In-source laser spectroscopy of At isotopes and decay studies of 178Au

The region surrounding the Z = 82 major-shell closure has exhibited the strongest known manifestation of shape coexistence, to date. Due to this, the nuclides that inhabit this region have been subject to extensive decay- and laser-spectroscopy studies. In this work, the results from two investigations performed at the CERN, ISOLDE facility will be presented: the first, an α-decay study of two states in 178 Au, and the second, an in-source laser-spectroscopy experiment performed on a long chain of At isotopes. Two states, a low-spin ground state, and a high-spin isomer, were directly identified in 178 Au (Z = 79, N = 99) for the first time. Due to the highly selective resonant laser-ionisation method, it was possible to produce isomerically pure beams of the ground and isomeric states. These beams were then ustilised in order to perform dedicated α-decay studies upon the two states. Successful measurements were made for the half-lives, branching ratios, and decay patterns of 178g,mAu. The first ever laser-spectroscopy measurements were performed on a long chain of At isotopes, using the in-source resonant ionisation technique. The isotope shifts and hyperfine structures of long-lived states in 195−211,217−219At were measured. From these, values for the corresponding changes in mean-squared charge radius, and magnetic dipole moments were extracted. The charge-radii of the neutron-deficient At isotopes display a strong onset of deformation, as the neutron number approaches the N = 104 midshell. The observed onset is more pronounced than the one seen in the Po isotopes, which is noted to be exceptionally strong. Based on the extracted charge-radii and magnetic moments, cases for shape coexistence were identified in 195,197,199At. In the case of the neutron-rich At isotopes, an inversion of the normal odd-even-staggering has given evidence for the presence of octupole collectivity

Study of the neutron-rich region in the vicinity of 208Pb via multinucleon transfer reactions

The multinucleon transfer reaction mechanism was employed to populate isotopes around the doubly- magic 208 Pb nucleus. We used an unstable 94 Rb beam on 208 Pb targets of different thickness. Transfer channels were studied via the fragment-γ and γ-γ coincidences, by using MINIBALL γ spectrometer coupled to a particle detector. Gamma transitions associated to the different Pb isotopes, populated by the neutron transfers, are discussed in terms of excitation energy and spin. Fragment angular distributions were extracted, andcompared with the reaction model

Shape staggering of midshell mercury isotopes from in-source laser spectroscopy compared with density-functional-theory and Monte Carlo shell-model calculations

Neutron-deficient 177−185Hg isotopes were studied using in-source laser resonance-ionization spectroscopy at the CERN-ISOLDE radioactive ion-beam facility in an experiment combining different detection methods tailored to the studied isotopes. These include either α-decay tagging or multireflection time-of-flight gating for isotope identification. The endpoint of the odd-even nuclear shape staggering in mercury was observed directly by measuring for the first time the isotope shifts and hyperfine structures of 177−180Hg. Changes in the mean-square charge radii for all mentioned isotopes, magnetic dipole, and electric quadrupole moments of the odd-A isotopes and arguments in favor of I=7/2 spin assignment for 177,179Hg were deduced. Experimental results are compared with density functional theory (DFT) and Monte Carlo shell model (MCSM) calculations. DFT calculations using Skyrme parametrizations predict a jump in the charge radius around the neutron N=104 midshell, with an odd-even staggering pattern related to the coexistence of nearly degenerate oblate and prolate minima. This near-degeneracy is highly sensitive to many aspects of the effective interaction, a fact that renders perfect agreement with experiments out of reach for current functionals. Despite this inherent difficulty, the SLy5s1 and a modified UNEDF1SO parametrization predict a qualitatively correct staggering that is off by two neutron numbers. MCSM calculations of states with the experimental spins and parities show good agreement for both electromagnetic moments and the observed charge radii. A clear mechanism for the origin of shape staggering within this context is identified: a substantial change in occupancy of the proton πh9/2 and neutron νi13/2 orbitals

Home and Online Management and Evaluation of Blood Pressure (HOME BP) using a digital intervention in poorly controlled hypertension: randomised controlled trial

Objective: The HOME BP (Home and Online Management and Evaluation of Blood Pressure) trial aimed to test a digital intervention for hypertension management in primary care by combining self-monitoring of blood pressure with guided self-management. Design: Unmasked randomised controlled trial with automated ascertainment of primary endpoint. Setting: 76 general practices in the United Kingdom. Participants: 622 people with treated but poorly controlled hypertension (>140/90 mm Hg) and access to the internet. Interventions: Participants were randomised by using a minimisation algorithm to self-monitoring of blood pressure with a digital intervention (305 participants) or usual care (routine hypertension care, with appointments and drug changes made at the discretion of the general practitioner; 317 participants). The digital intervention provided feedback of blood pressure results to patients and professionals with optional lifestyle advice and motivational support. Target blood pressure for hypertension, diabetes, and people aged 80 or older followed UK national guidelines. Main outcome measures: The primary outcome was the difference in systolic blood pressure (mean of second and third readings) after one year, adjusted for baseline blood pressure, blood pressure target, age, and practice, with multiple imputation for missing values. Results: After one year, data were available from 552 participants (88.6%) with imputation for the remaining 70 participants (11.4%). Mean blood pressure dropped from 151.7/86.4 to 138.4/80.2 mm Hg in the intervention group and from 151.6/85.3 to 141.8/79.8 mm Hg in the usual care group, giving a mean difference in systolic blood pressure of −3.4 mm Hg (95% confidence interval −6.1 to −0.8 mm Hg) and a mean difference in diastolic blood pressure of −0.5 mm Hg (−1.9 to 0.9 mm Hg). Results were comparable in the complete case analysis and adverse effects were similar between groups. Within trial costs showed an incremental cost effectiveness ratio of £11 ($15, €12; 95% confidence interval £6 to £29) per mm Hg reduction. Conclusions: The HOME BP digital intervention for the management of hypertension by using self-monitored blood pressure led to better control of systolic blood pressure after one year than usual care, with low incremental costs. Implementation in primary care will require integration into clinical workflows and consideration of people who are digitally excluded. Trial registration: ISRCTN13790648

In-source laser spectroscopy of dysprosium isotopes at the ISOLDE-RILIS

A number of radiogenically produced dysprosium isotopes have been studied by in-source laser spectroscopy at ISOLDE using the Resonance Ionization Laser Ion Source (RILIS). Isotope shifts were measured relative to $^{152}$Dy in the 4 f$^{ 10}$6s$^{2}$ $^5$I$_8$ (gs) $\rightarrow$ 4 f$^{ 10}$6s6p (8,1)$^8_o$ (418.8 nm$_{vac}$) resonance transition. The electronic factor, F, and mass shift factor, M, were extracted and used for determining the changes in mean-squared charge radii for $^{145m}$Dy and $^{147m}$Dy for the first time.A number of radiogenically produced dysprosium isotopes have been studied by in-source laser spectroscopy at ISOLDE using the Resonance Ionization Laser Ion Source (RILIS). Isotope shifts were measured relative to $^{152}$Dy in the 4$f$$^{10}$6$s$$^{2}$ $^{5}$ I$_{8}$ (gs)→ 4$f$$^{10}$6$s$6$p$(8,1)$_{8}^{0}$ (418.8nm$_{vac}$) resonance transition. The electronic factor, $F$ , and mass shift factor, $M$ , were extracted and used for determining the changes in mean-squared charge radii for $^{145m}$Dy and $^{147m}$ Dy for the first time

Search for Isovector Valence-Shell Excitations in Nd-140 and Sm-142 via Coulomb excitation reactions of radioactive ion beams

Projectile Coulomb excitation experiments were performed at HIE-ISOLDE at CERN with the radioactive ion beams of 140Nd and 142Sm. Ions with an energy of 4.62 MeV/A were impinging on a 1.45 mg/cm2 thick 208Pb target. The γ-rays depopulating the Coulomb-excited states were recorded by the HPGe-array MINIBALL and scattered particles were detected by a double-sided silicon strip detector. Experimental intensities were used for the determination of electromagnetic transition matrix elements. A preliminary result of the B(M1; 2+ 3→2+ 1 ) of 140Nd and an upper limit for the case of 142Sm are revealing the main fragments of the proton-neutron mixed-symmetry 2+ 1,ms states.peerReviewe

Search for Isovector Valence-Shell Excitations in 140Nd and 142Sm via Coulomb excitation reactions of radioactive ion beams

Projectile Coulomb excitation experiments were performed at HIE-ISOLDE at CERN with the radioactive ion beams of 140Nd and 142Sm. Ions with an energy of 4:62 MeV/A were impinging on a 1.45 mg/cm2 thick 208Pb target. The γ-rays depopulating the Coulomb-excited states were recorded by the HPGe-array MINIBALL and scattered particles were detected by a double-sided silicon strip detector. Experimental intensities were used for the determination of electromagnetic transition matrix elements. A preliminary result of the B(M1; 2+3 → 2+1) of 140Nd and an upper limit for the case of 142Sm are revealing the main fragments of the proton-neutron mixed-symmetry 2+1;ms states

Study of the neutron-rich region in the vicinity of 208Pb via multinucleon transfer reactions

The multinucleon transfer reaction mechanism was employed to populate isotopes around the doubly-magic 208 Pb nucleus. We used an unstable 94 Rb beam on 208 Pb targets of different thickness. Transfer channels were studied via the fragment-γ and γ-γ coincidences, by using MINIBALL γ spectrometer coupled to a particle detector. Gamma transitions associated to the different Pb isotopes, populated by the neutron transfers, are discussed in terms of excitation energy and spin. Fragment angular distributions were extracted, andcompared with the reaction models