Search found 55 matches

by Niels Geerits
Sun Dec 17, 2017 1:59 pm
Forum: Vacuum Technology (& FAQs)
Topic: Turbomolecular Pump Controller V2
Replies: 1
Views: 261

Turbomolecular Pump Controller V2

I would like to share the second version of my TMP controller. I would like to thank Jeroen Vriesman (also present on the forum) and Jerome for helping me in my design of the constant current source and for helping me understand the hall sensor. As I stated this new design uses a constant current so...
by Niels Geerits
Tue Dec 12, 2017 11:29 pm
Forum: New User Chat Area
Topic: X radiation exposition
Replies: 11
Views: 1377

Re: X radiation exposition

The current voltage and pressure combination you mentioned seems unlikely to me. See the following FAQ http://www.fusor.net/board/viewtopic.php?f=24&t=2795 At 1 Torr and 5mA you he only had about 400V across his fusor. Your voltage was probably also in the ~1kV range. As for a formula. You can come ...
by Niels Geerits
Wed Nov 15, 2017 4:17 pm
Forum: Please Introduce Yourself
Topic: Greetings!
Replies: 15
Views: 974

Re: Greetings!

Great that simplifies things! Didn't expect it would come with a controller at such a low price. The fact that your meter starts at 1000 Microns is good, probably goes down to something like 10 microns? If you hook it up to your pump correctly, you will probably get some reading, which will tell you...
by Niels Geerits
Wed Nov 15, 2017 2:39 pm
Forum: Please Introduce Yourself
Topic: Greetings!
Replies: 15
Views: 974

Re: Greetings!

Welcome Samuel, depending on your TC and pump you may or may not measure something. Some TCs will work in the 5 Torr (such as the DV-4), others only start giving you a useful reading below the 100 micron range. I don't know if a single stage pump can get down below 100 microns. In addition some TCs ...
by Niels Geerits
Sun Nov 12, 2017 6:35 pm
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: Criticize my HV supply design
Replies: 26
Views: 1862

Re: Criticize my HV supply design

Hi Silviu, Great post! I might be repeating what others have already said. I also built my own working HVPS using a half bridge, a ferrite toroid and a CW Multiplier (40kV. 10kV @ 50mA is the most I have used for now). Now I am going to change the Inverter to a push pull type circuit with a center t...
by Niels Geerits
Tue Oct 24, 2017 6:26 pm
Forum: Vacuum Technology (& FAQs)
Topic: Silicone tubing with hose barbs OK to pull low vacuum?
Replies: 27
Views: 1801

Re: Silicone tubing with hose barbs OK to pull low vacuum?

Shireesh, my pump is 1/4" flare. If you want to go to any other connection type you need a special adapter. I got a flare to 3/8" BSP adapter it comes with a piece of copper that you have to put in between the flare and the adapter to get a good seal. I had to contact the pump manufacturer to get th...
by Niels Geerits
Fri Oct 20, 2017 6:16 pm
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Criticize my neutron detection setup
Replies: 18
Views: 1492

Re: Criticize my neutron detection setup

I can say a few things about moderators. Moderators are used to turn fast neutrons into thermal (slow) neutrons. This means that you only want a moderator if you expect to have more fast neutrons than thermal neutrons, like in a fusor. For your source you can look at this report http://digitalschola...
by Niels Geerits
Mon Oct 16, 2017 10:39 pm
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: High Voltage Multiplier Issue
Replies: 29
Views: 2187

Re: High Voltage Multiplier Issue

One more thing. You could get get 200kV referenced to ground. To do this you would have to float the centertap and ground the bottom connection. If floating the centertap results in a floating case this is a terrible idea of course. The reason I mention this is because 200kV "floating" could generat...
by Niels Geerits
Mon Oct 16, 2017 8:39 pm
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: High Voltage Multiplier Issue
Replies: 29
Views: 2187

Re: High Voltage Multiplier Issue

Dennis, yep that is what I thought. The drawing where I left the lower terminal floating is different from your drawing where you ground both the center tap and the lower terminal however it does generate the same output. In that case your lower terminal is connected to ground via the VM. Your cente...
by Niels Geerits
Mon Oct 16, 2017 7:33 pm
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: High Voltage Multiplier Issue
Replies: 29
Views: 2187

Re: High Voltage Multiplier Issue

Dennis, if the grounds in NST2 are the same (e.g. earth ground), then it is what I said above. To me it does look like that is what you are doing. In that case you just shorted the lower half of the transformer together (lower winding and centertap @ same potential), so it is the same as just connec...