The 1-Megapixel pnCCD detector for the Small Quantum Systems Instrument at the European XFEL: system and operation...

Area of Science:

• Instrumentation for X-ray Free-Electron Lasers (XFELs)
• Photon detection and imaging
• Quantum optics and spectroscopy

Background:

• X-ray Free-Electron Lasers (XFELs) require advanced instrumentation for low-energy photon detection (< 1 keV).
• High sensitivity, low noise, and high quantum efficiency are crucial for maximizing scientific output.
• The European XFEL (EuXFEL) facility necessitates sophisticated detectors for its user experiments.

Purpose of the Study:

• To introduce and detail a 1-megapixel pnCCD detector for imaging applications at EuXFEL.
• To present commissioning results and performance data from the detector's first user operation.
• To provide a benchmark for future detector development and endstation planning at FEL facilities.

Main Methods:

• Installation and commissioning of a 1024x1024 pixel pnCCD detector at the Nano-Sized Quantum System (NQS) station of the Small Quantum System (SQS) instrument.
• Characterization of detector performance, including electronic noise (3 e-) and quantum efficiency.
• Integration of the detector with spectroscopic techniques (photo-ion and photo-electron spectroscopy) for coherent diffraction imaging.

Main Results:

• The pnCCD detector successfully commissioned for operation in the 0.5-3 keV energy range.
• Demonstrated capability for single-photon imaging due to extremely low electronic noise and high quantum efficiency.
• Enabled advanced investigations of intense FEL pulse interactions with nano-sized quantum systems.

Conclusions:

• The installed pnCCD detector meets the demanding requirements for low-energy X-ray imaging at EuXFEL.
• The detector's performance supports detailed studies of nano-particles, clusters, and bio-molecules.
• This work serves as a valuable reference for users and for the design of future FEL endstations.