Gamma-ray and Neutron Processes in Detector Materials

Response functions for radiation detectors are critical to understanding the performance of, and collected data for, every detector technology in use or in development. Characteristic signals from radiation sources interact with detector (and neighboring) materials, producing signals that are the unique convolution of the source and the detector response to be analyzed and assessed for signatures of interest or unwanted backgrounds. Additionally, superconducting quantum devices (SQDs) for quantum computing are unwitting detectors of radiation whose computing capabilities could be affected by radiation sources. Response functions are purely empirical but built on realistic physics models and data libraries from auxiliary measurements. Detailed response functions are arguably best built by reliable simulation programs. Geant4 is a simulation toolkit to track a variety of primary particles that are injected into a geometry or secondaries that are spun off from physics processes that occur within the geometry. Geant4 uses optical properties of materials to generate and propagate the light output of scintillators. A more recent addition to the Geant4 toolkit, G4CMP, offers an opportunity to investigate the condense matter response (e.g. particle-hole excitations and phonons) in the presence of radiation. We will present results from simulations for gamma and neutron detectors and SQDs. We will present measurement data that illustrates the effects of uncertainties in models and data libraries.