  We have developed a Lorentz angle measurement system for cool gas mixtures in
the course of our R&D for a proposed JLC central drift chamber (JLC-CDC). The
measurement system is characterized by the use of two laser beams to produce
primary electrons and flash ADCs to read their signals simultaneously. With
this new system, we have measured Lorentz angles for CO2/isobutane gas mixtures
with different proportions (95:5, 90:10, and 85:15), varying drift field from
0.6 to 2.0 kV/cm and magnetic field up to 1.5 T. The results of the measurement
are in good agreement with GARFIELD/MAGBOLTZ simulations.
