The status and performance of Cosmic Ray Air Fluorescence Fresnel lens Telescope (CRAFFT) for the next generation UHECR observatory

The next generation ultra-high energy cosmic ray (UHECR) observatory should be expanded due to the very small flux. In order to realize a huge UHECR observatory, cost reduction of detectors is one of the useful strategy. Then we are developing a Cosmic Ray Air Fluorescence Fresnel lens Telescope (CRAFFT) which is a very simple structure fluorescence detector. CRAFFT detector consists of mainly a 1.4 m(2) Fresnel lens, an UV transmitting filter, an 8 inch photomultiplier tube, an FADC board, and power supply system. We tested CRAFFT detector performance at Telescope Array (TA) site, and succeeded to detect UHECR air showers synchronized with TA Fluorescence Detectors. CRAFFT detector will be deployed as a huge ground array with similar to 20 km spacing without the enough infrastructure such as in desert. Therefore, CRAFFT detectors can stand alone. We are developing automatic observation and protecting detector system. Additionally, we are studying our detector performance by detector simulation to estimate trigger efficiency, establish a reconstruction procedure, and optimize our detector configuration. In this presentation, we will report the result of the test operation of automatic observation and protecting detector system for CRAFFT detector, and the detector performance and optimization.