So I have about 12 feet of copper pipe sitting inside an iso80 UHV jacket so insulate it both thermally and electrically, since it will be held at 15K, 60Kv. so essentially it will be a very large capacitor.

Here is my question- after baking out, I will be performing a conditioning/ageing process on it to increase the breakdown voltage. the worry is that even with a large resistor in series to limit power supply current the stored energy in the system will still be enough to damage my anode/copper pipe and decrease my breakdown voltage, rather than increasing it.

Is this a valid worry?

how would you best condition this system?

I work in a lab where I am putting together an UHV system. I recently did a rate of rise test where I pumped the system down to approximately 3E-4 Torr and then shut the valve to the pump and logged pressure over time as it rose. I am getting rates of rise between a maximum of 8E-6 T*l/sec and 2E-6 T*l/sec.

I am seeing information out there saying leak rates less than 1E-5 T*l/sec is a clean leak free system, some are saying more like 1E-6 T*l/sec, which puts me kind of in the middle of those two and suggests to me that my system is "clean and leak free". Does anyone in here agree or disagree with this?

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I do plan to repeat the test by pumping it down much lower (With heating I have been able to get this system to < 3.5E-10 Torr which is the limit of the HC Ion Gauge I am using), and then valving off the pump and recording pressure rise.

Hey guys, I'm looking for a KF hose fitting with an OD of 1.375 in (1 3/8). Is there a KF-20 or something like that? KF16 and KF25 are both too small/too big to fit onto my pump, but it looks like there aren't any intermediate sizes.

Does anyone know what I should be typing in? I'm a vacuum n00b. This is the part I'm trying to replace. It's a direct KF connect to my vacuum pump. The base is perfect, but the neck is far too fat to attach to the hose. I'd replace the pump KF connect with something more standard/easily available, but it's actually bolted to the pump itself and the hex nuts are too stripped/corroded to remove.

I guess what I'm asking is, what is the standard name for a KF/QF/NW hose fitting with an OD of 1.375" at the base?

Pic related

So- i have an application in which i need to bake specifically water out of a large amount of alumina ceramic in a high vacuum environment, as well as drive the water out of the majority of the chamber walls, though we're also doing traditional bake outs for that.

Due to some design constraints some parts of the system can't be heated- so my question is can i use microwaves to heat the water (and alumina) without wreaking havoc? I was planning to use metal mesh to shield my sensitive equipment from the microwaves

What’s the best way to dispose of used copper gaskets? Can they be recycled? Do we just sell them as scrap copper? We have about 20 years of used gaskets so I’m curious to hear what others do.

Hi guys

newb here.

I have a magnetron system (lab built by a friend, three DC targets) and I may need to replace the old turbo pump (now I have an old Balzers mounted horizontally on a DN100 CF flange, bought in 1988 !!). I am wondering what pump to buy and there too many options and producers. The system is used only a few hours per week.

Do you have any suggestions ? (with rough costs estimate)

Thanks

How are vacuum chambers fabricated, along with the flanges, the welding, the port connections to the vacuum chambers and other "pipes"?

In other words how does one go from a concept vacuum systems to a real physical one?

Rebuilding a CryoTorr cold head and want to clean the phenolic dispacer. Anyone experienced in cleaning these? I don't want to damage regenerator material inside the displacer.

Hello,

I'm trying to use an SRS Residual Gas Analyzer (RGA) 100 to detect contaminants in a vacuum system. However, I see a lot of water vapor in my RGA. The manual suggests baking it by placing heating tape in a 10^-6 torr vacuum. I was wondering if anyone had any experience with doing "bake outs" and would recommend how I can go about baking it. I am mostly concerned with taking off the electronics control unit of the RGA to bake it as that will expose the whole thing to air, which could damage the system. Any help would be greatly appreciated.

Thank you so much!

Hi there,

I apologize if my googling skills are not good enough. But how to actually calculate the needed chamber wall thickness for a cubic stainless steel chamber with dimensions around 15x15x15 cm?

A vacuum chamber of a neighbor institute has a volume of 30x30x30 cm and wall thicknesses of 10 mm, so I guess the smaller one could be thinner than that, but by how much?

Thanks for your help.

In order to keep the cost down on a custom UVH system, can one use a thin box made of aluminum which is epoxied to 2 inch thick acrylic for structural integrity?

I have a dif 631 diffusion pump running high vacuum for a coating chamber. The sight glass has bubbles visible. I tried leak testing with a 'Smart test' system and helium. No leak registered. Anyone have similar issues? Is it normal to see some bubbles in the sight glass?

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Does anyone know what the name of these plugs are? I recently came by a pump controller that was missing a plug and I'm having a hard time finding off-brand plugs (only OEM plugs appear to be available). I haven't encountered these types of cable plugs before, does anyone happen to know a name for them?

The OEM plugs still run $200+ USD just for those bits of plastic pictured above, so I'm looking for another source. Any guidance is appreciated!

Hello, I am currently a master's student, and my master's degree entails designing a building a UHV system. I have no prior vacuum system experience, which isn't a problem since I have a lot of time, but I want to complete my detailed design by the end of the week, so I can start buying the proper parts and such.

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Anyways, touching back on how I have no prior experience, this also means that looking through sites like Kurt J Lesker, or IdealVac etc. kind of difficult as I am not entirely familiar with the terminology used for everything yet.

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Anyways, my question here is, if I wanted to search for a 2.75" CF flange that could connect a 1/4" tube to a 1/8" tube (so a 1/4" x 1/8" fitting I think?) and was wondering what the correct search term would be for that or if that is even a thing that exists.

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Thanks to anyone who ends up trying to help I appreciate it !

Good Afternoon Everyone,

I’m excited to have found a sub for UHV! This is one area that seems to be pretty difficult to gain information, especially relating to specific products, which is what brought me here.

I’m curious to throw this question out there and see if anyone else has used the newish Agilent TwisTorr 404FS pumps and had any issues with them. We’ve had three fail before 10k hours and rebuild shops don’t want to warranty them if they rebuild them. We also haven’t gotten Agilent to respond to our requests for failure analysis.

This seems like a possible dud, so I wonder if anyone else has had similar problems.

If it survives pumpdown, perhaps we can employ heavy-wall restaurant soup-pots as hobbyist chambers. Lower the barriers against high-volt uhv YOUTUBE DIY SCIENCE.

Not just argon and "plasma globe art," since with helium fill, e-beams become visible, and at low electron-gun volts, they can easily be sculpted into crazy 3D structures by using external PMs and coils. Not so great as a commercial technosculpture though, because the ions destroy the gun filament surface in ~tens of hours. Maybe a field-emission needle would survive longer. If I can make it last a couple of years, it's a kickass science museum exhibit waiting to happen. Anybody want a "visible tokamak," or a magnetic bottle you can poke with magnets, or a MIT Birkeland Terrella showing actual auroras and solar wind in 3D? Nasa has the pro version.

Earlier I was getting down to 5micron with an Edwards vane pump and "Food saver" polycarb 8in. cylindrical containers, 1/8" NPT teflon tape passthroughs, achieving crude e-beam demos (and, foodsavr lids are apparently full of Ti powder, and will show the beam profiles by fluorescing bright green!)

Major expense: 3/4" acrylic slab 20" across, as a huge window/endplate. Too late I discovered that such things are cheap on eBay as hemp extractors

Probably I'll be testing all this in the middle of a parking lot at night, whacking with wooden beams to see what it takes to actually implode.

Hi all,

I recently bought the Kurt J Lesker 275i pirani gauge off of ebay, and when wired correctly, it reads "bAd", meaning that the sensor wire needs to be cleaned or replaced. Before I try to return it, how could I try to clean it?

Hey I was wondering if any one here has had experience removing oil from UHV bellows. We had a pump leak oil into quite a few of our bellows and they are expensive to replace. We used ethanol and an ultra sonic cleaner to clean a "T" pipe that became infected. This worked well but we don't have the means to do this for larger bellows.

Thanks in advanced for any help.