#  type  matter  c    de maxpath / x0   y0   z0   a  b  c
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! This is for demo; the pipe length is very short.
!  in the actual case, it must be  several 10 m and 
!  pipe radius must be smaller.

!         inner radius of pipe
#eq    ir  8
!         outer radius  of pipe
#eq    or  8.3
!         length of the first pipe
#eq    len1   20
!         length of the second pipe
#eq    len2   80	
!         thin cylinder to count particles
#eq    thin  0.1
#eq    totalthick  100.2

1  pipe  Fe  0  0   /   0 0  -50   ir   or len1
2  cyl   sp  1  0  1000/ 0  0    +   =  thin
3  pipe  Fe  0  0   /    0  0  +    ir or  len2
4  cyl   sp  1  0  1000/ 0  0  +    =  thin
!       implicit world that contains all of the above
5  cyl   sp  0  0  1000 / 0 0 -50   =  totalthick / 1 2  3  4
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