The Cosmic Ray Event Spectrum in the Knee Region measured by the NICHE Array at Telescope Array

The NICHE array at Telescope Array is a non-imaging Cherenkov light detector situated close to the Telescope Array Middle Drum fluorescence detector site. It has been operating since September 2017. Data collected between June 2020 and July 2024 has been analyzed and we will present the energy spectrum of the cosmic rays observed. The threshold energy of the detector is about 1 PeV and the data collected gives significant statistics up to about 100 PeV. The energy reconstruction used in this analysis uses the CHASM model, a model which incorporates extensive air shower universality and Cherenkov photon production.