[pxhb]

I can’t tell for sure from the article but I think they are accelerating protons with TNSA (target normal sheath acceleration). I worked in a lab in undergrad that was doing something similar, except with lithium instead of boron. The main challenges that I recall from a decade ago with TNSA are (WARNING: there almost certainly has been progress since a decade ago):

-Conversion efficiency of laser energy into ion (proton) kinetic energy

-TNSA accelerates mainly the contaminated layer on the back of targets, which may not be a big deal if you are interested in accelerating protons

-TNSA protons are not beam like. They do not have a uniform kinetic energy, and they have a wide angular divergence.

-Various laser related issues (prepulse, focal spot size/shape).

I also anticipate that it will have the same engineering problem as ICF/NIF, in that it will need to continuously replenish targets.

[DennisP]

Here's their publications page, if you're interested in looking into it further.

https://www.hb11.energy/news-and-publications