Fusor

A lot of info on this wiki is for trying to better understand and streamline DIY fusors. Ultimately I (JM) would like to do a Kickstarter campaign to produce a fusor kit

Fusor kit

The aim of the kit is to accelerate DIY fusors. People struggle sourcing suitable surplus electronics despite that these could be made pretty low cost. Therefore, this project focuses on making a standard hobby fusor electronics platform. It should standardize:

• HV control
• Neutron readings
• Vacuum measurement
• Computer control

While I'd like to focus on computer control, I'm guessing the target market will have a general preference for knobs and dials. Therefore the setup must remain accessible to both sets of users. This is not believed to incur considerable design complexity. I'd ideally like to implement this as stuffing options on the PCB to keep costs down for users that don't require it.

Minimum viable product: a computer controlled high voltage power supply. This would be a great first step and technology demonstrator.

In more detail:

• All critical data can be read out via computer control or on board display
  • Suspect users will prefer galvos over LCD dispaly. Poll?
• All critical actuators can be actuated via computer control or on board controls
• Must provide HV sufficient to run a small fusor
  • Negative w/ respect to ground
  • kV?
  • mA?
  • Must provide actual mA and kV in addition to target
• Must be able to read surplus Russian neutron tubes
  • OOB: recommended settings for various tubes
  • OOB: higher price option that comes with tested tube
  • Simple circuit for counting on MCU
  • Breakout option for scope/PC
• Must be able to read a GP275 sensor
  • Extremely popular
• Target cost?
  • Fusor project as a whole is somewhat expensive
  • Survey cost of good used HV supplies as a selling point
  • Should definitely shoot for <$500, much less if possible
• Must provide some GPIO
  • Allow user to interface to pumps, etc
• Computer: must provide good out of box experience
  • A ready to use application that can control and monitor the board
  • Survey users for OS preferences
• Computer: must provide an API for advanced users
  • Survey users for language preferences
  • C and Python would be ideal
  • Python probably to start with
• HV insulation TBD
  • Oil
  • Potting
  • Low melt plastic like PLA might work well
• Burn in testing / calibration?
• Case?
  • May be required due to HV
• Shall provide basic instructions on how to hook up and calibrator sensors
• Shall publish design information
• Shall publish production information (layouts, case design, etc)
• Shall publish repair guide (as problems come up)
• Sold as is: no guaranteed support or

Out of scope:

• Shall not provide any pumps
• Shall not provide any complex pump control (ex: turbo controller)
• Shall not provide vacuum chambers
• Shall not provide feedthroughs
• Shall not provide galvos
• Not a cookbook: will not cover chamber design, pump selection, etc

Support? Although I don't mind doing development, how much assembly and such do I want to do myself? Repairs?

• Limit quantity?

Milestones:

• Design a DB-9 preamplifier power supply board
  • +/- 24 V
  • +/- 12 V
  • +/- 6 V?
    • Stuffing option?
• Design a HV power board
• Design a GP275 controller
• Design a neutron preamplifier / counter
• Integrate into unified assembly
  • Consider keeping the power board as a separate module

Successful fusors

High level summary here: http://fusor.net/board/viewtopic.php?t=13&f=7#p512

But doesn't have details

Unit	Chamber	-kV	mA	Pressure (mTorr)	Verification	Links	Notes
Nick Peskosky	6 CF?	22.5	0.3	8.5 - 9.5	He3	Link	Glassman 30 kV supply
Garrett Young	2.75 CF	27	20	33	Bubbles	Link	"27kV@20mA (29kV source with 100kohm series resistor)"

Plasma color

http://www.fusor.net/board/viewtopic.php?t=9910

• "The question was about the change of the emission spectra as pressure drops. The color changes dramatically from the well known blueish purple to very pale blue. The answer (even if it can be deduced with a bit more research) is a bit less trivial than the classic glow when air is excited at a fixed pressure in a certain range. The process behind the glow it self at any given state is the same of course. "
• "A "colder" more bluish color indicates that the average photon energy is higher. This is most probably due to the increase of the mean free path of particles in the chamber as pressure drops. Particles can travel a greater distance between collisions giving them more time to accelerate ,thus they can gain more energy which results in more energetic collisions, higher excitation, and that means higher photon energies when recombination occurs."
• "as the pressure decreasses the colour should get weaker not change colour most all amateur efforts are coloured by contaminents/ leakage in this case nitrogen (blue) oxygen whitish blue and hydrogen (pink scarlet)and not counting diff pump products etc"
• "A few years ago, there was a claim that a yellow-green spectral line detected by a contributor was due to a helium spectral line and thus a indicator of fusion. Discussion reviled though that any such helium was way too tine to be detected. The line was probably from sodium line emission derived from sodium sputtered off of the glass by the electron beams/ plasma bombardment. This illistrates that the net perceived color is a complex mixture of various element spectral lines, and this can change as the chamber is pumped down and plasma cleaned"

Neutristor

[1]

Mini IEC system?

Very low output flux