experiment

[preprint] Populating Low-Spin States in Radioactive Nuclei to Measure Magnetic Moments Using the Transient Field Technique

Populating Low-Spin States in Radioactive Nuclei to Measure Magnetic Moments Using the Transient Field Technique

D.A. Torres and F. Ramírez

arXiv: 1601.03602

The experimental study of magnetic moments for nuclear states near the ground state, I≥2, provides a powerful tool to test nuclear structure models. The study of magnetic moments in nuclei far away from the stability line is the next frontier in such studies. Two techniques have been utilized to populated low-spin states in radioactive nuclei: coulomb excitation reactions using radioactive nuclei, and the transfer of α particles to stable beams to populate low spin states in radioactive nuclei. A presentations of these two techniques, along with the experimental challenges presented for future uses with nuclei far away from the stability line, will be presented.

Jan 17, 2016 by experiment g factor 0

[Paper] Recent Advances in On-Line Laser Spectroscopy

Recent Advances in On-Line Laser Spectroscopy

B. Cheal et al.

doi: 10.1080/10619127.2015.1104126

Abstract

At radioactive ion beam facilities, particle accelerators are employed to induce nuclear reactions in order to provide short-lived nuclei for immediate study using a variety of spectroscopic techniques. These exotic isotopes/isomers are formed into a beam of fast ions, which are mass analyzed in-flight during transport to a chosen experimental set-up. As an additional filter, the atomic level structure provides a selective fingerprint, which distinguishes one element from another due to the varying numbers of protons and electrons. This property is exploited in laser ion sources whereby high power, pulsed tuneable laser radiation is used to excite and ionize the atom in order to enhance the yield of a selected element. This not only provides a means of identification but also purification.

Dec 26, 2015 by experiment 0

[paper] Laser spectroscopy of atoms in superfluid helium for the measurement of nuclear spins and electromagnetic moments of radioactive atoms

Laser spectroscopy of atoms in superfluid helium for the measurement of nuclear spins and electromagnetic moments of radioactive atoms

T. Fujita et al.

doi: 10.1007/s10751-015-1206-0

A new laser spectroscopic method named “OROCHI (Optical RI-atom Observation in Condensed Helium as Ion catcher)” has been developed for deriving the nuclear spins and electromagnetic moments of low-yield exotic nuclei. In this method, we observe atomic Zeeman and hyperfine structures using laser-radio-frequency/microwave double-resonance spectroscopy. In our previous works, double-resonance spectroscopy was performed successfully with laser-sputtered stable atoms including non-alkali Au atoms as well as alkali Rb and Cs atoms. Following these works, measurements with 84−87Rb energetic ion beams were carried out in the RIKEN projectile fragment separator (RIPS). In this paper, we report the present status of OROCHI and discuss its feasibility, especially for low-yield nuclei such as unstable Au isotopes.

Nov 26, 2015 by experiment 0

[Paper] The ASACUSA CUSP: an antihydrogen experiment

The ASACUSA CUSP: an anti hydrogen experiment

N. Kuroda et al.

doi: 10.1007/s10751-015-1205-1

In order to test CPT symmetry between antihydrogen and its counterpart hydrogen, the ASACUSA collaboration plans to perform high precision microwave spectroscopy of ground-state hyperfine splitting of antihydrogen atom in-flight. We have developed an apparatus (“cusp trap”) which consists of a superconducting anti-Helmholtz coil and multiple ring electrodes. For the preparation of slow antiprotons and positrons, Penning-Malmberg type traps were utilized. The spectrometer line was positioned downstream of the cusp trap. At the end of the beamline, an antihydrogen beam detector was located, which comprises an inorganic Bismuth Germanium Oxide (BGO) single-crystal scintillator housed in a vacuum duct and surrounding plastic scintillators. A significant fraction of antihydrogen atoms flowing out the cusp trap were detected.

Nov 10, 2015 by experiment 0

[paper] Orientation features of 24Mg(2+) aligned nuclei in (p,p) and (d,d) reactions at Ex ≈ 7.5 MeV per nucleon

Orientation features of 24Mg(2+) aligned nuclei in (p,p) and (d,d) reactions at Ex ≈ 7.5 MeV per nucleon

L.I. Galanina et al.

doi: 10.1134/S1063778815060095

Experimental angular dependences of cross sections for elastic and inelastic scattering and the result obtained by reconstructing the populations of magnetic sublevels, multipole-moment orientation tensors, and polarization tensors are presented for 24Mg (2+, 1.369 MeV) aligned nuclei produced in inelastic proton scattering at Ep = 7.4 MeV. The experimental results in question are compared with the results of calculations based on the coupled-channel method and on the compound-nucleus model, the 3/2+ resonance in the 25Al compound nucleus being taken into account. The orientation features of 24Mg (2+, 1.369 MeV) nuclei produced in inelastic proton and deuteron scattering on 24Mg at Ex ≈ 7.5 MeV per nucleon are found to be generally similar despite a substantial difference in the respective differential cross sections.

Oct 2, 2015 by experiment 0

[paper] Demonstration of the double Penning Trap technique with a single proton

Demonstration of the double Penning Trap technique with a single proton

A. Mooser et al.

doi: 10.1016/j.physletb.2013.05.012

Spin flips of a single proton were driven in a Penning trap with a homogeneous magnetic field.
For the spin-state analysis the proton was transported into a second Penning trap with
a superimposed magnetic bottle, and the continuous Stern–Gerlach effect was applied.
This first demonstration of the double Penning trap technique with a single proton suggests
that the antiproton magnetic moment measurement can potentially be improved by three
orders of magnitude or more.

Jun 4, 2013 by experiment 0

[paper] Erosion of N=20 shell in 33Al investigated through the ground-state electric quadrupole moment

Erosion of N=20 shell in 33Al investigated through the ground-state electric quadrupole moment

K. Shimada et al.

doi: 10.1016/j.physletb.2012.07.030

Electric quadrupole moment Q of the ground state has been measured by means of β-NMR spectroscopy using a spin-polarized beam produced in a projectile fragmentation reaction. The obtained Q moment, |Qexp(33Al)|=132(16) emb, shows a significant excess from the prediction of shell model calculations within the sd shell. The result indicates sizable admixing of pf intruder configurations in the ground state, demonstrating that the N=20 shell closure certainly erodes in 33Al, a nucleus located on the border of the island of inversion. Comparison was made with predictions of the Monte Carlo shell model, and also a particle-vibration coupling model treating the neutron pairing correlations in the ground state of 33Al. Again, a significant admixture of pf intruder configurations to the ground state was needed in both theoretical approaches to explain the observed large Q.

Aug 14, 2012 by experiment 0

[paper] Hyperfine structure anomaly and magnetic moments of neutron deficient Tl isomers with I=9/2

Hyperfine structure anomaly and magnetic moments of neutron deficient Tl isomers with I=9/2

A.E. Barzakh et al.

doi: 10.1103/PhysRevC.86.014311

The hyperfine structure of 276.9-nm atomic transition has been studied by the resonant ionization spectroscopy method at mass-separator IRIS (Investigation of Radioactive Isotopes on Synchrocyclotron), Petersburg Nuclear Physics Institute (PNPI) for the odd Tl isomers with I=9/2 and A=187–197. A differential hyperfine structure anomaly for 6p2P1/2 and 7s2S1/2 atomic states in Tl isomers with I=9/2 has been determined. It is described by the recently developed theoretical approach fairly well. This enables one to recalculate the magnetic moments of 187−193Tlm(I=9/2) from previously measured hyperfine splittings for 7s2S1/2 states and to determine for the first time the magnetic moments for 197Tlm and 195Tlm(I=9/2) from hyperfine splittings for 6p2P1/2 states with properly taking into account the rather great hyperfine structure anomaly. Similar measurements with greater accuracy have been proposed for the other nuclear states in odd-odd Tl isotopes. These measurements could shed light on the nuclear magnetization distribution in these isotopes.

Jul 18, 2012 by experiment g factor 0

[preprint] Spectroscopy on a single trapped 137Ba+ ion for nuclear magnetic octupole moment determination

Spectroscopy on a single trapped 137Ba+ ion for nuclear magnetic octupole moment determination

N.C. Lewty et al.

arXiv: http://arxiv.org/abs/1205.6908

We present precision measurements of the hyperfine splittings in the 5D3/2 manifold of a single trapped Barium ion, 137Ba+. Measurements of the hyperfine splittings are made between mF = 0 sublevels over a range of magnetic fields allowing us to interpolate to the zero field splittings with an accuracy below 10 Hz. Our results, in conjunction with theoretical calculations, allow the determination of the hyperfine coupling constant, C, with an accuracy below 0.1 Hz. This gives a subsequent determination of the nuclear magnetic octupole moment with an uncertainty limited almost completely by the accuracy of theoretical calculations.

Jun 3, 2012 by experiment 0

[paper] Observation of 239Pu Nuclear Magnetic Resonance

Observation of 239Pu Nuclear Magnetic Resonance

H. Yasuoka et al.

doi: 10.1126/science.1220801

In principle, the spin-½ plutonium-239 (239Pu) nucleus should be active in nuclear magnetic resonance spectroscopy. However, its signal has eluded detection for the past 50 years. Here, we report observation of a 239Pu resonance from a solid sample of plutonium dioxide (PuO2) subjected to a wide scan of external magnetic field values (3 to 8 tesla) at a temperature of 4 kelvin. By mapping the external field dependence of the measured resonance frequency, we determined the nuclear gyromagnetic ratio 239γγn(PuO2)/2π to be 2.856&plusm;0.001 megahertz per tesla (MHz/T). Assuming a free-ion value for the Pu4+ hyperfine coupling constant, we estimated a bare 239γγn/2π value of ~2.29 MHz/T, corresponding to a nuclear magnetic moment of μn ≈ 0.15 μμN (where μN is the nuclear magneton).

May 28, 2012 by experiment g factor 0

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21Mg 22Mg 23Mg 24Mg 25Mg 26Mg 27Mg 28Mg 29Mg 30Mg 31Al 31Mg 32Mg 33Al 33Mg 40Ar 42Sc 43S 43Sc 44Ar 44Cl 44Sc 45Sc 46Sc 55Ni 57Cu 58Cu 59Cu 61Cu 62Cu 63Cu 64Cu 65Cu 66Cu 67Cu 68Cu 69Cu 70Cu 71Cu 72As 72Cu 72Zn 73Cu 74Cu 74Se 75Cu 76Kr 76Se 77Cu 78Cu 78Kr 78Se 80Kr 80Se 82Kr 82Se 84Kr 84Sr 86Sr 88Kr 88Sr 88Zr 96Ru 100Pd 100Sn 102Ag 104Ag 106Ag 108Ag 110Ag 110Cd 112Sn 114Sn 116Sn 122Sn 124Sn 132Sn 137Ba 140Xe 142Xe 144Nd 146Ba 146Ce 146Nd 148Ce 148Nd 150Nd 154Gd 156Gd 157Er 158Er 168Hf 171Hf 172Hf 187Tl 189Tl 191Tl 193Tl 195Tl 197Tl 229Th 239Pu 250Bk 253Es 254Es 255Fm actinides antiproton arxiv B(E2) b-NMR BCS Be charge radd charge radii chiral effective field theory chiral quark model collinear laser spectroscopy conference paper correlation attenuation Coulex covariant CPT cranker database DSAM electric quadrupole moment electromagnetic moments electron EPJA experiment Gammasphere GANIL g factor Green functions HVTF hydrogen like hyperfine field Hyperfine Interactions hyperfine splitting IBM IBM-2 IBMFM IGISOL in-gas-cell laser spectroscopy island of inversion ISOLDE isomer isotope shift JPhysG KISS laser laser-induced nuclear orientation laser spectroscopy Li LISE LISOL magnetic moment magnetic quadrupole moment mean field MEC moments Monte Carlo N3LO Nilsson-Strutinsky NMR NMR/ON nuclear moments nuclear spin nucleon octupole nuclear magnetic moment PAC PAN paper Paul trap Penning PLB PRC preprint PRL proton QCD QED quadrupole deformation quadrupole moment resonant ionization spectroscopy RIKEN Rutgers Science Science China SDPF-U shell model spin expectation value TDPAD TF theory TIPAD triaxial Λ resonance α-transfer