X- RAYS


Untitled1 EXTREME CAUTION ADVISED! X-Rays and high voltages are dangerous.

Ensure you have a Geiger Counter switched on at all times when experimenting.



Power supply.

Not satisfied with seeing the weedy flyback power supplies used on the web, delivering nano amps, I used a 70Kv underground cable tester connected to a variac. This was limited in output by a 1.2 meg high voltage resistor to keep the tube current under its maximum of 8mA. The filament voltage of 3.5V was gained from wrapping a few turns of cable round the core of a handy transformer.

Tube.

Dental X-ray tube from Ebay. rated at 360W, 70Kv 8mA. Tungsten anode.

Head.

Made from lead flashing, soldered together.

Scintillation screen.

Ebay 120mm X 120mm. The SLR camera photographs this from 10 feet away via a mirror placed underneath it and a zoom lens. This avoids placing the camera in the x-ray beam and the need for lead glass to shield the camera.


Operation.

Unfortunately I ran into problems straight away, I took some successful shots but due to the buildup of ozone inside the tube case, there would be a spark-over at only 32KV, despite the gap from anode to case being some 70mm. This severely limited the hardness of my x-rays. I also did not anticipate the amount of heat that comes from the anode.




Head unit beams x-rays downwards through target and scintillation screen onto mirror.

xray tube

Tube in holder.

xraytube2


My first ever X-ray. :)

xrayimage


After a meltdown and insulation problems with the above setup, came MKII. Stripped out version with anode heat-sinking, corona ring and huge insulation. Unfortunately my 70KV tube can only withstand 50KV before it arcs over, so that was the limit. The other option is put it in messy oil. This setup needs me to be out of the room and far away though, so everything was done via a remote camera trigger and a CCTV link, and a Geiger counter at my side.


newx2



Power supply. Ironically this is actually an X-ray tank but has had its innards replaced with a 70KV cable burnout tester.



newx3






Images with the new setup at 50KVDC.

Hard drive

hard drive


Alarm clock

clock


Plug in timer

timer


Car key

key



PCB


circuit boards