The LENA instrument consists of a collimator, conversion unit, extraction lens, dispersive energy analyzer and time-of-flight mass analyzer with position-sensitive particle detection.
Neutral particles (1) enter the instrument through a collimator (2) which filters charged particles. LENA converts neutrals to negative ions through a near specular glancing reflection from a tungsten surface (3). Negative ions from the surface are then collected by the extraction lens (4) which focuses all negative ions with the same energy to a fixed location. In the extraction lens, the ions are accelerated by 20 kV (5) prior to entering the electrostatic analyzer (6). Finally, the ions pass into a time-of-flight/position sensing section where ion mass, energy, and angle are determined.