Prospects for plasma excitation of 186mRe nuclear isomer

Oct 15, 2020, 5:15 PM


Oral report Section 6. Plasma physics and thermonuclear fusion. Section 3. Modern nuclear physics methods and technologies


Vladimir Koltsov (Khlopin Radium Institute, Saint Petersburg, Russia)


In [1], a laser plasma with electron temperature $\Theta_{e}$ ~ 1 keV and the lifetime of $\tau$ ≈ 0.5 ns was formed from rhenium metal containing ${}^{186m}$Re isomer nuclei ($T_{1/2}$ = 2×$10^{5}$ years) with an isomer concentration of ~ $10^{–3}$ %. In this plasma the stimulated de-excitation of ~ $10^{–5}$ % isomeric nuclei was observed. The experimental results made it possible to assume in the ${}^{186}$Re nucleus at an energy of a slightly higher isomer energy the existence of a previously unknown level to which a trigger transition occurs upon stimulation of de-excitation of the ${}^{186m}$Re isomer. Later this assumption was supported by the study of the decay curve of ${}^{186}$Re nuclei produced in the (p, n) reaction on ${}^{186}$W nuclei [2].
Only a weak effect was observed in [1], and for its amplification, a technique was proposed for the reactor production of the ${}^{186m}$Re isomer to a concentration of ~ 0.1 % and a technique for isolating the pure ${}^{186m}$Re isomer as a separate phase. Also instead of a laser plasma it was proposed to use a high-current electric discharge plasma, the lifetime of which increases to ~ 50 ns while maintaining the plasma temperature $\Theta_{e}$ ~ 1 keV [3].
To further enhance the stimulation effect, the irradiation of plasma, containing isomeric nuclei, by the photons resonant to the trigger transition was proposed [4], however, for this, it is first necessary to determine the energy of the trigger transition. In this work, the plasma itself is considered as a source of resonant irradiation when atoms with resonant characteristic X-ray radiation are introduced into it. With an increase in the lifetime of the discharge plasma and with resonant photon irradiation of ${}^{186m}$Re atoms, the probability of de-excitation of the ${}^{186m}$Re isomer in the plasma can be increased by four orders of magnitude compared to [1].
The results already give grounds for the development of a power unit based on the stimulated de-excitation of the ${}^{186m}$Re isomer with the following parameters: specific energy capacity ~ $10^{8}$ J/g, specific operating power ~ 1 kW/g, specific storage power ~ 70 $\mu$W/g.

  1. V.V.Vatulin, N.V.Jidkov, A.A.Rimsky-Korsakov et al. //Bull. Russ. Acad. Sci.: Phys. 2017. V. 81.No 10. P. 1159.
  2. V.V.Karasev, V.V.Koltsov, A.A.Rimskii-Korsakov // Bull. Russ. Acad. Sci.: Phys. 2018. V. 82. No. 10. P. 1237.
  3. V.V.Koltsov “On stimulation of nuclear isomer de-excitation in plasma of electric explosion of conductors”. Proc. Int. Conf. “Nucleus-2018” - 68th Meeting on Nuclear Spectroscopy and Atomic Nucleus Structure. Voronezh, Russia July 2-5, 2018. P. 127.
  4. V.V.Koltsov // Bull. Russ. Acad. Sci.: Phys. 2019, V. 83, No. 9, P. 1141.

Primary author

Vladimir Koltsov (Khlopin Radium Institute, Saint Petersburg, Russia)

Presentation materials