The Kam LAND detector is a huge balloon filled with 1000 tonnes of mineral oil that is monitored by more than 1800 photomultiplier tubes.
There are five types of radioactive decay: alpha emission, beta emission, positron emission, electron capture, and gamma emission.
Each type of decay emits a specific particle which changes the type of product produced.
While the Kam LAND experiment cannot detect the lower-energy antineutrinos from potassium-40 decay, the researchers believe that the value predicted by the BSE model of 4 TW is correct.
Although 20 TW from uranium and thorium is more than the 16 TW predicted by the BSE model, it is still within the experimental uncertainty – and is much less than the total flux of 44 TW.
The result, which agrees with previous calculations of the radioactive heating, should help physicists to improve models of how heat is generated in the Earth.
Geophysicists believe that heat flows from Earth’s interior into space at a rate of about 44 × 10 W (TW).
The positron then annihilates with an electron to create two gamma-ray photons.
These two processes happen very quickly and the light can be detected by the photomultiplier tubes.
Now, the Kam LAND team has bagged a total of 111 of these tiny almost massless particles.