  In an ideal germanium detector, fully-absorbed monoenergetic gamma-rays will
appear in the measured spectrum as a narrow peak, broadened into a Gaussian of
width determined only by the statistical properties of charge cloud generation
and the electronic noise of the readout electronics. Multielectrode detectors
complicate this picture. Broadening of the charge clouds as they drift through
the detector will lead to charge sharing between neighboring electrodes and,
inevitably, low-energy tails on the photopeak spectra. We simulate charge
sharing in our germanium cross strip detectors in order to reproduce the
low-energy tails due to charge sharing. Our goal is to utilize these simulated
spectra to develop an analytical fit (shape function) for the spectral lines
that provides a robust and high-quality fit to the spectral profile, reliably
reproduces the interaction energy, noise width, and the number of counts in
both the true photopeak and the low-energy tail, and minimizes the number of
additional parameters. Accurate modeling of the detailed line profiles is
crucial for both calibration of the detectors as well as scientific
interpretation of measured spectra.
