Ядерна фізика та енергетика Nuclear Physics and Atomic Energy   ISSN: 1818-331X (Print), 2074-0565 (Online)   Publisher: Institute for Nuclear Research of the National Academy of Sciences of Ukraine   Languages: Ukrainian, English, Russian   Periodicity: 4 times per year   Open access peer reviewed journal

Full text (ru)

Abstract: In order to verify the data from ¹³⁷Cs decay, γ-spectrum was measured using the high-resolution detector with Compton background suppression. It was found that the transition γ279 keV, detected in a number of works, has not been observed and should be regarded as wrong. Evaluation of the intensity of γ279 keV in our work is I_γ < 7 ⋅ 10^-7. Energy of the transition γ283.4(1) keV is in good agreement with previous works, as well as with data presented in the latest compilation of data on ¹³⁷Cs. Intensity of transition γ283.4(1) keV, where data from different projects were significantly different from each other, is refined as I_γ = 67(20) ⋅ 10^-7. Our evaluation of intensity of γ378 keV (I_γ < 6 ⋅ 10^-7) confirms low intensity of recently discovered weak transition γ377.9 keV which comes from the 661.7 keV level to 283.5 keV level.

Keywords: ¹³⁷Cs decay, γ spectra, γ rays intensity and energy, HPGe detector.

1. C.M. Lederer, J.M. Hollander, I. Perlman. Table of Isotopes. 6-th ed. (New York: Wiley, 1968). Google Books

2. C.M. Lederer, V.S. Shirley (eds.). Table of Isotopes. 7-th ed. (New York: Wiley, 1978) 1600 p. Amazon

3. A. Kerek, J. Kovnacki. The level structure of the N = 81 and 82 nuclides ^137,138Ba as investigated in ¹³⁶Xe (α, xn) reactions. Nucl. Phys. A 206 (1973) 245. https://doi.org/10.1016/0375-9474(73)90531-9

4. V.A. Bondarenko, I.L. Kuvaga et al. 34-th Meeting on Nuclear Spectroscopy and Nuclear Structure (Alma - Ata, 17 - 20 April, 1984) (Leningrad: Nauka, 1984) p. 108. (Rus)

5. V.A. Bondarenko, I.L. Kuvaga et al. 41-st Meeting on Nuclear Spectroscopy and Nuclear Structure (Alma - Ata, 16 - 19 April, 1991) (Leningrad: Nauka, 1991) p. 77. (Rus)

6. V.A. Bondarenko, I.L. Kuvaga et al. Levels of ¹³⁷Ba studied with neutron-induced reactions. Nucl. Phys. A 582 (1995) 1. https://doi.org/10.1016/0375-9474(94)00314-D

7. B.K. Wagner, P.E. Garret et al. On the first excited state of ¹³⁷Ba. Journal of Radioanalytical and Nucl. Chemistry 219 (1997) 217. https://doi.org/10.1007/BF02038503

8. I. Bikit, I. Anicin et al. Population of 283 keV level of ¹³⁷Ba by β-decay of ¹³⁷Cs Phys. Rev. C 54 (1996) 3270. https://doi.org/10.1103/PhysRevC.54.3270

9. V.O. Sergeev, F.F. Valiev. Unique second-forbidden β transitions: Decay of ¹³⁷Cs. Bull. Rus. Ac. Sci.: Physics 71(6) (2007) 827. (Rus) https://doi.org/10.3103/S1062873807060159

10. A.M. Savrasov. Excitation of isomeric states of nuclei in reactions with light particles and gamma quanta: Ph. D. Thesis (Kyiv, 2011) 110 p. (Ukr)

11. E. Browne, J.K. Tuli. Nucl. Data Sheets for A = 137. Nucl. Data Sheets 108 (2007) 2173. https://doi.org/10.1016/j.nds.2007.09.002

12. K. Morgan, E.A. McCutchan, C.J. Lister et al. E5 decay from the J^π = 11/2 isomer in ¹³⁷Ba. Phys. Rev. C 90 (2014) 041303(R). https://doi.org/10.1103/PhysRevC.90.041303