source: trunk/examples/novice/gemc/src/fst_strip.cc@ 1190

Last change on this file since 1190 was 807, checked in by garnier, 17 years ago

update
File size: 3.5 KB
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1// %%%%%%%%%%%%%
2// gemc headers
3// %%%%%%%%%%%%%
4#include "fst_strip.h"
5
6#include <iostream>
7#include <cmath>
8
9void fst_strip::fill_infos()
10{
11 // all dimensions are in mm
12
13 Pi = 3.14159265358;
14 interlayer = 2.75; // distance between 2 layers of a superlayer
15 intersuperlayer = 15.0; // distance between 2 superlayers
16 Nsector=15; // number of sectors for each layer
17
18 alpha = (360.0/Nsector/2.0)*Pi/180.0; // angle of the strips
19 pitch = 0.150; // pitch of the strips
20
21
22 DZ = 0.934; // size of the band of dead zones
23 Rmin = 19.029; // inner radius of disks
24 Rmax = (Rmin+45.419+123.552); // outer radius of disks
25 Z_1stlayer = 238.065; // z position of the 1st layer
26
27 // z of the upstream part of the layer
28 Z0.push_back(Z_1stlayer);
29 Z0.push_back(Z0[0]+interlayer);
30 Z0.push_back(Z_1stlayer+intersuperlayer);
31 Z0.push_back(Z0[2]+interlayer);
32 Z0.push_back(Z_1stlayer+2.*intersuperlayer);
33 Z0.push_back(Z0[4]+interlayer);
34
35
36 // mid angle of the sector
37 MidTile.push_back((360.0/Nsector/2.0)*Pi/180.0);
38 MidTile.push_back((360.0/Nsector/2.0)*Pi/180.0);
39 MidTile.push_back((360.0/Nsector/2.0)*Pi/180.0);
40 MidTile.push_back((360.0/Nsector/2.0)*Pi/180.0);
41 MidTile.push_back((360.0/Nsector/2.0)*Pi/180.0);
42 MidTile.push_back((360.0/Nsector/2.0)*Pi/180.0);
43
44 // Number of strips
45 Nstrips = (int) floor((2.*Rmax*tan(alpha)-2.*DZ)/pitch);
46
47}
48
49
50
51
52
53int fst_strip::FindStrip(int layer, int sector, double x, double y, double z)
54{
55 // 1st define phi of the hit point
56 double phi;
57 if(x>0 && y>=0) phi = atan(y/x);
58 else if(x>0 && y<0) phi = 2.*Pi+atan(y/x);
59 else if(x<0) phi = Pi+atan(y/x);
60 else if(x==0 && y>0) phi = Pi/2.;
61 else if(x==0 && y<0) phi = 3.*Pi/2.;
62 else phi = 0; // x = y = 0, phi not defined
63
64 // now find the tile number
65 int ti=0;
66 double theta_tmp=0;
67 for(int t=0; t<Nsector; t++)
68 {
69 theta_tmp = MidTile[layer]+2.*t*Pi/Nsector;
70 if(theta_tmp>2.*Pi) theta_tmp = theta_tmp - 2.*Pi;
71 if(theta_tmp<0) theta_tmp = theta_tmp + 2.*Pi;
72 if(fabs(phi-theta_tmp)<Pi/Nsector || fabs(2.*Pi-fabs(phi-theta_tmp))<Pi/Nsector) ti=t; // gives tile #
73 }
74
75 double thetaij = MidTile[layer]+2.*ti*Pi/Nsector;
76 int ClosestStrip=0;
77 if(layer%2==0)
78 ClosestStrip = (int) (floor( (-DZ+x*(cos(thetaij)*tan(alpha)+sin(thetaij))+y*(sin(thetaij)*tan(alpha)-cos(thetaij)))/pitch) +
79 floor(2.0*((-DZ+x*(cos(thetaij)*tan(alpha)+sin(thetaij)) + y*(sin(thetaij)*tan(alpha)-cos(thetaij)))/pitch -
80 floor((-DZ+x*(cos(thetaij)*tan(alpha)+sin(thetaij)) + y*(sin(thetaij)*tan(alpha)-cos(thetaij)))/pitch))));
81
82 if(layer%2==1)
83 ClosestStrip = (int) (floor( (-DZ+x*(cos(thetaij)*tan(alpha)-sin(thetaij))+y*(sin(thetaij)*tan(alpha)+cos(thetaij)))/pitch) +
84 floor(2.0*((-DZ+x*(cos(thetaij)*tan(alpha)-sin(thetaij))+y*(sin(thetaij)*tan(alpha)+cos(thetaij)))/pitch -
85 floor((-DZ+x*(cos(thetaij)*tan(alpha)-sin(thetaij))+y*(sin(thetaij)*tan(alpha)+cos(thetaij)))/pitch))));
86
87 int IsOK=1;
88
89 // now check if the position is in the acceptance of the detector:
90 if(ClosestStrip<0 || ClosestStrip>Nstrips) IsOK = 0;
91 if(x*cos(thetaij)+y*sin(thetaij)< Rmin || x*cos(thetaij)+y*sin(thetaij)>Rmax)
92 {
93 // cout << " Outside Acceptance " << endl;
94 IsOK = 0;
95 }
96
97 if(IsOK) return ClosestStrip;
98 else return -1;
99
100
101}
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