Home detector target (5)
I believe the answer is:
radon
'home detector target' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for radon that I've seen before include "Colourless gas, atomic number 86" , "Inert gas - adorn (anag)" , "Rare noble gas" , "Noble gas, Rn" , "A radioactive gas, symbol Rn" .)