A self-locking wire terminal assembly and a shape memory wire termination system includes an electrical terminal constructed with spring legs which provide two opposing points of contact on a mating electrical conductive pin. Each of the segments has a tubular portion with a first circumferential edge and a second circumferential edge and a helical portion extending from the second circumferential edge. The transducer is effective in detecting axial displacement simply and low cost. 1 m deep into the body material. In a direction intersecting a beam traveling direction and a beam scanning direction or in a direction intersecting the beam traveling direction and a beam spread direction of the sheet-like or the ribbon-like beam, the electrons are supplied to neutralize electric charges. In one example, pixel size is increased according to the distance of the pixel from the x-axis andor the y-axis of the pixel array to correct for lens shading.