Programs for setting up photocathode trajectories (xmpl2d41.dat).
These can be copied from the end of file xmpl2d41.dat, which is supplied with the CPO2D package.
C Program (in Fortran) for setting up photocathode trajectories:
DIMENSION traj (6)
OPEN (UNIT=2,FILE='tempres.dat',STATUS='UNKNOWN')
C =results file
C Initialise some parameters:
n = 10
C =require number of trajectories
spacing = 0.1
C =initial spacing from cathode
rmax = 50.
C =maximum distance of initial rays from the axis
energy = 0.5
C =initial energy
rad = 150.
C =radius of photocathode
C Start calculation:
z0 = rad + spacing
traj(5) = energy
traj(6) = 0.
C =current
theta_max = ASIN(rmax/rad)
DO i = 1 , n
theta = theta_max*real(i-0.5)/real(n)
C -ie trajectories start from centres of n steps
sn = SIN(theta)
cs = COS(theta)
traj(1) = rad*sn
traj(2) = z0 - rad*cs
traj(3) = -sn
traj(4) = cs
WRITE (2,'(1P6E11.3)') (traj(j), j = 1 , 6)
C =required output
ENDDO
STOP
END