HiCal 2: An instrument designed for calibration of the ANITA experiment and for Antarctic surface reflectivity measurements

TL;DR

HiCal-2 is a calibration instrument flown with ANITA-4 in Antarctica, providing RF calibration pulses and surface reflectivity data critical for neutrino detection experiments.

Contribution

The paper introduces the design, construction, and performance of HiCal-2, a novel balloon-borne calibration instrument for the ANITA experiment and surface reflectivity measurements.

Findings

Collected over 10,000 RF pulses from HiCal-2 during flight.

Provided extensive data on Antarctic surface reflectivity.

Demonstrated effective calibration for high-altitude radio experiments.

Abstract

The NASA supported High-Altitude Calibration (HiCal)-2 instrument flew as a companion balloon to the ANITA-4 experiment in December 2016. Based on a HV discharge pulser producing radio-frequency (RF) calibration pulses, HiCal-2 comprised two payloads, which flew for a combined 18 days, covering 1.5 revolutions of the Antarctic continent. ANITA-4 captured over 10,000 pulses from HiCal, both direct and reflected from the surface, at distances varying from 100-800 km, providing a large dataset for surface reflectivity measurements. Herein we present details on the design, construction and performance of HiCal-2.