L_AFREE=radius*ThetaQ1Start 
L_BFREE=radius*(ThetaK1Start - ThetaQ1End)
L_CFREE=radius*(ThetaQ2Start - ThetaK3End)
L_DFREE=radius*(ThetaQ3Start - ThetaQ2End)  - collimator5[l]/radius
L_EFREE=radius*(ThetaQ4Start - ThetaQ3End)
L_EFREE_HALF=radius*(ThetaQ4Start - ThetaQ3End)/2- collimator4[l]/2./radius
L_FFREE=radius*(twopi - ThetaQ4End) - collimator4[l]/radius


AFREE[wall]= { superimpose = .true., thickness = 0.00001,      &
                     section = { type = wall_start, s = 0.01,                  v(1)={0.2,-0.1}, v(2)={0.2, 0.1}, &
                                                                             v(3)={-0.2,0.1}, v(4)={-0.2,-0.1} }, &
                     section = { type = wall_end,   s=L_AFREE-0.01, v(1)={0.2,-0.1}, v(2)={0.2, 0.1}, &
                                                                            v(3)={-0.2,0.1}, v(4)={-0.2,-0.1} } }
AFREE[aperture_at] = continuous
AFREE[aperture_type] = wall3d

!BFREE[wall]= { superimpose = .true., thickness = 0.00001,       &
!                     section = { type = wall_start, s = 0.,                  v(1)={0.2,-0.1}, v(2)={0.2, 0.1}, &
!                                                                             v(3)={-0.2,0.1}, v(4)={-0.2,-0.1} }, &
!                     section = { type = wall_end,   s=L_BFREE, v(1)={0.2,-0.1}, v(2)={0.2, 0.1}, &
!                                                                            v(3)={-0.2,0.1}, v(4)={-0.2,-0.1} } }
!BFREE[aperture_at] = continuous
!BFREE[aperture_type] = wall3d

CFREE[wall]= { superimpose = .true., thickness = 0.00001,       &
                     section = { type = wall_start, s = 0.,                  v(1)={0.2,-0.1}, v(2)={0.2, 0.1}, &
                                                                             v(3)={-0.1,0.1}, v(4)={-0.1,-0.1} }, &
                     section = { type = wall_end,   s=L_CFREE, v(1)={0.2,-0.1}, v(2)={0.2, 0.1}, &
                                                                            v(3)={-0.1,0.1}, v(4)={-0.1,-0.1} } }
CFREE[aperture_at] = continuous
CFREE[aperture_type] = wall3d

DFREE[wall]= { superimpose = .true., thickness = 0.00001,       &
                     section = { type = wall_start, s = 0.,                  v(1)={0.2,-0.1}, v(2)={0.2, 0.1}, &
                                                                             v(3)={-0.1,0.1}, v(4)={-0.1,-0.1} }, &
                     section = { type = wall_end,   s=L_DFREE, v(1)={0.2,-0.1}, v(2)={0.2, 0.1}, &
                                                                            v(3)={-0.1,0.1}, v(4)={-0.1,-0.1} } }
DFREE[aperture_at] = continuous
DFREE[aperture_type] = wall3d

EFREE[wall]= { superimpose = .true., thickness = 0.00001,       &
                     section = { type = wall_start, s = 0.,                  v(1)={0.2,-0.1}, v(2)={0.2, 0.1}, &
                                                                             v(3)={-0.2,0.1}, v(4)={-0.2,-0.1} }, &
                     section = { type = wall_end,   s=L_EFREE, v(1)={0.2,-0.1}, v(2)={0.2, 0.1}, &
                                                                            v(3)={-0.2,0.1}, v(4)={-0.2,-0.1} } }
EFREE[aperture_at] = continuous
EFREE[aperture_type] = wall3d

!EFREE_HALF[wall]= { superimpose = .true., thickness = 0.00001,       &
!                     section = { type = wall_start, s = 0.,                  v(1)={0.2,-0.1}, v(2)={0.2, 0.1}, &
!                                                                             v(3)={-0.2,0.1}, v(4)={-0.2,-0.1} }, &
!                     section = { type = wall_end,   s=L_EFREE_HALF, v(1)={0.2,-0.1}, v(2)={0.2, 0.1}, &
!                                                                            v(3)={-0.2,0.1}, v(4)={-0.2,-0.1} } }
!EFREE_HALF[aperture_at] = continuous
!EFREE_HALF[aperture_type] = wall3d

FFREE[wall]= { superimpose = .true., thickness = 0.00001,       &
                     section = { type = wall_start, s = 0.,                  v(1)={0.2,-0.1}, v(2)={0.2, 0.1}, &
                                                                             v(3)={-0.2,0.1}, v(4)={-0.2,-0.1} }, &
                     section = { type = wall_end,   s=L_FFREE, v(1)={0.2,-0.1}, v(2)={0.2, 0.1}, &
                                                                            v(3)={-0.2,0.1}, v(4)={-0.2,-0.1} } }
FFREE[aperture_at] = continuous
FFREE[aperture_type] = wall3d