Observation techniques and properties of α-cluster states at high excitation inA = 16-40 nuclei

Abstract

Summary. -Groups of narrow states with seemingly rotational-like structures are observed in -particle elastic scattering from the Coulomb barrier up to excitation energies of about 35 MeV. These states are best studied in 28 Si, but similar states are observed in nuclei ranging from 16;18 O to 36;38 Ar. For each`-value some 10-15 states with narrow widths, 20 -80 keV, are observed in 28 Si and apparently in other midsd-shell nuclei, but the properties of these states are not yet fully understood. Existing models, mostly based on rotation-vibration molecular arguments are not able to explain the experimental findings in a consistent way. Non-linear models, interpreting the alpha-particle as a soliton on the nuclear surface, provide a sufficient number of states with the desired properties. Their microscopic interpretation, however, because of the non-linearity, has not yet been made physically clear. In addition to conventional scattering experiments, using -particle beams on solid targets, we have developed a "thick-target" method which makes the data acquisition much faster, and gives continuous energy spectra. We further develop an inverse-geometry method, impinging various heavy ions on helium gas in a target chamber with variable pressure, also providing continuous excitation-energy spectra. This method saves enormously beam time, but has some disadvantages which are being studied.PACS 25.55.Ci -Elastic and inelastic scattering. PACS 29.25 -Particle sources and target. PACS 01.30.Cc -Conference proceedings.

The Explaining of “Magic” Nuclear Numbers by a Quasi-Crystalline Nuclear Model, of Possible Cold Genesis

“…For a 'magic' or semi-magic quasi-crystalline form, the nuclear mass and the S q -surface may be calculated by considering three crystalline levels: a., b. and c. of squared or hexagonal forms of particles on each upper or lower part of the nucleus ( fig. 1), with a number: n a 2 , n b 2 and n c 2 of particles on each level of squared forms (and 3n a 2 , 3n b 2 and 3n c 2 for each hexagonal form), n a , n b and n c being the number of -particles on the side length l q of the squared or hexagonal form: M q s =m  (K a n a 2 +K b n b 2 +K c n c 2 ); M q h =m  3(K a n a 2 +K b n b 2 +K c n c 2 ) (14) with: K a =(1; 2; 3), (K b , K c )=(0; 1; 2) -the total number of squared or hexagonal forms on the levels a., b., c. and: S q =S q u +S q l =s  2n a 2 +½(s  )4(K a n a +K b n b +K c n c )=s  2(n a 2 +K a n a +K b n b +K c n c ) (15) (s  -the surface of the -particle), for a nucleus formed by quasi-crystalline squared forms and: S q =S q u +S q l =s  6n a 2 +½(s  )6(K a n a +K b n b +K c n c )=s  3(2n a 2 +K a n a +K b n b +K c n c ) (16) for a nucleus formed by quasi-crystalline hexagonal forms, with S q u -the (upper +lower) surface, S q l -the lateral surface (geometrically considered, taking of two times the surface of corner nucleons).…”

“…2 )=517; Nucleons or alpha-weakly-linked particles formed from valence nucleons may be rotated around the nuclear quasi-crystalline core (Lonnroth, [16]), particularly-as in the extreme-uniparticle model (Schmidt,[17]) by the action of the quantum vortex   of the nuclear magnetic moment  N (according to the quantum-vortexial nature of the magnetic field, considered in CGT [1][2][3][4]) which explains also the nuclear centrifugal potential.…”