Optical potting of solid-state detector cells

• US 4,491,732 A
• Filed: 08/25/1982
• Issued: 01/01/1985
• Est. Priority Date: 08/25/1982
• Status: Expired due to Term

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Golner, Thomas M., Hoffman, David M., Pritzkow, Dennis H., Loomis, Neil W.
• Primary Examiner(s): Smith, Alfred E.
• Assistant Examiner(s): FIELDS, CAROLYN
• Application Number:
  US06/411,419
• Time in Patent Office: 860 Days
• Field of Search: 250/370, 250/366, 250/367, 250/368, 250/363 S
• US Class Current: 250/366
• CPC Class Codes: G01T 1/1644 using an array of optically separate scintillation elements permitting direct location of scintillations G01T1/1645 takes precedence
• CPC Class Codes: G01T 1/20182 Modular detectors, e.g. tiled scintillators or tiled photodiodes stacked detectors G01T1/20181
• CPC Class Codes: G01T 1/20185 Coupling means between the photodiode and the scintillator, e.g. optical couplings using adhesives with wavelength-shifting fibres
• CPC Class Codes: G01T 1/2019 Shielding against direct hits

Abstract

In a modular solid state detector of the type including a scintillator and diodes for converting x-ray flux to a measurable electrical signal, the diodes are mounted out of the path of incident x-radiation to minimize noise and to limit degradation. The resulting configuration reduces efficiency because the active diode area is limited and the length of the light path between the scintillator and diode is increased. In order to compensate for that reduction in efficiency, optical potting material is used to join the scintillator to the diodes in order to minimize light attenuation between those elements. In addition, the outer surface of the cured optical potting material is coated with a thin specular layer of silver to keep the light within the optical potting material and thus most efficiently reflected from the scintillator to the diode.

Claims

1. In a reflective cavity scintillation detector for a CT scanner for receiving a swath of radiation from an x-ray source to create a plurality of detector readings, the detector having a plurality of cells each including a scintillator and diode means mounted on a reflective collimator plate to form a cell, the improvement comprising, means shielding a part of the detector from the swath of radiation, the diode means being so arranged on the reflective collimator plate as to be within the shielded part of the detector, optical potting means joining the scintillator to the diode means, thereby to enhance the coupling of the scintillator to the shielded diode means.

2. The improvement as set out in claim 1 further including a reflective coating on the optical potting means for enhancing the internal reflectivity of the optically potted scintillator and diode means, thereby to further enhance light transmission to the diode means.

3. The improvement as set out in claim 2 wherein the reflective coating is a silver coating deposited on the outside of the optical potting means.