The elusive β − p + decay was observed in 11 Be by directly measuring the emitted protons and their energy distribution for the first time with the prototype Active Target Time Projection Chamber (pAT-TPC) in an experiment performed at ISAC-TRIUMF. The measured β − p + branching ratio is orders of magnitude larger than any previous theoretical model predicted. This can be explained by the presence of a narrow resonance in 11 B above the proton separation energy.

In the Letter, we presented the first direct observation of the elusive β −-delayed proton emission (β − p þ) in 11 Be using a time projection chamber. There is an error in the extracted logðftÞ, which should read 2.8(4). The corrected logðftÞ value does not affect the conclusions presented in the Letter, since it was only used to assert the allowed character of the transition, a conclusion that is not changed. We would like to point out that, assuming a pure Gamow-Teller (GT) transition, it yields BðGTÞ ¼ 5.5 þ8.3 −3.3 , thus, including the BðGTÞ < 3 limit for a single neutron decay within one sigma. It should be noted that, due to the small energy window, the uncertainty in the resonance energy amounts to nearly 75% of the error budget for the logðftÞ value. Thus, a more precise measurement of the resonance energy could bring the B(GT) to within theoretical limits without significantly affecting the measured branching ratio.

High resolution spectral measurements of electron plasma frequency emission from Alcator C tokamak reveal a level of coherence indicative of maser activity (Aw/u=6 x 10-6). A full-wave theoretical analysis yields the complete mode structure of the electromagnetic fields as well as the dispersion relation. This analysis shows that for wave frequencies near the central plasma frequency the waves are highly localized and thereby the plasma forms a high-Q cavity for these waves.

The 80 Ge structure was investigated in a high-statistics β-decay experiment of 80 Ga using the GRIFFIN spectrometer at TRIUMF-ISAC through γ, β-e, e-γ, and γ-γ spectroscopy. No evidence was found for the recently reported 0 þ 2 639-keV level suggested as evidence for low-energy shape coexistence in 80 Ge. Largescale shell model calculations performed in 78;80;82 Ge place the 0 þ 2 level in 80 Ge at 2 MeV. The new experimental evidence combined with shell model predictions indicate that low-energy shape coexistence is not present in 80 Ge.

The r-process has been shown to be robust in reproducing the abundance distributions of heavy elements, such as europium, seen in ultra-metal poor stars. In contrast, observations of elements 26 < Z < 47 display overabundances relative to r-process model predictions. A proposed additional source of early nucleosynthesis is the weak r-process in neutrino-driven winds of core-collapse supernovae. It has been shown that in this site (α,n) reactions are both crucial to nucleosynthesis and the main source of uncertainty in model-based abundance predictions. Aiming to improve the certainty of nucleosynthesis predictions, the cross section of the important reaction 86Kr(α,n)89Sr has been measured at an energy relevant to the weak r-process. This experiment was conducted in inverse kinematics at TRIUMF with the EMMA recoil mass spectrometer and the TIGRESS gamma-ray spectrometer. A novel type of solid helium target was used.