PIG (Penning Ionization Gauge) Ion source

[sam2212]

Hi
I built pig ion source, the gas I'm using hydrogen gas to create negative ion . You can see ion source here:

My question is why in high vacuum more than 10×3 mmpa the plasma disappear even is if gas is supplied?
Thanks

 

[berkeman]

Welcome to PF.

Is there a reason you are using Hydrogen instead of the more common argon, neon, krypton, xenon?

https://www.gsi.de/en/work/beschleunigerbetrieb/beschleuniger/ionenquellen/sources/ion_sources

 

[sam2212]

Well... long story,but im building homemade linear particals accelerator! ,60% done.
The chamber ,the drift tubes, rf system....etc.
Stuck somewhere in the ion source. I built ion source with a filament :

and pig ion source. Testing which one is the best for my accelerator.

 

[berkeman]

Can you say a few things about safety considerations for your home accelerator? How are you handling the high voltage, high vacuum and x-ray issues? Also, what do you have in place to deal with the RF EMI issues?

 

[sam2212]

I'm aware of all these issues, the xrays are shielded
The high voltage are covered. I'm not an idiot

 

[berkeman]

I'm not an idiot

I don't mean to imply that you are an idiot. Most people who post here at PF asking for help on building their own particle accelerators do not have the experience to do it safely, and are a danger to themselves and their neighbors.

What is your experience with high voltage and high vacuum? Do you have experience with using those in a lab environment from your years at university? What is your experience with RF, and how are you complying with your local EMI laws to be sure you do not cause harmful interference with your neighbors? What RF frequencies and powers are you using in your setup?

 

[sam2212]

Dear berkeman
I'm an amateur in nuclear science. I built many things including fuser. I have multiple devices to measure radiation (gama, neutrons,xrays) im advanced amateur guy , I read a lot.
My vacuum setup is 2 stage vacuum pump with turbomolecular pump
High voltage Ac and dc do not exceed 30kv 10ma
My rf systems. I have 1400mhz 100w, and 70-100mhz 200w. With matching network. All in metal enclosure.
I'm protecting my self don't worry. Regarding EMI laws there is non.
And my lab is shielded with 50cm concentrate walls not wood or gypsum board.. so regarding my question?

 

[Vanadium 50]

First, why do you need such a high current source? For that matter, why do you need ions at all? Why not electrons?

Second, presumably your source involves hot cesium. Is that right? If so, doesn't that scare you? Which gets back to the original question - why do you need high current?

Third question - 1.4 GHz means a maximum cavity length of about 10 cm. Why do you want them so small. What gradient are you shooting for, and why does it need to be this large?

 

[sam2212]

First, why do you need such a high current source? For that matter, why do you need ions at all? Why not electrons?

Second, presumably your source involves hot cesium. Is that right? If so, doesn't that scare you? Which gets back to the original question - why do you need high current?

Third question - 1.4 GHz means a maximum cavity length of about 10 cm. Why do you want them so small. What gradient are you shooting for, and why does it need to be this large?

1- there is no high current: I'm using resistors
I'm telling what I have not using.
2- who said im using cesium?
3- i need to build compact accelerator the more compact it is the better.
Now back to my question?

 

[berkeman]

im building homemade linear particals accelerator!

3- i need to build compact accelerator the more compact it is the better.

You live in a small house?

Regarding EMI laws there is non.

Using my Mentor superpowers, I can see that your statement is false. Do you have any idea what emergency services use communication frequencies near your accelerator's RF frequency? Do you know what harmonics are present in your RF setup?

 

[sam2212]

Y

You live in a small house?


Using my Mentor superpowers, I can see that your statement is false. Do you have any idea what emergency services use communication frequencies near your accelerator's RF frequency? Do you know what harmonics are present in your RF setup?

I need it to be compact.
Again I told what I have not using.
I'm using my 70 to 100mhz , to be accurate 100mhz
The worse what I can do is spoil someone's radio podcast.
Now can you please use your super powers and answer my question

 

[berkeman]

The worse what I can do is spoil someone's radio podcast.

False. If you interfere with emergency services radio transmissions, you can be liable for interfering with the Fire Department, Police Department and Emergency Medical Services. Not good.

In addition to my EE work, I am an Amateur Radio operator (HAM), and we routinely are called by law enforcement to track down interference sources. You don't want me knocking on your door (well, my counterpart in your country knocking on your door).

Do you have an experienced Mentor in this project? Do you have access to a portable spectrum analyzer and antennas so you can ensure that you are complying with EMI limits so you don't interfere with emergency RF comms?

 

[Alex A]

There seems to be a clash of expectations here. Some of the descriptions are fairly pedestrian for vacuum experimenters and far outside the norm for proper science, so this may be something like a drift tube accelerator where the RF source generates the ions (not the accelerating potential), and the goal may be beam on target fusion at keV energies not atom smashing at MeV energies. This would fit with it being a hydrogen (deuterium) ion source.

These are still complex topics in regulation, law and safety and may not be a good fit for PF which has a much more academic and professional slant.

sam2212, you sound young and you are only digging yourself into a huge hole. Slow down, listen, accept what you are being told.

 

[sam2212]

No issues. I will go down to 13.56MHZ frequency and
I will prepare some snacks and tea. While your counterpart arrives , now where's the answer to my question .

 

[sam2212]

There seems to be a clash of expectations here. Some of the descriptions are fairly pedestrian for vacuum experimenters and far outside the norm for proper science, so this may be something like a drift tube accelerator where the RF source generates the ions (not the accelerating potential), and the goal may be beam on target fusion at keV energies not atom smashing at MeV energies. This would fit with it being a hydrogen (deuterium) ion source.

These are still complex topics in regulation, law and safety and may not be a good fit for PF which has a much more academic and professional slant.

sam2212, you sound young and you are only digging yourself into a huge hole. Slow down, listen, accept what you are being told.

Thanks for the reply. Now we start talking, let consider this beam on target. I asked a simple question why im having issue with plasma in high vacuum?

 

[Vanadium 50]

there is no high current: I'm using resistors

Beam current.

You want an intense beam - for no good reason. You want ions and not electrons. For no good reason. You want high accelerating gradients. For no good reason.

All of these things make the project harder, and all of them make the project more dangerous. I can tell that @berkeman is struggling to keep the thread open. You might want to give him fewer reasons to lock it.

 

[Vanadium 50]

I'm not an idiot

Convince us. Give us the design parameters of this machine - how many stages, what's the expected current, what's the expected gradient, what's the expected emittance, and so on.

I will go down to 13.56MHZ

You have given us three different operating frequencies, differing by 2 orders of magnitude. It is hard to believe you have any design at all - you're just jumping into construction. That is not smart.

 

[berkeman]

I can tell that @berkeman is struggling to keep the thread open.

IBTL?

 

[DaveE]

I can tell that @berkeman is struggling to keep the thread open.

Because he's nicer than us.
What is the good result that can come from all of this?

 

[berkeman]

It is hard to believe you have any design at all - you're just jumping into construction. That is not smart.

What is the good result that can come from all of this?

Good points. Thread is paused for Moderation...

 

[berkeman]

Thread will remain closed for safety reasons. @sam2212 -- Please find a local Mentor in your area who can try to help you do this project in a safe manner. Trying to get help with this potentially dangerous project from the Internet (with the potential to injure others and interfere with emergency communication services) is not a good idea.