user wants a long article for the keyword "desi sec". This likely refers to the DESI (Dark Energy Spectroscopic Instrument) experiment. I need to provide a comprehensive overview. Following the search plan, I will perform multiple searches to gather information on various aspects. search results provide a good starting point. I will now open some of the most relevant pages to gather detailed information. search results provide comprehensive information about DESI. I will structure the article with an introduction, sections on the survey, scientific goals, instrumentation, key discoveries, international collaboration, future plans, and a conclusion. I will cite the sources appropriately. is a long article on the Dark Energy Spectroscopic Instrument (DESI).