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Radioactivity in cathode ray tubes
Nancy P Kirner1, G L Troyer, R A Jones
1Kirner Consulting, Inc., Tacoma, WA, USA. Kirner@harbornet.com
Health Physics
|January 28, 2004
Summary
Radioactivity from naturally occurring radioactive materials is present in 100% of surveyed cathode ray tube computer monitors and televisions. This radioactivity is incorporated during manufacturing and is not easily removed.
Area of Science:
- Environmental Science
- Materials Science
- Radiation Safety
Background:
- Used computer equipment surveys revealed radioactivity significantly above background levels.
- Radioactivity was found on the cathode ray tube (CRT) face, edges, and seals, often not amenable to decontamination.
- Similar findings in monitors not exposed to contamination zones and in new televisions indicate radioactivity is inherent to the devices.
Purpose of the Study:
- To investigate and quantify radioactivity in cathode ray tube (CRT) computer monitors and televisions.
- To identify the source and nature of the radioactivity detected.
- To propose a method for the safe release of electronic equipment containing naturally occurring radioactive materials (NORMs).
Main Methods:
- Radioactivity surveys of used and new computer monitors and televisions.
- Gamma spectroscopy analysis to identify radioactive isotopes.
- Assessment of decontamination effectiveness.
Main Results:
- 100% of surveyed CRT monitors exhibited radioactivity significantly above background.
- The primary radioactive presence was on the CRT face, with hot spots on edges and seals.
- Gamma spectroscopy identified naturally occurring radioactive materials (NORMs) as the source.
- Previous literature often overlooked NORMs in CRTs due to focus on energized, low-energy X-rays.
Conclusions:
- Naturally occurring radioactive materials (NORMs) are integral to the manufacturing of cathode ray tubes (CRTs) in monitors and televisions.
- The radioactivity is persistent and not easily decontaminated.
- A method for the safe release of existing electronic equipment containing NORMs is presented.
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