Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 7 de 7
Filtrar
Mais filtros

Base de dados
Tipo de documento
Assunto da revista
País de afiliação
Intervalo de ano de publicação
1.
Phys Rev Lett ; 130(1): 012501, 2023 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-36669221

RESUMO

The atomic masses of ^{55}Sc, ^{56,58}Ti, and ^{56-59}V have been determined using the high-precision multireflection time-of-flight technique. The radioisotopes have been produced at RIKEN's Radioactive Isotope Beam Factory (RIBF) and delivered to the novel designed gas cell and multireflection system, which has been recently commissioned downstream of the ZeroDegree spectrometer following the BigRIPS separator. For ^{56,58}Ti and ^{56-59}V, the mass uncertainties have been reduced down to the order of 10 keV, shedding new light on the N=34 shell effect in Ti and V isotopes by the first high-precision mass measurements of the critical species ^{58}Ti and ^{59}V. With the new precision achieved, we reveal the nonexistence of the N=34 empirical two-neutron shell gaps for Ti and V, and the enhanced energy gap above the occupied νp_{3/2} orbit is identified as a feature unique to Ca. We perform new Monte Carlo shell model calculations including the νd_{5/2} and νg_{9/2} orbits and compare the results with conventional shell model calculations, which exclude the νg_{9/2} and the νd_{5/2} orbits. The comparison indicates that the shell gap reduction in Ti is related to a partial occupation of the higher orbitals for the outer two valence neutrons at N=34.


Assuntos
Nêutrons , Titânio
2.
J Chem Phys ; 139(8): 084317, 2013 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-24007007

RESUMO

Mobilities of Li(+)-attached butanol isomers, (n-BuOH)Li(+), (s-BuOH)Li(+), (i-BuOH)Li(+), and (t-BuOH)Li(+), in helium gas were measured over a range of reduced electric fields (E/N = 25-96 Td) at room temperature. Arrival time measurements accurately identified small differences in the measured mobilities of the isomer ions. At low E/N (≤30 Td, corresponding to a mean collision energy ε≤0.05 eV), (n-BuOH)Li(+) showed a mobility about 1.5% greater than that of the other ions, but at high E/N (≥75 Td, ε≥0.1 eV) its mobility was about 1.1% less.

3.
Rev Sci Instrum ; 87(6): 065104, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27370494

RESUMO

A gas circulation and purification system was developed at the RIKEN Radioactive Isotope Beam Factory that can be used for gas-cell-based low-energy RI-beam production. A high-flow-rate gas cell filled with one atmosphere of buffer gas (argon or helium) is used for the deceleration and thermalization of high-energy RI-beams. The exhausted buffer gas is efficiently collected using a compact dry pump and returned to the gas cell with a recovery efficiency of >97%. The buffer gas is efficiently purified using two gas purifiers as well as collision cleaning, which eliminates impurities in the gas. An impurity level of one part per billion is achieved with this method.

4.
Rev Sci Instrum ; 85(1): 014302, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24517788

RESUMO

We present a novel facility for micro-irradiation of living targets with ions from a 1.7 MV tandem accelerator. We show results using 1 MeV protons and 2 MeV He(2+). In contrast to common micro-irradiation facilities, which use electromagnetic or electrostatic focusing and specially designed vacuum windows, we employ a tapered glass capillary with a thin end window, made from polystyrene with a thickness of 1-2 µm, for ion focusing and extraction. The capillary is connected to a beamline tilted vertically by 45°, which allows for easy immersion of the extracted ions into liquid environment within a standard cell culture dish. An inverted microscope is used for simultaneously observing the samples as well as the capillary tip, while a stage-top incubator provides an appropriate environment for the samples. Furthermore, our setup allows to target volumes in cells within a µm(3) resolution, while monitoring the target in real time during and after irradiation.


Assuntos
Ambiente Controlado , Microtecnologia/instrumentação , Aceleradores de Partículas/instrumentação , Prótons , Sobrevivência Celular , Desenho de Equipamento , Células HeLa , Humanos
5.
Phys Rev Lett ; 101(21): 212502, 2008 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-19113405

RESUMO

The ground state hyperfine splitting of (7)Be+ has been measured by laser-microwave double-resonance spectroscopy in the online rf trap of RIKEN's slow RI-beam facility. Be ions produced by projectile fragmentation of 13C at approximately 1 GeV were thermalized in a rf ion guide gas cell and subsequently laser cooled in the ion trap to approximately 1 microeV. This 10(15)-fold reduction of the kinetic energy allows precision spectroscopy of these ions. A magnetic hfs constant of A=-742.772 28(43) MHz was measured for 7Be+, from which a nuclear magnetic moment of mu(I)=-1.399 28(2)mu(N) was deduced.

6.
Phys Rev Lett ; 93(19): 195001, 2004 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-15600840

RESUMO

A new positron accumulation scheme compatible with ultrahigh vacuum conditions has been developed, which is realized by preparing a high density electron plasma as high as approximately 10(11) cm(-3) and an ion cloud as energy absorbers. The present accumulation rate normalized by the intensity of 22Na positron source is (3.6+/-0.3)x10(2)e(+)/s/mCi, which is more than one and a half orders of magnitude higher than other ultrahigh vacuum compatible schemes so far reported.

7.
J Synchrotron Radiat ; 5(Pt 3): 1058-60, 1998 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-15263744

RESUMO

Photon-ion merged-beam apparatus using a compact ECR ion source and a high-brilliance light source has been designed for the study of photoabsorption processes of multiply charged ions. Photoion spectroscopy will be performed along isoelectronic, isonuclear and isoionic sequences. The main features of this apparatus are described.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA