One paying out money for nuclear physicist (6)

I believe the answer is:

teller

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'nuclear physicist' is the definition.
(I know that Teller is a nuclear physicist)

I don't understand the remainder of the clue.

Can you help me to learn more?

(Other definitions for teller that I've seen before include "one reckons" , "Election official" , "one gives relation" , "Cashier - vote counter - narrator" , "Bank official or reporter" .)

I've seen this clue in The Times.

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