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DETECT

Scores energy deposition on an event by event basis (detector), providing coincidence and anti-coincidence capabilities such as those of a trigger.

In the following, an "event" means energy deposited in one or more DETECTOR REGIONS by one primary particle and its descendants, i.e. between two successive calls to the FEEDER subroutine (case of an incident beam) or to a user-written SOURCE subroutine (case of an extended source, or of a source read from a collision file or sampled from a distribution). A "signal" means energy deposited in one or more TRIGGER REGIONS by the same primary particle and descendants (i.e., between the same calls). The output of DETECT is a distribution of energy deposited per event in the region(s) making up the detector in (anti)coincidence with a signal larger than a given cutoff or threshold in the trigger region(s). It is also possible to define DETECTOR COMBINATIONS. [NOT YET IMPLEMENTED!!]

This option can extend over several sequential cards. The meaning of the parameters on the first card are:

     WHAT(1) = 0.0 for a detector, > 0.0 for a combination of detectors

If WHAT(1) = 0.0:

     WHAT(2) = minimum total energy to be scored in the detector regions in one
               event, i.e. lower limit of the event distribution.
               Default: 0.0

     WHAT(3) = maximum total energy to be scored in the detector regions in one
               event, i.e. upper limit of the event distribution
               No default

     WHAT(4) = cutoff energy for the signal (coincidence/anticoincidence
               threshold). The energy deposition event is scored only if a total
               of more than WHAT(4) GeV are/aren't correspondingly deposited in
               the trigger regions.
               Default: 1.E-9 (= 1 eV)

     WHAT(5) = > 0.0 : the detector regions, taken together, must be considered
               in COINCIDENCE with the trigger regions (also taken together)
               < 0.0 : the detector regions must be considered in
               ANTI-COINCIDENCE with the trigger regions
               Default: anti-coincidence

     WHAT(6) = region number or name not preceded by a minus sign: first region
               of the DETECTOR
               region number or name preceded by a minus sign: first region of
               the TRIGGER
               (the other regions will be given with continuation cards, see
               below).
               No default

     SDUM    = detector name (max. 10 characters) unless the character "&"
               is present

Continuation card (if present):

     WHAT(1) = same as WHAT(1) for the first card

     WHAT(2-6) = following regions (with sign). If not preceded by a minus sign,
               they are considered detector regions, otherwise trigger regions

     SDUM      =  "&" in any position in column 71 to 78 (or in the last field
               if free format is used)

     Note:     if no trigger region is given (i.e. no region with negative sign)
               a simple event-by-event scoring takes place.

If WHAT(1) > 0: [NOT YET IMPLEMENTED!!!]

     WHAT(2):  first detector to be considered for this combination, in
               coincidence if WHAT(2) is not preceded by a minus sign, in
               anticoincidence otherwise
               Default: ignored

     WHAT(3):  second detector to be considered for this combination, in
               coincidence if WHAT(3) is not preceded by a minus sign, in
               anticoincidence otherwise
               Default: ignored

     WHAT(4):  third detector to be considered for this combination, in
               coincidence if WHAT(4) is not preceded by a minus sign, in
               anticoincidence otherwise
               Default: ignored

     WHAT(5):  fourth detector to be considered for this combination, in
               coincidence if WHAT(5) is not preceded by a minus sign, in
               anticoincidence otherwise
               Default: ignored

     WHAT(6):  fifth detector to be considered for this combination, in
               coincidence if WHAT(6) is not preceded by a minus sign, in
               anticoincidence otherwise
               Default: ignored

     SDUM    = combination name (max. 10 characters) unless the character "&" is
               present

Continuation card (if present):

     WHAT(1) = same as WHAT(1) for the first card

     WHAT(2-6) = following detectors (with sign). If not preceded by a minus sign,
                 they are considered in coincidence, otherwise in anti-coincidence

     SDUM    = "&" in any position (or in the last field if free format is used)

     Default (option DETECT not requested): no (anti)coincidence scoring

Notes:

• 1) Output from DETECT is written unformatted on logical unit 17. To recover the output, it is necessary to run a Fortran program containing the following lines:

      .........................................
      CHARACTER*80 RUNTIT, RUNTIM*32, CHNAME*10
      INTEGER*4 NCASE, NDET, NBIN, IV(1024)
      REAL EMIN, EBIN, ECUT
      .........................................
      .........................................
      READ(17) RUNTIT, RUNTIM, WEIPRI, NCASE
      READ(17) NDET, CHNAME, NBIN, EMIN, EBIN, ECUT
      READ(17) (IV(I), I = 1, NBIN)
      .........................................

This is the meaning of variables read:

             RUNTIT: title of the job (as given by input option TITLE)
             RUNTIM: time of the job (printed also at the beginning of the main
                     output)
             WEIPRI: total weight of the primary particles
             NCASE:  number of primary particles
             NDET:   detector number
             CHNAME: detector name (= SDUM of the first DETECT card)
             NBIN:   number of energy bins (presently fixed = 1024)
             EMIN:   minimum total energy (= WHAT(2) of the first DETECT card)
             EBIN:   width of each energy bin
             ECUT:   cutoff energy for the signal (= WHAT(4) of the first DETECT
                     card)

The NBIN values IV(I) are the spectrum channels, or energy bins.

• 2) Important: option DETECT will give meaningful results ONLY when FLUKA is used in a completely analogue mode, since correlations are destroyed by biasing. Thus, DETECT cannot be used together with any biasing option or weight-changing facility. It is recommended for this purpose to issue a GLOBAL command with WHAT(2) < 0.0 at the beginning of input (see GLOBAL). A list of incompatible options is: BIASING, EMF-BIAS, LOW-BIAS, LAM-BIAS, WW-FACTOr, EMFCUT with WHAT(3) > 0, EMF with WHAT(6) <> 1, EXPTRANS, LOW-DOWN.

Example (number-based):

 *...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
 DETECT           0.0     1.E-4     1.E-2     5.E-5       1.0      7.0 Coincid_1
 DETECT           0.0      -9.0     -12.0      10.0      11.0           &
 *   The meaning of the above lines is the following:
 *   a "signal" equal to energy deposition in regions 7 + 10 + 11 will be
 *   scored if:
 *   1) that signal is larger than 1.E-4 GeV and smaller than 0.01 GeV
 *   2) at the same time (in coincidence) an energy deposition of at least
 *   5.0E-5 GeV occurs in regions 9 + 12
 *   The output will give a signal (event) spectrum between the energy
 *   limits 1.0E-4 and 0.010 GeV, distributed over a fixed number of channels
 *   (1024 in the standard version).

The same example, name-based:

 *...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
 DETECT           0.0     1.E-4     1.E-2     5.E-5       1.0 The7thRg Coincid_1
 DETECT           0.0 -The9thRg -Region12  Region10  Region11           &