Speaker
Description
A new and unproven technology is being explored to potentially enable and radically change the use of HPGe sensors with existing room temperature ASICs in hybrid pixel detectors. The goal is to control high temperature gradients (~130 C) over a short distance (100’s μm) between HPGe sensors and ASICs. A micro-thermal divider translates the physics requirements set by the Fourier’s Law of heat conduction, into an engineered solution exploiting the capabilities offered by micro-fabrication and micro-machining processes, and by micro-electronics interconnection techniques.
Hybrid pixel-detectors have proven to be a very powerful technology for X-ray detection by combining direct photon detection and small pixel size, with the flexibility to match the same readout chip to the optimal sensor material for the application. High-Z sensors different than silicon are required to achieve high quantum efficiency for X-rays above 20 keV. However, many high-Z materials such as GaAs, CdTe and CdZnTe often suffer from unfavourable material properties or nonuniformities. Remarkably, HPGe crystals provide a unique combination of favourable crystal properties and material purity that translates into a high and uniform detection efficiency, as well as an excellent energy resolution over a large area (wafer dia. 90mm). The deployment of HPGe sensors in hybrid pixel detectors is currently limited by the cryogenic requirements of the sensors, representing a barrier to wider adoption.
Prototypes were manufactured with an embedded micro-thermal divider to evaluate the effects on electrical performance and mechanical stability. Results from the latest batch of prototypes will be presented and next steps outlined.