No explanation is necessary. However, I could say that this filter doesn't really need the massive coil / cap trap for the third harmonic.
NB. To make an air core coil of 530 henries requires about 500 turns with a diameter of 1 kilometer. It is possible that CERN may have the money and spare time to wind coils like this. They have lots of money!
Please enquire at CERN for enormous grants to do this.. They certainly made a pigs dinner out of KICAD which has had loads a money thrown at it to make it into the horrible mess it is today... So why not wind massive coils instead?
P.S. Use gEDA not KICAD - it works!
https://en.wikipedia.org/wiki/CERN
Enjoy
111 octal
