Mark 3 Anode Layer Ion Source

 

Overview:

An anode layer ion source consists of a positively biased ring shaped anode between two grounded magnetic poles that create a radial magnetic field across the anode ring. Electrons drift above the ring due to the ExB force and ionize gas (either ambient or a controlled flow over the anode ring) which is then directed into a rind shaped beam. Anode layer sources have been used as satellite thrusters, plasma sources, for thin film deposition or surface treatment.

 
 

Ion Source Specs:

  • Voltage: 0-4kV
  • Current: ~2mA
  • Pressure: 1E-4 torr to ~2E-2 torr

 
 

Complete Ion Sources

 
 

Complete Ion Source

 
 

Complete Ion Source

 
 

Quad Ion Source Fusor

Four ion sources mounted on fusor
 

Ion Source CAD (3/14/2009)

CAD of anode layer ion source.
 

Ion Source CAD (3/14/2009)

CAD of anode layer ion source casing.
 

Ion Source CAD (3/14/2009)

CAD of anode layer ion source pole peace.
 

410 SS Bar stock (3/14/2009)

410 stainless steel is a magnetic alloy allowing it to concentrate the magnetic field at the gap between the pole pieces while retaining the chemical resistant properties of stainless steel.

1.25" bar stock is used for the ion source casings

(Mcmaster 86705K141)

0.625" bar stock is used for the ion source central pole piece.

(Mcmaster 86705K421)
 

Casing Blanks (3/14/2009)

1" long blanks for the ion source casings.
 

Casing Construction (3/14/2009)

Facing off the casing and turning down to 1" length after cutting off blank with band saw.
 

Casing Construction (3/14/2009)

Drilling out center of casing.
 

Casing Construction (3/14/2009)

Increasing drill size.
 

Casing Construction (3/14/2009)

Casing that has been faced off and drilled with those just cut off with the band saw.
 

Casing Construction (3/14/2009)

Drilled out to almost 0.875" ID
 

Casing Construction (3/14/2009)

Carbide tool is used to take ID out to 0.875" and to flatten out bottom of casing.
 

Casing Construction (3/14/2009)

Pole piece angle turned into face.
 

Casing Construction (3/14/2009)

Casing that has been bored out to 0.875", angled, and flattened on the bottom next to one that has just been drilled.
 

Casing Construction (3/14/2009)

Boring bar is used to turn out inner relief to 1" and form back end of pole piece lip.
 

Casing Construction (3/14/2009)

After turning on the lathe is complete, four pilot holes at 0.75" radius are center drilled on the mill.
 

Casing Construction (3/14/2009)

Feed through holes for 0.125" OD high alumina ceramic tubing are drilled on a drill press.
 

Magnet Installation (3/14/2009)

N40 rare earth magnet provides magnetic field.

Magnet specs:

  • 0.50" OD
  • 0.25" ID
  • 0.50" Length
 

Alumina Standoffs (3/14/2009)

Alumina standoffs are cut using diamond power coated cutter disk.

(Mcmaster 8746K11)

Shaft retaining snap rings position the standoffs along their length.

(Mcmaster 97633A110)
 

Alumina Standoffs (3/14/2009)

Alumina standoffs are installed through feed through holes.

Spacer washer in place.

(Mcmaster 90945A740)
 

Anode Construction (3/14/2009)

Anodes are fabricated out of SS shims, 0.875"OD 0.626"ID.

(Mcmaster 94773A778)

Shims are scribed at 0.75" radius.

 
 

Anode Construction (3/14/2009)

Hole locations are punched into surface.
 

Anode Construction (3/14/2009)

Holes are drilled to allow welding of threaded rods into anode.
 

Anode Construction (3/14/2009)

1" long 0-80 threaded rods are TIG welded into anode

(Mcmaster 95412A300)
 

Anode Construction (3/14/2009)

Surface is belt sanded flat to provide uniform electric field
 

Anode Construction (3/14/2009)

Five anodes for set of injectors.
 

Anode Installation (3/14/2009)

Anodes are installed into ion sources with threaded rods sliding through center of alumina standoffs.
 

Center Pole Piece (3/14/2009)

Center pole piece is installed with 10-32 screw traveling through injector body.

(Mcmaster 93235A248)
 

Anode Feedthroughs (3/14/2009)

Threaded rod ends on other side of standoffs.
 

Anode Feedthroughs (3/14/2009)

Snap rings

(Mcmaster )

and nuts installed on other sides of standoffs.

(Mcmaster 91841A115)
 
 

 
 

Flange Construction (3/14/2009)

Blank 2.75" conflat flange is cleaned with scotchbrite.
 

Flange Construction (3/14/2009)

Flange is center drilled at the center.
 

Flange Construction (3/14/2009)

Hole is drilled to 0.3125" depth in center of flange.
 

Flange Construction (3/14/2009)

Drilled flange ready for taping.
 

Flange Construction (3/14/2009)

Flange is tapped with 10-32 tap.
 

Flange Construction (3/14/2009)

Flange is tapped with 10-32 tap.
 

Flange Construction (3/14/2009)

Taped flange.
 

Flange Construction (3/14/2009)

Vented standoff screws into flange.

(Mcmaster 91075A174)
 

Flange Construction (3/14/2009)

Round nuts are used to allow flange to be evenly clamped in a vice.
 

Flange Construction (3/14/2009)

Flange clamped in mill vice.
 

Flange Construction (3/14/2009)

Pilot holes for Feedthroughs are center drilled into flange.
 

Flange Construction (3/14/2009)

Center drilled flange.
 

Flange Construction (3/14/2009)

Holes are drilled out to size.
 

Flange Construction (3/14/2009)

0.25" hole is drilled for gas feed through and 0.5" hole is drilled for MHV feed through.

0.25 hole is 0.375" from center, 0.5" hole is 0.4375" from center

10-32 thread is drilled to 0.3125" depth in center of flange.
 

Flange Construction (3/14/2009)

Flanges before and after drilling to size.
 

Flange Construction (3/14/2009)

Flange with 1/4" VCR gas feed through and MHV electrical feed through.
 

Flange Construction (3/14/2009)

Feedthroughs TIG welded to flange
 

Flange Construction (3/14/2009)

Completed flange.
 
 

 
 

Ion Source Assembly (3/14/2009)

Source screws into flange.
 

Ion Source Assembly (3/14/2009)

Spring connects electrical feed through to anode nut.

(Mcmaster 9663K12)
 

Ion Source Assembly (3/14/2009)

Alumina tube allows source body to be filled with feed gas.
 

Ion Source Complete (3/14/2009)

Completed ion source.
 

Ion Source Operation (3/14/2009)

Front view.
 

Ion Source Operation (3/14/2009)

Side view.
 

Ion Source Operation (3/14/2009)

Side view with faraday cup collector.
 

Ion Source Power Supply (7/30/2014)

Buck converters for high voltage power supply control.
 

Ion Source Power Supply (7/30/2014)

Emco F40 high voltage power supplies, 0-12v input voltage 0-4kV output voltage.
 

Ion Source Power Supply (7/30/2014)

Complete power supply
 

Ion Source Operation (7/30/2014)

Ion Source operation in test bed
 

Ion Source Operation (7/30/2014)

Ion Source operation in test bed
 

Fusor Setup (7/30/2014)

With 4 ion sources
 

Fusor Setup (7/30/2014)

With 4 ion sources
 

Fusor plasma (7/30/2014)

With 4 ion sources, argon plasma
 

Focusing Anode Ring (3/06/2016)

Stainless Steel Belleville Disc Spring (mcmaster 9713K437) (6.6 degree inward angle) and jig to bore to correct ID
 

Focusing Anode Ring (3/06/2016)

Beveled anode ring with original flat ring
 

SmCo Magnet (3/06/2016)

SmCo magnet is compatible with deuterium and tolerant of high temperatures for long operation runs (up to 300C instead of 80C for the NdFeB)
 

Focusing Anode Ring (3/06/2016)

Installed in ion source
 

Focusing Anode Ring (3/06/2016)

Ion beam with focusing anode ring
 

Focusing Anode Ring (3/06/2016)

Ion beam with focusing anode ring
 

Focusing Anode Ring (3/06/2016)

Ion beam with focusing anode ring
 

Pole Piece Testing (3/06/2016)

  • Numbers 1 to 5 from left, pole piece 1 was the one used in all previous tests
  • The version 1 has a 1/8" step of 0.5" dia, then a 1/16" step of 0.625" dia, then a 45degree taper over 1/16"
  • The version 2 has a 1/16" step of 0.5" dia, then a 1/16" step of 0.58" dia, then a 15degree taper over 1/16"
  • The version 3 has a 1/16" step of 0.5" dia, then a 15degree taper over 0.1875"
  • The version 4 is 7.5mm long 14mm dia
  • The version 5 has a 1/16" step of 0.5" dia, then a 1/16" step of 0.58" dia, then a 15degree taper over 1/8"
  • Version 4 and 5 have a pump out groove milled in the base to vent the trapped volume inside the magnet
 

Pole Piece Testing (3/06/2016)

Version 4 and 5 have a pump out groove milled in the base to vent the trapped volume inside the magnet
 

Pole Piece Testing (3/06/2016)

Version 2
 

Pole Piece Testing (3/06/2016)

Version 2 plasma focus
 

Pole Piece Testing (3/06/2016)

Version 2, recessed
 

Pole Piece Testing (3/06/2016)

Version 2, recessed plasma focus
 

Pole Piece Testing (3/06/2016)

Version 3, recessed
 

Pole Piece Testing (3/06/2016)

Version 3, recessed plasma focus
 

Pole Piece Testing (3/06/2016)

Version 3
 

Pole Piece Testing (3/06/2016)

Version 3 plasma focus
 

Pole Piece Testing (3/06/2016)

Version 4
 

Pole Piece Testing (3/06/2016)

Version 4 plasma focus
 

Pole Piece Testing (3/06/2016)

Version 5
 

Pole Piece Testing (3/06/2016)

Version 5 plasma focus
 

Pole Piece Testing (3/06/2016)

Version 5 plasma focus
 

Pole Piece Testing (3/06/2016)

Pump out duct in standoff washer. Standoff has axially drilled pump out hole, pump out duct in washer prevents trapped volume in washer interior. Standoff washer designed to prevent hex standoff from sitting on the weld of the MHV feed through which was causing a slight misalignment of the ion source.
 

Pole Piece Testing (3/06/2016)

Modified sources installed, now using copper o-rings instead of viton
 

Fusor plasma (3/06/2016)

With 4 ion sources, deuterium plasma
 
 

 
 
 

Useful links:

http://www.fusor.net/ Open Source Fusion Research Consortium.
 

 

 

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