&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
  -----------------------------------------------------------

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.

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-ELECTRON
  option is specified.

  [Tracing is on by default.]	

Keyword index. Formatted on 10/11/98.