Neutron can be utilized as the probes for R&D in the scientific challenges for which many countries carry their banner. I take one example (Delayed Choice Experiment) which contributes understanding of quantum mechanics to the students. However for that purpose, the Cold Neutron Source (CNS) is essential to enhance cold neutrons which are vital for researches of materials and fundamental physics. We talk the preliminary design of the CNS from view point of TMR and discuss the compatibility of the Ultra-cold Neutron Source (UCNS). And also we take one example of the UCN application to the material science.