A versatile, energy-efficient instrument for detecting X-rays and gamma-rays in compact CubeSat missions.
This hybrid detector combines Cadmium Zinc Telluride (CZT) and Cesium Iodide (CsI(Tl)) with Silicon Photomultipliers (SiPMs) to achieve full spectral coverage from 1 keV to 1 MeV. The system leverages a layered architecture: low-energy X-rays are absorbed in the CZT layer, while high-energy gamma-rays pass through to be detected by CsI(Tl)/SiPMs. This configuration enhances efficiency, allows background rejection through coincidence detection, and ensures cross-calibration across the energy bands.
CZT Detectors (1–150 keV): These provide excellent spectral resolution (approximately 3–5% at 60 keV), operate at room temperature, and are compact, efficient, and low in power consumption. CZT detectors have heritage from missions like Swift/BAT and NuSTAR.
CsI(Tl)/SiPM Detectors (150 keV–1 MeV): These detectors produce high light yield and good resolution. They are compact, low-voltage, and magnetic field tolerant, with heritage in missions such as AGILE and Fermi/GBM. However, they require hermetic sealing due to their hygroscopic nature.
Alternative Options: Silicon Drift Detectors (SDDs) offer better low-energy resolution but require cooling. Lanthanum Bromide (LaBr₃(Ce)) provides superior resolution (~3% at 662 keV) but comes at higher cost and handling complexity.
This compact detection system is tailored for CubeSat constraints. It occupies between 0.5 and 1U of satellite volume, consumes 2–5 watts of power, and weighs between 200 and 500 grams. The detectors are arranged in a layered format with CZT in front and CsI(Tl) behind. The system incorporates ASIC-based readout electronics, supports digital pulse shape analysis, and includes onboard spectral binning to reduce telemetry. It is engineered for thermal stability and uses radiation-hardened electronics for operation in space.
This hybrid architecture offers CubeSats a powerful, efficient tool to monitor transient astrophysical events, conduct high-energy surveys, and contribute real-time alerts. Its modularity and compactness make it ideal for student-led and budget-conscious space missions.