Ad. Bass et al., MEASUREMENTS OF CHARGE ACCUMULATION INDUCED BY MONOCHROMATIC LOW-ENERGY ELECTRONS AT THE SURFACE OF INSULATING SAMPLES, Journal of applied physics, 84(5), 1998, pp. 2740-2748
We investigate charging of insulators with an apparatus that allows me
asurements of trapped charges resulting from the impact of monoenerget
ic electrons of 0.1-28 eV. Details are given on the construction and o
peration of this instrument. A high-resolution electron monochromator
provides a pulsed electron beam of variable energy and current. Accumu
lated surface charge is monitored using a Kelvin probe and a high-sens
itivity electrometer. An ultraviolet source of adjustable maximum freq
uency allows the sample to be discharged for multiple measurements on
the same sample. We illustrate the use of the instrument with prelimin
ary measurements for similar to 100 mu m thick samples cut from an ind
ustrial polyethylene cable. The incident electron-energy dependence of
the trapping probability exhibits large variation and indicates that
electrons with energies <5 eV are the most efficiently trapped; chargi
ng near 10 eV is attributed to dissociative electron attachment to pol
yethylene molecules. (C) 1998 American Institute of Physics. [S0021-89
79(98)04817-8]