Could be a million things you subconsciously notice.
* the warning signage
* things that are related to the lead shielding (micro changes in gravity, smell of lead salts, ...)
* infrasound caused by the machinery
* people waiting for an x-ray around who are less-than-happy...
The problem with this kind of thing is that it is often highly individual, and barely, if all measurable with our current scientific instruments. Some people keep claiming that humans are incapable of even hearing infrasound, or sense gravity, claiming anyone who can sense them is spreading new-age esoteric nonsense or is mentally ill. See also: Electrosensitivity.
I'm not saying these things do or do not exist, just that it is in the realm of possibility.
* the warning signage
* things that are related to the lead shielding (micro changes in gravity, smell of lead salts, ...)
* infrasound caused by the machinery
* people waiting for an x-ray around who are less-than-happy...
The problem with this kind of thing is that it is often highly individual, and barely, if all measurable with our current scientific instruments. Some people keep claiming that humans are incapable of even hearing infrasound, or sense gravity, claiming anyone who can sense them is spreading new-age esoteric nonsense or is mentally ill. See also: Electrosensitivity.
I'm not saying these things do or do not exist, just that it is in the realm of possibility.