New High Vacuum Equipment
Posted: Fri Aug 11, 2017 11:29 pm
Just wanted to share some pictures of my newly acquired high vacuum equipment that I have recently obtained. As mentioned in a couple of prior posts, I will be working on constructing a rather large, multi-purpose high vacuum system to accommodate a wide range of experiments, ranging from fusor applications, to ion beams, electron beams, and general plasma physics.
My first piece of equipment is the center of my system design, consisting of a large custom welded stainless steel vacuum chamber I found off ebay. I had been scouring ebay for a few years looking for chambers, and I couldn't pass this beauty up. The chamber has an internal bore of 8" and a total height of 28". It has 21 conflat ports of the following sizes: (x2) 10", (x1) 8", (x2) 6", (x5) 4.5", (x9) 2.75", and (x2) 1.33" ports. Only $250 on ebay, and all the knife edges are in excellent condition, with only scratches on the bottom input port, and a little bit of rust here and there and some dust inside. It is on the heavy side, weighing in at 100lbs, so mounting and moving this thing is gonna be a real pain. Earlier this week I went in with a toothbrush and some baking soda and scrubbed out the minor rust spots, gave it several washes with mildly soapy water, a thorough wipe down with mineral spirits, and further washing and drying to remove any residue left, and have it currently sealed up with aluminum foil over the ports (the pictures below are prior to cleaning and sealing up). Since it will be quite a while before I start piecing it together and pulling vacuum, I will be placing a large bucket of desiccant inside the chamber with all the ports closed up to keep moisture down to a minimum while in storage. I will do a more rigorous cleaning as I install blanks and assemble the unit as I go.
The second piece of equipment is an Edwards EO4 600L/s diffusion pump. I ended up getting three for free - one (photo below) is in near brand new condition, barely used, and the other two are still hermetically sealed, never been used units.
The last piece of equipment just arrived today, and is another awesome ebay find. It is a combination pneumatic-actuated gate valve/butterfly valve combo with an additional side pumping port, which is perfect for what I am looking for, and solves a lot of issues and costs of finding and mating two separate units. The internal bore of the system is 6", which allows me to keep an extremely high throughput in the system to my main chamber (the diffusion pump has a diameter of about 5"), in addition to having high vacuum isolation and throttling control. The seller tested the pneumatic actuation and stated it worked without issue, but was being sold as-is since they could not perform high vacuum testing on it. Its original price was almost $300, but they accepted an offer for $100. Looking over the whole unit, it seems like it is in terrific condition. Looks very new with no scratches, scuffs, or rust. The butterfly valve turns smoothly, and the gate valve is very solid and at this point appears to fully seat. The only downside is that the system is very heavy as well, about 70lbs, which means the total weight of my system is going to be very heavy. But if it checks out and is vacuum tight it will be well worth it, especially for the bargain price I got it at.
This whole endeavor is going to be a very long term and continually evolving process. I have roughly broken down my workflow to several major phases, and am currently in the process of cadding out and designing to full Phase I system. My first objective is to build a mobile support cart from 8020 to house the major components, in addition to blanking off the entire chamber and mating all of the major parts to the chamber. I also plan on building and integrating a water-cooled baffle and an additional peltier-pumped cold trap. Once this is accomplished, I will begin to work on pumping down and conditioning the whole chamber, which will include extended pumping times, leak checking, partial baking with heat tapes around the chamber, and possibly simple plasma cleaning. I have been doing vacuum calculations to give estimates of outgassing rates, pump requirements, etc, as well to start preparing for this endeavor. My ultimate goal is to be able to reach a final pressure of around 10^-6 torr, which I believe should be achievable with the pump I have and following proper high vacuum handling and preparation, though I will be more than happy to reach 10^-5 torr in the beginning. After I establish a reasonable vacuum, I will begin to slowly add equipment to the chamber. At this point, I plan on adding 4 ion guns, one for each of the 45 degree ports at the top, a fusor grid, an electron beam source, a magnetron sputtering gun, ion/plasma engine for space propulsion testing, simple mass spectrometer, and a laser interferometer for plasma density diagnostics. I will be cadding these basic systems and adding them to my overall master model as I go. At this point since I have a limited budget each month, physical progress will be very slow, but I will be at least updating the design work and cad models and posting them as I go along to show the conceptual design of the system, as well as whatever electrostatic simulations I do for various parts, such as the ion guns.
My first piece of equipment is the center of my system design, consisting of a large custom welded stainless steel vacuum chamber I found off ebay. I had been scouring ebay for a few years looking for chambers, and I couldn't pass this beauty up. The chamber has an internal bore of 8" and a total height of 28". It has 21 conflat ports of the following sizes: (x2) 10", (x1) 8", (x2) 6", (x5) 4.5", (x9) 2.75", and (x2) 1.33" ports. Only $250 on ebay, and all the knife edges are in excellent condition, with only scratches on the bottom input port, and a little bit of rust here and there and some dust inside. It is on the heavy side, weighing in at 100lbs, so mounting and moving this thing is gonna be a real pain. Earlier this week I went in with a toothbrush and some baking soda and scrubbed out the minor rust spots, gave it several washes with mildly soapy water, a thorough wipe down with mineral spirits, and further washing and drying to remove any residue left, and have it currently sealed up with aluminum foil over the ports (the pictures below are prior to cleaning and sealing up). Since it will be quite a while before I start piecing it together and pulling vacuum, I will be placing a large bucket of desiccant inside the chamber with all the ports closed up to keep moisture down to a minimum while in storage. I will do a more rigorous cleaning as I install blanks and assemble the unit as I go.
The second piece of equipment is an Edwards EO4 600L/s diffusion pump. I ended up getting three for free - one (photo below) is in near brand new condition, barely used, and the other two are still hermetically sealed, never been used units.
The last piece of equipment just arrived today, and is another awesome ebay find. It is a combination pneumatic-actuated gate valve/butterfly valve combo with an additional side pumping port, which is perfect for what I am looking for, and solves a lot of issues and costs of finding and mating two separate units. The internal bore of the system is 6", which allows me to keep an extremely high throughput in the system to my main chamber (the diffusion pump has a diameter of about 5"), in addition to having high vacuum isolation and throttling control. The seller tested the pneumatic actuation and stated it worked without issue, but was being sold as-is since they could not perform high vacuum testing on it. Its original price was almost $300, but they accepted an offer for $100. Looking over the whole unit, it seems like it is in terrific condition. Looks very new with no scratches, scuffs, or rust. The butterfly valve turns smoothly, and the gate valve is very solid and at this point appears to fully seat. The only downside is that the system is very heavy as well, about 70lbs, which means the total weight of my system is going to be very heavy. But if it checks out and is vacuum tight it will be well worth it, especially for the bargain price I got it at.
This whole endeavor is going to be a very long term and continually evolving process. I have roughly broken down my workflow to several major phases, and am currently in the process of cadding out and designing to full Phase I system. My first objective is to build a mobile support cart from 8020 to house the major components, in addition to blanking off the entire chamber and mating all of the major parts to the chamber. I also plan on building and integrating a water-cooled baffle and an additional peltier-pumped cold trap. Once this is accomplished, I will begin to work on pumping down and conditioning the whole chamber, which will include extended pumping times, leak checking, partial baking with heat tapes around the chamber, and possibly simple plasma cleaning. I have been doing vacuum calculations to give estimates of outgassing rates, pump requirements, etc, as well to start preparing for this endeavor. My ultimate goal is to be able to reach a final pressure of around 10^-6 torr, which I believe should be achievable with the pump I have and following proper high vacuum handling and preparation, though I will be more than happy to reach 10^-5 torr in the beginning. After I establish a reasonable vacuum, I will begin to slowly add equipment to the chamber. At this point, I plan on adding 4 ion guns, one for each of the 45 degree ports at the top, a fusor grid, an electron beam source, a magnetron sputtering gun, ion/plasma engine for space propulsion testing, simple mass spectrometer, and a laser interferometer for plasma density diagnostics. I will be cadding these basic systems and adding them to my overall master model as I go. At this point since I have a limited budget each month, physical progress will be very slow, but I will be at least updating the design work and cad models and posting them as I go along to show the conceptual design of the system, as well as whatever electrostatic simulations I do for various parts, such as the ion guns.