Irradiation by electrons

Experimental details for the cross-section measurements were presented in the literature. Briefly, after the irradiation by electron beam pulse for a few nanoseconds, the time-dependent absorption for the atomic line transition Rg Rg -i-/zv was measured to observe the time-dependent population of the excited rare gas atoms Rg. The population of excited Rg was determined using an absorption law for the atomic lines, where the broadening of the absorption profile due to the thermal Doppler effect and due to the attractive interatomic potentials was reasonably taken into consideration. The time-dependent optical emission from energy transfer products, such as ... 

The range of the gzz values is shown clearly by a comparison of the results for the NaY and NaX zeolites. Since the migration of Na+ ions is related to the presence of water (76), it is likely that the type of precursor (Na4)4+ -(H20)x complex formed after a proper degree of dehydration (278) will be strongly dependent on the pretreatment conditions. This will be reflected in the gzz values of the OJ produced during y irradiation by electron transfer from the precursor (278). It is also likely that the OJ can migrate after its formation as shown by Kasai and Bishop (264). These authors (272) have detected a superhyperfine interaction from Na nuclei (I = ) in the EPR spectrum of OJ formed in Na-reduced NaY zeolite and characterized by gzz = 2.113. This value is very close to those observed for alkalisuperoxides trapped in krypton matrices (Ref. 44, Appendix A). 

Different pol)uneric materials respond to irradiation by electron beam in different ways. A large number of them will be modified by the formation of a cross-linked network, by changing their surface properties or structure, and some will be degraded. Another field applicable to polymeric systems is polymerization and grafting. Electron beam can also be used for pol5unerization and cross-linking of oligomers and monomers, i.e., in conversion of liquids to solids. 

Electron paramagnetic resonance measurements only identify vacancies or vacancy complexes in Si irradiated by electrons. The absence of Si self-interstitials has been ascribed to rapid athermal migration even at 2 K (13). 

When ground beef is irradiated by electron beam and gamma-ray irradiation and its proteins assayed for amino acid content, the most sensitive amino acid to irradiation by either source is cystine. Approximately 50% of cystine is destroyed under the most damaging conditions used. Under the same conditions tryptophan shows about 10% destruction while arginine, phenylalanine, and tyrosine showed no destruction, and the rest of the amino acids show little destruction. From the cystine and tryptophan data, it appears that for electron beam irradiation the extent of destruction is not related primarily to total dose but to dose rate and particularly to energy level of irradiating dose. 

Fig. 5. Energy dependence of the luminescence of CH4 fragments with irradiation by electrons (Reproduced by permission from Ref. 79). Plotted along the axis of ordinates is the intensity of luminescence in arbitrary units.

The contribution of VCR to radioluminescence has been also studied in Refs. 324 and 325. The results close to those of Ref. 323 have been obtained by Zhuravleva325 in a comparative study of radioluminescence of 3-aminophthalamide (AP) in ethanol solutions irradiated by electrons with Ee = 3.5 MeV and by X rays with Eph = 50 keV. 

The time (or dose) dependences of the subbands turned out to be a very precise and sensitive tool to study the defect formation, and STE can be used to both trigger and probe the dynamics of lattice rearrangement in RGS. Figures 5 and 6 show examples of evolution of luminescence spectra of RGS under irradiation by electrons (Fig.5) and photons (Fig.6). In all cases a pronounced increase in the intensity of the defect component during... 

Silicone Fluids (IO 6 - IO 9) Are thermally stable and are resistant to oxidation and reasonably resistant to chemical attack. Are also reasonably priced. Form insulating polymeric layer when irradiated by electrons, so they cannot be used where physical electronic equipment is being pumped, such as in helium leak detectors. 

Neutron [102] and electron [70,103] irradiated TCNQ salts were investigated by IR spectroscopy. The spectra of irradiated samples gradually become weaker when the dose is increased the broad lines change shape and decrease in intensity some even vanish (Fig. 18). It was shown [103] that the vibrational features connected with the totally symmetric modes of the TCNQ are particularly sensitive to structural disorder. In some cases, for example, in MTPP(TCNQ)2 irradiated by electrons, the disappearance of distinct doublets of activated ag modes was noticed. Different mechanisms of the excitation of both the narrow and wide components explain their different dose and temperature dependences [70]. The changes of band intensity in the UV-VIS region imitate the electrical conductivity as a function of dose. 

OSHA PEL TW A 0.01 mg(A /m3 ACGIH TLV WA 0.01 mg(Ag)/m3 DOT CLASSIFICATION Forbidden SAFETY PROFILE Explodes when heated above 270°C or on impact. Pure silver azide explodes at 340°. An electric field or irradiation by electron pulses can explode the crystals. Shock-sensitive when dry and has detonated 250°C. Solutions in aqueous ammonia explode above 100°C. Reacts to form more explosive products with iodine (forms iodine azide) bromine and other halogens. The presence of metal oxides or metal sulfides increases the azide s sensitivity to explosion. Mixtures with sulfur dioxide are explosive. When heated to decomposition it emits toxic fumes of NO,. See also AZIDES and SILVER COMPOUNDS. 

Modern bulk analysis methods make possible non-destructive chemical identification, which means that the sample remains intact after the analysis. Such a procedure is provided by electron microprobe or X-ray fluorescence analyses, in which the sample is irradiated by electron beams or X-rays and the elemental composition is determined on the basis of induced characteristic X-ray emissions. These methods have been successfully employed to study both stratospheric (Junge, 1963) and tropospheric (Gillette and Blifford, 1971) aerosol particles. Neutron activation analysis is also widely used to identify the chemical composition of atmospheric particulate matter (e.g. Duceef ai, 1966 Rahn etal., 1971) this is also a non-destructive procedure. 

FIGURE 14.3 Dose dependence of the nnmber averaged molecular weight (Mn) and the distribution of the molecular weight (M Mn) irradiated by electron beam (1 MeV, 0.1 mA). 

FIGURE 31.7 Radiation and chemical-radiation degradation of chitosan (hydrogen peroxide is added before irradiated by electron beam). (From Chmielewski, A.G. et al., Radiat. Phys. Chem., 76, 1840, 2007. With permission.)... 

PEs are immiscible with nearly all polymers thus the standard strategies are applicable (i) non-compatibilized blends with low concentration of the dispersed phase, e.g., blends of either PP or PE with 2 wt% PVAl (ii) non-compatibilized blends for the use in noncritical applications (iii) non-compatibilized blends having co-continuous morphology, e.g., PE, blended with neoprene rubber at a ratio 1 1 and then irradiated by electron beam and (iv) compatibiUzed blends. 

Polyethylene, PE, was blended with neoprene rubber at a ratio 1 1. The blends were irradiated by electron beam for improved tensile strength and other mechanical properties ... 

Freeman, G.R., 1987d, Stochastic model of charge scavenging in liquids under irradiation by electrons or photons, Kinetics of... 

When irradiated by electron beam, a VDF-based fluoropolymer can imdergo many radical reactions that are going to be detailed in this section. The crosslinking reaction is a particular one. 

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