Hi Jim:
X-radiation is produced when an electron is
rapidly decelerated as in hitting a target.
The process is known as "bremsstrahlung." See
this web site for a more detailed explanation
of bremsstrahlung:
http://hyperphysics.phy-astr.gsu.edu/Hbase/quantum/xrayc.html
The magnitude of the x-radiation is a function
of voltage, current, and the work function of
the target.
The lower the voltage, the "softer" the x-
radiation, and vice-versa. "Soft"
x-radiation has a relatively long wavelength
and is relatively easy to attenuate.
As a general rule, x-radiation produced by
voltages up to 5 kV are sufficiently "soft"
that a sheet of paper will attenuate the
x-radiation to a safe level.
Between 5 kV and 15 kV, x-radiation shielding
is "iffy." For a crt, the glass necessary for
structural purposes also usually suffices for
x-radiation shielding.
Above 15 kV, materials and material
thicknesses must be selected for their
x-radiation attenuating properties in order
to attenuate the x-radiation to a safe level.
At about 20 kV, and for materials used in a
color crt, the x-radiation is roughly
proportional to the 20th power of voltage!
At 8 kV, the materials used to construct the
magnetron are likely to also attenuate the
x-radiation below detectable levels. I
suggest you contact the magnetron
manufacturer and request x-radiation data.
As mentioned by another respondent, a search
of the internet will find many radiation
survey meters readily available. I used
the Victoreen 440RF/C meter as well as a
proprietary scintillation counter.
Best regards,
Rich
> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On Behalf
> Of Speakman, Jim
> Sent: Monday, March 06, 2006 2:34 AM
> To: '[email protected]'
> Subject: Ionising Radiation (X-radiation) from High Voltage Sources
>
>
> Am interested in the possibility of adventitious output of
> X-Radiation from high voltage sources, in this particular
> instance, magnetrons operating at around 8 kV.
>
> Two questions:
>
> 1. Does anybody know whether there is a level of x-radiation
> produced at these sorts of power levels that could
> conceivably generate a health hazard (.e.g, in excess of 7.5
> micro Sieverts/hour at about 0.5 m from the source) ????
>
> 2. Can anybody identify an appropriate device with which to
> survey and accurately measure the output of x-radiation from
> such sources ????
>
>
> Many thanks, in anticipation
>
> Jim
>
> Jim Speakman
> (Design Safety Representative (Crawley))
>
> Thales UK Limited
> Aerospace Division
> Manor Royal
> Crawley
> RH10 9PZ
>
> Tel: 01293 644911 (Direct Dial)
> 07817 873496 (Cellular)
>
> mailto:[email protected]
>
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