The angular range collected from the scattering plane is 22 . The energy range is given as 0.01949 E pass . The height of the entrance slit controls the accepted angular range, and the height of the beam spot is made small so to give good energy resolution. This allows the beam spot to be widened, in turn giving a good beam current to the target without a corresponding loss of angular resolution. The channel plates operate in the pulse-saturated mode, thus enabling single event counting.
Particles impinging on the first micro-channel plate create secondary electrons.
Two linear arrays of interweaving triangular electrodes, each set coupled with resistors and capacitors, lead to four electrodes at the corners. The angle and energy of incident ions are computed from the relative amounts of charge collected at each corner by charge sensitive amplifiers. Since the charge cloud overlaps several triangles, the angular resolution is actually much better than that given by the width of one triangle. This resolution can be found by examining the signal from an element with submonolayer coverage on a very flat surface. Au surface peak signal is shown below.