Density Gradient and Absorption Effects in Gas-Filled Magnetic Axion Helioscopes

TL;DR

This paper theoretically investigates how absorption and density variations in gas-filled solar-axion helioscopes affect their sensitivity, concluding that increasing length, density, or tilt angle does not enhance performance.

Contribution

It provides a theoretical analysis of absorption and density effects on the sensitivity limits of gas-filled axion helioscopes, highlighting constraints on experimental improvements.

Findings

The 10-meter CAST helioscope is near its sensitivity limit.

Increasing length, gas density, or tilt angle does not improve sensitivity.

Absorption and density variations negatively impact helioscope performance.

Abstract

The effects of absorption in the gas, and of density variations on the sensitivity of gas-filled solar-axion helioscopes are theoretically investigated. It is concluded that the 10-meter long CAST helioscope, the most sensitive experiment to date is near the limit of sensitivity in axion mass. Increasing the length, gas density, or tilt angle all have negative influences, and will not improve the sensitivity.