When you use 2 kW ultrasound on a forging, cracks give off X-rays, but also produce bubbles of He and O gas – as I learened during my Me.Eng at Sheffeild University in 1982.
I was reminded about this during me PhD nit ochemical engineering in 2000 – which gto ended with no explanation when I started talking nuclear fusion.
Talk to email@example.com about this! Molecular Nuclear Fusion
1 H2O+US -> He +O+E2+X-ray
Along a crack in the forging.