An Investigation into the Radiation Damage of the Silicon Detectors of the H1-PLUG Calorimeter within the HERA environment

TL;DR

This paper investigates radiation-induced aging effects in silicon detectors of the H1-PLUG calorimeter at HERA, identifying low-energy electrons and photons as primary damaging agents affecting signal stability.

Contribution

It provides a detailed analysis of radiation damage mechanisms in silicon detectors within a high-energy physics environment, highlighting the role of low-energy particles and excluding bulk silicon damage.

Findings

Degradation of signal-to-noise ratio observed during operation.

Leakage currents increase significantly due to surface passivation damage.

Depletion voltages remain stable, indicating no bulk silicon damage.

Abstract

The silicon detectors used in the H1-PLUG calorimeter have shown increasing aging effects during the '94 run period of the electron proton storage ring HERA. These effects were particularly manifest as degradation of the signal to noise level and the calibration stability. The reasons for this behaviour have been found to be correlated with radiation damage to the silicon oxide passivation edges of the detectors in strong and fluctuating increases of the leakage currents and in severe changes of the flat band voltages. Depletion voltages however are found to be stable and therefore bulk damage of the silicon can be excluded. A comparison with measurements made by thermoluminescence dosimeters as well as related laboratory experiments suggest that the aging is due to very low energetic electrons and photons.