Characterizing Novel Indium Phosphide Pad Detectors with Focused X-ray Beams and Laboratory Tests

TL;DR

This study evaluates indium phosphide pad sensors for high-energy physics tracking, demonstrating their uniform response and potential as a cost-effective alternative to silicon sensors using laboratory and synchrotron tests.

Contribution

It introduces the fabrication and characterization of InP pad sensors, highlighting their uniform response and suitability for future tracking detectors.

Findings

High uniformity in sensor response within and between devices

Successful use of micro-focused X-ray beams for response characterization

Indicates potential of InP sensors as a cost-effective alternative

Abstract

Future tracking systems in High Energy Physics experiments will require large instrumented areas with low radiation length. Crystalline silicon sensors have been used in tracking systems for decades, but are difficult to manufacture and costly to produce for large areas. We are exploring alternative sensor materials that are amenable to fast fabrication techniques used for thin film devices. Indium Phosphide pad sensors were fabricated at Argonne National Lab using commercially available InP:Fe 2-inch mono-crystal substrates. Current-voltage and capacitance-voltage characterizations were performed to study the basic operating characteristics of a group of sensors. Micro-focused X-ray beams at Canadian Light Source and Diamond Light Source were used to study the response to ionizing radiation, and characterize the uniformity of the response for several devices. The results show a high degree of performance uniformity in our evaluations, both within a device and between the 48 tested devices. This motivates further studies into thin film devices for future tracking detectors.