  The Proton Improvement Plan - II (PIP-II) is a new linear accelerator (LINAC)
complex being built at Fermilab. It is based on superconducting radiofrequency
cavities and will accelerate H- ions to 800 MeV kinetic energy before injection
into the existing Booster ring. Measurements of the profile of the beam along
the LINAC must be done by non-intercepting methods due to the superconducting
cavities. The method chosen is photoionization of a small number of H- by a
focused infrared laser, aka laserwire. The number of ionized electrons is
measured as a function of laser position within the H- beam. To aid in the
design of the collection mechanism, a simulation was written in MATLAB with
input from the commercial electromagnetic simulation, CST. This simulation
calculates the number and positions of the liberated electrons and tracks them
through the magnetic collection and H- beam fields to the collection point.
Results from this simulation for various points along the LINAC will be shown.
