Search found 1469 matches

by Dennis P Brown
Thu Jul 19, 2018 9:50 pm
Forum: Please Introduce Yourself
Topic: Hello from the Bay Area in California
Replies: 2
Views: 70

Re: Hello from the Bay Area in California

Glad you are pursuing a physics degree but generally, unless you are not sure of an area to study, a master's degree is not useful (it carries no significant value as a terminal degree); mostly it just delays your real degree. Mr. Ferrari is correct - diffusion pumps are very easy to repair since th...
by Dennis P Brown
Mon Jul 16, 2018 5:25 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: Couple of questions
Replies: 21
Views: 1361

Re: Couple of questions

Spell check is your friend; best to avoid posting via cell phones.
by Dennis P Brown
Mon Jul 16, 2018 2:34 pm
Forum: New User Chat Area
Topic: Working Diffusion Pump?
Replies: 7
Views: 300

Re: Working Diffusion Pump?

Putting oil into a diffusion pump (DP) is trivial for most units - one simply pours the REQUIRED amount of DP oil through the main opening (the DP throat. Don't over fill and you need to find out the exact amount for that specific pump.) Also, you may need to clean the inside of the DP first. Aceton...
by Dennis P Brown
Mon Jul 16, 2018 12:14 pm
Forum: New User Chat Area
Topic: Working Diffusion Pump?
Replies: 7
Views: 300

Re: Working Diffusion Pump?

I do not know the policy for groups here (there are, of course) so if that has not already been done, then it should be completed. Richard can address that issue if you don't know what to do. That is one old diffusion pump. As for your questions I can only give guesses since I am not familiar with t...
by Dennis P Brown
Thu Jul 12, 2018 3:23 am
Forum: Please Introduce Yourself
Topic: Bonjour from Montreal
Replies: 1
Views: 132

Re: Bonjour from Montreal

Best of luck; finding good deals is a bit of an art but well worth one's time! Do update as you get items and decide on a build direction.
by Dennis P Brown
Thu Jul 12, 2018 3:14 am
Forum: Images du Jour
Topic: Fusor progress, Antoine Fleitz
Replies: 1
Views: 294

Re: Fusor progress, Antoine Fleitz

Very nice setup and your approach is logical - you are correct that the vacuum system is the most versatile - one can do metal coatings or sputtering with these systems. Getting a proper electrical supply can be involved but far easier than the neutron detection system (of course, one can buy a turn...
by Dennis P Brown
Sat Jul 07, 2018 4:53 pm
Forum: Books & References
Topic: Answer keys w/ explanation?
Replies: 19
Views: 803

Re: Answer keys w/ explanation?

A hint: consider a single layer of atoms (each atom is about 2.7 angstrom in diameter as you calculated) and view these as circular disks. You know that a nucleus is 10-4 the size of this atom so the nuclear disk size is what? To get 1% coverage, one needs 1% of the total area desired (assume 1 cm2)...
by Dennis P Brown
Sat Jul 07, 2018 4:15 pm
Forum: Fusion --- Past, Present, and Future
Topic: First IAEA Workshop on Fusion Enterprises
Replies: 2
Views: 366

Re: First IAEA Workshop on Fusion Enterprises

The issue with stellarators in the past was the magnet manufacturing technology - it was far too primitive when the idea first was conceived. Thanks to very, very powerful computers to do the extremely complex optimization calculations and amazing computer controlled winding/milling devices built ov...
by Dennis P Brown
Thu Jul 05, 2018 6:26 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: Ballast resistor construction
Replies: 11
Views: 853

Re: Ballast resistor construction

Glad the power load isn't too high. A word of caution: the difference between 20 kV and 30 kV can be significant relative to corona's and how the system behave's. When one gets over 20 kV, especially in fairly dry air, the arc over's can be unusual and even somewhat inconsistent.
by Dennis P Brown
Sun Jul 01, 2018 12:31 pm
Forum: Vacuum Technology (& FAQs)
Topic: Back-Streaming Diffusion Oil
Replies: 10
Views: 650

Re: Back-Streaming Diffusion Oil

I agree with Rich - something is wrong; either the operation, the set up or the pump. To start isolating the problem, first off, do the test I suggested and determine if the roughing pump is even operating properly - certainly you should get below 70 microns. Getting just 70 microns with no load is ...