Abstract
Secondary cosmic radiation in atmosphere is generated by interaction of primary galactic cosmic radiation with the constituents of air. Humans at sea level receive certain dose exposure from secondary cosmic radiation, if at flight altitudes or mountains, the dose contribution becomes much higher. Because of the complexity of secondary cosmic radiation, measurement alone is not enough to provide details of the radiation field. Based on the results of a series of Monte Carlo simulations, this study established a rather complete database of secondary cosmic radiation in atmosphere considering the effective dose variations of each components as functions of altitude, location, and time. The FLUKA Monte Carlo transport code was used to study the characteristics of secondary cosmic radiation in atmosphere. In total, 44 simulation cases were carried out in this study. The simulation results were benchmarked, analyzed and summarized in a database by applying curve fitting for effective dose rates at various altitudes and vertical cut-off rigidities for the two extremes of the sun's 11-year activity cycle. The database established in this study could have many potential applications. One example is to quickly and accurately estimate the dose exposure for any flight route. Focusing on those popular flights in Taiwan, this study estimated the aviation doses for the following flight routes from Taiwan to New York, Los Angeles, Frankfurt, Amsterdam, Sydney, Tokyo, Singapore, Dubai, Beijing, Hong Kong and Kinmen. The models and results presented in this study could not only be beneficial for those cosmic-ray related studies but also provide useful dada about natural background radiation for regulatory agencies and general public in Taiwan.