Example

Assume an electromagnetic calorimeter ECAL divided into 40 PHI sections called EPHI. Each EPHI division is in turn divided along the z axis in 60 sections called EZRI. Each EZRI is finally divided into 4 lead glass blocks called BLOC. The geometrical information to describe one hit will then be:

• the EPHI section number (between 1 and 40);
• the EZRI division number (between 1 and 60);
• the BLOC number (1 to 4).

The quantities which should be stored for each hit are:

X

x position of the hit in the lead glass block (-1000<x<1000);

Y

y position of the hit in the lead glass block (-1000<y<1000);

Z

z position of the hit in the lead glass block (-1000<z<1000);

E

energy of the particle;

ELOS

the energy deposited;

In this scheme a hit could look like:

Element	Value
EPHI	12
EZRI	41
BLOC	3
X	7.89 cm
Y	-345.6 cm
Z	1234.8 cm
E	12 Gev
ELOS	11.85 Gev

The code to define the SET/DET/HIT information could be:

      CHARACTER*4 CHNMSV(3),CHNAMH(5)
      DIMENSION   NBITSV(3),NBITSH(5)
      DIMENSION   ORIG(5),FACT(5)
*---
      DATA CHNMSV/'EPHI','EZRI','BLOC'/
      DATA NBITSV/     6,     6,     3/
*---
      DATA CHNAMH /'X   ','Y   ','Z   ','E   ','ELOS'/
      DATA NBITSH /    16,    16,    16,    16,    16/
      DATA ORIG   / 1000., 1000., 1000.,    0.,    0./
      DATA FACT   /   10.,   10.,   10.,  100.,  100./
*---
      CALL GSDET ('ECAL','BLOC',3,CHNMSV,NBITSV,2,100,100,ISET,IDET)
      CALL GSDETH('ECAL','BLOC',5,CHNAMH,NBITSH,ORIG,FACT)

CALL GFDETH (CHSET,CHDET,NH*,CHNAMH*,NBITSH*,ORIG*,FACT*) Returns the hit parameters for detector CHDET of set CHSET. All arguments are as explained above.

HITS120