I've not done any hard to do or fancy activations at this point, but we use Silver and Indium in a moderated "neutron oven" here as a backstop for our other neutron detectors. These low hanging fruit have nice, short half lives so they are easy to read out, and large cross sections so they are easy to activate in the first place. The big advantage you get using these is they they have no dead time effects, and no sensitivity to EMI, both of which can easily fool real-time counters and detectors. You simply cannot fake it with silver or indium -- you have to have neutrons or they don't get hot, and they catch them all pretty well. So I consider these the gold standard for neutron measurement in the flux ranges we are getting here. Gold itself works too, but is fairly "numb" due to the longer half life it has. And besides, transmuting gold into mercury is kind of going the wrong way, eh?
Above is our little oven. This is made from 4" UHMW HDPE rod stock, a good moderator, and is sized to allow some neutrons in the resonance energy range to get to the samples, where they tend to have better cross sections. The bottom piece was cut to fit over the cylinder sidearm my fusor runs in. and I had to add some carbon rod spacers under there to keep it from melting. The top is just more of the same stuff, wrapped in lead so not so many X rays get out into the room (normally there's lead over the top, too). The samples shown are a silver sheet that just covers the pancake detector we use for counting, and a pea sized bit of indium I got from RotoMetals and just pounded flat with a hammer. The indium doesn't get as "hot" due to its longer half life, but has only one half life, so it's easier to measure if you get things hot enough. Silver has two possible isotopes that get made, with two different half lives, so it's a bit tougher to get any kind of absolute numbers out of it. But due to that real short one, it's also the one that really makes the counter sing after a run.
According to my rather ancient CRC handbook (53rd edition), for silver the main numbers are:
107Ag, stable, 51.82% natural occurence
108 Ag 2.42 min half life (and there is evidently a metastable state with > 5 hr life you can also get)
109Ag, stable 48.18% natural occurence
110Ag, 24.4 second half life, and there's also a long life metastable state.
There are some other states and decay modes of the above listed, but evidently they are rare.
For indium:
113In is stable, 4.28% natural abundance
114In has 3 possible states, half lives, the main one of which is 72 seconds
115In is stable, 95.72% abundance
116In also has several states, the main decay of which is 54 min.
I am leaving out out quite a lot of the data in the book here, each of these has several decay modes, energies, and probabilities, so I'm quoting just the numbers that are near what most experimenters are using.
There is a good chance better numbers are out there now at any rate, and if you know them, please post! Silver and In both take a few book pages of tables each to fully describe. We usually measure the silver first, then the indium if we baked both at the same time, and usually see about 10:1 ratio of counting, silver being the hotter, especially at first.
So I'd class this as a relative measurement as far as metrology goes, but a very reliable one.