Solid State Detectors

An example of an array solid state detector

Concept: Pass charge from one capacitor to another by changing applied voltage in a coordinated fashion. The photon strikes silicon and is converted to a charge that can be transported and measured by electronic structure built on monolithic Silicon chip.

Two types of optical solid state detectors

• Charge Coupled Device (CCD)
• Charge Injection Device (CID)

Advantages of Solid State Detectors

• Wide range of elements and wavelengths
• Global analysis over the range of the chip
• Retrospective analysis for 'extra' elements
• Simultaneous analysis of different spectral areas
• Simultaneous analysis of signal and background radiation
• Cheap
• Compact design of optics

Disadvantages (compared with photomultiplier tubes)

• Smaller signals, mainly because of the much smaller surface area of the light sensitive region
• Higher noise, chiefly counting noise
• Poorer signal to background ratios, particular for short acquisition time
• Occasionally worse detection limits, but not necessarly
• Poorer spectral resolution - mathematical corrections required
• Resolution changes with wavelength in some designs
• Blooming at high intensities occurs in nearby pixels
• Slower response time
• Speed usually limited by the need to integrate to overcome counting noise
• Smaller dynamic range of intensities

Further Information on the WWW

• Photomultiplier Tube (PMT)
• Electron-tubes
• Hamamatsu

Authors: Jean Charles Lefebvre and Geoff Tyler, Horiba Jobin-Yvon, France

First published on the web: 15 January 2000.

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