within

[mengta]

Within a few years of inventing the cyclotron, Lawrence and his colleagues were using these high-energy particles for another purpose.

Does it mean that after Lawerence invented the cyclotron......
or he used it while he was still inventing

thanks

[Fizi]

Does it mean that after Lawerence invented the cyclotron......
or he used it while he was still inventing

He began using it after he invented it, but no more than a few years after.

[Casiopea]

Additionally,

First, Lawrence invents the cyclotron. Then, at some time "within" the following short span of time (two to three years after inventing the cyclotron), Lawrence and his colleagues start using high-energy particles for another purposes.