Bubble Chambers for Experiments in Nuclear Astrophysics

TL;DR

This paper introduces a bubble chamber detector system for low energy nuclear astrophysics experiments, enabling more efficient measurement of reaction cross sections relevant to stellar processes by using photodisintegration techniques.

Contribution

A novel bubble chamber detector system compatible with gamma-ray beams is developed, improving measurement capabilities for nuclear reactions in astrophysics.

Findings

Higher cross section measurements due to phase space transformation.

Significantly increased target density compared to gas targets.

Detector insensitivity to gamma-ray beams enhances measurement accuracy.

Abstract

A bubble chamber has been developed to be used as an active target system for low energy nuclear astrophysics experiments. Adopting ideas from dark matter detection with superheated liquids, a detector system compatible with gamma-ray beams has been developed. This detector alleviates some of the limitations encountered in standard measurements of the minute cross sections of interest to stellar environments. While the astrophysically relevant nuclear reaction processes at hydrostatic burning temperatures are dominated by radiative captures, in this experimental scheme we measure the time-reversed processes. Such photodisintegrations allow us to compute the radiative capture cross sections when transitions to excited states of the reaction products are negligible. Due to the transformation of phase space, the photodisintegration cross sections are up to two orders of magnitude higher. The main advantage of the new target-detector system is a density several orders of magnitude higher than conventional gas targets. Also, the detector is virtually insensitive to the gamma-ray beam itself, thus allowing us to detect only the products of the nuclear reaction of interest. The development and the operation as well as the advantages and disadvantages of the bubble chamber are discussed.