Secondary reaction of Ps in the positron spur

Hirade, Tetsuya; Mogensen, Ole

doi:10.1007/bf02060699

Cited by 6 publications

(6 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For a mean positron thermalization distance equal to b + = 50 nm, the simulated o-Ps fraction is 42%. This value agrees with the experimental results reported in refs , , and 40, which were obtained by fitting a sum of three exponentials to PAL spectra measured for n -hexane, ,, see the values of I 3 in Table . Note that the mean positron thermalization distance needed to reproduce the experimental o-Ps fractions is about six times larger than that of electrons in n -hexane .…”

Section: Resultssupporting

confidence: 91%

“…This value is higher than 1/3, which is the statistical formation ratio of p-Ps and o-Ps that was used in the simulations, see section II.B. Such a deviation has been obtained from PAL experiments on a variety of organic liquids 1,11,12,40 and polymers. [44][45][46][47] The data in Table 1 show that the intensities obtained from a fit of eq 5 to the simulated PAL spectrum are close to the experimental values for n-hexane from refs 11, 12, and 40.…”

Section: Resultsmentioning

confidence: 89%

“…According to the Ore model “hot” Ps is formed during the slowing down of the positron at energies in the “Ore gap”, which typically ranges from several to a few tens of eV . However, the inhibition of Ps formation in organic liquids by electron scavengers ,− and the observed effects of an external electric field on the yield of Ps in nonpolar liquids and polymers − cannot be explained in terms of the Ore model. These effects are explained in terms of Ps formation by reaction of a thermalized positron with an electron produced along its radiolysis track in competition with cation−electron recombination.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Positronium Formation Dynamics in Radiolytic Tracks: A Computer Simulation Study

et al. 2002

View full text Add to dashboard Cite

Positron track structures were simulated by stochastic modeling of the collision-by-collision slowing down of positrons in n-hexane. The details of the inelastic scattering of positrons and of electrons produced in ionizing collisions were taken into account until the particle energies had degraded to less than 25 eV. Further slowing down to thermal energy was assumed to result in a spherically symmetric thermalization distribution around the position where the particle energy becomes less than 25 eV. The dynamics of positronium formation in competition with electron-cation recombination and positron annihilation was followed by a simulation of the diffusive motion of the charged species in each other's Coulomb field. Positronium formation was found to involve reaction of the thermalized positron with electrons produced along the last few hundred nm of its track-end, corresponding to several keV of energy attenuation. Positronium formation occurs mainly during the first few tens of picoseconds after positron implantation and extends to hundreds of picoseconds. Simulation reproduces the experimental positron lifetime spectra reported in the literature. The experimentally reported electric-field dependence of the ortho-positronium yield in liquid n-hexane could be reproduced with an exponentially decaying positron thermalization distribution with a mean distance of 50 nm, while a Gaussian positron thermalization distribution was found to be inappropriate.

show abstract

Section: Resultssupporting

confidence: 91%

Section: Resultsmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Positronium Formation Dynamics in Radiolytic Tracks: A Computer Simulation Study

et al. 2002

View full text Add to dashboard Cite

show abstract

“…[4] The radical reaction depends on the spin state of the radicals. The radical reaction of the o-Ps and the OH radical, reactions (6) and (7), can just occur when the spin state of the radical pair is a singlet. The reactions between the o-Ps and the OH radical, (6), (7) and (8), are diffusion controlled and the spin conversion reaction or the radical reaction occur when they meat each other.…”

Section: Introductionmentioning

confidence: 99%

“…[5] Hirade indicated that there existed reactions of o-Ps and cation radicals in n-hexane. [6] The reactions between geminate pairs should be possible. It means that the quantum beats are also expected on S(t) for n-hexane.…”

Section: Introductionmentioning

confidence: 99%

OH radical in water studied by Quantum beats on positron annihilation -the effect of water liquid structures-

Lee

Oka

Hirade

2010

J. Phys.: Conf. Ser.

View full text Add to dashboard Cite

OH radical in water studied by Quantum beats on positron annihilation -the effect of water liquid structuresTo cite this article: Jeong-Jae Lee et al 2010 J. Phys.: Conf. Ser Abstract. Singlet radical pairs of ortho-positronium and hydroxyl (OH) radical were generated in positron radiolysis in water. Quantum beats on the energy distribution of positron annihilation γ-rays caused by the reaction of electron-spin-correlated pairs of orthopositronium and OH radical were newly measured at 32°C by using positron annihilation agemomentum correlation (AMOC) measurement. The quantum beats can provide information of hyperfine coupling constants of the OH radical in water liquid structures, and hence can provide the information of change of the water liquid structures. The quantum beats appeared at 32°C could not be explained easily. The reason was continuous and slow change of water liquid structures at 32°C. The water liquid structures probably can be understood by using the positron annihilation quantum beat measurements.

show abstract

Intra-spur positronic processes

Ito

1996

Journal of Radioanalytical and Nuclear Chemistry, Articles

View full text Add to dashboard Cite

Secondary reaction of Ps in the positron spur

Cited by 6 publications

References 6 publications

Positronium Formation Dynamics in Radiolytic Tracks: A Computer Simulation Study

Positronium Formation Dynamics in Radiolytic Tracks: A Computer Simulation Study

OH radical in water studied by Quantum beats on positron annihilation -the effect of water liquid structures-

Intra-spur positronic processes

Contact Info

Product

Resources

About