X-ray detector module with data acquisition system

 

An X-ray detector system is a tool for the detection of single X-ray quanta and for determining their energy. High counting rates significantly shorten the measurement time. A small form factor and modular design offers the user high flexibility. A compact and comprehensive data acquisition system and a swivel with temperature, humidity and pressure sensor guarantee high user friendliness and a reliable operating status. This development opens up a wide range of applications in the analysis with X-rays.

 

Problem

The fluorescent light analysis is a highly frequently process, used on synchrotron sources in the X-ray absorption spectroscopy. It requires powerful detectors, which, once arranged, enable a fast and economic user-specific extension.
Subject of development is compact silicon drift detector system with a 50 mm² active area, which has been optimized for the energy range between about 2 keV and 17 keV. Either chilled or at room temperature, it achieves an energy resolution of a few hundreds of eV at MHz counting rates and spectral signal-to-background ratios of above 1000.

Innovation

A monolithic 7-cell sensor and a readout chip are the core of the sensor head. Photons that are being absorbed in the sensor will be converted into electrical impulses. A mask on the entrance surface covers inefficient sensor fields and significantly improves the spectral signal-to-background ratio.
In the readout chip, the detection of the impulses and their transformation into an output signal, whose amplitude is directly proportional to the energy of the absorbed photon, takes place. The compact, pen-like casing with Peltier cooling, hexagonal exterior shape and cable connection enables minimal sampling distance offers high flexibility in term of its implementation in the experiment. This also allows flat or curved arrangements of several modules in a confined space.

Benefit

For small counting rates and 8 keV, FWHM line width of 223 eV at 10° C and 297 eV at 24° C can be achieved. At 24 ° C and high counting rates, this increases to 400 eV for 1.1 million counts per second and 600 eV for 3.3 million counts per second. An Item-specific analysis for dilution levels below 100 ppm is possible. The system operates autonomously and requires no additional components.

Development status

Development and manufacturing is complete. A batch is in use at HASYLAB. Further information can be found at

  • NIM A 589 (2008) 25
  • IEEE TNS 56 (2009) 1666-1670
  • J. Synchrotron Radiation 16 (2009) 293–298