Two methods were proposed for determining alpha-particle fluence for radiobiological experiments. The first involved calculating the probabilities of hitting the target for alpha particles emitted from a source through Monte Carlo simulations, which when multiplied by the activity of the source gave the fluence at the target. The second relied on the number of chemically etched alpha-particle t...

PURPOSE To create a user friendly, accurate, real time computer simulator to facilitate the design of dual foil scattering systems for electron beams on radiotherapy accelerators. The simulator should allow for a relatively quick, initial design that can be refined and verified with subsequent Monte Carlo (MC) calculations and measurements. METHODS The simulator consists of an analytical algo...

The individual impacts of slow (300 eV/amu) highly charged Xe ions induce nanometer sized pitlike structures on the KBr (001) surface. The volume of these structures shows a strong dependence on the ions potential energy. Total potential sputter yields from atomically flat (001) terraces are determined by imaging single ion impact sites. The dependence of the sputter yield on the ions initial c...

GRB941017, a gamma-ray burst of exceptional fluence, has recently been shown to have a high-energy component which is not consistent with the standard fireball phenomenology. If this component is the result of photomeson interactions in the burst fireball, it provides new and compelling support for substantial high-energy neutrino fluxes from this and similar sources. In this letter, we conside...

We report a transient absorption study of photocarrier dynamics in transition metal dichalcogenide alloy, Mo0.5W0.5S2. Photocarriers were injected by a 400-nm pump pulse and detected by a 660-nm probe pulse. We observed a fast energy relaxation process of about 0.7 ps. The photocarrier lifetime is in the range of 50 - 100 ps, which weakly depends on the injected photocarrier density and is a fe...

The microstructural evolution and helium retention in polycrystalline tungsten (W) implanted with 100 keV ions at different temperatures to a wide range of fluences were studied. Rutherford backscattering spectrometry (RBS) shows that atoms well retained tungsten, no loss occurred before surface blistering/flaking occurred. Within certain windows fluence temperature, ordered bubble superlattice...

Instrumental selection effects can act upon the estimates of the peak energy Eobs peak, the fluence F and the peak flux P of GRBs. If this were the case, then the correlations involving the corresponding rest frame quantities (i.e. Epeak, Eiso and the peak luminosity Liso) would be questioned. We estimated, as a function of Eobs peak, the minimum peak flux necessary to trigger a GRB and the min...

The flux and spectrum of the black hole candidate GX339-4 has been monitored by the Burst and Transient Source Experiment (BATSE) on the Compton Gamma-ray Observatory (CGRO) since the observatory became operational in May 1991. Between the summer of 1991 and the fall of 1996, eight outbursts from GX339-4 were observed. The history of these outbursts is one of declining fluence or total energy r...

Silicon photovoltaic cells have design and material requirements different from those of most other silicon electronic devices. Not only are nearly ideal silicon surfaces required, but also the bulk properties must be of uniform high quality for high-energy conversion efficiency. In this paper, emission spectra of laser-generated plasmas from titanium dioxide antireflection coatings in solar ce...