The polymerization of styrene in latex particles by means of pulsed high-energy electrons has been studied. Using a sequence of electron beam pulses, periodic initiation is accomplished, similar to that used in pulsed laser polymerization. The larger penetration depth of electron beams offers advantages as compared to laser light in heterogeneous systems since samples do not need to be optically transparent. Therefore pulsed electron beam irradiations are more suitable to study polymerizations homogeneously irradiated in emulsion. From the molar mass distribution of the formed polymer, the monomer concentration in the particles can be determined. Polystyrene particles swollen with styrene were used. A typical dose per pulse was 1.5 Gy. The monomer concentration in 46 nm diameter particles was found to be 6 mol dm-3. Cationic and anionic polymerization of styrene was suppressed by the presence of water.

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We have produced an optically clear, close to water-equivalent gel that is radio-fluorogenic, i.e. fluoresces in UV light after exposure to high-energy radiation. Its potential as a 2D and 3D dosimetric medium is demonstrated by fixed fluorescent images of the cross-section, track and intersection of collimated (10 × 10 or 5 × 5 mm(2)) 205 kVp x-ray beams. The images, produced by doses on the order of 10 Gy, are formed instantaneously and can be digitally recorded and scanned with a spatial resolution on the order of 0.1 mm. No loss of spatial resolution occurs on standing under ambient conditions for at least 3 days.

In order to study the ionization in the track of a high-energy electron in liquid cyclohexane, the lifetime distribution of the charged species is considered, with and without solutes present that can react with the species and change their mobility. Calculations of the lifetime distributions of the ions are presented, which have been made on the basis of the assumption that the precursors of the ion scavenging reactions can be considered as classically diffusing ions, initially present as pairs of oppositely charged species in each other's field. The calculations are compared with the lifetime distributions of biphenyl ions in solutions of biphenyl in cyclohexane with and without other solutes present, as determined by nanosecond pulse radiolysis. It is concluded that the precursor of the positive biphenyl ion is a positive species, which is considerably more mobile than a molecular ion.