Background generation

Chaib, J. et al., Stability over genetic backgrounds, generations and years of quantitative trait locus (QTLs) for organoleptic quality in tomato, Theoret. Appl. Genet. 112, 934, 2006. 

The PIXE microbeam technique has a spot size in the range 1-10 pm, and this enables a study of the spatial distribution of elemental concentrations. The advantage of p-PIXE over EPMA is a very much increased analytical sensitivity due to the much lower Bremsstrahlung background generated by the proton beam. The detection limits are of the order 0.1% for EPMA and 0.001% using the p-PIXE technique. 

CONCEPTUAL BACKGROUND GENERATING A MORE LEWIS ACIDIC CATALYTIC CENTER... 

Background generated in the specimen or x-ray spectrometer due to characteristic lines of other elements fluoresced in the specimen [i.e., weak inelastic scattering mechanisms in the specimen, the Si(Li) detector background shelf, higher order diffraction]... 

Most nonradioactive systems are particularly sensitive to background generated by careless handling of the gel or membrane. Therefore it is important that surfaces contacting the gel or membrane should be clean, and where possible the solutions should be sterile. 

Fig. 4.14. Background-generated carrier concentration An vs background radiation flux density 4>, for representative thermal equilibrium carrier concentrations in n-type Hg, gCdg jTe at 77 K...

The KamLAND detector, shown in Figure 5, consists of a sphere of liquid scintillator, surrounded by neutron and gamma ray absorbing buffers made of liquid paraffin and water. The liquid scintillator is enclosed in a transparent nylon composite balloon that has low permeability to radon, a background-generating contaminant. The total mass of liquid scintillator is 1000 tons, filling a sphere with a radius of about 6.3 m. A 500 ton fiducial spherical volume is defined within the main volume to help reduce backgrounds from photomultiplier tubes and from external radioactive decay sources. The liquid parafrin buffer is enclosed in a spherical stainless steel vessel, which is in turn surrounded by a water Cerenkov veto counter. The entire detector is shielded by a rock overburden of 2700 meters of water equivalent (m.w.e.). 

Table 3 The number of raw antineutrino interactions required to guarantee no more than one background-generated false positive 1 kt event per century. Also shown is the distance from a 1 kt nuclear test at which this mass of scintillator Is sensitive to the indicated number of events, as derived from equation 4. The background estimate has been scaled to a depth of 50 m.w.e.

If external IR flux is present, we add the optical generation term (1.79) or (1.81) into (1.85). If we take into account background generation as well, we add (1.82). 

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