NEUTRON DECAY FROM THE ISOBARIC ANALOG STATE IN SB-120 POPULATED IN SN-120(HE-3,T)SB-120 AT E(HE-3)=200 MEV, THETA=0-DEGREES
| Autor: | DA ROBERTS, Ashktorab, K., FD BECCHETTI, Janecke, J., Muhsin N. Harakeh, SY VANDERWERF, GPA BERG, CC FOSTER, JE LISANTTI, Rinckel, T., EJ STEPHENSON, SP WELLS, Nadasen, A., Shaheen, S. |
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| Přispěvatelé: | KVI - Center for Advanced Radiation Technology |
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| Zdroj: | University of Groningen Physical Review C, 52(3), 1361-1367. AMER PHYSICAL SOC |
| ISSN: | 0556-2813 |
| Popis: | The Sn-120(He-3,t)Sb-120 charge-exchange reaction has been investigated at E(He-3) = 200 MeV and theta approximate to 0 degrees to study neutron decay from the isobaric analog state at E(x)=10.20 MeV in Sb-120. The low-energy neutrons (average energy similar to 0.85 MeV) were detected in coincidence with tritons observed in the focal plane of a high-resolution magnet spectrometer. Four small deuterated NE230 scintillation detectors were mounted at distances of 9.5 cm from the target resulting in an overall neutron detection efficiency including solid angle of >1%. This efficiency was obtained by combining the measured dependence on neutron energy with a calculated neutron evaporation spectrum. From the measured ratio of coincidence to singles events a branching ratio of >86% was deduced for neutron decay. The observation of isospin-violating neutron decay with a branching ratio close to 100% is in agreement with the expectation that the escape width (Gamma up arrow) of the isobaric analog state in Sb-120 is small compared to its spreading-width (Gamma down arrow). Triton spectra measured in coincidence with gamma rays from the deexcitation of the final nucleus display pronounced structures related to the thresholds for neutron emission, in agreement with the characteristics of calculated evaporation spectra. |
| Databáze: | OpenAIRE |
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