SiLi Detector X-ray

Description

Silicon Lithium X-Ray Detectors are the heart of solid state x-ray spectroscopy systems. These detectors, which are p-i-n devices formed by lithium compensation or drifting of p-type silicon, are the result of some of the most carefully controlled manufacturing processes in existence. These detectors are fabricated to exacting quality standards, which is essential in ensuring a product of high performance and excellent long term reliability.

The Si(Li) x-ray detector is an integral part of a detector system which includes a liquid nitrogen cryostat and a low noise Integrated Transistor Reset Preamplifier (I-TRP).

These detectors certainly have a place in the market for x-ray applications next to Silicon Drifted Detectors (SDD's), such as our X-PIPS™ units, and low-energy germanium detectors (LEGe™ and Ultra-LEGe™ detectors). Si(Li) detectors can be made with thicknesses up to 5 mm, which means they have a much higher stopping power than SDD's (max. 500 µm) and can be used up to higher energy x-rays (see graph below). Compared to germanium, however, silicon has a lower stopping power for the same detector thickness. But the big advantage of silicon is that it has characteristic x-rays at much lower energies (around 1.7 keV) compared to germanium (10-11 keV). Therefore the generated x-rays are less likely to escape the detector volume, which makes the escape peak less prominent. This means the ratio of the full energy peak to the escape peak is 2-3 orders of magnitude higher for a Si(Li) detector compared to a HPGe detector. Additionally the germanium x-rays lie around 10 -11 keV, which is right in the region of interest for some experiments or applications. The absorption edges of germanium in the region of interest complicate the spectrum and the analysis.

Applications

• XRF, XRD
• Synchrotron applications (EXAFS, XANES,…)
• X-ray spectroscopy (e.g. EDS)
• PIXE
• Mossbauer spectroscopy