Hello Michael, 10E-6 torr is not necessary. For testing purposes is 10-2 torr enough, because then the tube is filled to somewhere around 30 torr what is much higher pressure.. The initial pressure is not so critical in nixie tubes, but influeces the total lifetime of the tube.. However it would be better to use at least 10-4 torr for real production..
Dalibor 2013/1/26 Michael Gregg <mgregggph...@gmail.com> > On 01/25/2013 03:52 PM, jb-electronics wrote: > > Hi folks, > > > > I am still working on Nixie tubes, but I have to take it a little slow > > at the moment because I switched my university and I am currently sort > > of living in two cities ;-) > > > > However, today I had some time so I took a look at my vacuum system. > > My problem was that even after I closed the valve to my pump at a > > pressure of 1.5E-2 mbar, the pressure would rise up to 20mbar in 20 > > minutes. So there was a leak. > > > > I then checked every part of my system (swagelok adapter, needle > > valve) by replacing them with a blind flange and recording the > > pressure after 10s, 20s, 30s, 40s, 50s, 60s, 120s, 300s, 600s, 1200s > > and plotted them. I realised that there was insufficient greasing on > > my needle valve, and the most interesting thing is that it is not > > airtight if the scale is adjusted to just zero. You have to (gently) > > adjust it below the scale zero point. Then I get a leakage rate of > > just 1.2 琨ar/s which is very low. > > > > My system has a volume of at most (!) 65ml, so the leakage rate now is > > Q = 5.4E-6 mbar l/s which is pretty good I think. See my results here: > > > > http://www.jb-electronics.de/tmp/leakage.png > > http://www.jb-electronics.de/tmp/leakage_extensive.png > > > > Note that the Q value in these diagrams needs to be multiplied with 65ml. > > > > The next step will be to find a good connection to the pressure > > reducer for my gas bottle. Right now I am using a PVC hose (terrible), > > and I have huge leakage rates. > > > > But as always: One thing at a time ;-) > > > > Jens > > > > Very cool. > > So the leakage rate seems pretty low, but I'd be concerned about the > total vacuum that your system can accomplish. > > Although I have never built nixie tubes myself, I did a good amount of > research to go down that road. > > My research came up with some claims that you need to get down in the > 10E-6 torr before the fill for good results with a nixie tube. > > Anyhow, please keep a image journal of your work. It looks like a great > deal of fun. > > Michael- > > -- > 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. > For more options, visit https://groups.google.com/groups/opt_out. > > > -- Dalibor Farny http://dalibor.farny.cz -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
