Simultaneous Investigation of the Nuclear Reactions $${}^{11}$$ B $$\boldsymbol{(p,3\alpha)}$$ and $${}^{11}$$ B $$\boldsymbol{(p,n)^{11}}$$ C as a New Tool for Determining the Absolute Yield of Alpha Particles in Picosecond Plasmas

The results of experimental investigations devoted to initiating the promising nuclear fusion reaction $${}^{11}$$ B $$(p,3\alpha)$$ in picosecond laser plasmas at a laser-radiation intensity of $$5\times 10^{18}$$ W/cm $${}^{2}$$ are presented. A new tool for determining the absolute yield of alpha particles in the reaction $${}^{11}$$ B $$(p,3\alpha)$$ on the basis of simultaneously measuring the number of neutrons in the reference nuclear reaction $${}^{11}$$ B $$(p,n)^{11}$$ C is proposed. At the above values of the laser-pulse parameters, the application of this new procedure to estimating the total number of alpha particles per pulse from the reaction $${}^{11}$$ B $$(p,3\alpha)$$ leads to a value of 10 $${}^{8}$$ particles within a solid angle of 4 $$\pi$$ sr. The results presented here differ substantially from the data obtained in measuring the single-channel yield of alpha particles.