Flux of high charge positive ions, how?

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Discussion Overview

The discussion revolves around the generation of high charge positive ions, specifically focusing on penta-valent ions (5+ or higher). Participants explore methods for producing such ions, including the use of heavy ion accelerators and stripper foils, while addressing technical details and challenges involved in the process.

Discussion Character

  • Technical explanation
  • Exploratory
  • Debate/contested

Main Points Raised

  • One participant inquires about generating a flux of penta-valent ions, noting the availability of proton flux sources but expressing a need for higher charge ions.
  • Another participant suggests that heavy ion accelerators can produce such ions by ionizing them once, accelerating them, and then using thin stripper foils to remove additional electrons.
  • A later reply discusses the historical context of "canal rays" and questions the properties of the stripper foil, including whether it has holes or slits and its charge state.
  • Another participant clarifies that the foil does not need to be positively charged and explains the mechanism by which nuclei pass through without significant scattering, referencing the Rutherford experiment.
  • Further elaboration is provided on the process of fully ionizing large atoms like lead, detailing the multi-step ionization and acceleration process used in the LHC.

Areas of Agreement / Disagreement

Participants present multiple viewpoints regarding the properties and functioning of stripper foils, with some agreeing on the general process of ionization and acceleration while others raise questions and challenges about specific details. The discussion remains unresolved on certain technical aspects.

Contextual Notes

There are limitations in the discussion regarding assumptions about the vacuum conditions required for the process and the specific characteristics of the stripper foils used in ion acceleration.

Amy
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I need a flux of highly positive ions, at least penta-valent ions (5+ or more, 6+, 7+, ...);
there are ion sources that can generate a proton flux, but I need 5+ ions;
do you know how I can do that?
 
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Heavy ion accelerators routinely do that, did you check how?

Typically they ionize the ions once, accelerate them, then let them fly through thin stripper foils to remove more electrons.
 
mfb said:
Typically they ionize the ions once, accelerate them, then let them fly through thin stripper foils to remove more electrons.

cool ... learn something new every day :smile:

after a little reading, this seems to be where the early term canal rays was coined.
tho I couldn't seem to find anything much with good details of the foil makeup and charge

I'm assuming the foil you are talking about has holes/slits in it ?
It would have to be positively charged so it could strip the electrons from the +ions ?
if so, does that last one pose problems with the interaction of + ions coming close to a + charged foil grating ?Dave
 
davenn said:
I'm assuming the foil you are talking about has holes/slits in it ?
Holes would be places where the ionization doesn't work. Holes would also mean you need the same vacuum conditions on both sides, which is often not wanted.

The foil does not need a positive charge. The approach works based on the huge size difference between electron orbitals and the nucleus. Many nuclei pass through without large scattering (->Rutherford experiment), most electrons do not.

Fully ionizing large atoms like lead for the LHC is done in multiple steps. The source provides Pb27+ (55 electrons left), this is accelerated to 4 MeV per nucleon and shot through a stripper foil. While many charge states are produced, the most likely one is Pb54+ (28 electrons left). This is accelerated to 6 GeV per nucleon and shot through another stripper foil, removing the remaining electrons.
 
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mfb said:
Holes would be places where the ionization doesn't work. Holes would also mean you need the same vacuum conditions on both sides, which is often not wanted.

The foil does not need a positive charge. The approach works based on the huge size difference between electron orbitals and the nucleus. Many nuclei pass through without large scattering (->Rutherford experiment), most electrons do not.

Fully ionizing large atoms like lead for the LHC is done in multiple steps. The source provides Pb27+ (55 electrons left), this is accelerated to 4 MeV per nucleon and shot through a stripper foil. While many charge states are produced, the most likely one is Pb54+ (28 electrons left). This is accelerated to 6 GeV per nucleon and shot through another stripper foil, removing the remaining electrons.
Thanks for that
 

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