[ RadSafe ] So, in terms of health physics, what goes on in television?
Ted de Castro
tdc at xrayted.com
Mon Dec 21 23:06:48 CST 2015
Say what you will - BUT - the diffuse nature of a raster scan beam, that
strikes on the mask or grid wires would be more like transmission anodes
with considerable self attenuation and that the larger the CRT the
greater the kV but also the thicker the glass. The problem was just NOT
the CRT! I know - I was there! I measured many TV sets - it was the
shut regulator tube in the back - ALSO - there was a considerable period
when TVs (and data terminals) were STILL using CRTs - LARGE CRTs - and
running the same (or higher in high resolution data color date
terminals) kV but had solid state high voltage supplies - ie. NO shunt
regulator tube - and it was at that point that the problem disappeared.
On 12/21/2015 6:42 PM, Hansen, Richard wrote:
> In the old style TVs with a Cathode Ray Tube (CRT), the electron beams strike the metal shadow mask or aperture grill wires, phosphors, and leaded glass. The high-speed electrons penetrating into these objects generate bremsstrahlung radiation (x rays). Current flat screen TVs do not have CRTs and do not generate x rays.
> NCRP Report No. 160, Ionizing Radiation Exposure of the Population of the United States, 2009
> 5.2 Television Receivers and Video Terminals
> "Television and display monitors currently utilize display technologies that no longer employ cathode-ray tube components (the source of x-ray emissions). Most of the radiation reported earlier from these sources (NCRP, 1987, Radiation Exposure of the U.S. Population from Consumer Products and Miscellaneous Sources, NCRP Report No. 95) was from [TV] receivers manufactured before the federal performance standard (FDA, 2007, "Performance standards for ionizing radiation emitting products. Television receivers," 21 CFR Part 1020.10) (originally published in 1968) was issued. X-ray emissions from receivers manufactured under the standard are essentially zero. Technologies such as liquid crystal, plasma, and other such display monitors have no potential for generating x rays."
> Best regards,
> Rick Hansen
> Principal Scientist
> CTOS - Center for Radiological/Nuclear Training at the Nevada National Security Site
> National Security Technologies, LLC (NSTec)
> Contractor to the United States Department of Energy
> Office: 702-295-7813 Cell: 702-630-1131
> hansenrg at nv.doe.gov<mailto:hansenrg at nv.doe.gov>
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