SuperHero Element time. THOR: An essential part of his hammer is of course, Thorium.
For ordinary mortals, Thorium 2% is added to tungsten welding rods. Here it has a count of 564 CPM (counts per minute). Background radiation is about 50 CPM.
“Continue reading” for more interesting facts about thorium and lantern mantles plus links…
The red tips of the tungsten rods are the ones that have thorium. I have other tungsten that has no radioactivity. The radioactivity increases the high-temperature strength of tungsten electrodes and improves arc stability.
Here is another source of thorium, gas lantern mantles.
Thoriated lantern mantle on Geiger counter. Reads 10,000 CPM which is surprisingly “hot” compared to background radiation which is about 50 CPM.
Now let’s determine the type of radiation by seeing what the effect of paper, aluminium and lead are. Alpha radiation is blocked by paper, beta by aluminium and gamma by lead.
A small sheet of paper between the mantle and the Geiger counter shows attenuation to 7000 CPM from the original 10,000. This is not much, so it is largely passing through. Hence, it is not likely to be alpha radiation.
Now there is a sheet of thin aluminium between mantle and counter. The count has dropped to 3600 from the original 10,000. Much of it is still passing through. Hence beta radiation is unlikely.
Now a sheet of lead makes a big difference and the count drops to 180 from the original 10,000. This is only 2% of the original. Gamma rays are being blocked here.
I use tungsten in my Tesla coils spark gaps. The tungsten I have used however, does not use thorium. There are no traces of radioactivity in the whitish tungsten oxides that coat the box. The rods I used have labelled gold rather than red ends to signify non radioactivity.
Now to the familiar microwave oven and unfamiliar magnetron that is at the core of all of them. They all have a heating filament to emit the current of perhaps and half an amp at 2000 volts. The filaments usually have thorium incorporated to improve emission and temperature characteristics. This makes the inside of the Magnetron slightly radioactive.
“So you bought some radioactive thorium today?”
“Yeah but shielded by a microwave oven..”
The internals of the magnetron with one cut in half. The filament assembly is the purple end that has two electrodes.
The assembled magnetron with aluminium heat sinks sandwiched between two black ceramic magnets. The little broken rings on the right side of the small pink component are parts of the filament. This filament contains tungsten with thorium which is mildly radioactive.
The Geiger count is minimal though, with one filament reading 114 CPM with background 55. The first three time divisions are background readings only.
Related pages
Try something else
Sword swallowing and sparks
External links
Gas lantern mantles – Wikipedia
Thorium – Wikipedia
Google+ Superhero element time: Thor
Photo date: June 10,2013