the invention relates to a vacuum treatment chamber for work pieces which comprises at least one induction coil for at least co - generating a treatment plasma in a discharge chamber which is located in the interior of the coil . it also comprises a screen which is arranged between the discharge chamber and the coil , and which is coaxial in relation to the axis of the coil . the screen comprises slots which have a directional component which is parallel to the coil axis . the screen is formed by a self - contained body . the slots are provided along at least the main part of the body &# 39 ; s circumference in a slot density per circumferential length unit of s =/ cm equaling 0 . 5 ≦ s .