Friday, February 1, 2008

WB-6 Shopping List

Peter in the comments at Making the Well posted this nice parts list and operating procedure for WB-6. With his permission I'm reposting it here. A lot of the material has already been covered, but this is a nice recap.


I've been working on a shopping list of the specifications and requirements of WB-6.

Most of the data comes from:
Dr. Bussard's Final Lab Notes
Valencia Paper
Google Video
Other bits are referenced.

If there are any mistakes or additions updates will be most welcome.

Polywell reactor specifications for a WB-6 equivalent reactor:

Vacuum chamber
  • 2m diameter tank with a Faraday cage inside (WB-6 was 2m by 3.5 m) that can go down to 1*10^-9 Torr

Vacuum pump

  • Able to pump (2m diameter chamber) down to less than 1*10^-9 Torr

Electron emitters
  • Banks of headlight filaments

  • Grounded

  • Activated by fiber optically isolated Siemens switch

  • Heating current of about 40 amps

  • (Stainless steel?) poles to place them at a standoff distance approximately equal to the mean radius of the cusp face through which they are injected.
    (to minimize electrostatic droop in the potential well at these corners)

  • poles attached to the corners of the 'square' Faraday cage.

Microwave generator
  • "microwaves at the ECR frequency corresponding to the magnetic field makes a death zone for neutral gas". (What is the ECR freq in WB-6?) Tom Ligon at the Fusor Forum

Magnetic field
  • Preferably superconducting magnets (greatly reduces power requirements and magnet strength possible in a smaller space.)

  • Otherwise 200 turns of approx 1000m of 0.15mm diameter copper magnet windings.

  • Cross-sectional diameter of toroid about 3cm, inner diameter about 20cm and outer diameter about 30cm

  • Linked in series with up to 2000A of current running through them for just over 20ms.

  • Make sure no tight bends in the windings.

Magnetic Grid Shell
  • Stainless steel tubing welded and then polished. (Laser or electron beam welding should do the trick, so as not to damage the windings inside) M Simon in the comments

  • Tightly conformal to the magnetic coils inside.

  • Joined by small (approx 1cm long) tubing just outside the midplane of the magnetic field of the coils.

  • Structural strength required to survive vacuum and force produced by six 0.2T magnets trying to separate from each other.

  • No metal surface may penetrate the magnetic fields by more than 1*10^-4 of the total surface available to the recirculating electrons.

Structural support of Magnetic Grid
  • Four support stands on the base toroid (or three or four on each with no (or slimmer) pipes joining the toroids.)

  • (Stainless steel again?) encased and thus ˜hidden" from electrons by tapered ceramic supports.

  • Has current carrying conductors inside helping to protect it from electrons by magnetic shielding.

  • Make sure no tight bends in power supplies through the legs or the joins.

Gas supply
  • Supplied by a (or several) tubes of a known tiny finite
    o volume (less than 5cm^3)
    o and pressure (300mili Torr too high. Must be small enough that the resulting gas pressure in the chamber is less than 3*10^-6 Torr).(This allows for the volume of gas in the reactor to be increased by tiny discrete intervals to ensure complete ionization and no flooding of the outer chamber with neutral gas.)

  • Last section of tubing is glass to minimize electron losses.

  • Gas input from tubes controlled by a fast acting (<1ms) solenoid valve

  • Glass tube releases gas just inside the inner perimeter of the magnets. To one of the coil/coil spaced seam areas. The magnetic fields here are very strong and that reduces the likelihood of electron losses by electrons impacting the tube.


  • Sensitive Photomultiplier system
  • Pressure sensors (sensitive down to 1*10^-9 Torr)

  • Optical spectrometer

  • Sensors for all currents and voltages on all supplies and lines and grounding cables.

  • 3 neutron detectors at varying distances (of a type not affected by high voltage and able to give quick electronic output.)

  • Cameras (They had two black and white ccd and 1 color camcorder) High speed color cameras operating at frame rates of much less than 0.1miliseconds would be best.

"The earliest Polywell, HEPS, was also verified to make a potential well, I believe by using four 94 GHz microwave beams across the chamber to map electron density.

The more recent machines have used at least Langmuir Probe methods (stick a wire in the thing and see what happens). And generating DD fusion is fairly convincing evidence, as well." Tom Ligon at Fusor.Net board.

Power supplies
  • Car batteries for the electron emitters

  • 240 RV batteries connected via an IGBT switch(able to safely produce at least 2000A)

  • Twelve 225uF capacitors producing up to 15kV, 400kJ at 5A current (or 30kV at 2.5A) these can be discharged through the magnet windings.

  • Fast acting pneumatic-driven copper block switch to connect capacitors.

  • At least 1200W supply for microwave generator

Check Dr. Bussard's Final Lab Notes for operating procedure.

Update: 31 May 008 0337z

EMC2 has pulled the lab notes and they are no longer available on the www. You may be able to get a copy from EMC2.

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