In Marcley's book, The Apparatus Drawing Project, it is recommended that one make a glass to metal seal for an electrode in a Balmer series spectrum tube by using a tunsten rod and sealing it to a bead of uranium glass, which is then sealed to the pyrex glass that is the main material of the Balmer series tube. It mentions that one can use Nonex instead of uranium glass but says it isn't as good and one has to anneal it much more carefully. It also refers to Strong's book, Procedures in Experimental Physics, for the fact that the tunsten has to be specially made for glass seals to avoid leaking. That fact is indeed in Strong's book but I was surprised to find that it has no information on the thermal expansion coefficient of uranium glass. Also, my copy (64th edition) of the CRC book has no information on the thermal expansion coefficient of uranium glass. I also haven't found it on the web. I'm sure it isn't a big secret, I'm just looking in the wrong places. Does anyone know the right reference for this?
19 years ago