In the beam deceleration technique, an electron beam is accelerated
at a high voltage (Vacc) and passed through an objective lens
with a small chromatic aberration coefficient. It is then decelerated
by a bias voltage (Vd) before arriving at the sample surface as shown
in Fig. 1. This technique provides improved resolution and reduced
beam damage. Fig. 2 shows SEM images observed (a) without and
(b) with the beam deceleration technique. Hexagonally arranged
mesopores of SBA-15 are clearly observed even at a landing voltage
of 500V by beam deceleration.