Inter-calibration of VAP-HOPE particle detectors to obtain the anisotropy of electron Pitch angle distribution

Whistler mode chorus waves play a key-role in the formation of prompt changes in outer radiation belts. Despite of that, the generation mechanism of chorus emissions is still a subject of debate. Many theories aim at explaining the results of empirical studies on wave-particle interaction. Validation requires a thorough investigation based on precise datasets. EMFISIS, HOPE and MagEIS on the Van Allen Probes provide excellent measurements of electromagnetic waves and particles for such studies. In this summary paper we present the reliability and efficiency of HOPE instrument from this point of view. The 5 polar pixels of HOPE have not been inter-calibrated yet, leading to inaccuracies in angular measurements and in pitch angle distribution (PAD) data also. A preliminary investigation of HOPE L1 data's count rates is presented, in the aim of using count ratios of neighboring pixels with overlapping pitch angle intervals. A list of cross-calibration data was produced for the entire mission. Finally, a case study on 14 November 2012 is presented to represent the efficiency of the corrected dataset, as defining isotropy or anisotropy in PADs. To calculate anisotropy of PADs is essential to determine times and energies of an electron population which presumably interacting/generating chorus wave emissions.