Dresden 2000 – scientific programme

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HK: Physik der Hadronen und Kerne

HK 16: Postersitzung / Kernphysik

HK 16.3: Poster

Thursday, March 23, 2000, 10:15–12:45, B 69

Probing the nuclear shape in the hyperdeformed third minimum of the potential surface of ²³¹Th^* — •P.G. Thirolf¹, M. Csatlós², Y. Eisermann¹, T. Faestermann³, D. Gassmann¹, G. Graw¹, D. Habs¹, J. Gulyás², R. Hertenberger¹, M. Hunyadi², H. Hübel⁴, A. Krasznahorkay², H.J. Maier¹, Z. Máté², E. Mergel⁴, N. Neneff⁴, and P. Reiter¹ — ¹Ludwig-Maximilians-Universität München — ²Inst. of Nucl. Res. of the Hung. Acad. of Sci., Debrecen — ³Technische Universität München — ⁴Universität Bonn

The existence of a (hyperdeformed) third minimum in ²³¹Th is already well-known [1]. From the rotational bands only the moment of inertia and the reflection asymmetry is known for the nuclear shape in the third well. Theoretical predictions expect an octupole-type nuclear shape consisting of a superposition of a spherical component and an elongated complementary constituent [2]. This configuration should manifest itself in the fission mass distribution, because the transition path from the third minimum to scission is rather short. Therefore we measured the fission mass distribution of ²³¹Th via the ²³⁰Th(d,pf)-reaction, detecting the fission fragments in two position sensitive avalanche detectors in coincidence with the proton ejectils using the Munich Q3D magnet spectrograph. The fission mass distribution in coincidence with the transmission resonance of the fission probability in the third well will be compared to that originating from a neighbouring excitation energy region.
[1] B. Blons et al., Nucl. Phys. A477 (1988) 231
[2] S. Cwiok et al., Phys. Lett. B322 (1994) 304
^*Supported by the DFG