Output phosphor

Changed by Raymond Chieng, 28 Feb 2023
Disclosures - updated 17 Aug 2022: Nothing to disclose

Updates to Article Attributes

Body was changed:

The output phosphor is a component of the image intensifier in fluoroscopic systems that converts the energy from the electrons into light photons. In an II, the large number of light photons produced are subsequently captured by various imaging devices to produce a visible image.

Composition 

Output phosphor is composed of a fluorescent compound (known as P20) made of silver-activated zinc cadmium sulphide (ZnCdS:Ag) particles2. The output phosphor layer is very thin (4-8 μm) and plated directly on the glass output window of the image intensifier:

  • electrons that strike the output phosphor result in the emission of a large number of light photons (~2000 luminescent photons are generated for every 25keV accelerated electron)

  • the emission spectrum of these light photons is around 530nm (green light) – this matches well the sensitivity of most orthochromatic film and video targets

  • the luminescence decay time of the output phosphor determines the temporal resolution of the image intensifier

  • -<p>The <strong>output phosphor</strong> is a component of the <a href="/articles/image-intensifier">image intensifier</a> in <a href="/articles/fluoroscopy">fluoroscopic systems</a> that converts the energy from the electrons into light photons. In an II, the large number of light photons produced are subsequently captured by various imaging devices to produce a visible image.</p><h4>Composition </h4><p>Output phosphor is composed of a fluorescent compound (known as P20) made of silver-activated zinc cadmium sulphide (ZnCdS:Ag) particles. The output phosphor layer is very thin (4-8 μm) and plated directly on the glass output window of the image intensifier:</p><ul>
  • -<li>electrons that strike the output phosphor result in the emission of a large number of light photons (~2000 luminescent photons are generated for every 25keV accelerated electron)</li>
  • -<li>the emission spectrum of these light photons is around 530nm (green light) – this matches well the sensitivity of most orthochromatic film and video targets</li>
  • -<li>the luminescence decay time of the output phosphor determines the <a href="/articles/temporal-resolution">temporal resolution</a> of the image intensifier</li>
  • +<p>The <strong>output phosphor</strong> is a component of the <a href="/articles/image-intensifier">image intensifier</a> in <a href="/articles/fluoroscopy">fluoroscopic systems</a> that converts the energy from the electrons into light photons. In an II, the large number of light photons produced are subsequently captured by various imaging devices to produce a visible image.</p><h4>Composition </h4><p>Output phosphor is composed of a fluorescent compound (known as P20) made of silver-activated zinc cadmium sulphide (ZnCdS:Ag) particles <sup>2</sup>. The output phosphor layer is very thin (4-8 μm) and plated directly on the glass output window of the image intensifier:</p><ul>
  • +<li><p>electrons that strike the output phosphor result in the emission of a large number of light photons (~2000 luminescent photons are generated for every 25keV accelerated electron)</p></li>
  • +<li><p>the emission spectrum of these light photons is around 530nm (green light) – this matches well the sensitivity of most orthochromatic film and video targets</p></li>
  • +<li><p>the luminescence decay time of the output phosphor determines the <a href="/articles/temporal-resolution">temporal resolution</a> of the image intensifier</p></li>

References changed:

  • 2. Wang J & Blackburn T. The AAPM/RSNA Physics Tutorial for Residents. Radiographics. 2000;20(5):1471-7. <a href="https://doi.org/10.1148/radiographics.20.5.g00se181471">doi:10.1148/radiographics.20.5.g00se181471</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/10992034">Pubmed</a>

ADVERTISEMENT: Supporters see fewer/no ads

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.