Forming of precision thin-wall hollow electron beams for microwave generators

The electron gun producing the precision hollow relativistic electron beam for coherent microwave generator applications has been developed and tested. It is based on the large non-adiabatic compression of the beam emitted by ring-shaped cathode with an active surface big enough to produce a wanted current level. Further improvement of beam quality is possible by decreasing of the width of the annular emitter and increasing its emissive power

Searching singlet extensions of the supersymmetric standard model in Z6−II Z_{6-II} orbifold compactification of heterotic string

We search for supersymmetric standard model realizations with extra singlets and extra $U(1)$ using the heterotic string compactification on the $Z_{6-II}$ orbifold with two Wilson lines. We analyze the vacuum restabilization mechanism for three representative Pati-Salam string models obtained in the literature and present detailed results for the effective superpotential compatible with the string selection rules. An automated selection of semi-realistic vacua along flat directions in the non-Abelian singlet modes field space is performed by requiring the presence of massless pairs of electroweak Higgs bosons having trilinear superpotential couplings with massless singlet modes and the decoupling of color triplet exotic modes needed to suppress $B$ and $L$ number violating processes.Comment: revtex4 format, 21 pages, 7 tables, shortened version added reference