Different Vacuum Tubes

To make Geissler tube you need to go to at least medium vacuum (in my case ~1Torr). Without it you will not get Faraday's dark space. 

Here you can see Faraday's dark space on right and positive column on left

Although, it seems like very standard (everyone has it at home), it VERY tricky to make. The reason is for that is hot cathode instead of cold one. In cold cathode mode it's OK to use glue to seal tubes and connect feed through electrodes. It getting a little bit warm but it doesn't leak. Here the electrodes gets very hot. As this light bulb is 12Volt at 3 Amperes. (Which makes it 36 Watt bulb) 

It turned out that building Crookes tube is quite easy. All you need is some basic glasswork, epoxy glue, beer bottle and 3D-printed part for better hold cathode. Connect everything together and apply vacuum. Once it reaches certain level it will shine more and more. Then you can place a magnet to see how electron deflected from magnet. 

Magnetic lens is really cool concept! Here is Crook's tube I've bought (was not able to make by myself yet) and magnetic lens was added. Actually it is a simple coil. By varying voltage, hence current in the coil. The spot can be concentrated to about 2mm 

I've bought simple 0.3Pa vacuum pump which seemed to be reliable. I've pumped the air out until the glow turned to dim blue. Then I've cut close using standard torch. It's amazing! I feel the video doesn't show how really beautiful it is. 

Another interesting thing is how glow change when tube depressurized. The color change from dim blue to red through white bright 

Note: Most of sites/video like jdflyback and simplifier use metal to glass connection. I was not able to make one which not leaked. Instead I've used different heat resisstent glue. It is success and was not leaked yet.