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Laser-assisted α decay of actinide nuclei in bichromatic fields

You-Tian Zou, Tong-Pu Yu

TL;DR

This paper addresses whether ultra-intense laser fields can measurably modify α decay in actinide nuclei. It develops a deformed one-parameter model that combines a double-folding Coulomb potential with WKB Gamow factors to quantify laser effects on barrier tunneling, including deformation via $\beta_{\lambda}$ and turning-point geometry. The results show that realistic near-term intensities (around $I_0 \sim 10^{25}$ W cm$^{-2}$) can produce small but finite changes in α-decay half-lives (0.01%–0.1%), with the sensitivity controlled by nuclear shell structure and $Q_{\alpha}$; notably, $N=126$ remains robust under laser fields and hints of a deformed sub-shell near $N=142$ emerge. Importantly, a bichromatic $\omega$–$2\omega$ field can amplify the time-averaged tunneling modification by one to two orders of magnitude, with phase relations offering precise control, suggesting practical pathways for applications in nuclear transmutation, radiotherapy, and nuclear battery regulation.

Abstract

Actinide nuclei provide a suitable platform for studying the laser-assisted nuclear $α$ decay, with potential applications in nuclear transmutation, nuclear radiotherapy, and nuclear battery regulation. In the present work, we develop a deformed one-parameter model to quantitatively study the influence of ultra-intense laser fields on the $α$ decay of actinide nuclei. Our calculations show that the $α$-decay half-lives of these nuclei can be altered to some finite extent under laser intensities anticipated at near-future laser facilities. Furthermore, we found that, from the perspective of the nucleus, the laser field's effect on $α$ decay is governed by the nuclear shell structure and decay energy. The $α$-emitting nuclei with lower decay energies and located farther from neutron shell closures are more susceptible to the laser fields. From the perspective of the laser driver, we proposed a bichromatic laser scheme to enhance the effects of laser fields on $α$ tunneling of actinide nuclei. With appropriate phase conditions and amplitude ratios, it is shown that a fundamental-second-harmonic ($ω$-$2ω$) bichromatic field can increase the time-averaged modification by one to two orders of magnitude.

Laser-assisted α decay of actinide nuclei in bichromatic fields

TL;DR

This paper addresses whether ultra-intense laser fields can measurably modify α decay in actinide nuclei. It develops a deformed one-parameter model that combines a double-folding Coulomb potential with WKB Gamow factors to quantify laser effects on barrier tunneling, including deformation via and turning-point geometry. The results show that realistic near-term intensities (around W cm) can produce small but finite changes in α-decay half-lives (0.01%–0.1%), with the sensitivity controlled by nuclear shell structure and ; notably, remains robust under laser fields and hints of a deformed sub-shell near emerge. Importantly, a bichromatic – field can amplify the time-averaged tunneling modification by one to two orders of magnitude, with phase relations offering precise control, suggesting practical pathways for applications in nuclear transmutation, radiotherapy, and nuclear battery regulation.

Abstract

Actinide nuclei provide a suitable platform for studying the laser-assisted nuclear decay, with potential applications in nuclear transmutation, nuclear radiotherapy, and nuclear battery regulation. In the present work, we develop a deformed one-parameter model to quantitatively study the influence of ultra-intense laser fields on the decay of actinide nuclei. Our calculations show that the -decay half-lives of these nuclei can be altered to some finite extent under laser intensities anticipated at near-future laser facilities. Furthermore, we found that, from the perspective of the nucleus, the laser field's effect on decay is governed by the nuclear shell structure and decay energy. The -emitting nuclei with lower decay energies and located farther from neutron shell closures are more susceptible to the laser fields. From the perspective of the laser driver, we proposed a bichromatic laser scheme to enhance the effects of laser fields on tunneling of actinide nuclei. With appropriate phase conditions and amplitude ratios, it is shown that a fundamental-second-harmonic (-) bichromatic field can increase the time-averaged modification by one to two orders of magnitude.

Paper Structure

This paper contains 10 sections, 22 equations, 6 figures.

Table of Contents

  1. Introduction
  2. Theoretical framework
  3. The deformed one-parameter model
  4. $\alpha$ decay under the Gaussian laser field
  5. RESULTS AND DISCUSSIONS
  6. Laser-induced instantaneous modifications to the $\alpha$-decay half-lives
  7. Time-averaged modifications to the tunneling probability in few-cycle monochrome fields
  8. Laser-assisted $\alpha$ decay in bichromatic fields
  9. Summary
  10. Supplementary Data

Figures (6)

  • Figure 1: Schematic diagram of the total potential with laser field (red dotted line) and without laser field (black line).
  • Figure 2: The relationship between the standard deviation $\sigma$ and the adjustable parameter $\rm{g}$ in the deformed one-parameter model.
  • Figure 3: (a)The instantaneous rate of the change of tunneling probability $\delta P_t$ and half-lives $\delta T$ for the different actinide nuclei. (b)The influence of the shell effect on the $\delta P_t$ for the isotopic nuclei. (c)The influence of the shell effect on the $\delta P_f$ for different actinide nuclei. (d)The relationship between $\delta P_t$ and the $\alpha$ decay energy $Q_{\alpha}$ for different actinide nuclei at the laser intensity $I_0 = 1.0 \times 10^{25}\ \rm{W/cm^2}$.
  • Figure 4: (a)The time-averaged modifications to the tunneling probability as a function of the laser intensity for three elements $^{232}$Th, $^{210}$Pa, and $^{238}$Pu, respectively. (b)The effects of the carrier envelope phase $\Phi_{\text{CEP}}$ on the $\Delta P_t^{\text{avg}}$ in the case of the number of the laser period $m = 2$. The horizontal underline with different colors marks the values of the $\Delta P_t^{\text{avg}}(\Phi_{\text{CEP}} = 0)$ for different nuclei. (c)The correction factor $\chi$ as a function of the $m$ for the $\Phi_{\text{CEP}} = \frac{3\pi}{2}$. (d)The correction factor $\chi$ as a function of mass number A for different actinide nuclei.
  • Figure 5: (a)-(b)The phase scan heatmaps of the $\Delta P_t^{\text{avg}}$ for $^{238}$Pu under the conditions of $n = 2$ and $n = 3$, with the amplitude ratio $a =0.5$ and the pulse width $\tau =2 T_0$. (c)-(d)The effects of the different frequency ratio $n$ and the amplitude ratio $a$ of the Gaussian bichromatic laser pulses on $\Delta P_t^{\text{avg}}$ for $^{238}$Pu under the maximal and minimal phase modulation conditions, respectively.
  • ...and 1 more figures