  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.
