"Jeff Liebermann"

Most of the x-rays emitted by CRT's come out the BACK of the tube, not
the front. The shadow mask blocks most of them.


** How so ??

X-rays are generated at the point where maximum electron deceleration
occurs - ie as the moment they

1. Hit the colour phosphors.

2. Are intercepted and absorbed by the shadow mask while on the way
there.

In case 1, x-rays travelling towards the viewer are absorbed only by the
face glass.

In case 2, x-rays are generated on the reverse side of the shadow mask
and then travel both forward and backwards. Those travelling forwards
are absorbed by the face glass.

The face glass is many times thicker than the rest of a CRT's glass - so it
contains most of the of lead.

The shadow mask itself is made from very thin alloys sheet ( " invar " or
nickel-iron) so will not absorb x-rays to any great extent.



...... Phil






That's also why
there's much more lead in the neck of the CRT, than in the face.