Homemade 8w tube using sylvania t8 cathodes

Just for fun i put half of a 36w t8 cathode in each end of this tube, im hoping it lasts a long time, though the resistance is only 3R at each end so it will not work in switch start unless a diode is placed in series with the starter, it however works fine on hf. It was processed using helium at 300 milibar and a high voltage which allows me to run the tube at a low current yet get it to the required temperature to remove impurities. Cathodes dont get that hot during this so id suspect its unlikely to affect life.