Mostly empty foam overturns assumptions of electron beam stopping

When physicists fire beams of fast electrons at materials, they often need to know exactly how much energy those electrons will lose as they travel through. Through new research published in Physical Review Letters, a team led by Ke Jiang at Shenzhen Technology University in China has found that porous, mostly empty foam materials can stop high-current electron beams far more effectively than denser materials—overturning many previous assumptions about how these beams interact with solid materials.