Simulation of the secondary electrons energy deposition produced by proton beams in PMMA: influence of the target electronic excitation description

We have studied the radial dependence of the energy deposition of the secondary electron generated by swift proton beams incident with energies T = 50 keV–5 MeV on poly(methylmethacrylate) (PMMA). Two different approaches have been used to model the electronic excitation spectrum of PMMA through its energy loss function (ELF), namely the extended-Drude ELF and the Mermin ELF. The singly differential cross section and the total cross section for ionization, as well as the average energy of the generated secondary electrons, show sizeable differences at T ⩽ 0.1 MeV when evaluated with these two ELF models. In order to know the radial distribution around the proton track of the energy deposited by the cascade of secondary electrons, a simulation has been performed that follows the motion of the electrons through the target taking into account both the inelastic interactions (via electronic ionizations and excitations as well as electron-phonon and electron trapping by polaron creation) and the elastic interactions. The radial distribution of the energy deposited by the secondary electrons around the proton track shows notable differences between the simulations performed with the extended-Drude ELF or the Mermin ELF, being the former more spread out (and, therefore, less peaked) than the latter. The highest intensity and sharpness of the deposited energy distributions takes place for proton beams incident with T ~ 0.1–1 MeV. We have also studied the influence in the radial distribution of deposited energy of using a full energy distribution of secondary electrons generated by proton impact or using a single value (namely, the average value of the distribution); our results show that differences between both simulations become important for proton energies larger than ~0.1 MeV. The results presented in this work have potential applications in materials science, as well as hadron therapy (due to the use of PMMA as a tissue phantom) in order to properly consider the generation of electrons by proton beams and their subsequent transport and energy deposition through the target in nanometric scales.

Single photon emission mammography with convergent collimators

Tese de doutoramento, Engenharia Biomédica e Biofísica, Universidade de Lisboa, Faculdade de Ciências, 2016

[Works of Rudyard Kipling].

Each volume has special t.p. only.

Works.

v.1. Plain tales from the hills.--v.2. Phantom ̀rickshaw [and other stories]--v.3. The light that failed.--v.4. Soldiers three [and other stories]--v.5. Wee Willie Winkie [and other stories] City of the dreadful night. American notes.--v.6. Under the deodars.--v.7. Story of the Gadsbys.--v.8. Mine own people.--v.9. Letters of marque.--v.l0. Poems and ballads.

In the days of the pioneers /

Sequel to The phantom of the river.

Shod with silence; a tale of the frontier,

Sequel: The phantom of the river.

The writings in prose and verse of Rudyard Kipling ...

"Outward bound" edition.

The Ghost /

"Edic̦ão crítica de Maria Leonor Machado de Sousa."

Dramas,

v. 1. Romiero: a tragedy. The alienated manor: a comedy. Henriquez: a tragedy. The martyr: a drama--v. 2. The separation: a tragedy. The stripling: a tragedy ... written in prose. The phantom: a musical drama. Enthusiasm: a comedy.--v. 3. Witchcraft: a tragedy in prose. The homicide: a tragedy in prose, with occasional passages of verse. The bride: a drama. The match: a comedy. Appendix [notes, etc.]

The Wildfire Club /

The princess: a vision of royality in the spheres -- The monomaniac, or, the spirit bride -- The haunted grange, or the last tenant: being an account of the life and times of Mrs. Hannah Morrison, sometimes styled the Witch of Rookwood -- Life: a fragment -- Margaret Infelix, or, a narrative concerning a haunted man -- The improvvisatore, or, torn leaves from life history -- The Witch of Lowenthal -- The phantom mother, or, the story of a recluse -- Haunted houses. No.1. The picture spectres -- Haunted houses. No.2. The Sandford ghost -- Christmas stories. No.1. The stranger guest: an incident founded on fact -- Christmas stories. No.2. Faith, or Mary Macdonald -- The Wildlife Club: a tale founded on fact.

A crime of the under-seas /

Short stories.

The romance of history : France /

--Bertha ; or, The court of Charlemagne.--The last of the Breton kings.--The adventures of Eriland.--The man-wolf.--The king of the beggars.--The serf.--The pilgrim of Saint James.--The bondsman's feast.--The phantom fight.--The magic wand.--The rock of the fort.--The dream-girl.--The black mask ; or, the lottery of jewels.

Selected works of Rudyard Kipling.

v. 1 Soldiers three; In black and white; The story of the Gadsbys; The phantom 'rickshaw and other tales; Wee Willie Winkie and other child stories.--v. 2 The light that failed; Plain tales from the hills.--v. 3 Mine own people; The courting of Dinah Shadd and other stories; American notes; Under the deodars and other tales; Departmental ditties; Barrack-room ballads and other verses.

Works of Rudyard Kipling.

Limited ed. of 1000 sets.

Fairy and folk tales of the Irish peasantry /

Variant issue: series title on half title; errata slip inserted at p. [ix].