I was a postdoc at Lawrence Livermore National Lab (LLNL) from 2013-2016, working on computational particle physics (lattice QCD). Pay was extremely high (for

I was a postdoc at Lawrence Livermore National Lab (LLNL) from 2013-2016, working on computational particle physics (lattice QCD). Pay was extremely high (for a postdoc) but not high by comparison to other bay-area employers. What you get instead is reliable job security, and some sense of civil service (as most of the programs are federally funded). LQCD is kind of funny because it doesn't YET have anything practical to say about nuclear physics, which is what the lab cares about, but it will someday. So I was pretty insulated from all the weapons+complex integration stuff; my work was 'pure research', which is not that common (though it is more common at the postdoc level, which the lab views as a way of recruiting talent). But unless you can find your own funding (usually from a DOE grant), you're working on something that advances the lab's programs. I can't bring myself to work on nuclear weapons, which is why I didn't stay [there's a lot more to LLNL than that, of course, but it's what my field funnels into, broadly speaking]. The computational expertise for HPC is really unparalleled, especially at Livermore (and Oak Ridge, which I've only visited). They're consistently pushing the envelope in terms of high-performance machines which can address scientific questions that require extremely tight coupling between computing resources, rather than a cluster, and they have a lot of experimental architectures and things like that. LLNL publishes a lot of open-source software; if you've used a cluster in a scientific setting you might be most familiar with SLURM or spack. The day-to-day can be a bit surreal. At the defense labs people with enormous machine guns thoroughly check your badge on the way in. On your walk to the cafeteria you might pass a beach volleyball court that's inside the superblock [an extra-high-security area where they've got plutonium etc.], next to a machine gun turret. Very few employers have teams that regularly win SWAT competitions. The food was fine. No luxuries like free snacks or anything else I'd seen my tech-company friends enjoy. No dogs allowed. LLNL has a lot of employee organizations for sports, charities, exercise, etc. Transportation around the LLNL site is via sporadic shuttles but more practically there's a bike share, which is just a bunch of bikes you can leave anywhere (on the sidewalk / by a building).