Phase-imaging ion-cyclotron-resonance technique has been implemented at the Penning-trap mass spectrometer JYFLTRAP and is routinely employed for mass measurements of stable and short-lived nuclides ...produced at IGISOL facility. Systematic uncertainties that impose limitations on the accuracy of measurements are discussed. It was found out that the phase evolution of the radial motion of ions in a Penning trap during the application of radio-frequency fields leads to a systematic cyclotron frequency shift when more than one ion species is present in the trap during the cyclotron frequency measurement. An analytic expression was derived to correctly account for the shift. Cross-reference mass measurements with carbon-cluster ions have been performed providing the mass-dependent and residual uncertainties.
.
The Phase-Imaging Ion-Cyclotron-Resonance (PI-ICR) technique has been commissioned at the JYFLTRAP double Penning trap mass spectrometer. This technique is based on projecting the ion motion in the ...Penning trap onto a position-sensitive multichannel-plate ion detector. Mass measurements of stable
85
Rb
+
and
87
Rb
+
ions with well-known mass values show that relative uncertainties
Δ
m
/
m
≤
7
·
10
-
10
are possible to reach with the PI-ICR technique at JYFLTRAP. The significant improvement both in resolving power and in precision compared to the conventional Time-of-Flight Ion Cyclotron Resonance technique will enable measurements of close-lying isomeric states and of more exotic isotopes as well as ultra-high precision measurements required,
e.g.
, for neutrino physics. In addition, a new phase-dependent cleaning method based on the differences in the accumulated cyclotron motion phases has been demonstrated with short-lived
127
In
+
and
127m
In
+
ions.
Abstract
Article presents the results of studies on the effect of minimizing the main tillage on the bulk density of southern chernozem in the conditions of the dry steppe of the Southern Urals. ...Influence of the system of annual shallow tillage (Mini-till) and direct sowing technologies (No-till) on the density of the root layer and the general porosity of the soil during the cultivation of spring wheat was studied. It was revealed that the absence of soil loosening for several years leads to its compaction above the optimal values for most grain crops. The condition for the application of No-till technology has been determined - the formation of a layer of plant mlch, which loosens the top layer of soil to a depth of up to 15 cm and excludes its overcompaction. Absence of the influence of fine tillage on the density of the root layer of the soil was revealed, its role in the fight against weeds and the creation of technological conditions for sowing was confirmed. The compaction limit of the southern chernozem and its equilibrium density in the 15-40 cm horizon were determined.
•New scheme for the modification of PS-DVB surface with functional groups.•Novel PS-DVB based anion exchangers with bulky and hydrophilic anion exchange groups.•Advantages of using ...(2,3-dihydroxypropyl) substitutes in the quaternary ammonium site.•Drastic changes in ion-exchange selectivity with increase of the hydrophilicity of substitutes.•Separation of 7 anions in less than 10min on the 5cm long column.
Novel poly(styrene-divinylbenzene) (PS-DVB) based anion exchangers having one and two (2,3-dihydroxypropyl) substitutes in the quaternary ammonium functional groups are prepared and characterised by ion chromatography (IC). The introduction of bulky and hydrophilic substitutes to the anion-exchange groups allows the elimination of non-ionic interactions between the polarisable anions and the aromatic rings from the matrix and the improvement of separation selectivity as compared with the traditional trimethylammonium (TMA) functionalised ion exchangers. The synthesis of the ion exchangers includes acylation of PS-DVB particles with acetic anhydride followed by reductive amination either with methylamine hydrochloride or dimethylamine and further alkylation with oxiranes under varied conditions. The ion exchange selectivity and separation efficiency of nine adsorbents having different structure of bonded groups, ion exchange capacity (9–98μequiv.g−1) or particle size is studied for model mixture of inorganic anions (F−, Cl−, NO2−, Br−, NO3−, HPO42− and SO42−) using carbonate and hydroxide eluents. The adsorbents with more hydrophilic substitutes provided superior columns efficiencies and better peak symmetry as compared with analogues having hydrophobic functional groups. The calculated values of column efficiencies for polarisable NO3− and HPO42− are 18,500 and 29,000N/m, respectively, for anion-exchanger, having N-methyl-N′,N″-di-(2,3-dihydroxypropyl)ammonium groups which is significantly higher than 1800 and 12,000N/m obtained for these anions with anion exchanger bearing TMA functional groups.
Abstract
Understanding the evolution of the nuclear charge radius is one of the long-standing challenges for nuclear theory. Recently, density functional theory calculations utilizing Fayans ...functionals have successfully reproduced the charge radii of a variety of exotic isotopes. However, difficulties in the isotope production have hindered testing these models in the immediate region of the nuclear chart below the heaviest self-conjugate doubly-magic nucleus
100
Sn, where the near-equal number of protons (
Z
) and neutrons (
N
) lead to enhanced neutron-proton pairing. Here, we present an optical excursion into this region by crossing the
N
= 50 magic neutron number in the silver isotopic chain with the measurement of the charge radius of
96
Ag (
N
= 49). The results provide a challenge for nuclear theory: calculations are unable to reproduce the pronounced discontinuity in the charge radii as one moves below
N
= 50. The technical advancements in this work open the
N
=
Z
region below
100
Sn for further optical studies, which will lead to more comprehensive input for nuclear theory development.
•Use of 1,4-BDDGE and RDGE for covalent attachment of functional groups to PS-DVB surface.•Novel PS-DVB anion exchangers with branched functional layers of various hydrophilicities.•General ...selectivity decrease with increase of hydrophilicity of linker and functional group.•Separation of 7 anions in less than 12min in isocratic mode on the 5cm long column.
Novel polystyrene-divinylbenzene (PS-DVB) based anion exchangers differing from each other in the structure of the branched functional ion exchange layer are prepared to investigate the role of linker and functional site on ion exchange selectivity. The proposed method of synthesis includes the obtaining of aminated PS-DVB particles by means of their acylation with following reductive amination with methylamine. Further modification of the obtained secondary aminogroups is provided by the alkylation with either 1,4-butanediol diglycidyl ether (1,4-BDDGE) or resorcinol diglycidyl ether (RDGE), which form the linkers of different hydrophobicity, and amination of terminal epoxide rings with trimethylamine (TMA), dimethylethanolamine (DMEA), methyldiethanolamine (MDEA) or triethanolamine (TEA). The variation of the structure and hydrophobicity of the linker and terminal quaternary ammonium sites in the functional layer allows the alteration of selectivity and separation efficiency of the obtained adsorbents. The ion exchange selectivity and separation efficiency of the anion exchangers are evaluated using the model mixtures of anions (F−, HCOO−, Cl−, NO2−, Br−, NO3−, HPO42− and SO42−) in potassium hydroxide eluents. The adsorbents show the decrease of selectivity with increasing the hydrophilicity of the terminal functional site. The anion exchangers having more flexible and hydrophilic 1,4-BDDGE linker provide smaller separation factors for most of the analytes as compared with RDGE-containing adsorbents with the same terminal ion exchange sites, but are characterized with higher column efficiencies and better peak symmetry for polarizable anions. In case of 1,4-BDDGE-modified anion exchangers of the particle size of 3.3μm functionalized with DMEA and MDEA the calculated values of column efficiencies for polarizable NO3− and Br− are up to 49,000 and 53,000N/m, respectively, which is almost twice higher than the values obtained for the RDGE-containing analogues.
In a measurement of isomeric yield-ratios in fission, the Phase-Imaging Ion-Cyclotron-Resonance technique, which projects the radial motions of ions in the Penning trap (JYFLTRAP) onto a ...position-sensitive micro-channel plate detector, has been applied. To obtain the yield ratio, that is the relative population of two states of an isomer pair, a novel analysis procedure has been developed to determine the number of detected ions in each state, as well as corrections for the detector efficiency and decay losses. In order to determine the population of the states in cases where their mass difference is too small to reach full separation, a Bayesian Gaussian Mixture model was implemented. The position-dependent efficiency of the micro-channel plate detector was calibrated by mapping it with
133
Cs
+
ions, and a Gaussian Process was trained with the position data to construct an efficiency function that could be used to correct the recorded distributions. The obtained numbers of counts of excited and ground-state ions were used to derive the isomeric yield ratio, taking into account decay losses as well as feeding from precursors.
We report the first high-precision mass measurements of the neutron-rich nuclei 74,75 Ni and the clearly identified ground state of 76 Cu, along with a more precise mass-excess value of 78 Cu, ...performed with the double Penning trap JYFLTRAP at the Ion Guide Isotope Separator On-Line (IGISOL) facility. These new results lead to a quantitative estimation of the quenching for the N = 50 neutron shell gap. The impact of this shell quenching on core-collapse supernova dynamics is specifically tested using a dedicated statistical equilibrium approach that allows a variation of the mass model independent of the other microphysical inputs. We conclude that the impact of nuclear masses is strong when implemented using a fixed trajectory as in the previous studies, but the effect is substantially reduced when implemented self-consistently in the simulation.
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