# Difference between revisions of "Solid Baffle"

## Zhiwen's work with geant4 simulation

New Idea: can we have the baffles straight where the detectors are and more curved near the target? Now the spokes are straight near the target. The detectors would then have a simpler geometry, reducing cost. Anyway, we need a Monte Carlo to check out new ideas. (by Paul Souder?)

## Eugene's work with geant3 simulation

### Eugene's procedure

```the slits were defined using the following procedure:

a) I ran GEANT simulating production in a long target,
at the edges of a phi-theta sector. The sector
width was 5 deg at thet_min and 9 deg at thet_max.
At the low phi edge (against the rotation in the field),
I took the max XBj and calculated the momentum for the given
theta. At the higher edge I took the min XBj.

b) GEANT generated hits of these tracks in the planes of the baffles.
The target length in Z makes things a bit complex, but it turned
out that simple rules could be used to select the most inner
points for the given R.
I took the hits and extrapolated the phi-R curves with parabolas
as phi=p0+p1*r+p2*r**2.
The results were stored in the PAW session.

c) Using the stored parameters of the baffles, I printed
the input to GEANT, splitting the holes in the baffles into

It was not possible to define a slit as a single shape in GEANT3.
I do not know about GEANT4. It would be a complex slice of a paraboloid,
overlapping with other volumes.
Multiple volumes work well in GEANT. One slit was defined,
then copied to all 30 sectors of the given ring. This part of the FFREAD input
code defining the geometry was generated by a script (too many lines to type
by hand).
```

### The plots in a pdf file and results in a kumac

6 plates, 30 slits per plate, 20 blocks per slit

``` macro baffle xmin=-100 xmax=100 ymin=-100 ymax=100

application data tmp.dat
3.90    5.44   176.26  183.00
5.44    6.98   176.44  182.13
6.98    8.52   176.61  181.67
8.52   10.06   176.75  181.78
10.06   11.60   176.89  181.90
11.60   13.14   177.03  182.01
13.14   14.68   177.18  182.12
14.68   16.22   177.32  182.24
16.22   17.76   177.46  182.35
17.76   19.30   177.60  182.46
19.30   20.84   177.74  182.58
20.84   22.38   177.88  182.69
22.38   23.92   178.02  182.80
23.92   25.46   178.16  182.92
25.46   27.00   178.30  183.03
27.00   28.54   178.44  183.15
28.54   30.08   178.58  183.26
30.08   31.62   178.72  183.37
31.62   33.16   178.86  183.49
33.16   34.70   179.00  183.60
tmp.dat

exec plotWedge same=[same] color=1 xmin=[xmin] xmax=[xmax] ymin=[ymin] ymax=[ymax]
* wait

application data tmp.dat
15.30   17.25   175.93  182.78
17.25   19.20   176.14  182.56
19.20   21.15   176.35  182.36
21.15   23.10   176.58  182.19
23.10   25.05   176.81  182.05
25.05   27.00   177.06  181.93
27.00   28.95   177.28  181.98
28.95   30.90   177.46  182.12
30.90   32.85   177.64  182.26
32.85   34.80   177.82  182.41
34.80   36.75   178.00  182.55
36.75   38.70   178.18  182.70
38.70   40.65   178.35  182.84
40.65   42.60   178.53  182.98
42.60   44.55   178.71  183.13
44.55   46.50   178.89  183.27
46.50   48.45   179.07  183.41
48.45   50.40   179.25  183.56
50.40   52.35   179.42  183.70
52.35   54.30   179.60  183.84
tmp.dat

exec plotWedge same=[same] color=2 xmin=[xmin] xmax=[xmax] ymin=[ymin] ymax=[ymax]
* wait

application data tmp.dat
26.60   28.96   175.71  182.49
28.96   31.32   175.95  182.40
31.32   33.68   176.20  182.32
33.68   36.04   176.46  182.27
36.04   38.40   176.73  182.23
38.40   40.76   177.02  182.22
40.76   43.12   177.31  182.22
43.12   45.48   177.62  182.23
45.48   47.84   177.93  182.28
47.84   50.20   178.15  182.46
50.20   52.56   178.36  182.63
52.56   54.92   178.58  182.81
54.92   57.28   178.80  182.98
57.28   59.64   179.01  183.16
59.64   62.00   179.23  183.33
62.00   64.36   179.45  183.51
64.36   66.72   179.67  183.68
66.72   69.08   179.88  183.85
69.08   71.44   180.10  184.03
71.44   73.80   180.32  184.21
tmp.dat

exec plotWedge same=[same] color=3 xmin=[xmin] xmax=[xmax] ymin=[ymin] ymax=[ymax]
* wait

application data tmp.dat
37.90   40.67   175.38  182.05
40.67   43.44   175.66  182.04
43.44   46.21   175.95  182.04
46.21   48.98   176.25  182.05
48.98   51.75   176.57  182.08
51.75   54.52   176.89  182.13
54.52   57.29   177.22  182.19
57.29   60.06   177.57  182.27
60.06   62.83   177.92  182.36
62.83   65.60   178.29  182.47
65.60   68.37   178.66  182.66
68.37   71.14   178.90  182.84
71.14   73.91   179.15  183.02
73.91   76.68   179.39  183.22
76.68   79.45   179.65  183.42
79.45   82.22   179.90  183.62
82.22   84.99   180.16  183.84
84.99   87.76   180.43  184.06
87.76   90.53   180.71  184.28
90.53   93.30   180.98  184.51
tmp.dat

exec plotWedge same=[same] color=4 xmin=[xmin] xmax=[xmax] ymin=[ymin] ymax=[ymax]
* wait

application data tmp.dat
49.20   52.38   175.06  181.61
52.38   55.56   175.37  181.64
55.56   58.74   175.70  181.70
58.74   61.92   176.04  181.76
61.92   65.10   176.39  181.84
65.10   68.28   176.76  181.94
68.28   71.46   177.13  182.05
71.46   74.64   177.52  182.17
74.64   77.82   177.91  182.31
77.82   81.00   178.32  182.46
81.00   84.18   178.75  182.63
84.18   87.36   179.20  182.85
87.36   90.54   179.48  183.06
90.54   93.72   179.76  183.28
93.72   96.90   180.05  183.51
96.90  100.08   180.35  183.75
100.08  103.26   180.65  183.99
103.26  106.44   180.96  184.24
106.44  109.62   181.27  184.49
109.62  112.80   181.59  184.75
tmp.dat

exec plotWedge same=[same] color=6 xmin=[xmin] xmax=[xmax] ymin=[ymin] ymax=[ymax]
* wait

application data tmp.dat
60.40   63.98   174.92  181.35
63.98   67.56   175.27  181.43
67.56   71.14   175.63  181.52
71.14   74.72   176.00  181.63
74.72   78.30   176.38  181.75
78.30   81.88   176.78  181.88
81.88   85.46   177.18  182.02
85.46   89.04   177.60  182.18
89.04   92.62   178.03  182.35
92.62   96.20   178.47  182.53
96.20   99.78   178.92  182.73
99.78  103.36   179.39  182.94
103.36  106.94   179.88  183.19
106.94  110.52   180.20  183.43
110.52  114.10   180.52  183.69
114.10  117.68   180.84  183.94
117.68  121.26   181.17  184.21
121.26  124.84   181.51  184.48
124.84  128.42   181.86  184.76
128.42  132.00   182.21  185.04
tmp.dat

exec plotWedge same=[same] color=7 xmin=[xmin] xmax=[xmax] ymin=[ymin] ymax=[ymax]

return

macro plotWedge same=' ' color=1  xmin=-100 xmax=100 ymin=-100 ymax=100

set plci [color]
if ([same] .eq. ' ') then
null [xmin] [xmax] [ymin] [ymax]
endif

DO I = 1, 30
do j = 1, 20
thmin = thmin([j])+([i]-1)*12
thmax = thmax([j])+([i]-1)*12
enddo
enddo

exec plotCompass

return

ndiv = 360/[deg]
message [ndiv]

angle = [offset]
do idiv = 1, [ndiv]
angle = [angle] + [deg]