I have found these in High grade emissions signal sources in Federation system that are in a Boom state.
You will find any of these Proto Radioilic Alloys, Proto Heat Radiators or Core Dynamics Composites in the signal source... To bad you will most often find the ones you do not need at the moment.
So what I usually do, look for Boom-state systems in galaxy map. then check if they are Federation.
Now the tricky part, you cannot be in shipping lane or close to planets..... withg orbital lines activated, I try to fly of the "plane" where most planets orbits in. you usually enter "deep space" at around 200 LS from the star, go in this direction for about 2500 LS and then turn around fly towards the star and pass at around 200 LS and continue past the star to around 2500 LS.
You must go with some speed, minimum throttle is to be avoided, I usually go 75% throttle. Full speed is also ok.
if it does NOT say you are in "deep space", you are most likely to close to planets in the system, or your client has bugged, happens sometimes.
I usually lock on to the star, so that I know the distance when to turn around. Then it should say say "Deep space" in the 3rd area from the top on the area next to the image of your target
Top area shows the star name (2 lines)
2nd area from the top, shows which faction controll of the system and what kind of star it is (3 lines)
3rd are, show if you are in "deep space" (1 line)
4 area shows faction in charge
Once you have got the hang of this.
Imperial shielding, Boom /Outbreak Imperial systems, High grade Emissions....
Pharmaceutical Isolators, Outbreak systems, High grade Emissions.
So when I go hunting for Imperial Shielding and Pharmaceutical Isolators, I go to an Imperial system in Outbreak ...