NQS end station

The Nano-sized Quantum Systems (NQS) end station is designed to investigate the interaction of nanoparticles, biomolecules, helium nanodroplets and rare gas or metal clusters. The end station consists of a differentially pumped vacuum system featuring interchangeable beam sources, photon, ion, and electron detectors that can be operated simultaneously.

The DSSC (DEPFET sensor with signal compression) detector is able to record  X-ray images with the maximum frame rate of 4.5 MHz.  For run 6, the DSSC detector will be based on mini-SDD sensors with a dynamic range of 256 photons at 1 keV photon energy. The four modules with the overall size of 210 x 210 mm² composed of 1024 x 1024 pixels with hexagonal shape are movable, such that the size of the central gap can be varied. 

This detector is installed in collaboration with the Detector Development group (European XFEL).

The large-area, pn-junction Charge Coupled Device (pnCCD) detector has a very high quantum efficiency and very low readout noise. It is capable of counting single photons in the full energy range of the SQS instrument while maintaining a high dynamic range. The two modules are movable, such that both the size of the central gap as well as the distance of the detector plane to the focus can be varied. Although pulse-resolved data recording is not feasible, it possible to integrate for an entire pulse train, and reading out at 10 Hz.

This detector is installed in collaboration with R. Hartmann, L. Strüder (PNSensor GmbH), and the Detector Development group (European XFEL).

Simultaneously to the scattered X-ray photons, ions and electrons can be detected by an ion Time-Of-Flight (iTOF) and/or a Velocity Map Imaging (VMI) spectrometer, respectively. Both are designed with conically shaped electrodes to minimize the shadow on the photon detector. The iTOF follows a standard Wiley-McLaren design. The achievable mass resolution Δm/m is about 0.1% when detecting only thermal ions, and about 0.2% for simultaneous operation of the electron VMI.

The VMI can be combined with a Timepix3 camera - a timestamping camera which makes it possible to fully exploit the high-repetition-rate burst-mode of EuXFEL for both, electron or ion VMI. The principle is illustrated in the sketch on the left. Recording VMI images of all ionic fragments, as well as full, high-resolution mass spectra is possible at around 200 kHz repetition rate (limited by the longest ion flight time). In electron VMI mode, single-shot electron VMI images can be recorded with up to 2.2 MHz rep. rate (limited by machine operation and pixel dead time in case of many electrons per pulse). In contrast to the reaction microscope, the VMI in combination with the Timepix3 camera can cope with significantly higher number of particles per shot. The AQS VMI, designed for high-energy electrons, can also be used with the Timepix3 camera.

For more information on the Timepix3 camera, contact Björn or Rebecca.

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