ACTIVATION LEVELS AND PROBABILITIES OF ELECTROMAGNETIC γ- TRANSITIONS IN THE REACTION (γ,γ')m ON AVERAGES AND HEAVY NUCLEI

Eduard Gohman; Viktor Zhaba

ᐊ P3-76

Open Readings 2019 • P3-77

P3-78 ᐅ

ACTIVATION LEVELS AND PROBABILITIES OF ELECTROMAGNETIC γ- TRANSITIONS IN THE REACTION (γ,γ')^m ON AVERAGES AND HEAVY NUCLEI

Eduard Gohman¹, Viktor Zhaba¹

¹ Department of Theoretical Physics, Uzhgorod National University, Uzhgorod, Ukraine

[email protected]

In the experimental determination of the outputs of reactions $(\gamma, \gamma')$ in the small interval of 5-9 MeV with a step up to 0.5 MeV there are points of deviation of the energy dependence of absolute outputs from a monotonically increasing curve [1]. This effect allows you to determine the values of individual or group of activation levels, through which the isomers of the nucleus are populated. In paper [1], the energy dependences of the outputs for reactions $(\gamma, \gamma')^m$ on the ⁷⁷Se, ⁷⁹Br, ⁸⁹Y, ¹⁰³Rh and ¹¹¹Cd nuclei were analyzed for the presence of fractures.

Also, the dependences of the absolute output from energies [2-4] for the reactions $(\gamma, \gamma')^m$ on heavy nuclei ¹³⁷Ba, ¹⁷⁹Hf, ¹⁹⁷Au and ¹⁹⁹Hg are analyzed. The number of detected activation levels in each of these $(\gamma, \gamma')^m$- reactions ranges from one to three values.

The probabilities for $\gamma$- transitions can be approximately calculated from the formulas [5]:

$$W(EJ) \approx \frac{1}{\lambda} \left(\frac{R}{\lambda}\right)^{2J}; \qquad W(MJ) \approx \frac{1}{\lambda} \left(\frac{R}{\lambda}\right)^{2J+2};\tag{1}$$

where $\lambda = \hbar c/E_{\gamma}$ - the wavelength for the emitted or absorbed $\gamma$- quanta's; J - multipolarity; EJ and MJ - the electric and magnetic $\gamma$- radiations with parity $P=(-1)^J$ and $P=(-1)^{J+1}$ accordingly; R - the radius of the emitted core. For the selenium nucleus, the transitions from metastable levels to the isomeric level ^77mSe are shown in Table 1, where the ratio of the $\gamma$ transitions is indicated

$$\alpha = \frac{W(EJ)}{W(MJ)}.\tag{2}$$

Table 1. Transitions to the isomeric level ^77mSe

λ, m	E_γ, keV	J	W(EJ), m^-1	W(MJ), m^-1	α
1.48E-11	13.38	8	1.02E-44	1.44E-51	7.12E+06
2.25E-12	87.86	6	2.19E-20	1.33E-25	1.65E+05
1.42E-12	139.22	6	8.70E-18	1.32E-22	6.58E+04
7.12E-13	277.53	6	6.83E-14	4.12E-18	1.66E+04
3.81E-13	518.18	6	2.29E-10	4.82E-14	4.75E+03
2.98E-13	662.51	6	5.58E-09	1.92E-12	2.91E+03

Similar calculations of the probability ratio of electromagnetic $\gamma$- transitions can be made for nuclides ^89mY, ^103mRh, ^179mHf and others.

[1] V.S. Bohinyuk, V.I. Zhaba, A.M. Parlag et al., Investigation of isomeric states in the reaction (γ,γ')^m on nuclei ⁷⁷Se, ⁷⁹Br, ⁸⁹Y, ¹⁰³Rh and ¹¹¹Cd. Uzhhorod Univ. Scien. Herald. Ser. Phys. 37, 161 (2015).

[2] V.I. Zhaba, I.V. Holovchak, Investigation of activation levels in the reaction (γ,γ')^m on medium and heavy nuclei, Proceedings of International conference of young scientists and post-graduates "IEP-2017", Institute of electron physics, Uzhhorod, Ukraine, p. 135 (2017).

[3] V.S. Bohinyuk, V.I. Zhaba, A.M. Parlag, Investigation of isomeric states in the reaction (γ,γ')^m on nuclei ⁷⁷Se, ⁷⁹Br, ⁸⁹Y, ¹⁰³Rh, ¹¹¹Cd, ¹³⁷Ba, ¹⁷⁹Hf, ¹⁹⁷Au and ¹⁹⁹Hg, Abstracts of the reports of XXII Annual Scientific Conference of Institute for Nuclear Research of the National Academy of Sciences of Ukraine, Kiev, Ukraine, p. 24-25 (2015).

[4] V.I. Zhaba, E.V. Gohman, Activation levels in the reaction (γ,γ')^m on medium and heavy nuclei, Abstracts of the XVI Conference on High Energy Physics, Nuclear Physics and Accelerators, Kharkov, Ukraine, p. 31 (2018).

[5] V.V. Varlamov, N.G. Goncharova, B.S. Ishhanov, Physics of nuclei and nuclear data banks: the Manual (Univ. Book, Moscow, 2010), 246 p.