Experimental data related to 40 MHz Argon plasma parameters in the RF power and pressure ranges of
25–200W and 0.2–0.5 Torr are presented. Electron temperatures are obtained using both double probe
and optical spectroscopy methods. Acceptable consistency between results is obtained. Double probe
method is also used to obtain the plasma electron density. At any particular pressure value, the effect
of increasing RF power seems to be restricted to increasing plasma electron density rather than affecting
the plasma electron temperatures. Signature of the Paschen law effect is reflected on the relation
between pressure and electron plasma density.