Average electron radii in many-electron atoms

In many-electron atoms, the average electron radius r represents the mean distance of a single electron from the nucleus when all the interelectronic interactions are averaged. If the electron-electron interaction is explicitly considered, the average radius r splits into two different radii, inner radius r(<) and outer radius r(>). For the 102 atoms He through Lr in their ground states, the radii r(<) and r(>) are systematically examined at the Hartree-Fock limit level. The effect of electron correlations on r(<) and r(>) is also discussed for the He atom and its isoelectronic ions.     

NMR and MO Studies on the Molecular Structure of a Fluoranthene-Benzene Complex

Fluoranthene (FA) forms a 1:1 van der Waals complex with benzene in cyclohexane. The ¹H NMR spectrum of this complex shows that the FA moiety in the complex state has five kinds of hydrogen atoms and that the ¹H NMR peaks assigned to the protons attached to the naphthalene skeleton are largely shifted to higher magnetic field on complex formation with benzene. These observations indicate that the complex takes the structure of C_S symmetry, in which the benzene molecule mainly interacts with the electronic system localized on the naphthalene moiety of FA. The present ab initio calculations reproduce well the ¹H NMR spectral shifts mentioned above and the experimentally predicted C_S structure of the complex. According to the PPP calculations for the electronic absorption spectral changes on the complex formation, the FA-benzene complex is considered to take a sandwich type structure.     

Experimental observation of soft X-rays and suprathermal ions from rare-gas cryogenic solid targets

We investigated characteristics of the soft X-ray emission in the wavelength range of 6–16 nm using various rare-gas cryogenic solid targets irradiated with a nanosecond laser pulse. Suprathermal ions having a maximum velocity of the order of 10⁷ cm/s were detected for three rare-gas targets (Ar, Kr, and Xe). The spatial distributions of the soft X-rays and the suprathermal ions were measured for Xe cryogenic solid targets and found to vary as cos² and cos⁵, respectively, where is the angle to the target normal. By integrating the observed cos² spatial distribution, the conversion efficiency of the soft X-ray emission in the wavelength range from 6 to 16 nm was evaluated to be 0.2%/pulse. PACS 52.38.ph; 52.50.Jm     

First results from KamLAND: evidence for reactor antineutrino disappearance

KamLAND has measured the flux of nu;(e)'s from distant nuclear reactors. We find fewer nu;(e) events than expected from standard assumptions about nu;(e) propagation at the 99.95% C.L. In a 162 ton.yr exposure the ratio of the observed inverse beta-decay events to the expected number without nu;(e) disappearance is 0.611+/-0.085(stat)+/-0.041(syst) for nu;(e) energies >3.4 MeV. In the context of two-flavor neutrino oscillations with CPT invariance, all solutions to the solar neutrino problem except for the "large mixing angle" region are excluded.     

Laser terahertz-emission microscope for inspecting electrical faults in integrated circuits

A laser terahertz-emission microscope (LTEM) system is proposed and developed for inspecting electrical faults in integrated circuits (IC). We test a commercial operational amplifier while the system is operating. Two-dimensional terahertz-emission images of the IC chip are clearly observed while the chip is scanned with a femtosecond laser. When one of the interconnection lines is cut, the damaged chip has a LTEM image different from that of normal chips. The results indicate that the LTEM system is a potential tool for IC inspection.     

Time-resolved Auger decay in CsBr using high harmonics

The temperature-dependent decay dynamics of innershell holes in CsBr was measured by using high harmonics. The measured lifetime was as short as 1.5 ps at 340 K due to increasing the Auger-allowed final state density in the Urbach exciton tail, whereas it is 1.1 ns at 10 K, determined by radiative recombination. The temperature-dependent Auger lifetime extrapolated to a high temperature corresponds to the fully energy-allowed Auger decay. In the model to be presented, this yields an interatomic Auger decay lifetime of 2.4+3.8/-1.5 fs, in line with a theoretical calculation for NaF.     

Development of the fiber neutron monitor for the energy range 15-100 MeV on the International Space Station (ISS)

In order to investigate the space environment, a new neutron monitor has been prepared. The sensor consists of scintillation fibers (FIB) and will be on board the exposed facility of the Japanese Experimental module (Kibo) of the International Space Station (ISS). The sensor is one of the instruments which measures the particle and plasma environment around the ISS. The sensor will be used by the cosmonauts who work on the ISS, to help them avoid a strong particle radiation which may arrive soon. We believe that such an alert is necessary for the cosmonauts to prevent unnecessary radiation from the sun. Furthermore, the sensor will be very useful in understanding the particle acceleration mechanism at the solar surface. The design of the Engineering Model (EM) was finished and its properties were investigated. This report discusses these results.     

Measurement Accuracy in Phase-Shifting Point Diffraction Interferometer with Two Optical Fibers

A phase-shifting point diffraction interferometer (PS/PDI) with point sources of two single mode optical fibers has been developed, which will be appropriate for the surface figure measurement of large aperture optics on a sub-nanometer scale. To reduce the measurement error factors, a fiber optic plate (FOP) is used as a projection plane for interference pattern. Errors caused by imperfection of optical alignment, such as position of point sources and tilt of FOP, are minimized by analyzing the measured phase data with an original method. Measurement accuracy in the PS/ PDI is estimated with the interference pattern produced by the two optical fiber sources. If inhomogeneity of the FOP and a systematic error of the PS/PDI are eliminated, the measurement accuracy of the present system is estimated to be less than 4nm P-V and 0.7nm rms, respectively, at a measurement wavelength of 632.8 nm.