Does the cavity magnetron in a microwave oven produce x-rays?
Just a google search for "magnetron x-rays" yields quite a bit of information. From this data sheet:
High voltage magnetrons emit a significant intensity of X-rays not only from the cathode sidearm but also from the output waveguide. These rays can constitute a health hazard unless adequate shielding for X-ray radiation is provided. This is a characteristic of all magnetrons and the X-rays emitted correspond to a voltage much higher than that of the anode.
A quick further glance seems to show that the penetration depth for x-rays into most materials at 7keV is dismal.