Neutron capture surrogates on astrophysical radionuclei: how the 205Pb radioactive clock can unlock the formation of our Sun

Projektbeschreibung

Instabile Bleiisotope können die Entstehung der Sonne datieren

Von instabilen Atomkernen eingefangene Neutronen liefern die entscheidenden Daten, die benötigt werden, um den Zeitpunkt der Entstehung unserer Sonne zu bestimmen sowie die Entwicklung von Teilchenbeschleuniger-Kernreaktoren voranzutreiben. Die Berechnung dieser Wechselwirkung für das radioaktive Isotop 205Pb ist schwierig, da das Material zu flüchtig ist, um ein stabiles experimentelles Target herzustellen. Dies hindert Wissenschaftlerinnen und Wissenschaftler daran, es als „kosmische Stoppuhr“ zur Datierung der Sonnenentstehung zu nutzen. Das durch die Marie-Skłodowska-Curie-Maßnahmen geförderte NECTARINE-Projekt wird diese Einschränkung umgehen, indem es Ersatzreaktionen in einer Schwerionen-Speicherringanlage nutzt. Anstatt Neutronen direkt auf 205Pb zu richten, werden die Forschenden alternative Kernkollisionen auslösen, die genau das energetische Nebenprodukt der angestrebten Reaktion nachbilden. NECTARINE wird die präzisen Kernquerschnitte liefern, die zur Kartierung der Sternentwicklung und zur Konstruktion von bleigekühlten Reaktoren benötigt werden.

Ziel

"Understanding neutron capture reactions on short-lived nuclei is important for uncovering how the heavy elements in our universe were created, and for advanced nuclear energy applications. Neutron capture on the radioactive nucleus 205Pb has not yet been measured at astrophysical neutron energies because of the extreme difficulties involved in making the target. This is despite 205Pb's considerable potential as a radioactive clock for timing how long it took our Sun to form and its important role in advanced nuclear reactors driven by particle accelerators that use lead as a target and coolant. I am proposing to conduct three nuclear reactions at the Experimental Storage Ring at the GSI/FAIR facility that will form the same intermediary state as neutron capture of 205Pb, namely the excited 206Pb compound nucleus. This method of simulating the neutron capture reaction with an experimentally feasible reaction is called a ""surrogate reaction"". To achieve this experiment, I will partner with Beatriz Jurado at the Laboratoire de Physique des Deux Inifis de Bordeaux (LP2iB), who is currently the world expert on surrogate reactions in heavy-ion storage rings. Beatriz will guide me through the process of being the spokesperson for a nuclear physics experiment and assist me in supervising a PhD student, both key missing skills in my research portfolio. I will bring expertise in nuclear astrophysics to LP2iB by involving the group with my established collaborations around my PhD work with 205Pb. Our combination makes a perfect match to go beyond the state-of-the-art by implementing the first surrogate reaction with a radioactive beam in a heavy-ion storage ring, and take us one step closer to using 205Pb as a radioactive clock to extract how long it took for our Sun to form."