Synchrotron light source X-ray detection with Low-Gain Avalanche Diodes

The response of Low Gain Avalanche Diodes (LGADs), which are a type of thin silicon detector with internal gain, to X-rays of energies between 6-70 keV was characterized at the SLAC light source (SSRL). The utilized beamline at SSRL was 11-2, with a nominal beam size of 3 cm x 0.5 cm, a repetition rate of 500 MHz, and very monochromatic. LGADs of different thicknesses and gain layer configurations were read out using fast amplification boards and digitized with a fast oscilloscope. Standard PiN devices were characterized as well. The devices' energy resolution and time resolution as a function of X-ray energy were measured. The charge collection and multiplication mechanism were simulated using TCAD Sentaurus, and the results were compared with the collected data.