cannot penetrate this aperture.
The use of suppression apertures has two undesirable consequences. The aperture introduces a boundary condition causing a sharp divergence in beam potential. This can exacerbate the beam blow-up downstream from the suppression aperture. Additionally, the electric field in the region of the aperture can deflect electrons from a beam neutralizer downstream to the region of the implantation chamber. This has the undesirable result of producing a region of positive charge at a central core of the ion beam and a negative charge at the outer periphery of the ion beam. Stated another way, the ion beam is neutral in a broad sense: but at the wafer surface, a positive charge build-up occurs at the wafer center and a negative charge occurs around the outer circumference.THE SESSIONS (originally titled The Surrogate) is an independent drama film written and directed by veteran Aussie filmmaker, Ben Lewin (Georgia). It is based on the true story of Mark O'Brien, a poet paralyzed from neck down due to polio who hired a sex surrogate to lose his virginity. The film debuted at the 2012 Sundance Film Festival, where it won the Audience Award (U.S. Dramatic) and a U.S. Dramatic Special Jury Prize for Ensemble Acting.

John Hawkes plays Mark O'Brien, a man in an iron lung who decides he wants to lose his virginity. After consulting with his priest (William H. Macy), he gets in touch with Cheryl Cohen-Greene (Helen Hunt), a professional sex surrogate.