XRays leaking from feedthru
Posted: Mon Sep 23, 2019 1:06 pm
This is nothing new but I haven’t seen a post about it for awhile. If anything, it’ll serve as a good reminder to folks currently building their systems.
There is always valid concern about xrays leaking from the glass viewport. However, don’t forget about the ceramic feedthru. My 2.75” system is heavily shielded with 1/8” lead and the viewport / camera arrangement is totally encompassed as well.
I generally use a pancake detector for monitoring xrays near the operating position. After pushing the fusor past 27kV I began to notice some X-ray leakage below the fusor near the feedthru. It wasn’t much, but enough to shine a bit into the operator area. After sweeping the feedthru with the pancake, it was clear this was the 2nd “window” of concern.
I then built another shield (yellow X) that dropped X-ray levels to nothing. Affixed to the backside of the panel is a sheet of 1/8” lead.
Mark Rowley
There is always valid concern about xrays leaking from the glass viewport. However, don’t forget about the ceramic feedthru. My 2.75” system is heavily shielded with 1/8” lead and the viewport / camera arrangement is totally encompassed as well.
I generally use a pancake detector for monitoring xrays near the operating position. After pushing the fusor past 27kV I began to notice some X-ray leakage below the fusor near the feedthru. It wasn’t much, but enough to shine a bit into the operator area. After sweeping the feedthru with the pancake, it was clear this was the 2nd “window” of concern.
I then built another shield (yellow X) that dropped X-ray levels to nothing. Affixed to the backside of the panel is a sheet of 1/8” lead.
Mark Rowley