Photonuclear Reactions induced by Intense Short Laser Pulses

TL;DR

This paper explores how intense short laser pulses induce photonuclear reactions, using random-matrix theory to analyze nuclear decay time functions and providing a new experimental test of nuclear models.

Contribution

It introduces a method to determine the nuclear decay time function from laser-induced reactions and proposes a novel test of random-matrix theory in nuclei.

Findings

Decay function is exponential below threshold energy.

Decay function combines exponential and power law above threshold.

Provides a new experimental validation for random-matrix theory.

Abstract

A measurement of the decay in time of nuclei excited by an intense short laser pulse of energy E(0) yields the Fourier transform of the autocorrelation function of the associated scattering matrix. We determine the optimal length (in time) of the pulse and evaluate the time-decay function using random-matrix theory. That function is shown to contain information not otherwise available. We approximate that function in a manner that is useful for the analysis of data. For E(0) below the threshold energy E(n) of the first neutron channel, the time-decay function is exponential in time t while it is the product of an exponential and a power in t for E(0) > E(n). The comparison of the measured decay functions in both energy domains yields an unambiguous and novel test of random-matrix theory in nuclei.