Example Problems

1. What is the velocity of a singly ionized As ions [a.m.u =74.9] accelerated through 200 kilovolts?

From the equations

Mv²/2 = qV

We get v = (2qV/M)^1/2

Putting in the values find the value of v, the velocity.

2. What is the radius of As ion accelerated through 10 kV in a magnetic field of 0.5 Wb/m² ( 5000 gauss)?

From the equation

Substituting the values of B, M, V and q we can find the radius, r.

Note the following:

• The number of implanted ions per unit area is termed the dose F and is given by

F = It/qA (ions/cm²)

Where I is in amperes, A is in cm² and implantation time, t is in seconds.

· Also the use of a doubly ionized species increases the energy capability of the machine by a factor of 2 since E=nqV.