For anyone interested in translucent alumina tubes for a glow reactor experiment, they are available from time to time on eBay (but not now). They are alumina and not transparent, but translucent. Of course borosilicate glass is also available but alumina could be relevant to gain.
A more translucent tube would be advantageous if external photons are to be introduced as a reaction trigger, instead of electrical current. Those who believe that SPP are responsible for initiating the gain in the glow reactor already see the futility of using incandescence (from resistance wiring) to produce photons at no more than 3% efficiency, when a proper external lamp can provide 60% efficiency - or a factor of 20x more photons per unit of electrical power. Imagine increasing COP by an order of magnitude via a simple change in input power, and at the same time eliminating the most common cause of tube failure. From: Mats Lewan You might have heard of the Japanese researchers making glass almost as strong as steel. Their paper: http://www.nature.com/articles/srep15233 The popular version here: http://gizmodo.com/japanese-researchers-make-glass-thats-nearly-unbreakabl-1739673940 What attracted my interest was the role of alumina in this new material. If alumina has properties that are important for Rossi’s reactors, and in particular since Rossi claims that he’s developing a new reactor called E-Cat X which will produce both heat and light, this new alumina based transparent glass material could be of interest. Mats www.animpossibleinvention.com

