  This paper presents the pre-experiment plan and prediction of the first stage
of Vacuum Laser Acceleration (VLA) collaborating by UCLA, Fudan University and
ATF-BNL. This first stage experiment is a Proof-of-Principle to support our
previously posted novel VLA theory. Simulations show that based on ATF's
current experimental conditions, the electron beam with initial energy of 15MeV
can get net energy gain from intense CO2 laser beam. The difference of electron
beam energy spread is observable by ATF beam line diagnostics system. Further
this energy spread expansion effect increases along with the laser intensity
increasing. The proposal has been approved by ATF committee and experiment will
be the next project.
