Embedding Charge in an Insulator

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Discussion Overview

The discussion revolves around methods for embedding charge in insulators, particularly focusing on techniques that could be employed without access to high-energy particle accelerators. Participants explore various approaches, including the use of lower energy sources and alternative methods such as doping in semiconductors.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • One participant expresses interest in the dielectric breakdown artwork and seeks to understand the penetration depth of electrons in acrylic, noting that it depends on the density of the material and energy of the electrons.
  • Another participant suggests that doping techniques in semiconductors might provide insights, although they acknowledge the complexity of creating a semiconductor that can control conduction effectively.
  • Concerns are raised about the limitations of using lower energy sources, such as those from CRTs, which may require targets with very low densities and could lead to complications like multipactor effects.
  • A participant discusses various electron production methods, including thermionic and Schottky emission, but finds them inadequate for the desired energy levels.
  • There is mention of the challenges associated with using Van de Graaff generators, including their voltage limitations and potential complications in achieving the necessary conditions for charge embedding.
  • One participant warns against the use of radioactive sources, suggesting that they may attract unwanted attention from authorities, while another counters that sealed sources can be legally obtained for educational purposes.
  • A historical reference is made to Lichtenberg's methods for producing similar effects, indicating a long-standing interest in the topic.

Areas of Agreement / Disagreement

Participants express a range of ideas and concerns, with no clear consensus on the best approach to embedding charge in insulators. Various methods are proposed, but significant uncertainty and disagreement about their feasibility and effectiveness remain.

Contextual Notes

Participants note that the behavior of charge embedding may not be linear with energy, and assumptions about the applicability of certain techniques at lower energies are questioned. The discussion highlights the complexity of the topic and the need for careful consideration of material properties and experimental conditions.

nlantz
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I have been really fascinated with the dielectric breakdown artwork by Bert Hickman seen here.

He is using a 5MeV accelerator to embed electrons in acrylic. He then discharges them to create beautiful fractal patterns. I emailed him last year asking how to calculate the penetration depth of the electrons and he responded that it was depended on the density of the acrylic and the energy of the electrons.
A more specific explanation can be found http://www.med.harvard.edu/jpnm/physics/nmltd/radprin/sect7/7.2/7_2.2.html.

I am trying to find a way to do this (safely) without renting out a particle accelerator. This is a hobby after all. In order to do this with a CRT for example (~25KeV) I would need a target that has an impossibly low density. About 0.5% the density of acrylic, Even so, this assumes the behavior is linear, and valid, for such low energies. A large assumption indeed.

Has anyone come across a novel way to embed charge densities in an insulator? It could be any charge, It doesn't have to be electrons. It could also be very gradual. Hours or days is OK.
 
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alw34 said:
This may be a wild shot in the dark: Would doping techniques in semiconductors offer any insights?

I have given this some thought also. If you could make a semiconductor that you could turn on and off the conduction, you could conduct electrons in and then force them to breakdown to get out. It would also need a very low dialectics strength.

I don't think i could build this without a really good materials lab... and 10 years of my life haha
 
alw34 said:
I did a quick google search...check out a load of illustrations here...maybe you'll get an idea...
https://www.google.com/search?q=cha...hUKEwjLsZ3r5IPKAhXL5SYKHYA1BqYQsAQIRw&dpr=0.9

hope that helps.

This may be a wild shot in the dark: Would doping techniques in semiconductors offer any insights?

Unfortunately, doing a search on "charge density in an insulator" will give you the WRONG concept back, because in condensed matter physics, there is a large topic on "charge density wave". So if you pay attention to the search results, you'll see that a lot of what you got back is related in some way to this topic. This is irrelevant to what is being asked.

Zz.
 
There are several "issues" here if one isn't knowledgeable enough in this area:

1. Doping a semiconductor will not work. What happens when you shoot charges at an insulator is that you are causing charging effects. This means that these charges are embedded into the insulator but doesn't change its structure and composition. The insulator becomes charged. Doping a semiconductor does NOT charge the semiconductor. It remains "neutral" overall. All you are you doing is shifting charge carrier from the dopant to the insulator's band.

2. The original experiment used electrons in the MeV range. If you use a lower energy, such in the keV range, you might easily run into the multipactor/secondary emission range for the insulator. This creates a whole set of problems that you would not anticipate.

Zz.
 
nlantz said:
I am trying to find a way to do this (safely) without renting out a particle accelerator. This is a hobby after all. In order to do this with a CRT for example (~25KeV) I would need a target that has an impossibly low density. About 0.5% the density of acrylic, Even so, this assumes the behavior is linear, and valid, for such low energies. A large assumption indeed.
Range is not linear with energy, it grows (and goes down) much faster than linear in this energy range.

A beta source can give electrons with MeV energies, but I don't know if the intensity of reasonable sources is sufficient.
 
nlantz said:
In order to do this with a CRT for example (~25KeV) I would need a target that has an impossibly low density.

good, I see you got some posts while I was poking around for any ideas. Take these comments lightly unless they give you a new idea...alas, I'm going to subject myself to ridicule here, I fear!

I checked out thermionic emission and found Shotkky emission here and some other forms of electron production...seem to be too low a voltage...I did not check the links to other emissions...

https://en.wikipedia.org/wiki/Thermionic_emission#Schottky_emission

[[Could a radar transmitter or microwave magnetron be modified...seems like a dead end...microwaves not electrons...]

I also checked van der graff generators...always liked them...

"A tabletop version can produce on the order of 100,000 volts and can store enough energy to produce a visible spark." still too low.

https://en.wikipedia.org/wiki/Van_de_Graaff_generator

but reading a bit further in the article...'tandem'...

"...For example, the Brookhaven National Laboratory Tandem Van de Graaff achieves about 30 million volts of potential difference.

The voltage produced by an open-air Van de Graaff machine is limited by arcing and corona discharge to about 5 megavolts. Most modern industrial machines are enclosed in a pressurized tank of insulating gas; these can achieve potentials up to about 25 megavolts..."

I fear too complicated, and too expensive, but should be easier to get access to than a real particle accelerator!
good luck.

PS: beware 'beta sources' or other radioactive sources...
Homeland security will be all "up in your business"...no joke.
 
alw34 said:
good, I see you got some posts while I was poking around for any ideas. Take these comments lightly unless they give you a new idea...alas, I'm going to subject myself to ridicule here, I fear!

I checked out thermionic emission and found Shotkky emission here and some other forms of electron production...seem to be too low a voltage...I did not check the links to other emissions...

https://en.wikipedia.org/wiki/Thermionic_emission#Schottky_emission

[[Could a radar transmitter or microwave magnetron be modified...seems like a dead end...microwaves not electrons...]

I also checked van der graff generators...always liked them...

"A tabletop version can produce on the order of 100,000 volts and can store enough energy to produce a visible spark." still too low.

https://en.wikipedia.org/wiki/Van_de_Graaff_generator

but reading a bit further in the article...'tandem'...

"...For example, the Brookhaven National Laboratory Tandem Van de Graaff achieves about 30 million volts of potential difference.

The voltage produced by an open-air Van de Graaff machine is limited by arcing and corona discharge to about 5 megavolts. Most modern industrial machines are enclosed in a pressurized tank of insulating gas; these can achieve potentials up to about 25 megavolts..."

I fear too complicated, and too expensive, but should be easier to get access to than a real particle accelerator!
good luck.

PS: beware 'beta sources' or other radioactive sources...
Homeland security will be all "up in your business"...no joke.

I'm sure you're trying to be helpful, but you are really muddying up the waters here because you yourself have no clue on what you are bringing up. Just because you know how to do a google search, it doesn't mean that you should do a core dump on here to see if something will stick.

And what's with the caution about beta sources and radioactive sources? You can buy SEALED sources for classroom demo, etc. without causing Homeland Security to knock on your door!

http://www.flinnsci.com/store/Scripts/prodView.asp?idproduct=17227

Zz.