TREE VIEW
How do we describe a radiation field? A radiation field is populated by particles busy with activities. Each particle is characterised by the its type (neutron, photon, alpha etc), its instantaneous energy at a point in space in a dynamic time scale:- 1st column: energy. Where marked as edep, this is the deposited energy. Otherwise, it's the kinetic energy.Where two values are given, separated by an underscore, the line is about neutrons under 20 MeV, where collision types are not differentiated, but marked as knock instead.
- 2nd column: time. The clock starts ticking when the source particle comes into being (line #0).
- 3rd and 4th columns: horizontal and vertical distances from beam-hit position, respectively.
- 6th column: particles and collisions, indented according to the respective generation. Beginning with the first generation (the carbon ion), collisions with matter produce 2nd-generation progenies (2nd indent level, eg. line #2), which in turn collide and produce 3rd-generation progenies (3rd indent level, eg. line #6), and so on and so forth. -> and +> mark the first appearance of a given particle on the tree view; the latter indicates that it is a sibling (not a cousin of any sort) of the the preceding particle. Ions are given in ZA notation.
MOVIE
The canvas stretches out to four rounded corners; please scroll and/or resize accordingly. Thin lines end with a collision / interaction / reaction; thick lines mark energy-depositing steps. The movie might take a while to load.
Here is an inventory of the 13032 progenies: 301 protons, 390 neutrons, 7354 electrons (most populous, as expected), 582 positrons, 4239 photons, 22 pions, 3 muons, 30 alphas, 11 deuterons, 3 tritons plus 97 heavier isotopes.
76 nuclear reactions were observed, including some by:
- positive pions:
- negative pions:
10 pion decays (pion disappears into a photon pair) and 3 muon decays were observed.
As expected, without reservation hadronic (neutrons and protons) cascades gives rise to electromagnetic (photons, electrons and positrons) cascades, which include the following interactions:
- 1881 bremsstrahlung (electron brakes, giving off a photon);
- 87 Moller (electron meets electron giving off an additional electron);
- 71 Bhabha (positron meets electron giving off an additional electron);
- 549 annihilation at-rest (thermalised positron meets electron, both disappear, giving off the famous back-to-back 511 keV photon pair);
- 33 annihilation in-flight (unthermalised positron meets electron, both disappear, giving off a photon pair which are neither back-to-back nor 511 keV);
- 1968 photoelectric (photon disappears, an electron appears, sometimes accompanied by a characteristic x-ray);
- 4576 Compton (photon in, an additional electron comes out);
- 579 pair production (photon disappears, giving off a electron-positron couple);
Progeny generation as deep as the 18th generation was observed (lines #47499, #47502, #47504. This may be verified by counting the dotted indents, 16 in total, for each of these lines. As expected it is the electromagnetic cascade which provides deeper generations.
A neutron navigates (lines #22051 to #22209) — through aluminium alloys, marble, lead composites and water, — finally crossing the finish, 200 m away her first foreparent.
