Reactor Antineutrino Directionality Measurement with the PROSPECT-I Detector

TL;DR

The PROSPECT-I detector successfully measured the direction of reactor antineutrinos with high precision, demonstrating the capability to reconstruct neutrino directions using inverse beta decay events.

Contribution

This work presents the most precise directional reconstruction of reactor antineutrinos using the PROSPECT-I detector, advancing neutrino detection and source localization techniques.

Findings

Reconstructed neutrino directions with ~3° precision

Achieved the most accurate reactor antineutrino direction measurement to date

Utilized approximately 48,000 inverse beta decay events

Abstract

The PROSPECT-I detector has several features that enable measurement of the direction of a compact neutrino source. In this paper, a detailed report on the directional measurements made on electron antineutrinos emitted from the High Flux Isotope Reactor is presented. With an estimated true neutrino (reactor to detector) direction of $\phi = 40.8\unicode{xB0} \pm 0.7\unicode{xB0}$ and $\theta = 98.6\unicode{xB0} \pm 0.4\unicode{xB0}$, the PROSPECT-I detector is able to reconstruct an average neutrino direction of $\phi = 39.4\unicode{xB0} \pm 2.9\unicode{xB0}$ and $\theta = 97.6\unicode{xB0} \pm 1.6\unicode{xB0}$. This measurement is made with approximately 48000 Inverse Beta Decay signal events and is the most precise directional reconstruction of reactor antineutrinos to date.