LAMBDA with High-Z sensor is well suited for energies above 20 keV
X-Spectrum has developed versions of the LAMBDA system where the silicon sensor is replaced with one of the “high-Z“ materials, Gallium Arsenide (GaAs) or Cadmium Telluride (CdTe), which provide greater detection efficiency at high X-ray energies. With these sensors, the LAMBDA system combines efficient hard X-ray detection with zero noise, high spatial resolution and high speed. In particular, the 2000 frames per second readout of a high-Z LAMBDA system is more than 1000 times faster than a typical flat-panel detector, enabling time-resolved hard X-ray experiments on millisecond timescales.
Sensor material: Gallium Arsenide or
As shown to the right, Cadmium Telluride has higher quantum efficiency than Gallium Arsenide at higher X-ray energies, so it is the natural choice for experiments at 60 keV and above. However, CdTe also strongly re-emits fluorescence photons around 25-30 keV when illuminated with higher-energy photons, which can reduce the detected signal and slightly blur the image.
So, GaAs is beneficial in the 25 – 50 keV range. After flat-field correction, GaAs sensors also deliver better image uniformity.
If you consider using high-Z material, contact our sales department beforehand. Together, we’ll find the best solution for your experiment.
Depending on the sensor material the following specifications are valid:
| ||Si ||GaAs ||CdTe |
|Energy range: ||6 – 25 keV ||8 – 75 keV ||8 – 150 keV |
|Adjustable threshold range: ||4 – 40 keV ||5 – 50 keV ||5 – 75 keV |