GEIM — Germanium Ionization Modeling
Welcome to the documentation for the GEIM project, dedicated to modeling photon and electron interactions with Germanium (Z=32) atoms to understand the fundamental shapes of full energy peaks (photopeaks) in HPGe spectrometers.
Core Scientific Goal
Based on recent experimental studies of photopeak shapes using \(^{137}\text{Cs}\) and \(^{60}\text{Co}\) sources, an asymmetric peak component (\(1 - \Delta \simeq 6\%\)) was observed across the entire volume of the crystal.
The primary hypothesis is that this effect is linked to electron scattering from the K-shell of Germanium.
Simulation Strategy
- Infinite Medium Approximation: Since crystal geometry only affects the escape probability of low-energy photons, we simulate a cascade inside an infinite volume where complete energy absorption is guaranteed.
- K-Shell Electron Counting: The simulation tracks the cascade down to the K-shell binding energy threshold (\(\sim 11.1\) keV) and builds a histogram of the number of K-electrons ejected per full absorption event.
- Validation: The final distribution will be analyzed to verify if the fraction of events involving K-shell interactions matches the experimental \(1 - \Delta\) parameters.
Project Structure
build_db.py— Parses ENDL (EADL, EEDL, EPDL) raw data files and creates optimized NumPy structures (EPICS2023.pckl).atom.py— Loads the database and configures high-precisionCubicSplineinterpolators for all interaction cross-sections.