Speaker
Description
Low-gain avalanche detectors (LGADs) have strong potential as next-generation sensors and imagers in photon science, especially for soft X-ray beamlines at synchrotron light sources. Their intrinsic gain provides higher signal-to-noise ratios when compared to traditional planar sensors, enabling direct detection of soft X-rays which would otherwise not be possible with hybrid imagers. While not currently widely used in photon science, LGADs are already being exploited in high-energy particle physics for their precise time resolution, in the timing layers of both the ATLAS and CMS detector upgrades.
In this poster, we present results from investigations of the damage caused by high-intensity photon beams to these devices. The investigations involved the irradiation of pad LGADs with flat-field and micro-focused X-rays. The evolution of current-voltage characteristics was measured, alongside how operational leakage and photo currents changed over a range of flat-field doses. These were generated by a tungsten-anode X-ray tube, and ranged from several hundred kilorad to several hundred megarad (SiO2). The same characteristics were monitored during tests at Diamond Light Source®, in which devices were exposed to an 8 keV micro-focused beam of order five square microns in area.
The results show strong promise for the survivability of LGADs in high-photon-intensity environments such as synchrotron light sources. We discuss how LGAD designs can be improved to maintain performance and reduce radiation-induced effects. Future work, already beginning, will involve exposing these devices to even higher X-ray doses, as well as making more accurate measurements of their gain and measuring the variation between different sensor designs.