Patent Number: 
Section: claims

1. A beta cell for converting beta-particle energies into electrical energy, comprising: a semiconductor junction incorporating an icosahedral boride compound, wherein the icosahedral boride compound is selected from the group consisting of B 12 As 2 , B 12 P 2 , elemental boron having an xcex1-rhombohedral structure, elemental boron having a xcex2-rhombohedral structure, and boron carbides of the chemical formula B 12-x C 3-x , where 0.15 less than x less than 1.7;  a beta radiation source; and  means for transmitting electrical energy to an outside load. 2. The beta cell of  claim 1 , further comprising a shield encapsulating said semiconductor junction and said beta source. claim 1 3. The beta cell of  claim 1 , wherein self-healing of beta-induced damage to the icosahedral boride compound is effective at ambient operating temperatures. claim 1 4. The beta cell of  claim 1 , wherein the beta radiation source is selected from compounds that contain  90 Sr,  147 Pm,  170 Tm,  3 H,  63 Ni,  137 Cs,  141 Ce, and  204 Tl. claim 1 5. The beta cell of  claim 1 , wherein said junction is a Schottky barrier comprising a metal contact deposited on an icosahedral boride semiconductor. claim 1 6. The beta cell of  claim 1 , wherein the semiconductor junction occurs in a free-standing icosahedral boride material. claim 1 7. The beta cell of  claim 1 , wherein said semiconductor junction comprises a p-n junction, said p-n junction comprising juxtaposed layers of an n-type region and a p-type region. claim 1 8. The beta cell of  claim 7 , wherein said n-type region comprises the icosahedral boride compound and incorporates an n-dopant selected from the group consisting of S, Se and Te. claim 7 9. The beta cell of  claim 7 , wherein said p-type region comprises the icosahedral boride compound. claim 7 10. The beta cell of  claim 7 , wherein said p-type region comprises the icosahedral boride compound and incorporates a p-dopant selected from the group consisting of Si, Ge and C. claim 7 11. The beta cell of  claim 7  wherein said layers have thickness from approximately 0.1 micron to approximately 1000 micron. claim 7 12. A beta cell for converting beta-particle energies into electrical energy, comprising: a semiconductor junction incorporating an icosahedral boride compound, wherein the semiconductor junction is deposited on a substrate selected from the group of substrates consisting of SiC and metal diboride compounds;  a beta radiation source;  means for transmitting electrical energy to an outside load; and  an electrical contact of a metal diboride compound layered between the substrate and the icosahedral boride compound. 13. A beta cell device for converting beta-particle energies into electrical energy, comprising: a stack of beta cells comprising beta radiation-emitting strata and semiconductor junction strata, said semiconductor junction strata incorporating an icosahedral boride compound, wherein the icosahedral boride compound is selected from the group consisting of B 12 As 2 , B 12 P 2 , elemental boron having an xcex1-rhombohedral structure, elemental boron having a xcex2-rhombohedral structure, and boron carbides of the chemical formula B 12-x C 3-x , where 0.15 less than x less than 1.7;  a means of forming electrical connections between individual beta cells in the stack;  a shield encapsulating said beta radiation-emitting strata, said semiconductor junction strata, and said electrical connections;  a positive conductor terminal and a negative conductor terminal being accessible externally of said shield; and  said positive conductor terminal and said negative conductor terminal operatively connected to means for transmitting electrical energy to an outside load. 14. The beta-cell device of  claim 13 , with one externally accessible conductor terminal being operatively connected to the positive-polarity electrical connections between parallel individuals cells, and at least one externally accessible conductor terminal being operatively connected to the negative-polarity electrical connections between parallel individual cells. claim 13 15. The beta-cell device of  claim 13 , with one externally accessible conductor terminal of the beta-cell stack being operatively connected to the positive terminus of a series of individual cells with the positive terminal of each other cell being connected to the negative terminal of a successive cell and the final negative terminus of said series being connected to the other externally accessible conductor terminal of the beta-cell stack. claim 13 16. The beta-cell device of  claim 13 , wherein the beta radiation source is selected from compounds containing  90 Sr,  147 Pm,  170 Tm,  3 H,  63 Ni,  137 Cs,  141 Ce, and  204 Tl. claim 13 17. The beta-cell device of  claim 13 , wherein said semiconductor junction strata comprise Schottky-barrier junctions, each junction comprising a metal contact deposited on the icosahedral boride compound. claim 13 18. The beta-cell device of  claim 13 , wherein said semiconductor junction strata comprise p-n junctions, each p-n junction comprising juxtaposed layers of an n-type region and a p-type region. claim 13