IECF Mark Ⅱ

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Finn Hammer
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Re: IECF Mark Ⅱ

Post by Finn Hammer »

Sophie,

Welcome here, you are a striking example of the new world order.
In a world where many high tech products are produced in China, it should not come as any great surprise, that there is also a lot of surplus equipment available on the market.

Now to your fine fusion system.

Could you please tell how you manage to have a pressure suitable for fusion in a chamber that connects directly to the turbo pump?
It is my own experience that the turbo has to be sealed off from the chamber by a valve that is almost totally closed, in order to attain this pressure, in my case 20-35 microns, corresponding to 2.5-4.5 Pascal .
How do you do it? Slow down the turbo, or just pour deuterium liberally?


Cheers, Finn Hammer
Last edited by Finn Hammer on Fri Mar 11, 2022 5:35 am, edited 1 time in total.
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Sophie Yang
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Re: IECF Mark Ⅱ

Post by Sophie Yang »

Finn
My fusor works under the pressure of 5e-3Torr / 6.7e-3mbar / 6.7e-1pa.
A vacuum system that does not use a flapper valve between the turbo pump and the chamber is called a dynamic vacuum system. The pump speed and gas load will jointly determine the ultimate pressure you reach. Then for a large pumping speed system, a large flow of deuterium gas can stabilize the system pressure at fusor working pressure.All this can be done by Sapphire leak valve.
Sophie
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Dennis P Brown
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Re: IECF Mark Ⅱ

Post by Dennis P Brown »

First, I like your use of units - very useful. :)

Could you show a picture or diagram of that sapphire leak valve system? I'm curious how that is used - wouldn't there be issues pumping the entire system down through the leak valve or is it adjustable?
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Richard Hull
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Re: IECF Mark Ⅱ

Post by Richard Hull »

I have used a sapphire leak for 2 years on fusor V. I have posted images of it when I bought it in 2019 at the HEAS flea market for $50. These just special sapphire wedge plates that allow micro control of gas let into a system. New they are about S1200. Used, they typically can be had from Duniway for about $900. They are fully adjustable and are the ideal way to let in gas to a vacuum system. I run about 2 psi into the device and can easily get +/- 0.1 micron resolution in gas flow. They are simple gas in, gas out valves with a typical knob adjustment.

As most of you know, I used a thimble needle valve for years, but once I had this type leak in hand, I jumped on it.

I have acquired a second one of these valves at 2020 years HEAS flea market! It is currently in use on fusor IV. I swapped the original out as this latest purchase uses 1.33 CF fittings.

In use it is closed. I vacuum out the system. I throttle back the vacuum to where the baratron just tries to rise in pressure. I now open the leak to adjust the differentially pumped system to admit deuterium to my desired micron operational level.

Richard Hull
Attachments
Fusor V with second leak being swapped into the gas system.
Fusor V with second leak being swapped into the gas system.
I picked up this entire assembly for $40 in 2020 the sapphire leak here is in current use on fusor V
I picked up this entire assembly for $40 in 2020 the sapphire leak here is in current use on fusor V
Original $50 2019 HEAS flea market purchase
Original $50 2019 HEAS flea market purchase
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Liam David
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Re: IECF Mark Ⅱ

Post by Liam David »

Sophie, I don't know if you noticed since there wasn't an announcement (c'mon guys), but your name's been added to the neutron club, and in the "elite" category for your activation work. Congrats! I think you're our first fusioneer from China! Great work!

viewtopic.php?p=13#p13

You might already know, but I think your RGA is out of calibration. The partial pressures are too low for the total pressure measured by the PKR 251 gauge, and in one of your pictures, the D2 m/z = 4 peak is very low relative to the others. The peaks are in the right places (though I'm not sure what the peak at m/z = 7 is, perhaps N++). Speaking from personal experience and stated in some manuals, RGAs can drift over time and especially if they sit in atmosphere. My second-hand RGA was some 2-3 orders of magnitude off. Cleaning the oxidation and thin films off the ionizer should help, although there's probably some software calibration method.
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Richard Hull
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Re: IECF Mark Ⅱ

Post by Richard Hull »

I have created a clarification post in the fusioneer forum within the admin forum. This relates to why I placed Sophie in the Elite fusioneers.

viewtopic.php?t=14413

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Joe Gayo
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Re: IECF Mark Ⅱ

Post by Joe Gayo »

Richard,

I don't think an explanation was necessary. Sophie has demonstrated that her direct efforts yielded a professional setup and neutron activation.

Sophie,

Congratulations on earning elite fusor status! I sincerely hope you continue to improve your setup and report on your results here. I think Liam's advice and feedback are worth investigating.

Regards,

Joe
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Sophie Yang
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Re: IECF Mark Ⅱ

Post by Sophie Yang »

Dennis P Brown wrote: Fri Mar 11, 2022 3:38 pm First, I like your use of units - very useful. :)

Could you show a picture or diagram of that sapphire leak valve system? I'm curious how that is used - wouldn't there be issues pumping the entire system down through the leak valve or is it adjustable?
Dennis
The variable leak valve includes a movable piston with an optically-flat sapphire that meets a captured OFHC gasket. This forms a seal completely free from friction, seizing, and shear. The sapphire’s movement is controlled through a threaded shaft-and-lever mechanism having a mechanical advantage of 13,000 to 1.
This allows the sapphire leak valve adjust the leak rate accurately from 1e-10Torrl/s to the maximum flow 6l/m. means that the pressure can be adjusted from -11Torr to atmospheric pressure.
Sophie
Agilent Model 951-5106 Variable Leak Valve
Agilent Model 951-5106 Variable Leak Valve
Sealing principle diagram
Sealing principle diagram
OFHC Gasket assembly
OFHC Gasket assembly
Sapphire assembly
Sapphire assembly
Specifications
Specifications
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Sophie Yang
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Re: IECF Mark Ⅱ

Post by Sophie Yang »

Liam David wrote: Fri Mar 11, 2022 5:18 pm Sophie, I don't know if you noticed since there wasn't an announcement (c'mon guys), but your name's been added to the neutron club, and in the "elite" category for your activation work. Congrats! I think you're our first fusioneer from China! Great work!

viewtopic.php?p=13#p13

You might already know, but I think your RGA is out of calibration. The partial pressures are too low for the total pressure measured by the PKR 251 gauge, and in one of your pictures, the D2 m/z = 4 peak is very low relative to the others. The peaks are in the right places (though I'm not sure what the peak at m/z = 7 is, perhaps N++). Speaking from personal experience and stated in some manuals, RGAs can drift over time and especially if they sit in atmosphere. My second-hand RGA was some 2-3 orders of magnitude off. Cleaning the oxidation and thin films off the ionizer should help, although there's probably some software calibration method.
Liam

Thank you for your notice and congratulations. I'm glad I can enter the neutron club.

It would be appreciate of your advice,however the intensity of pressure is just an unexpected misunderstanding.Cause that coordinate units are different in those pics,total pressure unit is mbar and mass spectrum unit as amps.According to datasheet,the QMS200 has an sensitivity 1E-3A/mbar for argon.

Sophie
Matt_Gibson
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Re: IECF Mark Ⅱ

Post by Matt_Gibson »

Congratulations Sophie! Nice to see another added to the list! I look forward to seeing what all you accomplish and are able to do.

-Matt
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Dennis P Brown
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Re: IECF Mark Ⅱ

Post by Dennis P Brown »

Thanks for the information on that valve - I'm not familiar with that type till now - I'd think that level of valve is best for ultra-high vacuum systems but one uses what one can get. Again, impressive. Fusion research I'd think is in your future. I know China is looking into many areas of nuclear fusion. My bet is that the current German Stellarator is the best magnetic approch.
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