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Radiation detectors

Competence

VTT has two decades of experience in the design, production, hybridisation and product development of radiation detectors. Our resources include the largest clean room in the Nordic countries in Micronova, state-of-the-art semiconductor component simulators and experienced clean room equipment operators. In general, we use silicon as process material, but we also have process capabilities for GaAs and Cd(Zn)Te.

Challenges

We have produced various microstrip, pixel and double-sided radiation detectors in accordance with our customers' needs. The thicknesses of these detectors have varied from a few hundred micrometres to a few millimetres. Nowadays, there are increasingly challenging requirements imposed on radiation detectors, such as radiation hardness, edge activity and observation sensitivity. 

Side buttable (active edge) imaging detector modules for medical and pharmaceutical use.
These imaging detectors (1.4 x 1.4 cm2) can be tiled seamlessly to obtain large area images with high spatial resolution of ~10 um. Top: packaged (flip-chip bonded) imaging detector modules, where the detector is on top (face down) and the readout chip on the bottom. The readout chips here are Medipix2. Bottom left: active edge pixel detectors. Bottom right: active edge pixel detectors with under bump metalisation to allow contact with the Medipix2 readout chips. 






Solutions

With our utilisation of silicon wafer bonding technology in a variety of materials and our advanced processing technology, we are able to manufacture radiation detectors with a thickness ranging from a few micrometres to tens of micrometres. In addition, by utilising these resources we are able to manufacture edgeless, full 3D and back-illuminated radiation detectors.

Benefits

VTT’s strengths include our in-house multi-disciplined competence and close collaboration with the Aalto University, the Helsinki Institute of Physics and the University of Helsinki. Thanks to our cooperation, we are able to offer our customers comprehensive packages from the basic research to final testing of fabricated radiation detectors and their hybridisation on a readout circuit.

References and merits

Over the last 20 years VTT has been a significant supplier of radiation detectors in world-wide research projects in space technology and high-energy physics, some of which are ESA, NASA, CERN and Fermilab. In addition, we are continuously conducting jointly financed projects with medical imaging and non-destructive testing. Our project partners include both Finnish and foreign high-tech companies and research organisations in the field.

X-ray image of a small fish with active edge imaging module.
Image is taken with 20 keV X-ray tube with acquisition time of 36 s. Seamless large area images can be obtained by tiling the detectors in to matrices.


Additional information

Juha Kalliopuska
Research Scientist, Product Line Manager
+358 20 722 5815