in this paper

the resolving power limit with the SEM television pick-up tube at low light levels is calculated by use of quantum noise theory. Ways to improve the resolving power limit and the theoretical limitation for measurement are investigated.First

it is shown that

without the electrical noise of the television system

there exists in the television picture a theoretical resolving power limit at low light levels because of the presence of light quantum noise

its value depending on the photo quantum effect of the SEM photocathode and the modulation transfer function of television system.Next

in consideration of the existence of television system noise

the paper shows that the actual resolving power limit at low light levels is much lower than the theoretical value

and it can be improved by increasing the target gain.Finally

experimental results are given

and these results are found to agree favorably with the theoretical values as developed in this paper.