How to turn off particle generator without clearing already generated particles?

    Aug 13 2014 | 8:28 pm
    I am playing with Recipe 48 from Jitter Recipe book 4.
    I am trying to figure out how to turn off the particle generator without clearing the already generated particles. What is the best way to do this?
    One way I was trying to do this was by shortening the life of the particle, but it seems that any changes in the parameters I make effect all the particles currently generated.
    Is there a way to attach to a particle the parameters that were in place at the moment that particle was generated?