Hi Nick, thanks for following up on this. Yes, there are a couple of end of life statements criteria on that page, here <http://s9.postimg.org/a850emn67/page197.jpg> is p334 for reference. As far as the end of life luminosity is concerned, I have adopted a threshold of 30% of initial brightness taking into considering the modern applications of these tubes.
Indeed it is a good text with many references to research of the time. The chapter on sputtering does cover two-three theoretical models but these fail at the higher gas pressures in commercial tubes (sputtering rate inversely related to pressure). There is however at least one author who took the experimental path, Stocker B. J. 1961. I get the impression that research interest on sputtering, one of the most complex topic of this technology, faded away after the introduction of the LED in the late 60s mid 70s. Hopefully we will come to an agreement on the end of life of commonly used tubes using experimental methods, handmade tubes being of particular interest. Alex On Thursday, October 10, 2013 11:53:27 AM UTC+1, Nick wrote: > > On Wednesday, 2 October 2013 15:55:46 UTC+1, AlexTsekenis wrote: > >> Nick, thank you for the swift reply. >> >> I've scanned in p340, here <http://s23.postimg.org/t1sp4km0b/page196.jpg>. >> The book is the exact one in the reference. >> >> On this page Weston explains the impact of digit cycling on lifespan. The >> point of a gradual rather than abrupt end of life is also made. However I >> was not able to find the aforementioned 50% threshold. I also checked p240 >> and p140. Could it be that it is somewhere else in this chapter? I >> am conscious this would appear as pedantic, but the quoted end of life due >> to loss of luminosity comes down to this important threshold. >> > > Finally checked this - you are right - the actual references to > end-of-life are in paragraph 2 of page 334 where he considers EOL to be > either a discontinuous glow over the digit or the glow spreading to > elsewhere in the tube. I know I've seen the 50% reference somewhere else, > so I'll have to dig through my library. > > I'd forgotten what a comprehensive book Weston is - lots of good stuff > about sputtering in there, including detailed analysis of cathode > materials, their performance and lifespan with and without Hg doping... > > Nick > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/47d6e7af-f02d-46a7-8bf9-86a845292dc4%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
