Particle flux

Although direct coupling of a camera to a scintillator can give acceptable results one of its major drawback is the degradation of the quantum noise mainly related to the low transmission of the optics. The following schematics summarizes the particles flux (photons and electrons) across the different stages of the detector ... 

In the previous section the interaction of the plasma particle flux with the surface of graphite was discussed. However, the fate of the implanted particles (most importantly deuterium and tritium) following their impact with the graphite surface is also an important issue, and is seen by some as the major impediment to graphite s use as a PFM [58], Quantification of the problem, and determination of possible mitigating steps, is complicated by experimental data which can vary by orders of magnitude [59-66] as reviewed by Wilson [67]. 

In the fluid model the momentum balance is replaced by the drift-diffusion approximation, where the particle flux F consists of a diffusion term (caused by density gradients) and a drift term (caused by the electric field ) ... 

For the radical neutrals, boundary conditions are derived from diffusion theory [237, 238]. One-dimensional particle diffusion is considered in gas close to the surface at which radicals react (Figure 14). The particle fluxes in the two z-directions can be written as... 

In order to be able to explain the observed results plasma modeling was applied. A one-dimensional fluid model was used, which solves the particle balances for both the charged and neutral species, using the drift-diffusion approximation for the particle fluxes, the Poisson equation for the electric field, and the energy balance for the electrons [191] (see also Section 1.4.1). 

Aller RC, DeMaster DJ (1984) Estimates of particle-flux and reworking at the deep-sea floor using Th-234/U-238 disequilibrinm. Earth Planet Sci Lett 67 308-318 Amid D, Cochran JK, Hirschberg DJ (2002) disequihbrium as an indicator of the seasonal... 

Broecker WS, Kaufman A, Trier RM (1973) The residence time of Thorium in surface sea-water and its implications regarding the fate of reactive pollutants. Earth Planet Sci Lett 20 35-44 Buesseler KO (1991) Do upper-ocean sediment traps provide an accurate record of particle flux Nature 353 420-423... 

Gust G, Kozerski HP (2000) In situ sinking-particle flux from collection rates of cylindrical traps. Mar Ecol Prog Ser 208 93-106... 

Such OGCM modeling also suggests the importance of ice-cover in controlling the amount of Thxs advection (Henderson et al. 1999a). Low particle fluxes beneath sea-ice may lead to low scavenging rates in these areas, particularly where ice cover is permanent. In these areas, °Thxs may be advected to the edge of the ice sheet where it is... 

Simpson HJ, Trier RM, Toggweiler JR, Mathieu G, Deck BL, Olsen CR, Hammond DE, Fuller C, Ku TL (1982) Radionuclides in Mono Lake, California. Science 216 512-514 Smith CR, Berelson W, Demaster DJ, Dobbs FC, Hammond D, Hoover DJ, Pope RH, Stephens M (1997) Latitudinal variations in benthic processes in the abyssal equatorial Pacific control by biogenic particle flux. Deep-Sea Res Part II-Topical Studies in Oceanography 44(9-10) 2295 Smith CR, Pope RH, Demaster DJ, Magaard L (1993) Age-dependent mixing of deep-sea sediments. Geochim Cosmochim Acta 57(7) 1473-1488... 

In the EIPET boundary condition, the electrochemical reduction of electro-active ions adsorbed on the particle provides the essential surface binding interaction which is responsible for particle deposition on the electrode surface. The particle flux is given by... 

Rate constant temperature dependence Processing threshold Calculation of rate constants at different temperatures, including collision numbers and concentrations of species in steady state Calculation of the rate of photodissociation and cosmic ray-induced molecular processing from photon and particle fluxes... 

---