Electron beam accelerator

Figure 3 high resolution TEM images with Fourier transforms showing the real-time degradation of the BEA framework under a 200 kV accelerated electron beam images at a) time = 0s and after b) 10s, c) 20s and d) 40s. 

Machine sources such as electron accelerators and those converting accelerated electron beams to x-ray photons. Accelerated electrons have low penetrability. Thus they cannot meet all the goals of food irradiation. The 10 MeV electrons, the highest energy level of electron irradiation presently recommended by the Codex Alimentarius [6], can penetrate food with typically about 4-cm thickness. 

The primary effect of any ionizing radiation is based on its ability to excite and ionize molecules, and this leads to the formation of free radicals, which fhen initiate reactions such as polymerization and cross-linking or degradation. Accelerated electron beams have energy sufficient to affect the electrons in the atom shell, but not its nucleus, and can therefore only initiate chemical reactions. Typically, the reactions initiated by electron beam are extremely fast and are completed in fractions of a second. 

Fig. 11.9. Experimental setup used for the betatron experiment. Permanent magnets are used simultaneously to deviate the accelerated electron beam off-axis in order to make sure that the X-ray detection is unperturbed and to provide spectral information on the electron energy distribution. CCD pictures of the X-ray beam and the electron spectrum for a gas jet electronic density of 1019 cm-3 are also shown...

Martin, D.I., Margaritescn, I., Cirstea, E., Togoe, I., Ighigeanu, D., Nemtanu, M.R., Oproiu, C., and lacob, N. 2005. Application of accelerated electron beam and microwave irradiation to biological waste treatment. Vacuum, 77 501-06. 

Electron impact (El) ionization is a technique in which a neutral molecule, M, is ionized following bombardment by an accelerated electron beam creating a radical cation, M +, and an additional free electron [5—12] as follows ... 

Synthesis of P(CMS-2VN), aiming at Dg =1 p. C / cm2 sensitivity, was carried out by ordinary radical polymerization in an inert-gas-filled flask with stirring (60 °C, 5 hrs.). The polymer after fractionation was Mw = 7.8 x 10-5, and polydispersivity Mw /Mn = 1.3 (as measured by gel permeation chromatography). The mole fractions in the polymer were found to be 9 mole % of CMS and 91 mole % 2VN ( as determined by elemental analysis). These values are very close to the mole fractions in the feed. The polymer was dissolved in xylene (5 wt.%), spin-coated (2000 rpm) and prebaked (100 °C for 30 min) to get uniform 0.5 jl m-thick-films on Si substrate. Pattern delineation was made by a 3EOL 3BX-5A (20 kV acceleration) electron beam exposure system without proximity corrections. Images were developed by dipping in 1,1,2,2-... 

The first prerequisite for measurement of photoelectron spin-polarization is the ability to separately detect the photoelectrons ejected from the different fine-structure levels (e.g., 2n3/2 and 2n1/2 for HX+ X2n). When the molecule contains a heavy atom (e.g., large spin-orbit splitting), it becomes easier to use the electron kinetic energy to distinguish the photoelectrons ejected from the different fine structure channels. For spin-polarization analysis, the accelerated electron beam (20-120 keV) can be scattered by a thin gold foil in a Mott-detector. The spin-polarization is determined from the left-right (or up-down) asymmetry in the intensities of the scattered electrons (Heinzmann, 1978). Spin polarization experiments, however, are difficult because the differential spin-up/spin-down flux of photoelectrons is typically one thousandth that obtained when recording a total photoionization spectrum. 

Using an electron microscope offers the advantages of increased magnification and resolution. The TEM passes an accelerated electron beam flirough a thin sample (50-300 A). Some of the electrons are scattered by the atoms in the sample. 

This investigation s motivation essentially arises from a discovery of an unwanted real-time in situ nucleation and growth of Ag filaments on a-Ag2W04, Ag3P04, and Ag2Mo04 crystals which was driven by an accelerated electron beam from an electronic microscope under high vacuum [161-165]. 

This explains the predominance of radiation-chemical reactions as a means of initiating crosslinking in thermoplastic materials. In principle the effect can be induced by electromagnetic waves such as X-rays or gamma rays or by corpuscular radiation (beta rays) such as accelerated electron beams, for example. The differences between... 

Fig. 7. Schematic illustration of an existing common y-ray or accelerator electron beam irradiation industrial plant. The RTIL solution with metal salts is encapsulated in the glass ampoules imder vacuum or Ar atmosphere condition.

A recent approach carried out at an existing common accelerator electron beam or y-ray irradiation industrial plant for sterilizing medical kits may be a key in order to overcome the mass production issue (Tsuda et al., 2009a Tsuda et al., 2010a). As illustrated in Fig. 7, if the glass ampoules, in which RTIL solution with metal salts are encapsulated under vacuum condition or inert gas condition, placed on the container are automatically transferred to irradiation position, metal salts should be reduced to metal state in the ampoules without... 

Fig. 8. UV-vis spectra of the RTILs with 0.5 mmol L-i NaAuCl4 2H20 after accelerator electron beam irradiation at 20 or 6 kGy.

However, upon the exposure of about 100 kGy of accelerated electron beam (beta) radiation, the high temperature flow regime is replaced by a elastic plateau of about 0.2 MPa ( Figure 1), and previously shaped articles can maintain their shape and becomes autoclavable. 

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