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No-core configuration interaction (NCCI) calculations for p-shell nuclei give rise to rotational bands, identified by strong intraband E2 transitions and by rotational patterns for excitation energies, electromagnetic moments, and electromagnetic transitions. However, convergence rates differ significantly for different rotational observables and for different rotational bands. The choice of internucleon interaction may also substantially impact the convergence rates. Consequently, there is a substantial gap between simply observing the qualitative emergence of rotation in ab initio calculations and actually carrying out detailed quantitative comparisons. In this contribution, we illustrate the convergence properties of rotational band energy parameters extracted from NCCI calculations, and compare these predictions with experiment, for the isotopes 7-11 Be, and for the JISP16 and Daejeon16 interactions.

Army m i l l i m e t e r wave radar systems designers i m p o s e e v e r -i n c r e a s i n g r e s t r i c t i o n s o n t u b e volume, weight, and cost while at the same time r e q u i r i n g i m p r o v e d t u b e l i f e and r e l i a b i l i t y . The b u l k i e s t p o r t i o n o f a m i l l i m e t e r wave tube i s comprised o f t h e t h e r m i o n i c e l e c t r o n gun and t h e beam focusing magnet. The t h e r m i o n i c e l e c t r o n gun i s o f t e n t h e s o u r c e o f t u b e f a i l u r e . The magnet accounts f o r a b o u t 30% o f t h e c o s t and 60% o f t h e t u b e volume and weight. An RF a c t i v a t e d , n o n -t h e r m i o n i c , e l e c t r o n gun which employs the principle of secondary electron resonance (mu1 t i p a c t o r ) t o p h a s e -f o c u s e l e c t r o n s i n t o t i g h t , h i g h d e n s i t y e l e c t r o n bunches i s discussed. Since electrons are prebunched w i t h i n t h e gun i t s e l f , l o n g d r i f t l e n g t h s and the attendant need for magnetic focusing are eliminated or minimized, thereby decreasing tube s i z e , w e i g h t , a n d c o s t . R e l i a b t l l t y and l i f e a r e s u b s t a n t i a l l y i n c r e a s e d b y v i r t u e o f t h e f a c t t h a t t h e r m i o n i c e m i s s i o n i s n o t employed. C a p a b i l i t y o f m u l t i p a c t o r guns t o produce s i g n i f i c a n t beam c u r r e n t s has been established by numerous i n v e s t i g a t o r s . The p r a c t i c a b i l i t y and f e a s i b i l i t y o f such guns f o r u s e a t m l l l i m e t e r wavelengths, however, depends not only on their e l e c t r o n c u r r e n t c a p a b i l i t y , b u t a l s o o n t h e i r a b i l i t y t o be d r i v e n by l o w power, compact, RF sources. T e s t v e h i c l e s ( s c a l e d t o 5 GHz) t o demon? s t r a t e r e q u i r e d d r i v e l e v e l s have been b u i l t and e v a l u a t e d a t ET&DL, ERADCOM. Experimental res u l t s show t h a t d r i v e l e v e l s o n t h e o r d e r o f 10 m i l l i w a t t s a r e s u f f i c i e n t , d e m o n s t r a t i n g t h a t s m a l l , l i g h t w e i g h t , s o l i d -s t a t e RF drive sources a r e p r a c t i c a l . T h e o r e t i c a l e v i d e n c e .Is presented showing t h a t t h e l e v e l of d r i v e i s t h e same f o r millimeter frequencies (e.g. 95, 140, 220 GHz) as i t i s f o r t h e 5 GHz s c a l e d t e s t v e h i c l e s .

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