Prospects for plasma excitation of 186mRe nuclear isomer

Oct 15, 2020, 5:15 PM
25m
Online

Online

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

Speaker

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

Description

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