Mixed phase evaporation source

Claim 2

Apparatus for vaporizing a material to establish a vapor flow thereof comprising: a container for the material to be evaporated; a melt within said container and comprising: a mixture of said material to be evaporated; and a porous mass; means for heating said melt in a region to liquify said material to be evaporated in an area surrounding said region and to evaporate said material from a portion of the liquified region; the porous mass providing a convection current impedance to the liquified material.

Claim 3

The apparatus of claim 1 wherein said porous mass has a low vapor pressure compared to the material for evaporation at the temperature at which said material for evaporation vaporizes.

Claim 4

The apparatus of claim 2 wherein said material is uranium and said porous mass is tungsten.

Claim 5

The apparatus of claim 1 wherein said porous mass is liquified in the region of the liquified material.

Claim 6

The apparatus of claim 4 wherein the melt includes a mixed phase region where said material is liquified and said porous mass is solidified.

Claim 7

The apparatus of claim 5 wherein the material and the porous mass of the melt are solidified near the region adjacent to said container.

Claim 8

The apparatus of claim 6 wherein said container includes copper and said material includes uranium.

Claim 9

The apparatus of claim 1 further including means for replenishing the supply of said material for evaporation in the molten area thereof.

Claim 10

The apparatus of claim 8 further including means for sensing depletion of said material for evaporation and for actuating said replenishing means in response thereto.

Claim 11

The apparatus of claim 8 wherein the means for replenishing the material supply includes means for feeding a solid rod of said material above the melt to cause melting of a portion of the rod.

Claim 12

The apparatus of claim 1 wherein said material for evaporation includes aluminum and said porous mass includes particulate tantalum carbide.

Claim 13

The apparatus of claim 1 wherein said porous mass includes a particulate material having a low vapor pressure at the vaporization point of said material for evaporation.

Claim 14

The apparatus of claim 1 wherein said container includes a trough shaped crucible having therein a plurality of cooling passages for a cooling fluid to flow therethrough.

Claim 15

The apparatus of claim 1 further including means for ionizing with isotopic selectivity the material evaporated from said melt.

Claim 16

The apparatus of claim 1 wherein the heating means includes means for applying an electron beam to a surface of the melt.

Claim 17

The apparatus of claim 15 wherein the electron beam is applied in a line along the surface of the melt.

Claim 18

The apparatus of claim 16 wherein the power density of the electron beam is at least approximately 4 kw./cm. of applied beam length.

Claim 19

The apparatus of claim 17 wherein the material is elemental uranium and the porous mass is particulate tungsten.

Claim 20

Apparatus for vaporizing elemental uranium to establish a vapor flow thereof comprising: a cooled crucible; a melt within said crucible comprising a mixture of elemental uranium and particulate tungsten; sufficient elemental uranium being included in the melt to bring the uranium to the surface of the melt; and means for applying an electron beam to the melt within the crucible to heat the melt to a condition of molten uranium and tungsten in the region of electron beam impact, solid uranium and tungsten in the region adjacent the crucible and a mixed phase region of molten uranium and solid tungsten elsewhere; the mixed phase region including a substantial portion of the melt to provide a convection impedance to the flow of molten uranium convection currents.

Claim 21

Apparatus for vaporizing elemental uranium to establish a vapor flow thereof comprising: a cooled crucible; a melt within said crucible comprising a mixture of elemental uranium and particulate tungsten; sufficient elemental uranium being included in the melt to bring the uranium to the surface of the melt; and means for applying an electron beam to the melt within the crucible to heat the melt to a condition of molten uranium and tungsten in the region of electron beam impact, solid uranium and tungsten in the region adjacent the crucible and a mixed phase region of molten uranium and solid tungsten elsewhere; the mixed phase region including a substantial portion of the melt to provide a convection impedance to the flow of molten uranium convection currents.

Claim 22

The apparatus of claim 19 including means for generally maintaining a level of uranium in the mixed phase region to provide uranium at the surface of the melt.

Claim 23

An improved melt for use in apparatus for evaporating a material by local surface heating of the melt, said melt comprising in use: a material to be evaporated; a porous mass substantially in a solid phase and having the material to be evaporated substantially in a liquid phase distributed throughout said porous mass to provide a mixed phase region.

Claim 24

An improved melt for use in apparatus for evaporating a material by local surface heating of the melt, said melt comprising in use: a material to be evaporated; a porous mass substantially in a solid phase and having the material to be evaporated substantially in a liquid phase distributed throughout said porous mass to provide a mixed phase region.

Claim 25

The improved melt of claim 21 which has uranium as the material to be evaporated and particulate tungsten as the porous mass.

Claim 26

Apparatus for evaporating uranium from the improved melt of claim 22 comprising means for applying an energetic beam to a surface of said melt to provide local heating thereof to the vaporization temperature for the uranium.

Claim 27

The improved melt of claim 21 wherein the melt has the general characteristics of a cermet.

Claim 28

The melt of claim 21 wherein the mixed phase region of said melt surrounds a region wherein said porous mass and said material are both substantially in a liquid phase.