bank_mcpm

           MCPM     Monte Carlo PMT bank.  One for each PMT hit.
           ===================================================
 
    Contact:  D. L. Wark, Oxford.
 
    Revision History:-
    ================
 
    1.03  N. West     Converted to mixed format.
    2.05  N. West     Use double precision time.
    2.06  D. Wark     Add unwobbled time.
    2.08  N. west     Add _MCPM_SVX reference link.
    3.00  N. West     Update comment about _TIM.
    3.02  N. West     New _TYP value: Crosstalk.
          N. McCauley New _TYP value: Overlay.
    5.01  C. Kyba     Add mnemonics for Cerenkov history status word


 
Description
-----------
 
    One bank for each PMT hit in the Monte Carlo simulation.  If the same PMT is
hit more than once then there will be one MCPM bank for each hit and the banks
will be adjacent to each other in the MCPM  chain and arranged in ascending time
order (i.e. earliest time first).
 
Reference Links
---------------
 
 -1  -KMCPM_MCVX      MCVX  MCVX whose incoming track produced hit.  See note 1.
 -2  -KMCPM_MCPM_SVX  MCPM  Next MCPM hit by a photon from the Same VerteX.
                            See Note 1.
 
Structural Links
----------------
 
    None.
 
Status Bits
-----------
 
Note: Any status bit parameters are defined to work with bit functions such as
      IAND and BTEST.

See Note 2 for more information about the Cerenkov history (bits 4-17)

Bit  Mnemonic          Description
---  --------          -----------
  0                    Not yet defined (Not part of Cerenkov history)
  1  KMCPM_SPARE1      Spare (Not part of Cerenkov history)
  2  KMCPM_SPARE2      Spare (Not part of Cerenkov history)
  3  KMCPM_SPARE3      Spare (Not part of Cerenkov history)
  4  KMCPM_INDIRECT    Indirect photon.  See Note 3. 
  5  KMCPM_RSCAT       Photon was Raleigh scattered.
  6  KMCPM_PSUP_SREF   Photon had a spectral reflection from the PSUP.  See Note 4. 
  7  KMCPM_PSUP_DREF   Photon had a diffuse reflection from the PSUP.  See Note 4. 
  8  KMCPM_AV_SREF     Photon had a spectral reflection from the AV.
  9  KMCPM_AV_DREF     Photon had a diffuse reflection from the AV.
 10  KMCPM_NCD_SREF    Photon had a spectral reflection from the NCD OVL.  See Note 5.
 11  KMCPM_NCD_DREF    Photon had a diffuse reflection from the NCD OVL.  See Note 5.
 12  KMCPM_PMT_REF     Photon entered and then escaped the PMT code (vxpmt).
 13  KMCPM_IN_PMT      Photon was produced inside a PMT.
 14  KMCPM_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 KMCPM_NUM  PMT number.
 +2  D KMCPM_TIM  Hit time in nsecs since MC generation time (in MC bank).  First word.
 +3               Second word.
 +4  I KMCPM_TYP  Pulse type: =1 clean, =2 noise, =3 pre-pulse, =4 after-pulse,
                              =5 overlay, =26 crosstalk.
 +5  F KMCPM_HEI  Pulse height (charge).
 +6  D KMCPM_T0   Hit time in nsecs since MC time (as above), but without the
                  PMT time jitter.  First word.
 +7               Second word.
 
 
Notes
-----
 
1)   If the photon trajectory to the PMT has been removed by KILLVX then the
      _MCVX link will point to the MCVX that gave rise to the photon. That MCVX
      may have produced more than one photon.  In which case the MCVX will have
      a link to one of MCPMs and then the _MCPM_SVX link will be used to chain
      the other MCPMs that all share the same MCVX.
 

2)   The Cerenkov history is passed to the MCPM bank directly from the MCTK 
      bank.  As a Cerenkov photon is propagated through SNOMAN its history 
      mask is passed across each boundary, or interaction vertex.  If a 
      Cerenkov photon undergoes a recognized process (eg Rayleigh 
      scattering) then the appropriate bit is set in the track which 
      follows that vertex.  The only currently supported processes are 
      Rayleigh scatters and boundary crossing.


3)   An "indirect photon" is one which undergoes a scatter off of 
      something other than the AV, PSUP, or NCD.  A photon which is 
      absorbed and re-emitted by wavelength shifter is also currently 
      tagged as indirect.  If other possible Cerenkov photon vertices are 
      added to SNOMAN this bit (or a new bit) should be set, otherwise 
      photons passing through those vertices will not be tagged.


4)   A PSUP scatter is defined as a scatter occurring when a photon goes 
      from H2O to ABS sludge.  It was found that almost all of the 
      reflections occurring at the PSUP radius (other than those from the 
      PMTs) happened at an H2O-ABS sludge boundary, so this was chosen as 
      the PSUP reflection tag.


5)   An NCD scatter is currently only tagged if the photon is coming from 
      the D2O and hits the NCD outer volume.  A scatter off of the NCD 
      endcap, for example, will be tagged only with KMCPM_INDIRECT.