. Published by the American Physical Society 2024
The ISOLDE Radioactive Beam Facility is the dedicated CERN installation for the production and acceleration of radioactive nuclei far from stability. Exotic nuclei of most chemical elements are ...available for the study of nuclear structure, nuclear astrophysics, fundamental symmetries and atomic physics, as well as for applications in condensed-matter and life sciences. Since more than a decade it offers the largest variety of post-accelerated radioactive beams in the world today. In order to broaden the scientific opportunities beyond the reach of the present facility, the on-going HIE-ISOLDE (High Intensity and Energy) project will provide major improvements in energy range, beam intensity and beam quality. Post-accelerated beams will be available already this year boosting the beam energy of the current REX LINAC to 4.3 MeV/u reaching 5.5 MeV/u next spring. In this new energy regime the Coulomb excitation cross sections are strongly increased with respect to the previous energy of bearly 3 MeV/u and many transfer reaction channels will open. The second stage of the energy upgrade will allow energies of the beam up to 10 MeV/u for the worst scenario of A/q = 4.5. The funds are already secured and it is expected to be completed in 2017. In this contribution the present status of the ISOLDE facility will be discussed, some highlights will be briefly described to illustrate the advances of the facility. The HIEISOLDE project will be described together with a panorama of the physics cases to be addressed in the near future with emphasis in the day-one experiment to be done this year.
We have observed beta(-)-delayed proton emission from the neutron-rich nucleus Be-11 by analyzing a sample collected at the ISOLDE facility at CERN with accelerator mass spectrometry (AMS). With a ...branching ratio of (8.3 +/- 0.9). 10(-6) the strength of this decay mode, as measured by the B-GT-value, is unexpectedly high. The result is discussed within a simple single-particle model and could be interpreted as a quasi-free decay of the Be-11 halo neutron into a single-proton state.
Rare βp decays in light nuclei Borge, M J G; Fraile, L M; Fynbo, H O U ...
Journal of physics. G, Nuclear and particle physics,
03/2013, Letnik:
40, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Beta-delayed proton emission may occur at very low rates in the decays of the light nuclei 11Be and 8B. This paper explores the potential physical significance of such decays, estimates their rates ...and reports on first attempts to detect them: an experiment at ISOLDE/CERN gives a branching ratio for 11Be of (2.5 ± 2.5) × 10−6 and an experiment at JYFL a 95% confidence upper limit of 2.6 × 10−5 for 8B.
Search for beta-delayed proton emission from 11Be Riisager, K.; Borge, M. J. G.; Briz, J. A. ...
The European physical journal. A, Hadrons and nuclei,
2020/3, Letnik:
56, Številka:
3
Journal Article
Recenzirano
We report on an attempt to reproduce the observation of
β
-
-delayed proton emission from
11
Be through detection of the final state nucleus
10
Be with accelerator mass spectrometry. Twelve samples ...were collected at the ISOLDE facility at CERN at different separator settings, allowing tests of different sources of contamination to be carried out. The observed amounts of
10
Be per collected
11
Be rule out several contamination sources, but do not agree internally. Formation of BeH molecular ions in the ion source may explain our data, in which case an upper limit of the
β
p branching ratio of
2.2
×
10
-
6
can be derived.
DNA hypomethylation at the
(F2R like thrombin or trypsin receptor 3) locus has been associated with both smoking and atherosclerotic cardiovascular disease; whether these smoking-related associations ...form a pathway to disease is unknown.
encodes protease-activated receptor 4, a potent thrombin receptor expressed on platelets. Given the role of thrombin in platelet activation and the role of thrombus formation in myocardial infarction, alterations to this biological pathway could be important for ischemic cardiovascular disease.
We conducted multiple independent experiments to assess whether DNA hypomethylation at
in response to smoking is associated with risk of myocardial infarction via changes to platelet reactivity. Using cohort data (N=3205), we explored the relationship between smoking, DNA hypomethylation at
, and myocardial infarction. We compared platelet reactivity in individuals with low versus high DNA methylation at
(N=41). We used an in vitro model to explore the biological response of
to cigarette smoke extract. Finally, a series of reporter constructs were used to investigate how differential methylation could impact
gene expression.
Observationally, DNA methylation at
mediated an estimated 34% of the smoking effect on increased risk of myocardial infarction. An association between methylation group (low/high) and platelet reactivity was observed in response to PAR4 (protease-activated receptor 4) stimulation. In cells, cigarette smoke extract exposure was associated with a 4.9% to 9.3% reduction in DNA methylation at
and a corresponding 1.7-(95% CI, 1.2-2.4,
=0.04) fold increase in
mRNA. Results from reporter assays suggest the exon 2 region of
may help control gene expression.
Smoking-induced epigenetic DNA hypomethylation at
appears to increase PAR4 expression with potential downstream consequences for platelet reactivity. Combined evidence here not only identifies
DNA methylation as a possible contributory pathway from smoking to cardiovascular disease risk but from any feature potentially influencing
regulation in a similar manner.
The unexplained disagreement in the dependence of spectroscopic factors
(
C
2
S
exp
)
on the binding energy obtained by nucleon knockout using different targets is still a puzzle that needs to be ...addressed.
To find an explanation of this riddle through exclusive measurements using different targets.
The exclusive measurements were performed by using a
Ne
17
beam with an energy of 500 MeV/u incident on
C
and
CH
2
targets. Through the standard theoretical approach,
C
2
S
exp
were derived from the analysis of the experimental data on proton ejection from the proton halo in
Ne
17
as well as from its core
O
15
.
For the
C
target, proton ejection from the proton halo gave
C
2
S
exp
about 37% smaller than for the
H
target. But when protons are ejected from the core of
Ne
17
,
C
2
S
exp
are identical within statistical uncertainties.
An explanation for the difference in
C
2
S
exp
could be the removal of both halo protons, a more important reaction pathway for the
C
target. The
C
2
S
exp
values obtained by analyzing the proton ejection from the core indicate that it is not affected by the interaction with the halo protons.
Published by the American Physical Society
2024
Coulomb excitation of 74,76Zn Illana, A.; Zielińska, M.; Huyse, M. ...
Physical review. C,
10/2023, Letnik:
108, Številka:
4
Journal Article
Recenzirano
Odprti dostop
The first experiment using radioactive beams post-accelerated by the HIE-ISOLDE facility has enabled to obtain a precise set of B(E2) transition probabilities in neutron-rich 74,76Zn isotopes. The ...resulting B(E2; 2+1→0+1) values are consistent with those determined in earlier REX-ISOLDE measurements. While the B(E2; 4+1→2+1) transition probability in 76Zn is also in agreement with earlier Coulomb-excitation results, the value obtained for 74Zn is considerably lower. For the first time, a spectroscopic quadrupole moment of the 2+1 state was measured for an exotic nucleus in this mass region. A detailed comparison is presented with large-scale shell-model and Monte Carlo shell-model calculations.
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