The AIP’s Physics News Update this week highlights a paper on the laser cooling and trapping of radium by a group at Argonne National Laboratory. This is a new record for the heaviest atom ever cooled and trapped.
It’s not quite as cool as the previous record, which involved the trapping of francium atoms that were produced using an accelerator– you need to do a bit more work to get radium than just scraping off a bunch of old watch dials, but the basic apparatus is a fairly standard atomic beam system. It’s still pretty cool stuff, and a good bit of work has gone into it– before they could laser cool radium, they needed to do a good deal of spectroscopy to figure out what laser wavelength they needed, and that’s a good trick with unstable istopes.