New experiment with SuN: Nuclear Reactions in Supernovae

Gamma ray spectra for the two reactions of interest showing the characteristic gamma ray signal for each reaction. The background corresponds to the same measurement when the hydrogen gas was removed from the gas target.

A large number of nuclear reactions take place in supernova explosions. During the explosion, a shockwave moves from the inner parts of the star towards the outer layers, and depending on the temperature and density of each of the layers different types of reactions take place. As a result, different nuclei are produced or destroyed in this process, impacting the synthesis of elements in our Universe. This week the SuN group measured two reactions that take place during these explosions at temperatures of about 2 billion degrees Kelvin. Two isotopes of krypton (krypton-82 and krypton-84) were accelerated through the ReA3 linac, and interacted with a hydrogen gas target at the center of the SuN detector. The reaction of interest takes place when the krypton nucleus captures a proton from the gas target emitting gamma rays. The SuN detector collects the energy of the emitted gamma rays providing a unique signal from each reaction, as shown in the figure below. This experiment will be the main part of the PhD thesis of NSCL graduate student Alicia Palmisano.