The tube had a third electrode, an anticathode connected to the anode.
2.
This flux of negative particles leaving the filament generate X-rays as a consequence of their collision with an improvised anticathode placed exterior to the light bulb.
3.
A more common arrangement used a copper plate anticathode ( similar in construction to the cathode ) in line with the anode such that the anode was between the cathode and the anticathode.
4.
A more common arrangement used a copper plate anticathode ( similar in construction to the cathode ) in line with the anode such that the anode was between the cathode and the anticathode.