Abstract A search for a shape isomer in ^233 233 Th via delayed γ decay was performed using the Heidelberg–Darmstadt Crystal Ball spectrometer together with a E Δ E – E telescope for light charged particle identification. Excited states in ^233 233 Th were populated through the ^232 232 Th (d, p) reaction. The search for isomeric γ decay was based on a total-energy reconstruction method: prompt energy deficits E₌₈ₒₒ E Miss indicated possible long-lived isomeric states. Corresponding delayed summed energies E^Sum₃₄₋ E del Sum were recorded with the Crystal Ball. A two-dimensional analysis of E₌₈ₒₒ E Miss versus E^Sum₃₄₋ E del Sum was carried out for various prompt and delayed multiplicities and for delayed time intervals up to 200 ns within the excitation-energy range E^x = 3 E x = 3 –7 MeV. No evidence of isomeric γ decay was observed. The branching ratio for the population of a potential shape isomer in the second minimum of ^233 233 Th relative to the first minimum is constrained to 10 - 6, for isomeric states with energies E^x = 2 E x = 2 <
Reiter et al. (Thu,) studied this question.