A new combined Thomson and Rayleigh scattering setup is presented. A key problem in developing a Thomson-Rayleigh scattering setup is the level of the unwanted stray light. The level in the new setup is decreased to 10-2 torr Ar, making possible the measurement of neutral densities down to 1020 m-3. The setup is used to measure ne, n0, and Te in an expanding magnetized cascaded arc plasma, which, depending on the operating mode, has electron densities in the range 5 * 1017-1021 m-3, neutral densities in the range 1020-1023 m-3, and electron temps. of 1000-25,000 K. [on SciFinder (R)