A Thought Experiment on Ideal Conditions
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- Posts: 23
- Joined: Sat Nov 10, 2018 12:24 am
- Real name: Storm Antonio Chiune Silvawalker
Re: A Thought Experiment on Ideal Conditions
My apologies I completely misread the pressure of the tubes I was using, the mean free path with the pressure I hae is too short. My chamber can definitely work for the pressure but there is no way I'm going to be able to get there with this pump. I need to find an oil diffusion pump in the next 2 weeks which is a more difficult challenge than the actual experiment but I will find a way.
- Dennis P Brown
- Posts: 3190
- Joined: Sun May 20, 2012 10:46 am
- Real name: Dennis Brown
Re: A Thought Experiment on Ideal Conditions
Now that you are starting to understand the issues facing your experiment, I would caution you about high vacuum work: it is a very difficult techonolgy to master without proper equipment. Certainly a good vacuum system is required - hence you need to select connector types - either kf connectors (ok down to 10^-6 torr) or conflat (copper gaskets; essential for better than 10^-6 torr).) Building a quality vacuum system is essential for both achieving a leak tight system and one that can be more easily leak tested - which for high vacuum is an essential skill. This means finding good deals on e-bay or paying big $$$ on new.
A diffusion pump (DP) without a cold trap means you will be restricted to 10^-5 torr range - period; also, a dirty system. If you need 10^-6 torr or better, then a cold trap is essential (as well as a super clean and leak proof system.) Further, the vast majority of DP's available require water cooling; so that means plumbing of water lines. Air cool exist but are hard to find and need special adapters (usually must be custom made - this is true for many water cooled DP's, too. So that is a consideration in selecting units.) For these reasons (and others), most people use turbo's for high vacuum work.
Again, glad you are both experimenting and following your ideas. Good luck and do ask about specifics on DP's before buying one so you get both the right DP for your needs and a proper price. If you are going low cost, learning to use a lathe/drill press/mill are essential skills (and for undergrad physics students this use to be part of our suggested lab training - so maybe your future school will allow you access.)
A diffusion pump (DP) without a cold trap means you will be restricted to 10^-5 torr range - period; also, a dirty system. If you need 10^-6 torr or better, then a cold trap is essential (as well as a super clean and leak proof system.) Further, the vast majority of DP's available require water cooling; so that means plumbing of water lines. Air cool exist but are hard to find and need special adapters (usually must be custom made - this is true for many water cooled DP's, too. So that is a consideration in selecting units.) For these reasons (and others), most people use turbo's for high vacuum work.
Again, glad you are both experimenting and following your ideas. Good luck and do ask about specifics on DP's before buying one so you get both the right DP for your needs and a proper price. If you are going low cost, learning to use a lathe/drill press/mill are essential skills (and for undergrad physics students this use to be part of our suggested lab training - so maybe your future school will allow you access.)
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- Posts: 23
- Joined: Sat Nov 10, 2018 12:24 am
- Real name: Storm Antonio Chiune Silvawalker
Re: A Thought Experiment on Ideal Conditions
I am using all KF 50 pieces and have the system baked for 2 hours at 200°C, should be good for the diffusion pump setup. I have experience working with precise metal fabrication, I learned making art pieces and turbojet when I was younger and have a full shop to work with. I'm employed, with no tuition, and in my second year in aerospace engineering, so I have all the resources I need to pursue this the only resource I don't have at the moment is time. My deuterium gets here on the 19th so I'm moving heaven and earth to get a working diffusion pump and test the electrical before then. I am aiming for 10^-6 torr with this new setup but the next one, likely next year, will need to use a custom housing and cathode ray tube setup with as few openings as possible. This summer I'm rushed but this is definitely a long term project.