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&DRIFT: TRACK: HEED


particle

Some common particles can be described by name:

Name Particle Mass [MeV] Charge
ELECTRON electron (e-) 0.51099907 -1
POSITRON positron (e+) 0.51099907 +1
MU-MINUS negative muon (mu-) 105.658389 -1
MU-PLUS positive muon (mu+) 105.658389 +1
TAU-MINUS negative tau (tau-) 1777.00 -1
TAU-PLUS positive tau (tau+) 1777.00 +1
GAMMA photon 0 0
PION-MINUS negative pion (pi-) 139.56995 -1
PION-0 neutral pion (pi0) 134.9764 0
PION-PLUS positive pion (pi+) 139.56995 +1
KAON-MINUS negative kaon (K-) 493.677 -1
KAON-0 neutral K or anti-K 497.672 0
KAON-PLUS positive kaon (K+) 493.677 +1
PROTON proton (p) 938.27231 +1
ANTI-PROTON antiproton (p-bar) 938.27231 -1
NEUTRON neutron (n) 939.56563 0
ANTI-NEUTRON antineutron (n-bar) 939.56563 0

Although some neutral particles are included in this list, their use is, with the exception of photons, not meaningful since these particles do not cause ionisation losses in the Heed model.

Gamma's are scheduled for inclusion at a later stage.


MASS

If the particle is not known by its name, then one can describe it with its mass and charge.

The mass can either be a number, in which case it is assumed to be in MeV, or a number followed by a unit (eV, keV, MeV or GeV).

[Default: muon mass]


CHARGE

If the particle is not known by its name, then one can describe it with its mass and charge.

The charge of the particle should be in proton charges, i.e. an electron would have charge -1, a K+ would have +1.

Currently, only charges of +1 and -1 are accepted.


ENERGY

The energy of the particle traversing the chamber.

The energy can either be a number, in which case it is assumed to be in MeV, or a number followed by a unit (eV, keV, MeV or GeV).

[Default: 1 GeV]


MULTIPLE-SCATTERING

Heed will optionally make the incoming particle undergo multiple scattering.

Keep in mind that multiple scattering will slow Heed down.

Track preparation is compatible with multiple scattering but such a combination is not meaningful since the drift path of electrons produced far from the prepared track has to be computed without interpolation.

[Multiple scattering is on by default.]


DELTA-ELECTRONS

Heed generates its electrons through delta electrons. If you are not interested in the spatial extent of delta electrons, you may opt to have all electrons moved to the location of the interaction that created the delta electron.

The DELTA-ELECTRONS option is compatible with track preparation, e.g. in the context of signal calcultions, but the drift path of electrons produced far from the prepared track will be computed rather than interpolated.

Apart from this, there is no substantial gain in time by switching delta electrons off.

[Delta electrons are by default kept as they come out of Heed]


TRACE-DELTA-ELECTRONS

Delta electrons usually have a sufficiently low energy to be affected by the E and B fields present in the chamber.

When this option is switched on, they are traced from one collision to the next following the E and B field. Since this is a time consuming operation, you may wish to switch tracing off when studying only the cluster statistics.

Delta electrons are not traced either when the NODELTA-ELECTRONS option is specified.

[Tracing is on by default.]


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Formatted on 0100-09-02 at 06:56.