Ultraviolet B radiation (UVB) is widely used in agricultural plant growth and phototherapy. The traditional light sources have a low UVB radiation efficiency, poor uniformity radiation, high energy consumption, and short service lifetime. The multiband XeBr^* and XeCl^* planar excilamps as high-power UVB sources have not been researched in existing studies and the power density of XeBr^*/XeCl^* excilamps reported in the study are not high. This work presents a high-power density planar excilamp of homogeneous dielectric barrier discharge in a mixture of xenon and molecular bromine and chlorine (Xe/Br₂/Cl₂). The spectrum, electrical parameters, total gas pressure, and gas mixture composition, have been analyzed. For the multiband excilamp filled with Xe/Br₂/Cl₂, it has been demonstrated that the maximum UVB and total radiant efficiency is 7.9% and 9.7% with optimal chlorine ratio of 0.1% and the bromine ratio ranging from 0.1 to 0.2%, with the input power of 138 W at the total pressure of gas mixture of 200 mbar. This work has confirmed that the percentage of bromine molecules must be higher than the percentage of chlorine by a factor of about 2.6 to achieve the same intensities of the XeBr^* 282 nm and XeCl^* 308 nm bands. These results allow to find out the optimum radiation efficiency of multiband excilamps with a large planar geometry to meet the requirement of UVB industrial applications.

紫外线B辐射（UVB）广泛应用于农业植物生长和光疗。传统光源UVB辐射效率低、辐射均匀性差、能耗高、寿命短。现有研究中尚未研究多波段XeBr ^*和XeCl ^*平面准分子灯作为高功率UVB光源，并且研究中报道的XeBr ^* /XeCl ^{*准分子灯的功率密度不高。}_{这项工作提出了一种在氙和分子溴和氯 (Xe/Br 2} /Cl ₂ )的混合物中均匀介电阻挡放电的高功率密度平面准激电灯。分析了光谱、电参数、总气体压力和气体混合物成分。对于填充Xe/Br ₂ /Cl ₂的多波段准分子灯，已证明最大UVB和总辐射效率分别为7.9%和9.7%，最佳氯比例为0.1%，溴比例为0.1%至0.2%，混合气体总压为200 mbar时，输入功率为138 W。这项工作已证实，溴分子的百分比必须比氯分子的百分比高约 2.6 倍，才能实现 XeBr * ²⁸² nm 和 XeCl ^* 308 nm 波段的相同强度。这些结果可以找出具有大平面几何形状的多波段准分子灯的最佳辐射效率，以满足 UVB 工业应用的要求。