Stéphanie Teughels

g-factor measurements of μs isomeric states in neutron-rich nuclei around 68Ni produced in projectile-fragmentation reactions

We report the first g factor measurement on microsecond isomers of neutronrich nuclei produced in projectile-fragmentation reactions at intermediate energies. The nuclides in the vicinity of 68 Ni were produced and spin oriented following the fragmentation of a 76 Ge, 61.4 MeV u −1 beam at GANIL. The LISE spectrometer was used to select the nuclei of interest. The time-dependent perturbed angular distribution (TDPAD) method was applied in combination with th eh eavy-ion–gamma correlation technique to measure the g factors of 69m Cu (J π = 13/2 + , T1/2 = 350 ns) and 67m Ni (J π = 9/2 + , T1/2 = 13.3 µs). Specific details of the experimental technique and the comparison of the results (|g( 69m Cu) |= 0.225(25) and |g( 67m Ni) |= 0.125(6)) with theoretical calculations are discussed. These results provide another indication of the importance of proton excitations across the Z = 28 shell gap.

Pharmacokinetics and bio-distribution of novel super paramagnetic iron oxide nanoparticles (SPIONs) in the anaesthetized pig.

Manufactured nanomaterials have a variety of medical applications, including diagnosis and targeted treatment of cancer. A series of experiments were conducted to determine the pharmacokinetic, biodistribution and biocompatibility of two novel magnetic nanoparticles (MNPs) in the anaesthetized pig. Dimercaptosuccinic acid (DMSA) coated superparamagnetic iron oxide nanoparticles (MF66‐labelled 12 nm, core nominal diameter and OD15 15 nm); at 0.5, or 2.0 mg/kg) were injected intravenously. Particles induced a dose‐dependent decrease in blood pressure following administration which recovered to control levels several minutes after injection. Blood samples were collected for a 5‐h period and stored for determination of particle concentration using particle electron paramagnetic resonance (pEPR). Organs were harvested post‐mortem for magnetic resonance imaging (MRI at 1.5 T field strength) and histology. OD15 (2.0 mg/kg) MNP had a plasma half‐life of approximately 15 min. Both doses of the MF66 (0.5 and 2.0 mg/kg) MNP were below detection limits. MNP accumulation was observed primarily in the liver and spleen with MRI scans which was confirmed by histology. MRI also showed that both MNPs were present in the lungs. The results show that further modifications may be required to improve the biocompatibility of these particles for use as diagnostic and therapeutic agents.

Biodistribution and pharmacokinetic studies of SPION using particle electron paramagnetic resonance, MRI and ICP-MS

AIM Superparamagnetic iron oxide nanoparticles (SPIONs) may play an important role in nanomedicine by serving as drug carriers and imaging agents. In this study, we present the biodistribution and pharmacokinetic properties of SPIONs using a new detection method, particle electron paramagnetic resonance (pEPR). MATERIALS & METHODS The pEPR technique is based on a low-field and low-frequency electron paramagnetic resonance. pEPR was compared with inductively coupled plasma mass spectrometry and MRI, in in vitro and in vivo. RESULTS The pEPR, inductively coupled plasma mass spectrometry and MRI results showed a good correlation between the techniques. CONCLUSION The results indicate that pEPR can be used to detect SPIONs in both preclinical and clinical studies.

Quadrupole moments of the 11− intruder isomers in 194,196Pb in the particle-core coupling model

Abstract The recently measured spectroscopic quadrupole moments of the 11 − intruder isomers in 194,196 Pb are being discussed in the particle-core coupling model. The essential physics behind the nature of these isomers is revealed by a simple two-level-mixing calculation, showing that the coupling of the valence proton particles with vibrations of the underlying Hg core induces a factor of two increase of the quadrupole moments.

Study of the static quadrupole moment of the K=35/2 isomer in 179W

The quadrupole interaction frequency of the high-K five-quasiparticle isomer in W-179 implanted in a Tl host at a temperature of 473 K has been determined using the LEMS method. A value of 65.7(7.5) MHz has been found.

Nuclear moment studies with polarized radioactive nuclear beams

Magnetic dipole and electric quadrupole moments of nuclei in the light-mass neutron-rich region have been studied by taking advantage of spin-polarized radioactive nuclear beams that have been obtained from the projectile fragmentation reaction. Analyses of the results reveal a few interesting phenomena characteristic of nuclear structures in this region. In particular, we report in some detail the latest result on the magnetic moment of the 17C ground state. The distinctly small value of the g-factor obtained, |g(17C)|=0.5054±0.0025, clearly excludes a Iπ=1/2+ candidate for the spin-parity assignment of this marginally bound nucleus, providing a reasonable account of the non-halo nature reported in recent breakup reaction experiments. Finally, future plans at the upcoming radioactive beam facility presently under construction at RIKEN are briefly mentioned.

The quadrupole moment of18N, measured with the Level Mixing Resonance (LMR) method

SummaryWe report on the Level Mixing Resonance experiment performed on the ß-decaying18N nucleus produced and aligned in an intermediate-energy fragmentation reaction. From the resonantly induced change in the asymmetry of the ß-decay, measured as a function of a static magnetic field, we derived information on the nuclear moments of the neutron-rich18N nucleus. The spectroscopic quadrupole moment |Q(18N, 1−1)| = 3.2(3)e fm2 is compared to mean-field calculations.

Synchronous delay based UWB pulse generator in FPGA

This paper presents an architecture for generating UWB pulses with a high centre frequency accuracy. The architecture allows to generate frequencies twice that of the FPGA clock using synchronous delays and is implementable in all types of FPGA. With a FPGA clock of 150 MHz, we generate RF pulse of 300 MHz with a maximum fractional bandwidth of 30%. The architecture also allows pulse width increment in steps of the clock period.

Quadrupole moment of the 8{sup +} yrast state in {sup 84}Kr

The quadrupole moment of the 8{sup +} yrast state in {sup 84}Kr was measured using the level-mixing spectroscopy technique to be Q= 36(4) e fm{sup 2}. The result is compared with predictions of the shell model using common sets of effective charges. The comparison of experimental quadrupole moments with calculated values for 8{sup +} states in Kr, Sr and Zr isotopes with N= 48, 50 and for 9/2{sup +} states in isotopes with N= 47, 49 suggests a modification of the effective charges used in this region.

g‐Factor Measurements Of Isomeric States In Neutron Rich Nuclei

We report on the first application of the TDPAD method to measure the g factor of neutron‐rich isomeric states, produced and aligned in a projectile fragmentation reaction. The feasibility of similar measurement opens up a new, unexplored region of the nuclear chart for studies of the magnetic moments of microsecond isomers. Nuclei around 68Ni were produced following the fragmentation of 61.6 MeV/u 76Ge on a 145 mg/cm2 Be target. The isotopes of interest were selected using the LISE spectrometer at GANIL, Caen, France, and were implanted in a high purity Cu foil fixed between the poles of an electromagnet. Two Ge Clover detectors, positioned in a plane perpendicular to the holding magnetic field, were used to observe the rotation of the nuclear spin ensemble and to derive the experimental R(t) function. The experimental result for the isomer in 67Ni (Jπ = 9/2+, T1/2 = 13.3 μs, Ex = 1007 keV), |g| = 0.125(6), is presented herein and is also compared to the theoretical expectations.