8 research outputs found
Summit of the N=40 Island of Inversion: precision mass measurements and ab initio calculations of neutron-rich chromium isotopes
Mass measurements continue to provide invaluable information for elucidating
nuclear structure and scenarios of astrophysical interest. The transition
region between the and proton shell closures is particularly
interesting due to the onset and evolution of nuclear deformation as nuclei
become more neutron rich. This provides a critical testing ground for emerging
ab-initio nuclear structure models. Here, we present high-precision mass
measurements of neutron-rich chromium isotopes using the sensitive
electrostatic Multiple-Reflection Time-Of-Flight Mass Spectrometer (MR-TOF-MS)
at TRIUMF's Ion Trap for Atomic and Nuclear Science (TITAN) facility. Our
high-precision mass measurements of Cr confirm previous results,
and the improved precision in measurements of Cr refine the mass
surface beyond N=40. With the ab initio in-medium similarity renormalization
group, we examine the trends in collectivity in chromium isotopes and give a
complete picture of the N=40 island of inversion from calcium to nickel.Comment: 12 pages, 7 figure
Investigating nuclear structure near N=32 and N=34: Precision mass measurements of neutron-rich Ca, Ti, and V isotopes
Nuclear mass measurements of isotopes are key to improving our understanding of nuclear structure across the chart of nuclides, in particular, for the determination of the appearance or disappearance of nuclear shell closures. We present high-precision mass measurements of neutron-rich Ca, Ti, and V isotopes performed at TRIUMF's Ion Trap for Atomic and Nuclear science (TITAN) and the Low Energy Beam and Ion Trap (LEBIT) facilities. These measurements were made using the TITAN multiple-reflection time-of-flight mass spectrometer (MR-ToF-MS) and the LEBIT 9.4T Penning trap mass spectrometer. In total, 13 masses were measured, 8 of which represent increases in precision over previous measurements. These measurements refine trends in the mass surface around N=32 and N=34, and support the disappearance of the N=32 shell closure with increasing proton number. Additionally, our data do not support the presence of a shell closure at N=34.Nuclear mass measurements of isotopes are key to improving our understanding of nuclear structure across the chart of nuclides, in particular for the determination of the appearance or disappearance of nuclear shell closures. We present high-precision mass measurements of neutron-rich Ca, Ti and V isotopes performed at the TITAN and LEBIT facilities. These measurements were made using the TITAN multiple-reflection time-of-flight mass spectrometer (MR-ToF-MS) and the LEBIT 9.4T Penning trap mass spectrometer. In total, 13 masses were measured, eight of which represent increases in precision over previous measurements. These measurements refine trends in the mass surface around and , and support the disappearance of the shell closure with increasing proton number. Additionally, our data does not support the presence of a shell closure at
Mass measurements of 60â63Ga reduce x-ray burst model uncertainties and extend the evaluated T=1 isobaric multiplet mass equation
We report precision mass measurements of neutron-deficient gallium isotopes approaching the proton drip line. The measurements of Ga60â63 performed with the TITAN multiple-reflection time-of-flight mass spectrometer provide a more than threefold improvement over the current literature mass uncertainty of Ga61 and mark the first direct mass measurement of Ga60. The improved precision of the Ga61 mass has important implications for the astrophysical rp process, as it constrains essential reaction Q values near the Zn60 waiting point. Based on calculations with a one-zone model, we demonstrate the impact of the improved mass data on prediction uncertainties of x-ray burst models. The first-time measurement of the Ga60 ground-state mass establishes the proton-bound nature of this nuclide, thus constraining the location of the proton drip line along this isotopic chain. Including the measured mass of Ga60 further enables us to extend the evaluated T=1 isobaric multiplet mass equation up to A=60
Magnetic moments of short-lived nuclei with part-per-million accuracy: Towards novel applications of -detected NMR in physics, chemistry and biology
We determine for the first time the magnetic dipole moment of a short-lived
nucleus with part-per-million (ppm) accuracy. To achieve this two orders of
magnitude improvement over previous studies, we implement a number of
innovations into our -detected Nuclear Magnetic Resonance (-NMR)
setup at ISOLDE/CERN. Using liquid samples as hosts we obtain narrow, sub-kHz
linewidth, resonances, while a simultaneous in-situ H NMR measurement
allows us to calibrate and stabilize the magnetic field to ppm precision, thus
eliminating the need for additional -NMR reference measurements.
Furthermore, we use ab initio calculations of NMR shielding constants to
improve the accuracy of the reference magnetic moment, thus removing a large
systematic error. We demonstrate the potential of this combined approach with
the 1.1 s half-life radioactive nucleus Na, which is relevant for
biochemical studies. Our technique can be readily extended to other isotopic
chains, providing accurate magnetic moments for many short-lived nuclei.
Furthermore, we discuss how our approach can open the path towards a wide range
of applications of the ultra-sensitive -NMR in physics, chemistry, and
biology.Comment: re-submitte
Mapping the N=40 island of inversion: Precision mass measurements of neutron-rich Fe isotopes
International audienceNuclear properties across the chart of nuclides are key to improving and validating our understanding of the strong interaction in nuclear physics. We present high-precision mass measurements of neutron-rich Fe isotopes performed at the TITAN facility. The multiple-reflection time-of-flight mass spectrometer (MR-ToF-MS), achieving a resolving power greater than 600000 for the first time, enabled the measurement of Fe63â70, including first-time high-precision direct measurements (ÎŽm/mâ10â7) of Fe68â70, as well as the discovery of a long-lived isomeric state in Fe69. These measurements are accompanied by both mean-field and ab initio calculations using the most recent realizations which enable theoretical assignment of the spin-parities of the Fe69 ground and isomeric states. Together with mean-field calculations of quadrupole deformation parameters for the Fe isotope chain, these results benchmark a maximum of deformation in the N=40 island of inversion in Fe and shed light on trends in level densities indicated in the newly refined mass surface
Not Available
Not AvailablePhytic acid (PA) is an important antinutritional
component in maize that affects the availability
of major micro-nutrients like di- and multivalent
mineral cations like iron (Fe) and zinc (Zn).
The long-term consumption of maize as a staple food
crop leads to micronutrient malnutrition especially
iron and zinc deficiency in the human population. In
addition, it also acts as a storehouse of a major part of
mineral phosphorous (P), approximately 80% of the
total P stored as phytate P is not available to monogastric
animals like humans and poultry birds, and it gets excreted as such, leading to one of the major
environmental pollution called eutrophication. Of the
various low phytic acid (lpa) mutants, lpa2-2 generated
through mutagenesis reduces PA by 30%. BML 6
and BML 45, the parents of the popular maize hybrid
DHM 121 with high PA were selected to introgress
lpa2-2 through marker-assisted backcross breeding
(MABB). The percent recurrent parental genome
(RPG) in the selected BC2F2
plants ranged from 88.68
to 91.04% and 90.09â91.51% in the genetic background
of BML 6 and BML 45, respectively. Based
on the highest percentage of RPG, best five BC2F2
plants, viz., #3190, #3283, #3230, #3263 and #3292
with RPG 88.68â91.04% in the genetic background of
BML 6 and #3720, #3776, #3717, #3828 and #3832
with RPG 90.09â91.51% in the genetic background
of BML 45 were advanced to BC2F3.
The newly
developed near-isogenic lines (NILs) possessed low
phytate content (2.37 mg/g in BML 6 and 2.40 mg/g
in BML 45) compared to 3.59 mg/g and 3.16 mg/g in
recurrent parents BML 6 and BML 45, respectively
thereby reducing the phytate by an average of 34 and
24 per cent, respectively. These newly developed
progenies were similar to their recurrent parents for
various morphological traits. These inbreds assume
great significance in alleviating Fe and Zn deficiencies
in worldwide.Not Availabl
Summit of the N=40 Island of Inversion: precision mass measurements and ab initio calculations of neutron-rich chromium isotopes
International audienceMass measurements continue to provide invaluable information for elucidating nuclear structure and scenarios of astrophysical interest. The transition region between the and proton shell closures is particularly interesting due to the onset and evolution of nuclear deformation as nuclei become more neutron rich. This provides a critical testing ground for emerging ab-initio nuclear structure models. Here, we present high-precision mass measurements of neutron-rich chromium isotopes using the sensitive electrostatic Multiple-Reflection Time-Of-Flight Mass Spectrometer (MR-TOF-MS) at TRIUMF's Ion Trap for Atomic and Nuclear Science (TITAN) facility. Our high-precision mass measurements of Cr confirm previous results, and the improved precision in measurements of Cr refine the mass surface beyond N=40. With the ab initio in-medium similarity renormalization group, we examine the trends in collectivity in chromium isotopes and give a complete picture of the N=40 island of inversion from calcium to nickel