  For accurately obtaining the relationship between the carrier mobility and
the applied electric field, a new multi-layer sample has been designed.
Polyvinyl fluoride (PVF) films were hot pressed on both sides of linear low
density polyethylene( LLDPE) to block the charge injection from the electrode,
so as to better observe the migration of irradiated electrons. The new
multi-layer sample was firstly charged to form a charge packet in the electron
beam (e-beam) irradiation setup. And then it was transferred to the Laser
Induced Pressure Propagation (LIPP) setup to have the space charge evolution
monitored under DC voltages on the order 10-70 kV/mm. The migration of the
charge packet has been successfully obtained in this new multi-layer sample. By
using the packet front as the reference point, the range of the average
mobility of packets at a range from 0.06*10-14 to 1.02*10-14 m2/(V*s) under
calibration local field. The experimental results coincide well with the curve
relating charge mobility and the electric field predicted from the Gunn
effect-like model.
