Situated in the so-called "island of inversion," the nucleus \(^{32}\)Mg is considered as an archetypal example of the disappearance of magicity at \(N=20\). We report on high statistics in-beam ...spectroscopy of \(^{32}\)Mg with a unique approach, in that two direct reaction probes with different sensitivities to the underlying nuclear structure are employed at the same time. More specifically, states in \(^{32}\)Mg were populated by knockout reactions starting from \(^{33}\)Mg and \(^{34}\)Si, lying inside and outside the island of inversion, respectively. The momentum distributions of the reaction residues and the cross sections leading to the individual final states were confronted with eikonal-based reaction calculations, yielding a significantly updated level scheme for \(^{32}\)Mg and spin-parity assignments. By fully exploiting observables obtained in this measurement, a variety of structures coexisting in 32Mg was unraveled. Comparisons with theoretical predictions based on shell-model overlaps allowed for clear discrimination between different structural models, revealing that the complete theoretical description of this key nucleus is yet to be achieved.
The lifetime of the $2_1^+$ state at 2.1 MeV in $^{12}$Be has been measured using inelastic scattering of a $^{12}$Be beam at 43 MeV/nucleon with a gold target. Through the Doppler shift attenuation ...method, the mean-life of the $2_1^+$ state has been determined as 2.5±0.7(stat)±0.3 (syst) ps, which gives a B(E2; $2_1^+$ → $0_{g.s.}^+$)) value of 4.9±1.3±0.5 in Weisskopf units. The result shows a large quadrupole strength in the ground state transition, providing further evidence on the disappearance of the N=8 magic number. The B(E2; $2_1^+$ → $0_{g.s.}^+$) value together with the deformation length measured by proton inelastic scattering yields a neutron quadrupole matrix element two times larger than those for $^{14}$C and ${16}$O.
The Duromer molded interconnect device (MID) technology for realization of a stackable system-in-package (SiP) is similar to conventional MID technology, which is usually realized using thermoplastic ...polymers, combining the functionality of housing and substrate into one device. Advantages of the conventional MID technology are the reduction of parts during assembly by integrating mechanical and electrical functionality into a device and the reduction of space, as MID allows a three-dimensional (3-D) integration of devices. A disadvantage of conventional technology, especially if combined with typical technical thermoplastics, is the large mismatch in coefficient of thermal expansion (CTE) between substrate and advanced microelectronic components as chip scale package (CSP) or flip-chip. This is reducing the applicability of thermoplastic MID to moderate temperature ranges and/or to rather robust components. To overcome this disadvantage, the use of low CTE duromer as epoxy molding compounds (EMCs) as base material for device assembly is proposed, generating a unique technology well adapted to SiP and microelectromechanical system (MEMS) packaging needs, the Duromer MID approach. The technological realization of Duromer MID uses conventional backend processes as IC bonding to flex, transfer molding using epoxy molding compounds, laser machining, metallization, and structurization processes well known from PCB processing. The use of existing equipment allows both a rather fast process implementation and a cost-effective manufacturing of the components. Within this paper, the investigations described previously are driven further toward a description of a generic packaging technology integrating detailed analysis of metallization processes and assembly issues. Summarized, this paper presents further process development and feasibility analysis of wafer-level packaging technologies for SiP solutions based on a Duromer MID approach.
We report the first experimental constraints on spectroscopic factors and strengths of key resonances in the P-30(p, gamma)S-31 reaction critical for determining the production of intermediate-mass ...elements up to Ca in nova ejecta. The P-30(d,n)S-31 reaction was studied in inverse kinematics using the GRETINA gamma-ray array to measure the angle-integrated cross-sections of states above the proton threshold. In general, negative parity states are found to be most strongly produced but the absolute values of spectroscopic factors are typically an order of magnitude lower than predicted by the shell-model calculations employing WBP Hamiltonian for the negative-parity states. The results clearly indicate the dominance of a single 3/2(-) resonance state at 196 keV in the region of nova burning T approximate to 0.10-0.17 GM, well within the region of interest for nova nucleosynthesis. Hydrodynamic simulations of nova explosions have been performed to demonstrate the effect on the composition of nova ejecta.
Previous experiments observed a 4+ state in the N=28 nucleus S44 and suggested that this state may exhibit a hindered E2-decay rate, inconsistent with being a member of the collective ground state ...band. We populate this state via two-proton knockout from a beam of exotic Ar46 projectiles and measure its lifetime using the recoil distance method with the GRETINA γ-ray spectrometer. The result, 76(14)stat(20)syst ps, implies a hindered transition of B(E2;4+→2$+\atop{1}$)=0.61(19) single-particle or Weisskopf units strength and supports the interpretation of the 4+ state as a K=4 isomer, the first example of a high-K isomer in a nucleus of such low mass.
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