experiment

[conf] In-gas-cell laser ionization spectroscopy at KISS

In-gas-cell laser ionization spectroscopy at KISS

Yoshikazu Hirayama, Momo Mukai, Yutaka Watanabe, Peter Schury, Toshitaka Niwase, Hyunsuk Choi, Takashi Hashimoto, Shun Iimura, SunChan Jeong, Hiroari Miyatake, JunYoung Moon, Hitoshi Nakada, Michihiro Oyaizu, Marco Rosenbusch, Aiko Takamine, Minori Tajima, Akihiro Taniguchi, and Michiharu Wada

doi: 10.1007/s10751-024-01886-1

abstract

We have developed the KEK Isotope Separation System (KISS) at RIKEN to study the nuclear structure of the nuclei in the vicinity of neutron magic number N=126 from the astrophysical perspective. These neutron-rich nuclei have been produced by using multinucleon transfer (MNT) reactions with combinations of the low-energy ¹²⁶Xe beam and the production targets of W, Ir, and Pt. At the KISS facility, radioisotopes are ionized by applying in-gas-cell laser ionization technique. In this process, we can perform laser ionization spectroscopy of the refractory elements with the atomic number Z=70–78 such as Hf, Ta, W, Re, Os, Ir, and Pt, which cannot be performed in other facilities. Laser spectroscopy can effectively investigate nuclear structure through the measured magnetic moments, isotope shifts (IS) Δν, changes in the mean-square charge radii δ<r²>, and quadrupole deformation parameters |<β²>|^1/2. We have studied the ionization schemes of these elements through offline tests and performed in-gas-cell laser ionization spectroscopy of these refractory neutron-rich nuclei produced at KISS.

Mar 24, 2024 by Theo experiment 0

[paper] In-gas-cell laser spectroscopy of the magnetic dipole moment of the N≈126 isotope ¹⁹⁹Pt

In-gas-cell laser spectroscopy of the magnetic dipole moment of the N≈126 isotope ¹⁹⁹Pt

Y. Hirayama et al.
doi: 10.1103/PhysRevC.96.014307

The magnetic dipole moment and mean-square charge radius of $199 g Pt$ $(I^{π} =$ $5 / 2^{-}, t_{1 / 2} = 30.8$ min) ground state and $199 m Pt$ $(E_{ex} = 424$ keV, $I^{π} =$ (13/2) $^{+}, t_{1 / 2} = 13.6$ s) isomeric state are evaluated for the first time from investigations of the hyperfine splitting of the $λ_{1} = 248.792$ nm transition by in-gas-cell laser ionization spectroscopy. Ground and isomeric states of neutron-rich $199 Pt$ nucleus were produced by a multinucleon transfer reaction at the KEK Isotope Separation System (KISS), designed for the study of nuclear spectroscopy in the vicinity of $N = 126$ . The measured magnetic dipole moments $+ 0.75$ (8) $μ_{N}$ and $- 0.57$ (5) $μ_{N}$ are consistent with the systematics of those of nuclei with $I^{π} =$ $5 / 2^{-}$ and $I^{π} =$ $13 / 2^{+}$ , respectively.

Jul 11, 2017 by Theo experiment g factor radii 0

[paper] Spin and magnetic moment of ²³Mg

Spin and magnetic moment of ²³Mg

D. Yordanov et al.

doi: 10.1088/1361-6471/aa718b

A negative magnetic moment of ²³Mg has been determined by high-resolution laser spectroscopy at CERN-ISOLDE. The absolute value is in agreement with previous measurements by nuclear magnetic resonance while the sign points at high-seniority configurations. The result is consistent with shell-model predictions for nuclei with valence nucleons in the sd shell.

May 12, 2017 by Theo experiment g factor 0

[paper] Onset of deformation in neutron-deficient Bi isotopes studied by laser spectroscopy

Onset of deformation in neutron-deficient Bi isotopes studied by laser spectroscopy

A.E. Barzakh et al.

doi: 10.1103/PhysRevC.95.044324

In-source laser spectroscopy experiments for bismuth isotopes at the 306.77-nm atomic transition has been carried out at the Investigation of Radioactive Isotopes on Synchrocyclotron facility of Petersburg Nuclear Physics Institute. New data on isotope shifts and hyperfine structure for Bi ground states and isomers (^{189,190m1,190m2,191,192,192m,194,194m,198m}Bi) have been obtained. The changes in the mean-square charge radii δ⟨r²⟩ and magnetic-moment values have been deduced. For Bi nuclei a marked deviation from the isotopic trend of δ⟨r²⟩ in lead and thallium isotopic chains has been demonstrated at N<111. This has been interpreted as an indication of the onset of quadrupole deformation. Analysis of the magnetic moments for odd-odd Bi isotopes also points to the possible increase in deformation at N<111.

Apr 30, 2017 by Theo experiment g factor radii 0

[paper] The on-line low temperature nuclear orientation facility NICOLE

The on-line low temperature nuclear orientation facility NICOLE

T. Ohtsubo et al.

doi: 10.1088/1361-6471/aa5f22

We review major experiments and results obtained by the on-line low temperature nuclear orientation method at the NICOLE facility at ISOLDE, CERN since the year 2000 and highlight their general physical impact. This versatile facility, providing a large degree of controlled nuclear polarization, was used for a long-standing study of magnetic moments at shell closures in the region Z = 28, N = 28–50 but also for dedicated studies in the deformed region around A ~ 180. Another physics program was conducted to test symmetry in the weak sector and constrain weak coupling beyond V–A. Those two programs were supported by careful measurements of the involved solid state physics parameters to attain the full sensitivity of the technique and provide interesting interdisciplinary results. Future plans for this facility include the challenging idea of measuring the beta–gamma–neutron angular distributions from polarized beta delayed neutron emitters, further test of fundamental symmetries and obtaining nuclear structure data used in medical applications. The facility will also continue to contribute to both the nuclear structure and fundamental symmetry test programs.

Mar 16, 2017 by Theo experiment 0

[paper] MEMS switch integrated radio frequency coils and arrays for magnetic resonance imaging

MEMS switch integrated radio frequency coils and arrays for magnetic resonance imaging

S.B. Bulumulla et al.

doi: 10.1063/1.4975181

Surface coils are widely used in magnetic resonance imaging and spectroscopy. While smaller diameter coils produce higher signal to noise ratio (SNR) closer to the coil, imaging larger fields of view or greater distance into the sample requires a larger overall size array or, in the case of a channel count limited system, larger diameter coils. In this work, we consider reconfiguring the geometry of coils and coil arrays such that the same coil or coil array may be used in multiple field of view imaging. A custom designed microelectromechanical systems switch, compatible with magnetic resonance imaging, is used to switch in/out conductive sections and components to reconfigure coils. The switch does not degrade the SNR and can be opened/closed in 10 μs, leading to rapid reconfiguration. Results from a single coil, configurable between small/large configurations, and a two-coil phased array, configurable between spine/torso modes, are presented.

Feb 11, 2017 by Theo experiment 0

[paper] Sixfold improved single particle measurement of the magnetic moment of the antiproton

Sixfold improved single particle measurement of the magnetic moment of the antiproton

H. Nagahama et al.

doi: 10.1038/ncomms14084

Our current understanding of the Universe comes, among others, from particle physics and cosmology. In particle physics an almost perfect symmetry between matter and antimatter exists. On cosmological scales, however, a striking matter/antimatter imbalance is observed. This contradiction inspires comparisons of the fundamental properties of particles and antiparticles with high precision. Here we report on a measurement of the g-factor of the antiproton with a fractional precision of 0.8 parts per million at 95% confidence level. Our value g(antiproton)=2=2.7928465(23) outperforms the previous best measurement by a factor of 6. The result is consistent with our proton g-factor measurement g(proton)=2=2.792847350(9), and therefore agrees with the fundamental charge, parity, time (CPT) invariance of the Standard Model of particle physics. Additionally, our result improves coefficients of the standard model extension which discusses the sensitivity of experiments with respect to CPT violation by up to a factor of 20.

Jan 19, 2017 by Theo experiment g factor 0

[paper] Magnetic moment of the 13/2⁺ isomeric state in ⁶⁹Cu: Spin alignment in the one-nucleon removal reaction

Magnetic moment of the 13/2⁺ isomeric state in ⁶⁹Cu: Spin alignment in the one-nucleon removal reaction

A. Kusoglu et al.

doi: http://dx.doi.org/10.1103/PhysRevC.93.054313

We report on a new measurement of the g factor of the (13/2⁺) isomeric state in the neutron-rich nucleus ⁶⁹Cu. This study demonstrates the possibility of obtaining considerable nuclear spin alignment for multi-quasiparticle states in single-nucleon removal reactions. The time-dependent perturbed angular distribution (TDPAD) method was used to extract the gyromagnetic factor of the (13/2⁺) [T_½=351(14) ns] isomeric state of ⁶⁹Cu. Its g factor was obtained as g(13/2⁺)=0.248(9). The experimentally observed spin alignment for the state of interest was deduced as A=−3.3(9)%.

May 16, 2016 by Theo experiment 0

[Paper] Table of nuclear electric quadrupole moments

Table of nuclear electric quadrupole moments

N.J. Stone

doi: 10.1016/j.adt.2015.12.002

This Table is a compilation of experimental measurements of static electric quadrupole moments of ground states and excited states of atomic nuclei throughout the periodic table. To aid identification of the states, their excitation energy, half-life, spin and parity are given, along with a brief indication of the method and any reference standard used in the particular measurement. Experimental data from all quadrupole moment measurements actually provide a value of the product of the moment and the electric field gradient [EFG] acting at the nucleus. Knowledge of the EFG is thus necessary to extract the quadrupole moment. A single recommended moment value is given for each state, based, for each element, wherever possible, upon a standard reference moment for a nuclear state of that element studied in a situation in which the electric field gradient has been well calculated. For several elements one or more subsidiary EFG/moment reference is required and their use is specified.

The literature search covers the period to mid-2015.

Apr 12, 2016 by Theo experiment quadrupole 0

[Paper] Spectroscopic Quadrupole Moments in ^96,98Sr: Evidence for Shape Coexistence in Neutron-Rich Strontium Isotopes at N=60

Spectroscopic Quadrupole Moments in Sr96,98: Evidence for Shape Coexistence in Neutron-Rich Strontium Isotopes at N=60

E. Clément et al.

doi: 10.1103/PhysRevLett.116.022701

Neutron-rich ^96,98Sr isotopes have been investigated by safe Coulomb excitation of radioactive beams at the REX-ISOLDE facility. Reduced transition probabilities and spectroscopic quadrupole moments have been extracted from the differential Coulomb excitation cross sections. These results allow, for the first time, the drawing of definite conclusions about the shape coexistence of highly deformed prolate and spherical configurations. In particular, a very small mixing between the coexisting states is observed, contrary to other mass regions where strong mixing is present. Experimental results have been compared to beyond-mean-field calculations using the Gogny D1S interaction in a five-dimensional collective Hamiltonian formalism, which reproduce the shape change at N=60.

Jan 20, 2016 by Theo experiment quadrupole 0

In-gas-cell laser ionization spectroscopy at KISS

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