Electron beam, pulsed

Szule]ko J E and McMahon T B 1991 A pulsed electron beam, variable temperature, high pressure mass... 

In operation the electron beam is initially arrested by applying a small bias negative with respect to the filament to plate 2. The pulsed electron beam is then provided by applying a positive pulse to this plate. 

Figure 2, Pulsed electron beam ion source for operation at elevated pressures. A 3-kV e-beam enters through a 50-pm aperture located at the center of one wall of the ion source. Ions are sampled through a 50-pm aperture located at the center of the other wall of the ion source. A 2-mm thick copper gasket determines the depth of the active source volume.

Figure 14. A pulsed electron beam ion mobility spectrometer for the study of CPIC over the pressure range of 0.01 to 1.0 atm.

Finally in this section, we refer to classic studies on gas phase interactions carried out with a pulsed electron beam high ion source mass spectrometer, which have yielded details of hydrogen bonding of substituted pyridinium ions to water in the gas phase (79JA1675). These measurements afford thermodynamic data for the stepwise hydration of pyridinium ions XC6H4NH(OH2)n for values of n varying between 0 and 4. The attenuation of substituent effects is much less than for aqueous solution, because although the water molecules cluster round NH in the gas phase, they cannot provide an overall solvation network, the dielectric constant of which in the liquid phase serves to reduce the influence of the substituent dipole. 

Scaling of this laser to higher powers has now been achieved, and additional laser lines have been detected at 391.4 nm and 470.9 nm, arising from the (0,0) and (0,2) vibrational components 432 The experiments of Collins and co-workers utilized a fast-pulsed electron beam gun that injects the beam into a mixture of helium and nitrogen at a pressure of several atmospheres. A similar nitrogen ion laser in which ionization is produced by an electric discharge has also been reported.3 ... 

A series of pulsed electron beam tests were conducted on dextrinated and RD-1333 Pb azide pellets by Avrami et al (Ref 232), From the limited data in Table 14 it can be seen that sample ambient pressure, sample thickness and type of Pb azide are all important factors in the sensitivity of initiation by pulsed electron beam The question arises as to what mechanism can explain the observed pressure, thickness and type of Pb azide dependence. A purely thermal initiation mechanism or a compressive shock initiation resulting from nearly instantaneous energy deposition can account for some of the observations but not all... 

Attempts have been made to observe and experimentally determine the structure of CH5+ in the gas phase and study it in the condensed state using IR spectroscopy,764 765 pulse electron-beam mass spectrometry,766 and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS).767 However, an unambiguous structure determination was unsuccessful. Retardation of the degenerate rearrangement was achieved by trapping the ion in clusters with H2, CH4, Ar, or N2. 

Pulse electron-beam mass spectrometry was applied by Kebarle, Hiraoka, and co-workers766,772 to study the existence and structure of CH5+(CH4) cluster ions in the gas phase. These CH5+(CH4) clusters were previously observed by mass spectrometry by Field and Beggs.773 The enthalpy and free energy changes measured are compatible with the Cs symmetrical structure. Electron ionization mass spectrometry has been recently used by Jung and co-workers774 to explore ion-molecule reactions within ionized methane clusters. The most abundant CH5+(CH4) cluster is supposed to be the product of the intracluster ion-molecule reaction depicted in Eq. (3.120) involving the methane dimer ion 424. 

The pulsed electron beam MS technique was also used by Hiraoka and Kebarle842 to study the C4H + cations. In the ion-molecule reaction of ethane and the ethyl cation, two species were observed and identified as the 2-//-n-butoniu m cation 469 and the 2-C-w-butonium cation 470. C—C protonated ion 470 formed first rearranges to C—H protonated ion 469 (energy barrier = 9.6 kcal mol-1) and then dissociation to sec-C4H9+ + H2 takes place. 

Table 10.4. G (base release) (unit 10-7 mol J-1) from some pyrimidine nucleosides and 2 -deoxynucleosides induced by the S04 radical [G(S04 ) = 3.3 x 10-7 mol J"1) at different dose rates pulsed electron-beam irradiation ( 6 Gy per 2 ps pulse, high dose rate) and y-irradiation (0.013 Gy s-1, low dose rate Aravindakumar et al. 2003) ...

Another difference between conventional high pressure Cl and the FTMS Cl experiment is the duration of the electron beam event used to form primary ions and secondary electrons. In the conventional Cl source, the electron beam is on continuously during the experiment. The FTMS, in contrast, uses a pulsed electron beam, and the duration of the electron beam event may be varied from less than a millisecond to over a second. In the NICI studies using the FTMS, the electron beam was typically left on for ten milliseconds. However, it was found that in some cases, which will be discussed later, it was necessary to use a longer beam time, up to 1 sec, in order to observe the product ions normally produced... 

Pulsed electron beam deposition (PED) Pulsed electron beam source emitting 100 ns long electron pulses with 10-20 keV and kA intensity into the deposition chamber, no excimer laser is required, innovative complimentary technique to PLD, further extending the range of materials to be grown as thin films by pulsed energy techniques [128,135]... 

The equilibrium constant for the case X = Cl and i = 1 agrees well with that obtained in a pulsed electron beam high pressure mass spectrometer, the other data have not been previously reported. 

Tc 600°C), at which crystallization occurs. The released latent heat raises the local temperature further, and thermal conduction maintains self-sustaining explosive transformation until the crystallization front has propagated down the thermal gradient to a point below Tc. Pulsed electron beam heating experiments indicate that a-Si melts at 1170°K (Baeri et al., 1980). 

The approach of intramolecular cross-linking was further extended to temperature-sensitive polymers. PVME nanogels were obtained by irradiation of dilute PVME solutions by a pulsed electron beam [41], The Mw of these nanogels is independent of the radiation dose (above 2 kGy). The phase transition temperature Tc of PVME is slightly affected by the cross-linking reaction. With increasing radiation... 

Fig. 7 Dose dependence of the radius of gyration Rg in the swollen (25°C) and shrunken (50°C) state of PVME microgel particles synthesized by pulsed electron beam irradiation above the phase transition temperature...

Schmidt T, Janik I, Kadlubowski S, Ulanski P, Rosiak JM, Reichelt R, Arndt KF (2005) Pulsed electron beam irradiation of dilute aqueous poly(vinyl methyl ether) solutions. Polymer 46(23) 9908-9918... 

Gas-phase acidities and basicities for many organic compounds are now available, primarily due to the development within the past decades of three new experimental techniques pulsed high-pressure i.e. 0.1... 1300 Pa) mass spectrometry (HPMS) [22, 23, 118], the flowing afterglow (FA) technique with a fast-flowing gas like helium in the pressure range of ca. 10 . .. 10 Pa [119], and pulsed electron beam, trapped ion cell, ion cyclotron resonance (ICR) spectrometry, carried out at ca. 10 ... 10 Pa [24-26, 115]. 

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