Conceptual design report on a charge breeder for HIE-ISOLDE

In this conceptual design report the possible options for an upgrade of the REX/HIE-ISOLDE charge breeder are discussed. The performance requirements imposed by standard HIE-ISOLDE physics as well as injection into a possible future TSR@ISOLDE are discussed, and thereafter translated into machine parameters. Experimental results from tests of a high-current and high-density electron gun performed at Brookhaven National Laboratory are presented, and alternative gun designs are discussed. Finally, a cost estimate is given together with possible beneficiaries of the on-going R&D, and potential collaboration partners are identified

Radiative cooling of carbon cluster anions C2n+1− (n = 3–5)

Radiative cooling of carbon cluster anions C2n+1− (n = 3–5) is investigated using the cryogenic electrostatic ion storage ring DESIREE. Two different strategies are applied to infer infrared emission on slow (milliseconds to seconds) and ultraslow (seconds to minutes) timescales. Initial cooling of the ions over the millisecond timescale is probed indirectly by monitoring the decay in the yield of spontaneous neutralization by thermionic emission. The observed cooling rates are consistent with a statistical model of thermionic electron emission in competition with infrared photon emission due to vibrational de-excitation. Slower cooling over the seconds to minutes timescale associated with infrared emission from low-frequency vibrational modes is probed using time-dependent action spectroscopy. For C9− and C11−, cooling is evidenced by the time-evolution of the yield of photo-induced neutralization following resonant excitation of electronic transitions near the detachment threshold. The cross-section for resonant photo-excitation is at least two orders of magnitude greater than for direct photodetachment. In contrast, C7− lacks electronic transitions near the detachment threshold

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

Background: The EMPA KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population. Methods: EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110. Findings: Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5–2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62–0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16–1·59), representing a 50% (42–58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1). Interpretation: In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease. Funding: Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council

Mass measurements on short-lived Cd and Ag nuclides at the online mass spectrometer ISOLTRAP

In the present work, mass determinations of the eleven neutron-deficient nuclides (99-109)Cd, of ten neutron-rich silver nuclides (112-114,121,123)Ag, and seven neutron-rich cadmium nuclides (114,120,122-124,126,128)Cd are reported. Due to the clean production of the neutron-deficient nuclides it was possible to reduce the experimental uncertainties down to 2 keV, whereas the measurements of neutron-rich nuclides were hampered by the presence of contaminations from more stable In and Cs nuclides. In the case of 99Cd and 123Ag the masses were determined for the first time and for the other nuclides the mass uncertainties could be reduced by up to a factor of 50 as in the case of 100Cd. In the case of a potential isomeric mixture as for (115,117,119)Ag and 123Cd, where no assignment to either the ground state or the excited state was possible, the experimental results were adjusted accordingly. Afterwards all results were included in the framework of the atomic-mass evaluation and thus linked and compared with other experimental data. In the case of the neutron-deficient Cd nuclides a conflict between the mass values obtained in the present work and those published by the JYFLTRAP group could be solved by performing an atomic-mass evaluation. These mass measurements are an important step towards an understanding of the physics of the rp process that will enable a more reliable determination of the composition of the produced material at A = 99. It has been shown that the mass of 99Cd strongly affects the A = 99 production in an X-ray burst model, and that uncertainties have been significantly reduced from more than an order of magnitude to about a factor of 3. The dominant source of uncertainty is now the mass of 100In. In principle, other uncertainties will also contribute. These include those of masses of lighter Cd isotopes, where similar rp-process branchpoints occur and which might affect feeding into the 99Cd branchpoint. In addition, nuclear reaction rate uncertainties will also play a role. However, as reaction rates affect branchings in a linear fashion, while mass differences enter exponentially, mass uncertainties will tend to dominate. Also, which reaction rates are important depends largely on nuclear masses. For example, for low Sp(100In) a (p,γ)-(γ,p) equilibrium will be established between 99Cd and 100In and the 100In(p,γ) reaction rate would affect the A = 99 production, while for larger Sp(100In) the 99Cd(p,γ) reaction rate might be more relevant. Therefore, the mass uncertainties should be addressed first. The presented results are relevant for any rp-process scenario with a reaction flow through the 99Cd region. Here, an X-ray burst model has been used to investigate in detail the impact of the present measurements on such an rp process. The νp process in core collapse supernovae might be another possible scenario for an rp process in the 99Cd region. It it is planed to also explore whether in that case mass uncertainties have a similar impact on the final composition. On the neutron-rich side of the valley of stability for the Cd and Ag chains of nuclides, the r process has not yet been reached. Further technical development on suppression of contaminants are required. This includes improvements on the ISOLDE side, e.g., by improving the selectivity of the transfer line or on the ISOLTRAP setup by implementing an electrostatic ion beam trap for a fast and efficient isobaric selection. Nevertheless the obtained results contribute to the knowledge of nuclear structure. The trends in the two-neutron separation-energy S2n and the interaction between the last neutrons and last protons ΔVpn were corrected to more smooth evolutions, as already seen in other regions of the nuclear chart. The strongest corrections have been observed for even-N nuclides, were more new experimental data are available. Thus, new measurements on odd-N nuclides are suggested. This also is underlined by the trends observed in the Garvey-Kelson relations for the neutron-rich Cd nuclides. Furthermore, it has been shown, that the prominent structure of the ΔVpn for an entire chain of nuclides including inflexion points can be reproduced by using simple relations between quantum numbers of the occupied orbits. This approach connects ten values for each nuclide with only one adjusted parameter. This has been investigated for 63 ΔVpn values of even-even nuclides in the vicinity of Z = 50 and 50 ≤ N ≤ 82. The simple model works remarkably well for the elements Cd, Sn, and Te. Small deviation have been observed for the Xe and Pd nuclides which were explained with the limitations of the model to the vicinity of the close shells, where the nuclides have only few valence protons and neutrons.In der vorliegenden Arbeit werden die Messungen an elf neutronenarmen Nukliden (99-109)Cd, an zehn neutronenreichen Silbernukliden (112-114,121,123)Ag und an sieben neutronenreichen Cadmiumnukliden (114,120,122-124,126,128)Cd vorgestellt. Aufgrund einer sauberen Produktion der neutronenarmen Nukliden war es möglich die exprimentellen Unsicherheiten bis auf 2keV zu verringern, wärend die Messungen an den neutronenreichen Nukliden durch die Präsenz von stabilen In und Cs Kontaminationen behindert wurden. Für die Nuklide 99Cd und 123Ag konnten die Massen zum ersten mal experimentell bestimmt werden un für die anderen Nuklide war es möglich die Unsicherheiten um bis zu einen Faktor 50 zu verringern wie für das 100Cd. Für den Fall von einer potentiell präsenten isomeren Kontamination wie für (115,117,119)Ag und 123Cd, wo es nicht möglich war zwischen dem isomeren und dem Grundzustand zu unterscheiden, wurden die Ergebnisse entsprechend angepasst. Danach wurden alle Ergebnisse in die AME (atomic-mass evaluation) eingearbeitet und so mit anderen experimentellen Daten verbunden und verglichen. Für die neutronenarmen Cd-Nuklide konnten ein Konflikt zwischen den hier vorgestellten und denen von der JYFLTRAP-Gruppe veröffentlichten Ergebnissen durch eine AME gelöst werden. Diese Massenmessungen sind ein wichtiger Schritt zum Verständnis der dem rp-Prozess zu grunde liegenden Physik, welche eine verläßlichere Bestimmung der produzierten Materialzusammensetzung bei A=99 ermöglicht. Es wurde gezeigt, dass die Masse vom 99Cd die A=99-Produktion in einem "X-ray burst" Modell stark beeinflusst und dass die Unsicherheiten von über einer Größenordnung auf etwa eine Faktor 3 reduziert wurde. Die verbleibende Unsicherheit wird durch den Massenwert vom 100In und von den leichteren Cd-Nukliden erzeugt. Die aus dem benutzten Modell gewonnen Ergebnisse geben einen Anhaltspunkt für die Korrektur der Unterproduktion von Mo und Rh p-Nukliden. Zu einer genaueren Aussage werden weitere Massenmessungen benötigt, die allerdings zuvor noch technische Entwicklungen zur Kontaminationsunterdrückung vorraussetzen. Zusätzlich tragen die erhaltenen Ergebnisse zum Verständnis der Kernstruktur bei. Die Verläufe der zwei-Neutronen-Separationsenergie und der Wechselwirkung der letzten beiden Neutronen mit den letzten beiden Protonen ΔVpn wurden begradigt. Des weiteren wurden die signifikanten Strukturen mit Wendepunktberhalten der ΔVpn in der Mitte der Neutronenschale 50 ≤ N ≤ 82 um den Protonenschalenabschluss bei Z = 50 mittels eines einfachen Überlappmodell unter Einbeziehung des Paarungsformalismus erklärt

ERNST-MORITZ-ARNDT-UNIVERSITÄT

Mass measurements on short-lived Cd and Ag nuclides at the online mass spectrometer ISOLTRA

Parametric study of a high current–density EBIS Charge Breeder regarding Two Stream plasma Instability (TSI)

In this paper we report on our results from the design study of an advanced Electron Beam Ion Source (EBIS) based Charge Breeder (ECB). The ECB should fulfill the requirements of the HIE-ISOLDE upgrade, and if possible be adapted for ion injection into TSR@ISOLDE, as well as serve as an early prototype of a future EURISOL ECB. Fulfilling the HIE-ISOLDE/TSR@ISOLDE specifications requires simultaneous increase in electron beam energy, current and current density in order to provide the requested beams with proper charge state, high intensity and with a specified pulse repetition rate. We have carried out a study on the technical requirements of the ECB. The obtained parameters were optimized to comply with technical limitations arising from the electron beam technology and plasma physics in an EC