The proposed Penning trap mass spectrometer facility at TASCC

The proposed Penning trap mass spectrometer, to be located at the TASCC facility of the Chalk River Laboratories, is described. The facility will be used for precise atomic mass determinations among both stable and unstable nuclides. The unstable nuclides would be produced in heavy ion reactions using the TASCC facility. The products from these reactions would be collected using an He-jet transport system loaded with NaCl aerosols. After transport to a background free area, the nuclides of interest would be laser desorbed and resonantly ionized. Subsequently, these ions would be accumulated in a Paul trap, cooled and injected into a precision Penning trap mass spectrometer for mass analysis.     

Analysis of Quantum Rod Diffusion by Polarized Fluorescence Correlation Spectroscopy

To measure the polarization dependence of fluorescent probes, a confocal-microscope-based polarized fluorescence correlation spectroscopy system was developed, and the polarization dependence on the rotational diffusion of well-defined quantum rods (Qrods) was investigated and characterized. The rotational diffusion region of the Qrods was observed over a time range of less than 10^?5 s in a water solution, and the rotational diffusion parameters were extracted using a rotational diffusion model in which the viscosity of the solution media was varied. Our work demonstrated that polarized fluorescence correlation spectroscopy (FCS) is useful for investigating both the rotational and translational diffusion of fluorescent probes.     

Three-dimensional GaN-Ga2O3 core shell structure revealed by x-ray diffraction microscopy

In combination of direct phase retrieval of coherent x-ray diffraction patterns with a novel tomographic reconstruction algorithm, we, for the first time, carried out quantitative 3D imaging of a heat-treated GaN particle with each voxel corresponding to 17 x 17 x 17 nm3. We observed the platelet structure of GaN and the formation of small islands on the surface of the platelets, and successfully captured the internal GaN-Ga2O3 core shell structure in three dimensions. This work opens the door for nondestructive and quantitative imaging of 3D morphology and 3D internal structure of a wide range of materials at the nanometer scale resolution that are amorphous or possess only short-range atomic organization.     

Combinatorial search for optimal hydrogen-storage nanomaterials based on polymers

We perform an extensive combinatorial search for optimal nanostructured hydrogen-storage materials among various metal-decorated polymers using first-principles density-functional calculations. We take into account the zero-point vibration as well as the pressure- and temperature-dependent adsorption-desorption probability of hydrogen molecules. An optimal material we identify is Ti-decorated cis-polyacetylene with reversibly usable gravimetric and volumetric density of 7.6 wt % and 63 kg/m(3), respectively, near ambient conditions. We also propose "thermodynamically usable hydrogen capacity" as a criterion for comparing different storage materials.     

Radiation-driven hydrodynamics of high- hohlraums on the national ignition facility

The first hohlraum experiments on the National Ignition Facility (NIF) using the initial four laser beams tested radiation temperature limits imposed by plasma filling. For a variety of hohlraum sizes and pulse lengths, the measured x-ray flux shows signatures of filling that coincide with hard x-ray emission from plasma streaming out of the hohlraum. These observations agree with hydrodynamic simulations and with an analytical model that includes hydrodynamic and coronal radiative losses. The modeling predicts radiation temperature limits with full NIF (1.8 MJ), greater, and of longer duration than required for ignition hohlraums.     

Instability of Electromagnetic Ion Cyclotron Harmonic Waves in Plasmas

The stability of electromagnetic ion cyclotron harmonic waves propagating normal to an external magnetic field is studied for plasmas whose ions possess loss cone type velocity distributions. It is found that, if the ions are stationary, no instability develops except in the extreme case when the ratio of parallel to perpendicular "temperatures" of the ions is of the order mi/me, where mi and me are the ion and electron masses respectively. However, for the case of two counterstreaming ion beams in a neutralizing background of electrons, instability at zero frequency and near the first several ion cyclotron harmonics can occur if the streaming velocity is of the order of the electron thermal speed.     

Quantum State Sharing of an Arbitrary Three-Atom State by Using Five-Atom Cluster State in Cavity QED

We present a scheme for implementing the deterministic quantum state sharing of an arbitrary three-atom state by using a five-atom cluster state and a Bell-state in cavity QED. In the scheme, it does not involve Bell-state measurement and only needs to perform the single-atom measurements. Our scheme is not sensitive to both the cavity decay and the atom radiation, which is of importance in view of decoherence.