Hello! You most likely have a serious leak in the ball valve. You might get temporary seal in it by disassembling it and packing the seal areas solid with vacuum grease. This would be temporary and subject to begin leaking again at any time but could give you a few days of leak free operation without changing out the valve to a better one. You would do better to get a hardware store water valve with a standard packing that you could remove and replace with a teflon plug packing. I have done this and made valves that are tight to 10 -6 torr! Be sure to get a "plug" valve and not a gate valve. (a plug valve rams a rubber plug onto a seal surface. A gate valve slides a metal gate into a groove.) You should not have any problems at all with the rubber hose in those short sections so long as you use grease on the connections. Permeability of the rubber is minimal at room temperature and would take hours to affect the vacuum at the pressures you are using. How long will the pressure stay constant when you turn off the power and close the ball valve? It should remain below 100 microns for several hours if you don't have a leak. Important: Note that to outgas the system to do this test it will take about 4 hours of continuous pumping regardless of leaks! (surprise?!) Yes, it takes that long if you cannot heat the system a bit with a torch or heat lamp! Most new users in vacuum are very surprised at how long it actually takes to outgas a system that has been at atmospheric for any length of time! You may not have a leak, just normal outgassing! Just out of curiosity, why do you need such a close control of the neon into the tube? For nixies it surely isn't necessary. What are you going to make????? glasslinger
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