High electron bombardment

The use of inadiation or electron bombardment offers an alternative approach to molecular dissociation to the use of elevated temperamres, and offers a number of practical advantages. Intensive sources of radiation in the visible and near-visible are produced by flash photolysis, in which a bank of electrical capacitors is discharged tlrrough an inert gas such as ktypton to produce up to 10 joule for a period of about 10 " s, or by the use of high power laser beams (Eastham, 1986 (loc.cit.)). A more sustainable source of radiation is obtained from electrical discharge devices usually incorporating... 

Other considerations are that the source material, which forms a target for high-energy electron bombardment leading to the production of X-rays, should be a good conductor- to enable rapid removal of heat - and should also be compatible with UHV. 

We use commercial Ti02 crystals (Pi-Kent) cut and polished to within 0.3° of the (110) face and we prepare them further with cycles of Ar + bombardment and U H V annealing to approximately 950-1100 K, typically 5-10 min for each cycle. The samples are mounted onto tantalum back-plates via strips of tantalum spot-welded to the back-plate. Annealing is performed by high-energy electron bombardment of the back-plate from a hot filament. Temperatures are measured from optical pyrometers (Minolta) focused on the back-plate. The temperatures are not measured directly from the samples because they are translucent and get darker with each sputter/anneal cycle. 

The stress caused by H absorbed in the course of electroless deposition is a major obstacle to the utilization of electroless films in areas of electronics where metallization of smooth surfaces is desired as an alternative to expensive vacuum deposition processes. Lacking the high-energy bombardment aspect of most vacuum depo-... 

High-energy radiation may be classified into photon and particulate radiation. Gamma radiation is utilized for fundamental studies and for low-dose rate irradiations with deep penetration. Radioactive isotopes, particularly cobalt-60, produced by neutron irradiation of naturally occurring cobalt-59 in a nuclear reactor, and caesium-137, which is a fission product of uranium-235, are the main sources of gamma radiation. X-radiation, of lower energy, is produced by electron bombardment of suitable metal targets with electron beams, or in a... 

The epoxies can present some challenges in high-resolution imaging due to their instability and tendency to deform under intense electron bombardment. Because zeoHtes are essentially brittle materials, sectioning does not result in perfectly uniform thickness but instead tends to shave away segments of parallel chips of material [53]. 

Ordered multilayer deposits of phthalocyanine molecules could be observed by low-energy electron diffraciton with no apparent electron beam induced chemical effects. This appears consistent with the general trend for molecules with highly conjugated electron systems to be more stable under electron bombardment than other organic molecules. 

Electron bombardment of gas mixtures, although not strictly a photochemical process, has been used in conjunction with time-resolved SS interferometers to obtain rate constants for the vibrational relaxation of highly excited molecules [30, 35, 36, 71-73], Murphy et al. [35,71] observed the production and relaxation of vibrationally excited NO and the (0,0,1 - 0,0,0) bands of N20 and N02 following excitation of N2/02 mixtures with a pulsed electron gun. The infrared emission created by the electron beam decayed completely between pulses and the complete temporal... 

Production of Ions. Several methods are used (11 by bombardment with electrons from a heated filament (2 by application of a strong electrostatic field (field ionization, field desorption) Ot by reaction with an ionized reagent gas (chemical ionization) (4 by direct emission of ions from a solid sample that is deposited on a heated filament (surface ionization) (SI by vaporization from a crucible and subsequent electron bombardment (e.g.. Knudsen cell for high-lcmperalure sludies id solids and (6) by radio-frequency spark bomhardmenl of sample fur parts-per-biliion (ppb) elemental analysis of solids as encountered in metallurgical, semiconductor, ceramics, and geological studies. Ions also are produced by photoion izution and laser ionizalion. 

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