The ASPECT Dynamics analyser is a high-end multipurpose photoelectron spectrometer combining unsurpassed count rate performance and new controller technology to allow for advanced XPS studies such as new types of operando experiments and in-situ observations of surface reactions with chemical resolution.
The ASPECT analyser is optimised for highest sensitivity in electron spectroscopy. The electron optical lens modes are well balanced to combine transmission and energy resolution in high performance XPS applications.
The particle counting multi-channel detector is setup with easy to use calibration routines for quantitative snapshot detection for wide energy windows. The in-vacuum detector electronics ensures a low noise level and enables fast data transfer for successive snapshot acquisitions in the sub-millisecond range.
The spectrometer electronics supplying high voltages to the electron optical system are designed for fast rise and settling times. As a result, the full energy range of 3.5 keV is accessible within some milliseconds. This way, time resolved processes can be observed with XPS data acquisition of all core levels even with wide apart binding energies on the millisecond time scale. At the same time, synchronous data acquisition of up to four individual analogue signals with the spectrometer electronics enables the direct correlation of process parameters with XPS data.
With these capabilities, full range photoelectron spectra can be acquired in as little as 2 seconds where conventional XPS scans would take several minutes.
The ASPECT Dynamics consists of a thoroughly designed and characterised electron optical system with a 160 mm mean radius hemisphere offering highest transmission and fully quantitative XPS experiments.
The Aspect Dynamics analyser offers best-in-class transmission. The Ag 3d5/2 peak is measured at a count rate of > 3.5 Mcps with an energy resolution of 0.6 eV (FWHM) in combination with the monochromated X-ray source MECS.
The optimised lens modes ensure that photoelectrons are transferred from the sample surface onto the detector in a most efficient way with high energy resolution, making the ASPECT ideally suited for high sensitivity chemical state analysis.
High resolution spectrum of the Ag 3d5/2 peak in combination with the monochromated X-ray source MECS.
128-channel particle counting detector
The detector is embedded in a carefully designed electrical field environment at the exit of the hemisphere for accurate dispersion linearity at all pass energies and to eliminate fringe fields and their effects on line shape fidelity across the detection area.
A multichannel plate (MCP) stack multiplies incoming electrons to be picked up by anode stripes located long the dispersive direction of the detector. These are directly coupled to in-vacuum readout electronics to form 128 individual detection channels. A high speed data transfer link to the analyser controller allows for data acquisition orders of magnitude faster compared to standard XPS detectors. As a result, ASPECT Dynamics can detect as many as 50.000 spectra in a time window of 2.5 seconds.
In addition, the detector offers excellent life time and cost-of-ownership. Due to the low noise level at the detector a far lower MCP gain is required to detect electrons compared to other MCP driven detectors and therefore significantly reducing ageing of the MCP stack.
Left: Line shape fidelity across all 128 detection channels.
Snapshot energy interval and energy resolution on the Ag 3d 5/2 peak.
Ultra-fast electronics for up to 3.5 keV
The Electronics incorporates state-of-the-art voltage amplifiers allowing for ultra-fast ramp rates of lens voltages with settling times in the millisecond regime. Ultra-fast ramp rates guarantee that the spectrometer can change the analyser energy 100 times faster than normal spectrometers. Even large changes of the lens potentials of 5000 V can be applied in milliseconds without sacrificing accuracy in the measured peak positions or line shapes. Sophisticated embedded software and powerful processors ensure accurate timing of all required lenses during fast spectrum acquisition.
In addition, the powerful processors supported by a consequent design of controller architecture are geared up to process and store the fast stream of incoming and outgoing data. Ultimately, the electronics ensures that spectra are recorded with a precision in the milli electron volt regime.
A large kinetic energy range of up to 3.5 keV can be accessed with the ASPECT analyser offering an extended range when using higher excitation energies to detect photoelectrons and Auger electrons from deeper core levels.
The ASPECT controller unit comprises 4 analogue-to-digital converters (ADC) for auxiliary data acquisition in-sync with the spectroscopy data. The input signals (-10V…+10V) are configured in the NEO control suite for their physical representation to enable parallel process control.
NEO Control Suite
ASPECT Dynamics is operated through the NEO control suite. NEO is a modern, versatile and configurable software suite for electron spectroscopy applications.
Its guided workflows allow setting up and running of acquisitions and experimental sequences with ease while providing the user with full control over relevant parameters at the individual stage of an experiment.
Build in calibration and conditioning routines allow easy to use and automated setup and maintenance procedures of the spectrometer and detector.
The built-in result data browser lets you retrieve, review, manage, or analyse any acquired data and its associated information instantly, whenever you need it and regardless whether you've run your experiments today or a year ago.
Advanced Acquisition Modes - Multi Peak Monitoring
In the acquisition mode „Multi Peak Monitoring“ snapshot spectra are acquired at different binding energies (BE) in sequence, with each sequence repeated for a predefined number of times. The ASPECT Dynamics combines (1) high temporal resolution and (2) high data quality. This combination is ideally suited e.g. for studying transitions and reactions at surfaces, monitoring and optimising processes or controlled sample preparation.
Multi Peak Monitoring of Ag MNN, 3p and 3d peaks. Each line is a colour coded snapshot spectrum. The time between successive repetitions was <150 ms.
Advanced Acquisition Modes - Fast Survey Acquisition
With Fast Survey Acquisition full range overview spectra can be acquired in as short as 2 seconds. This mode of acquisition allows users an instant view of the analysed sample. Exposure times can be significantly reduced for sensitive samples in turn to reduce radiation damage otherwise impairing the spectroscopy data. For improved statistics the spectrum acquisition can be repeatedly run to accumulate the photoelectron counts.
Full range overview spectrum of silver taken within 2 seconds.
Monochromated XPS performance achieved on Ag 3d5/2.
XPS performance with dual-anode X-ray source operating at Mg Kα.
ARPES on Ag(111) with He I excitation.
Multi Peak Monitoring of the thermal reduction of Titanium oxides.
Multi-channel (snapshot acquisition)
DN100CF mounting flange
254 mm flange to sample distance
35 mm working distance
Software controlled aperture selector
Kinetic energy range up to 3.5 keV
160 mm mean radius
Fast survey acquisition
Multi Peak Monitoring (Dynamic XPS)
Analogue signal (4 channels)
High Speed Dynamic and Operando Experiments
The thermal reduction of Titanium oxides was observed in-situ by time-resolved XPS using a new type of multi peak monitoring allowing to observe several XPS lines in a timely manner (figure 1&2). The color-coded maps show multiple...
ASPECT & NEO: Exceptional XPS Performance
The ASPECT Dynamics analyser, operated through the NEO control suite, is a high-end multipurpose photoelectron spectrometer combining unsurpassed count rate performance and new controller technology to allow for advanced XPS studies such as new types of operando experiments and in-situ observations of surface reactions with chemical resolution.
Thermal Reduction of Titanium Oxides
The thermal reduction of Titanium oxides was observed in-situ by time-resolved XPS using snapshot acquisition of multiple spectral features. The oxygen reduction occurred within ~1 minute by applying a rapid temperature ramp and was found to be a stepwise process with an initial transition from 4+ to suboxide and the metallic state of Titanium at intermediate temperatures between 600 K and 725 K before further reduction of the 3+ oxidation state at temperatures > 725 K.