Development of low-energy X-ray detectors using LGAD sensors

Area of Science:

• Physics
• Materials Science
• Detector Technology

Background:

• Segmented low-gain avalanche detectors (LGADs) offer internal gain for sensitive particle detection.
• Detecting low-energy X-ray photons presents challenges due to low signal-to-noise ratios with standard silicon sensors.

Purpose of the Study:

• To investigate the performance of segmented LGAD microstrip sensors for low-energy X-ray detection.
• To evaluate the signal-to-noise ratio improvement offered by LGADs compared to standard silicon sensors.
• To demonstrate the application of LGADs in the soft X-ray energy range.

Main Methods:

• Fabrication of LGAD microstrip sensors by Fondazione Bruno Kessler.
• Characterization using X-rays with charge-integrating and single-photon-counting readout chips from Paul Scherrer Institut.
• Testing in an energy-dispersive fluorescence spectrometer at the Swiss Light Source.

Main Results:

• LGAD sensors demonstrate charge multiplication, leading to an improved signal-to-noise ratio for X-ray detection.
• Successful detection of sulfur Kα and Kβ lines (2.3 and 2.46 keV) in the soft X-ray energy range.
• Performance validation using both charge-integrating and single-photon-counting readout electronics.

Conclusions:

• LGADs are a promising technology for position-sensitive detection of low-energy X-ray photons.
• Further optimization of segmentation and low-energy quantum efficiency is needed.
• This work supports the development of single-photon-counting detectors for soft X-ray applications.