Due to the similarity of the tracking and muon detectors in CMSIM it is used the same detector element and hit definitions. The common hit format the GEANT hits (detector impact points) is defined in the title bank TKHT (TracK HiT):
*DO TKHT 0 -c4/60 #.TracKer /Muon hit definition
17 #.NO. OF HIT ELEMENTS
#. NAMESH ORIG FACT NBITSH
1 :X_G 2000.0 5.E5 0 #. VECT(1) at volume entrance
2 :Y_G 2000.0 5.E5 0 #. VECT(2) at volume entrance
3 :Z_G 2000.0 5.E5 0 #. VECT(3) at volume entrance
4 :DIRX 1.0 1.E9 0 #. VECT(4) at volume entrance
5 :DIRY 1.0 1.E9 0 #. VECT(5) at volume entrance
6 :DIRZ 1.0 1.E9 0 #. VECT(6) at volume entrance
7 :P 0.0 1.E6 0 #. VECT(7) at volume entrance
8 :TYPE 0.0 1.0 0 #.PARTICLE TYPE
9 :Xin 250.0 1.E6 0 #.ENTER POINT IN DETECTOR ELEMENT
10 :Yin 250.0 1.E6 0 #.(DETECTOR ELEMENT COORDINATE SYSTEM: LCS)
11 :Zin 250.0 1.E6 0 #.
12 :XOUT 250.0 1.E6 0 #.EXIT POINT FROM DETECTOR ELEMENT (LCS)
13 :YOUT 250.0 1.E6 0 #.
14 :ZOUT 250.0 1.E6 0 #.
15 :dEdX 0.0 1.E9 0 #.DEPOSITED ENERGY,
16 :T_OF 0.0 10. 0 #.TIME_OF_FLIGHT
17 :RADL 0.0 1.E6 0 #. Material traversed (in rad. lengths)
The ``HITS'' instructions which includes detector set and detector element names in the ``GEOM'' TZ-bank, for example for pixel barrel detector, like
#. set detector :HITS :PXLX :PXBD #. Pixel barrel :HITS :PXLX :PXFD #. Pixel endcap
in case if this detector set is a member of tracking detector superset (TRAK+MUON) will cause access to ``TKHT'' and its use for creation hit format bank for this particular detector element.
The bank will be filled by the GEANT HITS package and hence the reference to the track in kinematics structure which caused the hit, can be found by GEANT facilities. The reference to the sensitive volume parameters, such as rotation matrix and the detector user parameters, is provided by the GEANT system.
Using this common definition for GEANT hits (detector impact points) we have in the GUSTEP the same code for muon and tracker simulation. This allows also us to use the same code for track pattern recognitions.
Advantage of using the unique detector element identifier automatically
generated by GEANT for Central tracker and Muon system is obvious because of
the complexity of these systems. For calorimeters and especially for the Hadron
and Very forward ones where the tower structure has been designed to
be simple in term of pseudo-rapidity ( 
) and azimuth angle ( 
) this
advantage is not obvious. In this case it seems to be better to user define
hit-structure, for example for the Hadron calorimeter, we can define
hit-structure as follows:
*DO GEAN 1 -U -A4CW -c2/80 #. Hcal hit definitions
:HCAL
:DET :HCAL :HBS1 6 22101 5000 1000 #. HCAL barrel
:CALO 3 #. Calorimeter type
:BLOC 4 #. Depth/Block
:FB 2 #. Forward/Backward
:ETA 9 #. Eta subtower
:PHI 9 #. Phi subtower
:TSLI 5 #. Time slice
:DET :HCAL :HFS1 6 22201 5000 1000 #. HCAL endcap
:CALO 3 #. Calorimeter type
:BLOC 4 #. Depth/Block
:FB 2 #. Forward/Backward
:ETA 9 #. Eta subtower
:PHI 9 #. Phi subtower
:TSLI 5 #. Time slice
...
i.e. by call to GSDET instead GSDETV. Thus GEANT will provide in GUSTEP only
information ``Forward'' or ``Backward'' part of calorimeter was hit and user
should provide number for tower in and . This definition allows
also to use in digitisation stage a mixture hits simulated with the exact
geometry for trigger event with hits from pile-up event simulated with an
average geometry.