5. Conclusion

X-ray sources and generators are based on concepts that have hardly evolved since the 1920s, even if generators have benefited from advances in solid-state technology. But this does not mean that research is standing still. Several avenues are being explored to improve Coolidge tubes.

We know that the anode is a limiting factor for their peak power, and a Swedish team at KTH has been working for years on liquid anodes whose calorific extraction power would have no comparison with rotating anodes (a peak beam power of 10 MW/mm ² could be envisaged, whereas the current limit is around 100 kW/mm ² ).

There is also a great deal of work on cold cathodes, where electronic emission is forced and controlled by an external electric field (Fowler-Nordheim law)...