Search for low Energy solar Axions with CAST

TL;DR

This paper reports on the development and initial testing of a novel photon detector system for the CAST experiment aimed at detecting low-energy solar axions, including preliminary results from solar tracking runs.

Contribution

It introduces a new detector system sensitive to eV photons for axion detection, with initial successful tests and the first solar tracking measurements with an axion helioscope.

Findings

Detector reached background noise limits in ideal conditions.

Performed two solar tracking runs with the new system.

First measurement of this kind with an axion helioscope.

Abstract

We have started the development of a detector system, sensitive to single photons in the eV energy range, to be suitably coupled to one of the CAST magnet ports. This system should open to CAST a window on possible detection of low energy Axion Like Particles emitted by the sun. Preliminary tests have involved a cooled photomultiplier tube coupled to the CAST magnet via a Galileian telescope and a switched 40 m long optical fiber. This system has reached the limit background level of the detector alone in ideal conditions, and two solar tracking runs have been performed with it at CAST. Such a measurement has never been done before with an axion helioscope. We will present results from these runs and briefly discuss future detector developments.