Skin cancer is one of the most common forms of cancer in US. Prolonged exposure to sunlight is one of the major causes of skin cancer. UV‐B radiations in the region of 290–320 nm of the solar spectrum are absorbed by skin cells resulting in mutated DNA leading to cancer. A need to for a directed beam source of single wavelength UVB light to study DNA damage prompted us to develop this light source. We developed a small portable UVB light source with directed beam emitting single wavelength at 308 nm. A mixture of Xe and Cl was used to form the XeCl* excimer which specifically emits the wavelength of 308 nm. The source is completely sealed and portable and can be transported to any laboratory, classroom or clinic. The source generates UVB light inside a ¼ inch diameter sealed quartz tube such that the light leaves from one end of the tube (directed beam) which can be regulated in intensity. The utility of the UVB source was tested by studying quantitative DNA damage (6–4 photoproducts) in calf thymus DNA. We conclude that the formation of 6–4 pyrimidine‐pyrimidone photoproducts is proportional to the dose of UVB radiation. In addition to skin cancer research, future application of the source could also include classroom demonstrations and even precision laser phototherapy of skin conditions such as Vitiligo.Support or Funding InformationMilwaukee School of Engineering □ Summer Professional Development Grant‐2018This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.