Introduction

      SHINIE is acronym for Simulation of High-energy Neutrinos Interacting with the Earth, which is a Monte-Carlo simulation code for the interactions and propagations of neutrinos and leptons inside the Earth at energy greater than 10¹⁴eV. This code can be used for underground or above-ground neutrino telescopes. Since 2004, we had made several major updates, which include stochastic energy loss for τ and μ modification for underground detector, addition of ν_τ, ν_μ, μ, electron, and a new material salt for simulation of underground salt dome neutrino detector. Details of this code are described in introduction. A benchmark test of tau lepton flux passing through 100 km of standard rock are performed and concluded that all processes behave properly and consistent with previous versions.

      We knew the neutrino telescope experiment, IceCube^[1] or KM3NeT^[2], with target volume in the order of km³ water-equivalent. In terms of detector acceptance, their typical values are approximately in the order of 2πkm²sr, since it is sensitive to up-going events and its efficiency dependents on the zenith or nadir angle. Tseng et al.^[3] estimated that 1km²sr is required to detect PeV level neutrinos from AGN ^[4] and 100km²sr is required to detect GZK neutrinos ^[5]. Such km3 size detectors are predicted to observe AGN neutrinos in several years of full-detector operation. The fluorescence detector (FD) such as Fly ' s Eye/HiRes has larger observation range. This compact size detector can reach acceptance in the order of 300km²sr(assumed 10% duty cycle)^[6]. However, the current threshold of FD is approximately 3x10¹⁷ eV and requires some modifications to extend to lower energy. In order to increase photon counts, Cherenkov lights must be included. NuTel ^[7,8] and CRTNT^[9] experiments try to develop a wide FOV Cherenkov telescopes to aim for detection of high energy neutrinos. Based on analytical calculation, Tseng et al. ^[3] had provided many useful insights for the design of neutrino telescope using Earth skimming neutrinos. However, detailed simulation of neutrino interactions with the Earth is still required to produce events for urther detector simulation . We had developed a Monte-Carlo simulation code for ground based neutrino detector and underground detectors such as IceCube, KM3NeT etc.. This code called SHINIE, Simulation of High-energy Neutrino Interacting with the Earth . Several preliminary versions of SHINIE were used in various stages of NuTel^{[7, 8, 10, 11]} and a semi-Monte-Carlo version ^[10] was used in NuTel^[12] and CRTNT^[9]. This semi-Mote-Carlo code use deterministic energy loss for tau leptons, which is similar to the formula used in Tseng et al.^[3]

      Most of previous studies treat the Earth as same material of standard rock. SHINIE use a complete set of materials to describe the Earth, which has iron in the core and rock in the mantle. Since the real surface layer of Earth could be mountain, sea or icy plateau. The materials of surface in SHINIE can be defined by requestion of user. SHINIE support five materials, rock, water, ice, salt, and iron as surface layer.