(a) a typical thermionic emission source used in a sem has a total current of 1.6ha. if 10 % of the electron current is included in the probe, how many electrons are incident on the specimen in 10s? using this sem to image a zone-plate made of alternating layers of c6 and w74. make the you are following assumptions- (0)the secondary electron (se) yield is 0.2% for c and 0.05% for w.(ii)the back scattered electron(bse) yield is 0.12 %, where z is the atomic number. (ii) the efficiency of detection for both electrons is 10% (y) the standard deviation, o-n, where n is the counts. (b) how many secondary electrons of c and w will be detected in 1s? (c) how many bse of c and w will be detected in 1s? (d) what will be the contrasts across a w/c boundary for secondary and back-scattered electrons? (e) is the contrast statistically significant in each case? (f) which method, se or bse, would be better to image the w/c boundary? give a brief explanation.