R4000 Detectors Options 

The Scienta R4000 is made for easy fit with all detector types available for the Scienta spectrometers:

MCP-CCD Camera System for PES/ARPES

The R4000 electron spectrometers are delivered with a MCP/CCD detection system as a standard. This detection system is based on a 40 mm diameter multi-channel plate (MCP) detector monitored by a FireWire CCD camera. The 2D detector image is seen in real time on the computer screen or on an external monitor, which allows for complete control over the experimental conditions and easy adjustment of, for example, intensity optimisation.

The MCP-CCD camera system yields high speed, two dimensional recordings at excellent resolution. It has an extraordinary signal-to-noise ratio due to its intelligent noise reduction system, in which the noise level is entirely controlled by the computer. Instead of a simple discriminator, the noise is removed by an image analysis process. This makes it possible to distinguish true events from noise, and gives a more accurate intensity scale (larger dynamic range) in the measurements.

This detection system can be operated in Quick Mode, where a spectrum can be recorded within seconds by taking a snap shot of the detector image, covering 8 % of the pass energy.

Spin detection system

The spin detection system combines the MCP-CCD camera detection system with a Mott detector for spin-resolved measurements. The 40 mm diameter multi-channel plate (MCP) detector normally used in the Scienta R4000 is replaced by a 25 mm diameter MCP and an output aperture to a spin transfer lens. The electrons passing through the aperture are accelerated in the transfer lens and are then scattered by a Au/Th target at 20-25 kV in the Mott detector and detected by four channel electron multiplier detectors. The MCP detection system works similarly to the 40 mm detector, using a FireWire camera for read out, and providing a real time detector image.

This solution allows for easy sample characterisation by PES/ARPES and spin-resolved PES. The MCP detector can be used for determining the suitable energy for spin analysis, and to check the sample properties at any time during the spin measurement to ensure that the sample has not changed during the analysis. Spin measurements can be very long, requiring periodic checking of sample quality so as not to spend time on samples which have undergone any unwanted change during acquisition. Switching between the MCP and the Mott detector is software controlled, and does not require any sample transfer or other change of analysis position. Hence, no mechanical adjustments or breaking of vacuum is needed.

Time-resolved PES/ARPES

The delay line detector is used for experiments that require information about the detection time of the electron as well as its position. It features true counting, highly linear signal transfer and can also be used to trigger other detectors. This detector also functions as a Scienta standard detector for Energy Distribution Curves (EDCs) and 2D data acquisition.

Gated detector

For experiments requiring the electron detection to be controlled via an external signal, Scienta delivers fully integrated detector solutions, based on the MCP detector. The measurements can be triggered for example by a laser pulse, or a free electron laser, with gating times in the few ns region.