First Determination Of An Astrophysical Cross Section With A Bubble Chamber: The N-15(Alpha, Gamma)F-19 Re-Action

We have devised a technique for measuring some of the most important nuclear reactions in stars which we expect to provide considerable improvement over previous experiments. Adapting ideas from dark matter search experiments with bubble chambers, we have found that a superheated liquid is sensitive to recoils produced from gamma rays photodisintegrating the nuclei of the liquid. The main advantage of the new target-detector system is a gain in yield of six orders of magnitude over conventional gas targets due to the higher mass density of liquids. Also, the detector is practically insensitive to the gamma-ray beam itself, thus allowing it to detect only the products of the nuclear reaction of interest. The first set of tests of a superheated target with a narrow bandwidth gamma-ray beam was completed and the results demonstrate the feasibility of the scheme. The new data are successfully described by an R-matrix model using published resonance parameters. With the increase in luminosity of the next generation gamma-ray beam facilities, the measurement of thermonuclear rates in the stellar Gamow window would become possible. (c) 2013 Elsevier B.V. All rights reserved.