[quote author=Fu-Kwun Hwang link=topic=33.msg7589#msg7589 date=1291629074]
Let me know all the parameters you have set for your simulation.
I do not know how to help you if I do not have any information about the simulation from you!
[/quote]

Am studying the motion in very small period of time and calculate the vector  of velocity and accelerate every moment
then I can calculate the position  of the particle in this moment then I draw it ....

in the Gap I need to know the electric filed to calculate the accelerate  vector acc =  (q.E)/m
and I need the proton mass and  charge ( I know them but they are so small that I couldn't represent them ..

in the Dee I need to know the magnetic filed to calculate the accelerate  vector acc= (q.vB)/m ..