Current developments and upgrades of the Adaptive Gain Integrating Pixel Detector at the European XFEL

Modern X-ray sources offer an opportunity for new techniques in photon science experiments and require detectors which can cope with their demanding constraints. The Adaptive Gain Integrating Pixel Detector (AGIPD) was developed in a collaboration of DESY, PSI and universities of Hamburg and Bonn as one of the main photon detectors for the experimental stations of the European X-Ray Free-Electron Laser (XFEL). AGIPD is a hybrid pixel detector with semiconductor sensor bump bonded to the front-end microelectronics capable of taking images in a burst mode with 4.5 MHz repetition rate providing a dynamic range up to 10
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12.5 keV photons and single photon sensitivity. Two 1 Megapixel systems were delivered to SPB and MID instruments of the European XFEL in 2017 and 2019 respectively, they provide users with high quality scientific data. The operation experience revealed certain imperfections which led to hardware upgrades. AGIPD utilizes an adaptive gain technique which requires to store information about the gain that was selected during data acquisition. These data were compromised due to analogue memory cell initial design and required an upgrade of the Application-Specific Integrated Circuit (ASIC), which was done in a separate engineering run. A calibration complication in form of a signal baseline shift due to the inappropriate filtering in high voltage circuit led to a major intervention performed during a shutdown time. Along with upgrades, the next generation of detectors is being developed for the SFX and the HIBEF user consortia. It features more dense and compact back-end electronics design which also required different cooling concept. An intermediate 0.5 Megapixel prototype system is already being used at the HED instrument. Delivery of the 4 Megapixel detector (SFX instrument) and 1 Megapixel (HED instrument) is scheduled for the end of 2023.