Absolute calibration method for laser megajoule neutron yield measurement by activation diagnostics Rev. Sci. Instrum. 82, 073501 (2011); 10.1063/1.3605485Experimental and theoretical studies of particle generation after laser ablation of copper with a background gas at atmospheric pressure Abstract. A numerical model for determining gas temperature distribution in the cross-section of the laser tube of a copper bromide (CuBr) laser is presented. The model is derived on the basis of quasistationary heat conduction equation subject to nonlinear boundary conditions. For the first time the real physical conditions, such as the temperature of the reservoirs and other design elements are taken into account. The obtained temperature profile allows finding out specific operating conditions when the laser generation fails to be effective due to the process of overheating. These results are applicable in research and engineering practice for improving the laser tube design and the overall device performance.