bank_mctk
MCTK Track bank
====================
Contact: N. West, Oxford.
Revision History:-
================
1.03 N. West Converted to mixed format.
2.00 N. West Add region code.
2.05 R.G. Van de Water Add step size.
2.07 N. West Add note about bank number. Add near distance (KMCTK_NEAR)
2.08 N. West New particle codes.
2.09 N. West Add clarifying comment about particle energy.
5.00 C. Kyba Add mnemonics for Cerenkov history status word
Description
-----------
Describes the transport of one particle between its start and end
vertices. Formally the information in the MCTK bank refers to the particle at
its end vertex. For most tracks the quantities will be invarient along the
track but see Notes below. For Cerenkov photons, a history of its trajectory
is encoded into the status word
Reference Links
---------------
-1 -KMCTK_MCVX MCVX Track end vertex.
Structural Links
----------------
None.
Status Bits
-----------
Note: Any status bit parameters are defined to work with bit functions such as
IAND and BTEST.
Bits 4-17 are used to store the "history" of Cerenkov photons.
The bit structure is the same as in the MCPM bank status word.
More details are available on the MCPM bank page.
Bit Mnemonic Description
--- -------- -----------
0 Undefined
1 KMCTK_IVX Indirect vertex. Track does not come directly from its
supporting vertex, see Notes below.
2 KMCTK_SPARE1 Spare (Not part of Cerenkov history)
3 KMCTK_SPARE2 Spare (Not part of Cerenkov history)
4 KMCTK_INDIRECT Indirect photon.
5 KMCTK_RSCAT Photon was Raleigh scattered.
6 KMCTK_PSUP_SREF Photon had a spectral reflection from the PSUP.
7 KMCTK_PSUP_DREF Photon had a diffuse reflection from the PSUP.
8 KMCTK_AV_SREF Photon had a spectral reflection from the AV.
9 KMCTK_AV_DREF Photon had a diffuse reflection from the AV.
10 KMCTK_NCD_SREF Photon had a spectral reflection from the NCD OVL.
11 KMCTK_NCD_DREF Photon had a diffuse reflection from the NCD OVL.
12 KMCTK_PMT_REF Photon entered and then escaped the PMT code (vxpmt).
13 KMCTK_IN_PMT Photon was produced inside a PMT.
14 KMCTK_THROUGH_AV Photon passed through the AV at least once.
15 Not yet defined (Assumed to be part of of Cerenkov history)
16 Not yet defined (Assumed to be part of of Cerenkov history)
17 Not yet defined (Assumed to be part of of Cerenkov history)
Data Words
----------
Data types: B(bit), I, F, D(double), H(hollerith 4 char)
+1 I KMCTK_IDP Particle_ID_Code id_particles.html).
+2 F KMCTK_DRX Direction cosine X.
+3 F KMCTK_DRY Direction cosine Y.
+4 F KMCTK_DRZ Direction cosine Z.
+5 F KMCTK_ENE Total energy (except for neutrons where it is kinetic).
+6 I KMCTK_RGN Region Code (see Region codes)
+7 I KMCTK_IDM Physical Media Code (see Media codes)
+8 F KMCTK_PLX Polarisation X. See note 5.
+9 F KMCTK_PLY Polarisation Y. See note 5.
+10 F KMCTK_PLZ Polarisation Z. See note 5.
+11 F KMCTK_STP Track step size. Only non-zero for CBV vertex. See note 2.
+12 F KMCTK_NEAR Minimum distance to nearest boundary or 0. See note 4.
Notes
-----
1) Normally the MCTK represents a straight line propagation of a particle but
possible exceptions are:-
o EGS4 will produce electron tracks at the point at which they interact to
produce Cerenkov photons.
o Unwanted vertex removal, if activated, will eliminate unwanted internal
verteces.
In such cases the track direction will not correspond to a straight line
joining its start and end vertices, and the KMCTK_IVX bit will be set.
2) A Cerenkov Bundle Vertex (CBV) is used to represent a bundle of photons
for a single track step within EGS4. See routine UNPCER.
3) All ZEBRA banks have a number as well as a name. The number has no
significance for the MCTK bank. It may be used as a short range
communication between the routine, called indirectly from TKMAIN, that
determines where the next interaction occurs, and the routine, called
indirectly from VXMAIN, that determines what the interaction products are.
4) The near distance (KMCTK_NEAR) may be used to speed up the tracking of
particles whose mean free path is small compared to the size of the region
through which they are travelling. The distance, which unlike all other
variables refers to the start vertex NOT the end vertex, is first computed
use GE_NEAR. Subsequently it is passed from input track to output track
decrementing by the step size and no further calls made to the geometry
until it reaches zero.
5) In CBVs, the polarisation of the electron is irrelevant. CBVs use
these three words for a second set of directional cosines (those at the
end of the step, after the particle has multiple scattered). This only
occurs in CBVs
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