Are CRTs Suitable for Use in Ion Thrusters?

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SUMMARY

This discussion centers on the suitability of cathode ray tube (CRT) electron guns for use in DIY ion thrusters. Participants clarify that electron guns are not appropriate for ion propulsion due to the mass difference between ions and electrons. Instead, they recommend exploring alternatives such as arc thrusters and simulating ion engines using infrared (IR) sources or radiometers. The conversation emphasizes the importance of safety and supervision when working with high voltages in such projects.

PREREQUISITES
  • Understanding of ion propulsion principles
  • Familiarity with high voltage safety protocols
  • Knowledge of infrared (IR) technology
  • Basic concepts of radiometers and their operation
NEXT STEPS
  • Research DIY arc thrusters and their construction
  • Learn about Crookes radiometers and their functionality
  • Investigate the use of infrared sources for simulating thrust
  • Contact MIT professor Steven Barrett for insights on ion thruster projects
USEFUL FOR

Students, hobbyists, and educators interested in experimental physics, particularly those exploring ion propulsion and related technologies in a safe and supervised environment.

RamSkull
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Hello!

I'm trying to make a simple ion thruster that will be used in a science fair so I'm not concerned about its efficiency but just creating at least some thrust. However I wanted to make it as close as reality as possible, using every component and respecting its details if possib
electron-gun-2.jpg
le.


Ion thrusters use 2 electron guns, and this is when I came across those electron guns used in CRTs inside old monitors and televisions. However, I don't know if they are suitable for this task. If not, are there another alternatives for the electron guns?

Thanks!
 
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That sounds very ambitious and exciting. I hope you succeed.

Ions are much more massive than electrons. An electron gun is not an ion gun, so don't confuse the two.

A Google search for DIY ion thruster finds many hits. However, most of those are not useful. One that does sound real is this

https://www.popularmechanics.com/mi...-fair-experiment-to-aircraft-engine-15326499/
and

http://lae.mit.edu/2013/04/03/ehd/
In those cases, the device did not try to levitate itself, but rather to create a wind of ionized air. The wind current could make some bits of paper move to demonstrate nonzero thrust.

So, first see if you can understand those articles. Then, I would recommend that you try to contact the MIT professor Steven Barrett mentioned in the article and talk to him about doing it as a science fair project.

However, be aware that even that project requires some high voltages. You can do that safely only with the supervision of a mentor or adviser with you face-to-face, not by asking strangers on the Internet. We do not discuss dangerous topics on PF, so if this thread goes in a dangerous direction, we may have to close it.
 
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Likes pinball1970, RamSkull, Rive and 1 other person
Try google up 'arc thruster'. I think that's DIY-able, without much vacuum involved.
 
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One could simulate thrusters, even build a scale model depending on the rules and education level of the science fair.

Radiometers are evacuated glass bulbs with a rotor with four vanes mounted on a spindle. Each vane has a dark absorbing side and a white or silver reflecting side.

Simulate the ion engines with a device that emits infrared (IR) and/or visible light. Not sure if CRTs are the proper device. Perhaps you could rig an IR source. A carbon rod arc-light with an IR filter certainly works but may be over-kill and requires adult supervision. Would laser pointers work?

Aim your simulated engine at the radiometer to simulate thrust by spinning the rotor.

1564509833283.png


For extra credit the OP could explain how Crookes radiometers work.
 
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Does it make sense just to make an air-breathing electric engine using MHD? Your ion engines are not working in a vacuum chamber by the way
 
Due to the constant never ending supply of "cool stuff" happening in Aerospace these days I'm creating this thread to consolidate posts every time something new comes along. Please feel free to add random information if its relevant. So to start things off here is the SpaceX Dragon launch coming up shortly, I'll be following up afterwards to see how it all goes. :smile: https://blogs.nasa.gov/spacex/

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