Jeff Hanneman

He used this pickup to record Reign in Blood.

Jeff used EMG 81 pickups on his ESP guitar, according to Guitar Geek's rig diagram of his 2002 rig.

Neck pickup for all of Jeff's guitars.

Articel in german. In a section about Jeffs first Les Paul it says: "More relevant for hsi sound and his playing were the Kahler Pro vibrato system, that he put into the guitar hand the new Joe Barden Two/Tone bridge pickup, which gave him the desired oomph.

"Hanneman’s Jackson Soloist was bought in 1988 for $2000 – it featured a 24 fret neck-thru design [maple neck with poplar wings], ebony fretboard, and a Kahler Model 2315 Flatmount Tremolo."

From the November 2009 issue of Guitar World magazine:

Q: Did you use any new gear on World Painted Blood? Hanneman: [...] I got my ESP with the EMG-81/85 pickup combo abd the EMG-SPC.

In this Instagram post you can see Jeffs Famous 1978 Les Paul Standard equipped with a Kahler Tremolo. I contacted Kahler support to find out what exact model it was, here is their response: "That’s a flat mount 2300 Kahler. Normally that’s not what we would recommend for a guitar like a Les Pau [sic] with an arched top. For that we recommend the Stud mount 2200 Kahler.

Chris Poland from Megadeth was the person who installed the tremolo for Jeff Hanneman and he had to do a lot of work to get a flat mount 2300 to work on the Les Paul. He has to use a flat piece of rosewood as a shim to help the 2300 sit flat and level which took a lot of work."

In these pictures of Jeffs Les Paul you can see the Kahler stringlock behind the nut